3D printing system and method with material changing function

Abstract

The invention relates to a 3D printing system and method with a material changing function. The 3D printing system comprises a printing head, a material changing device, a hot end and a cutting mechanism. The printing head can be detachably mounted at the hot end; the material changing device is used for being connected with the printing head and achieving printing material switching. The cutting mechanism is used for cutting off printing materials on the printing head. By the adoption of the material changing device and the cutting device, the printing material switching speed is higher, and the printing efficiency can be improved.

Description

Technical Field

[0001] This invention relates to the field of 3D printing technology, and specifically to a 3D printing system and method with material changing function. Background Technology

[0002] 3D printing is a process that constructs objects by printing layer by layer based on digital model files. One such process is Fused Filament Fabrication (FFF) or Fused Deposition Modeling (FDM). According to the layer pattern information in the digital model file, the nozzle moves relative to the platform in the XY plane. While the nozzle moves above the platform, it extrudes the flowable printing material along the printing path at an appropriate speed until one layer is printed. After one layer is printed, the print head and the printing platform move away from each other by a certain distance, such as the layer thickness, and then a new layer is printed. This process is repeated layer by layer until a three-dimensional solid is formed.

[0003] The printing process may require changing the printing ink. For example, different colored filamentary (or long thread) resin inks may be used to achieve color printing of the model or printing of multiple materials. Multi-material or multi-color printing can also be achieved by setting multiple nozzles on the print head, but due to the limitation on the number of nozzles that can be set, it is generally only used for printing applications with two materials or colors. If different inks are fed into the same nozzle in a controlled ratio, allowing them to mix and form a preset color before being extruded through the nozzle, color model printing can also be achieved. However, because the cavity inside the nozzle has a large volume, the color switching process is often not fast but rather gradual, posing a significant challenge for precise and rapid printing that requires abrupt color changes. Another approach is to use multiple printheads, each with its own independent feeding pipeline. Depending on the printing material or color, the corresponding printhead can be attached to the moving base. By changing the printheads, multiple materials or colors can be printed. However, when many colors or materials are required, the excessive number of printheads and feeding systems makes the system very complex. Moreover, due to the large size and complex structure of each printhead, the repeatability of the nozzles of each printhead is low after replacement, which can easily lead to poor bonding between the parts printed by different printheads in the printed model, significantly affecting the printing success rate.

[0004] It is necessary to improve existing technologies to enhance the efficiency and reliability of multi-material or multi-color model printing. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a 3D printing system and method with material changing function, which solves the problem of low material switching efficiency in existing 3D printing and improves the efficiency or reliability of printing multi-material or multi-color models.

[0006] The technical solution to achieve the above objectives is:

[0007] This invention provides a 3D printing system with a material changing function, including a print head, a material changing device, a hot end, and a cutting mechanism;

[0008] The hot end of the printhead can be detachably installed;

[0009] The feed changing device is used to connect to the print head and switch the printing material.

[0010] The cutting mechanism is used to cut the printing material on the print head.

[0011] The present invention also provides a material changing method for a 3D printing system, comprising the following steps:

[0012] The first print material on the print head is cut using a cutting mechanism;

[0013] The printing material on the print head is switched using a material changing device;

[0014] Continue printing using this printhead.

[0015] This invention also provides a material changing method for a 3D printing system.

[0016] The material changing device includes a material changing hub, which includes several inlet ports and several outlet ports. Each inlet port is provided with a switching mechanism. The inlet end of the switching mechanism is connected to the inlet port, and the outlet end of the switching mechanism has several outlets, which are adapted and connected to each outlet port, so that each inlet port can be connected to any outlet port by changing the state of the switching mechanism. The print head is connected to at least two outlet ports of the material changing hub through a feeding pipe.

[0017] The process of switching the printing material on the print head includes the following steps:

[0018] The first printing material to be used in the current step of the printhead and its corresponding first material source are determined. Under the conveying of the filament feeder equipped with the first material source, the first printing material is conveyed to the corresponding first feeding port of the material changing center or to the inlet end of the corresponding first switching mechanism of the material changing center. The corresponding first switching mechanism is controlled to connect the first feeding port with the first discharge port in the material changing center that is connected to the printhead, so that the first printing material is conveyed to the first discharge port. Under the action of the filament feeder equipped with the first material source, the first printing material is conveyed to the printhead through the first discharge port along the first feeding path in the feeding pipeline, and the printhead performs printing.

[0019] During the printing process of the first printing material, the second printing material to be used in the next step and its corresponding second material source are determined. Under the action of the filament feeder equipped with the second material source, the second printing material is transported to the corresponding second feeding port of the material changing center or to the inlet end of the corresponding second switching mechanism of the material changing center. The corresponding second switching mechanism is controlled to connect the second feeding port with the second discharge port in the material changing center that is connected to the print head, and the second printing material is transported to the second discharge port. Under the action of the filament feeder equipped with the second material source, the second printing material is transported through the second discharge port along the second feeding path in the feeding pipeline to a position near the intersection of the second feeding path and the first feeding path, ready for use.

[0020] After the printing process of the first printing material in the current step is completed, the first printing material is cut off at the notch (gap) on the print head or at a position downstream of the printing material conveying direction where the second feeding path intersects with the first feeding path. The first printing material is then pulled back to the position where the first feeding path intersects with the second feeding path in the feeding pipeline or back to a position that no longer obstructs the feeding path of the second printing material, so as to prevent the first printing material from obstructing the second printing material.

[0021] The second printing material is fed into the print head by the filament feeder of the second material source, and the print head prints the second printing material.

[0022] This invention also provides a material changing method for a 3D printing system.

[0023] The material changing device includes a material changing hub, which includes several inlet ports and several outlet ports. Each inlet port is provided with a switching mechanism. The inlet end of the switching mechanism is connected to the inlet port, and the outlet end of the switching mechanism has several outlet ends, which are adapted and connected to each outlet port, so that each inlet port can be connected to any outlet port by changing the state of the switching mechanism. There are two or more printheads, and each printhead is connected to at least one outlet port of the material changing hub through a feeding pipe.

[0024] The process of switching the printing material on the printhead includes the following steps:

[0025] The first print head, the first printing material, and its corresponding first material source are determined for the current step. Under the action of the filament feeder equipped with the first material source, the first printing material is transported to the corresponding first feed port of the material changing center or to the inlet end of the corresponding first switching mechanism of the material changing center. The corresponding first switching mechanism is controlled to connect the first feed port with the first discharge port of the material changing center that is connected to the first print head. Then, under the action of the filament feeder equipped with the first material source, the first printing material is transported to the first print head through the first discharge port and along the first feeding path in the feeding pipeline. The first print head then performs printing.

[0026] During the printing process of the first printing material, the second print head, the second printing material, and its corresponding second material source to be used in the next step are determined. Then, under the action of the filament feeder equipped with the second material source, the second printing material is transported to the corresponding second feeding port of the material changing center or to the inlet end of the corresponding second switching mechanism of the material changing center. The corresponding second switching mechanism is controlled to connect the second feeding port with the second discharge port of the material changing center that is connected to the second print head. Under the action of the filament feeder equipped with the second material source, the second printing material is transported to the second print head through the second discharge port and along the second feeding path of the feeding pipeline, ready for use.

[0027] After the first printing process is completed, the first print head is moved out of the printing area, and then the second print head is moved into the printing area to print the second printing material; or, the first print head and the second print head print simultaneously in the printing area.

[0028] The beneficial effects of this invention are:

[0029] 1. By employing a material changing device, the printing material can be switched more quickly, which helps improve printing efficiency. 2. A cutting mechanism can cut the printing material on the print head, facilitating material switching. 3. If the material changing device uses a material changing center, the printing material switching process can be even faster. Attached Figure Description

[0030] Figure 1a This is a schematic diagram of the first type of material changing system.

[0031] Figure 1b This is a schematic diagram of a hot-end clamping mechanism.

[0032] Figure 1c This is a schematic diagram of another hot-end clamping mechanism.

[0033] Figure 2This is a schematic diagram of the second type of material changing system.

[0034] Figure 3 This is a schematic diagram of the third type of material changing system.

[0035] Figure 4 This is a schematic diagram of the fourth type of material changing system.

[0036] Figure 5 This is a schematic diagram of the fifth type of material changing system.

[0037] Figure 6a This is a schematic diagram of the sixth type of material changing system.

[0038] Figure 6b This is a schematic diagram of a hot-end clamping mechanism.

[0039] Figure 6c This is a schematic diagram of another hot-end clamping mechanism.

[0040] Figure 7 This is a schematic diagram of the seventh material changing system.

[0041] Figure 8 This is a schematic diagram of the eighth material changing system.

[0042] Figure 9a This is a three-dimensional schematic diagram of a heat exchanger end structure.

[0043] Figure 9b This is a three-dimensional schematic diagram of the hot-end switching process in a heat exchanger structure.

[0044] Figure 10a This is a three-dimensional schematic diagram of another heat exchanger end structure.

[0045] Figure 10b This is a cross-sectional schematic diagram of another heat exchanger end structure.

[0046] Figure 10c This is a three-dimensional schematic diagram of the hot-end switching process in another heat exchanger structure.

[0047] Figure 11a This is a first-view three-dimensional schematic diagram of another heat exchanger end structure.

[0048] Figure 11b This is a two-dimensional schematic diagram from a second perspective of another heat exchanger end structure.

[0049] Figure 11c This is a three-dimensional schematic diagram from a third-view perspective of another heat exchanger end structure.

[0050] Figure 11d This is a four-dimensional schematic diagram from a fourth perspective of another heat exchanger end structure.

[0051] Figure 11eThis is a three-dimensional schematic diagram of a tool head with another heat exchange end structure.

[0052] Figure 11f This is a three-dimensional schematic diagram of a tool holder with another heat exchange end structure.

[0053] Figure 11g This is a three-dimensional schematic diagram of a printhead with another heat exchange end structure.

[0054] Figure 12a This is a three-dimensional structural diagram of the printhead in another heat exchanger end structure.

[0055] Figure 12b This is a three-dimensional structural diagram of the hot end in another heat exchanger structure.

[0056] Figure 13a This is a first-view schematic diagram of the three-dimensional structure of the tool holder in another type of heat exchanger end structure.

[0057] Figure 13b This is a schematic diagram from a second perspective of the three-dimensional structure of the tool holder in another type of heat exchanger end structure.

[0058] Figure 14a This is a schematic diagram of the three-dimensional structure of a 3D printing device in which the print head is located at the switching position of the tool holder in another heat exchange end structure.

[0059] Figure 14b This is a top view of a 3D printing device with two tool holders in a heat exchange end structure, where the print head is located in either the switching position of one tool holder or the switching position of the print head.

[0060] Figure 14c for Figure 14a The MM cross-sectional view shows the state of the print head at the switching position A of the tool holder.

[0061] Figure 14d To Figure 14c A cross-sectional schematic diagram of another implementation scheme of the shown scheme.

[0062] Figure 14e for Figure 14a The NN cross-sectional view shows the state of the print head at the switching position A of the tool holder.

[0063] Figure 14f for Figure 14a The MM cross-sectional view shows the printhead positioned at point T.

[0064] Figure 14g for Figure 14a The NN cross-sectional view shows the state of the printhead at point T.

[0065] Figure 14h for Figure 14aThe MM cross-sectional view shows the printhead positioned at point B.

[0066] Figure 14i for Figure 14a The NN cross-sectional view shows the printhead positioned at point B.

[0067] Figure 14j for Figure 14a The MM cross-sectional view shows the print head at point C, and is also a cross-sectional schematic diagram of another implementation scheme.

[0068] Figure 14k for Figure 14a The NN cross-sectional view shows the print head at point C, and is also a cross-sectional schematic diagram of another implementation scheme.

[0069] Figure 14L for Figure 14a The MM cross-sectional view shows the print head at point C, and is also a cross-sectional schematic diagram of another implementation scheme.

[0070] Figure 14m This is a schematic diagram of the three-dimensional structure of the printhead located at point C.

[0071] Figure 14n This is a three-dimensional structural diagram of a printhead for an alternative implementation located at point C.

[0072] Figure 14o for Figure 14n A three-dimensional structural diagram of the other side of the printhead is shown.

[0073] Figure 14p This is a top view of a 3D printing device with two printheads on the left and a tool holder on the right, where the tool holder is located at the printhead switching position or one printhead is located at the tool holder switching position, in another heat exchange end structure.

[0074] Figure 15 This is a schematic diagram of another heat exchanger structure in which the printhead can move directly from point A to point B.

[0075] Figure 16 This is a schematic diagram of another heat exchanger structure in which the tool holder can also move in the Z direction.

[0076] Figure 17a This is a three-dimensional schematic diagram of another type of hot-end switching structure.

[0077] Figure 17b This is a three-dimensional schematic diagram of another hot-end switching structure.

[0078] Figure 18a This is a flowchart illustrating one method for switching printing media.

[0079] Figure 18b This is a flowchart illustrating another method for switching printing media. Detailed Implementation

[0080] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0081] Example 1, as Figure 2 As shown, the 3D printing system with material changing function of the present invention includes a print head 1, a material changing device, a hot end 10, and a cutting mechanism 59. The print head 1 is detachably fitted with the hot end 10. The material changing device is connected to the print head 1 and switches the printing material, whereby the switching refers to changing the first printing material delivered to the print head 1 to a second printing material. The first and second printing materials can have different materials or colors. The cutting mechanism 59 is used to cut the printing material on the print head 1; that is, the first printing material delivered to the print head 1 is cut by the cutting mechanism 59, and then the material changing device switches the second printing material to the print head 1.

[0082] like Figure 2 As shown on the right, the material changing device includes a material source and a feeding pipeline. The device can withdraw the printing material from the feeding pipeline and also feed another piece of printing material into it. This feeding pipeline is connected to the print head 1, thus conveying the printing material to the print head 1. There are multiple material sources, such as material sources 731, 732, 733, and 734. These sources convey printing material to the print head 1 through the feeding pipeline. For example, each material source feeds its filamentous printing material to its corresponding output manifold 721, 722, 723, and 724. Each output manifold is connected to the corresponding inlet of a multi-inlet / one-outlet connecting pipe 701, and the outlet of the multi-inlet / one-outlet connecting pipe 701 is connected to a feeding pipe 72. The other end of the feeding pipe 72 is connected to the print head 1. A remote filament feeder 711 can also be installed on the output manifold corresponding to each material source to drive the printing material in the material source into the feeding pipeline. Figure 2 As shown, a material detection sensor 74 can also be installed on the inlet side of the remote filament feeder 711 to detect the presence of printing material, so as to determine whether to start or stop the remote filament feeder. A material detection sensor 74 can also be installed at each inlet of the multi-inlet-one-outlet connecting pipe 701 to detect whether printing material is present at that location or whether the end of the printing material has reached that location.

[0083] Figure 2The system has one printhead, which is connected to corresponding material sources 731, 732, 733, and 734 via a feed pipe 72, a multi-inlet-one-outlet connecting pipe 701, and output manifolds 721, 722, 723, and 724. The printing material from material source 731 is delivered to the hot end 10 of printhead 1 through output manifold 721, multi-inlet-one-outlet connecting pipe 701, and feed pipe 72, so that printhead 1 currently prints the printing material provided by material source 731. When switching printing materials, the next material to be printed can be pre-programmed. The printing material used, such as the printing material provided by material source 732, is conveyed to the outlet position of the multi-in-one-out connecting pipe 701 via the remote filament feeder 711. The printing material provided by material source 731 is then cut by a cutting mechanism. The printing material is then retracted by the remote filament feeder 711 at material source 731. When the printing material is retracted to the point where it leaves the outlet position of the multi-in-one-out connecting pipe 701, the remote filament feeder 711 at material source 732 can then feed printing material towards the print head 1, completing the switching of printing material at the print head. Of course, the timing of cutting off the previous printing material can be chosen when the remaining printing material on the print head is just enough to finish printing, to avoid wasting printing material. Alternatively, after cutting off the previous printing material, the hot end of the print head can be replaced so that a new hot end can receive the next batch of printing material. The switching of printing material and the switching of the hot end can be performed in parallel, serially, or partially in parallel.

[0084] The cutting mechanism 59 can be a cutting blade, which can be fixedly connected to the guide rail 81 or the printer frame. The movement of the print head 1 can drive the printing material to the cutting mechanism 59, where the cutting blade cuts the printing material in the gaps on the print head. Alternatively, the cutting mechanism 59 can be located on the print head 1, and a drive mechanism (such as a servo motor or electric motor) can be provided to move the blade to cut the printing material in the gaps. For example, a notch 18 can be provided on the conveyor line of the print head 1 that delivers the printing material to the hot end, exposing the printing material for cutting by the cutting mechanism.

[0085] The hot end 10 includes a nozzle (extrusion port) 11 for extruding printing material and a feed pipe for conveying the printing material. The feed pipe sequentially includes a heating section 12, a throat section 13, and a heat dissipation section 14. The heating section 12 is adjacent to the extrusion port 11. Heat dissipation fins 142 may also be provided on the heat dissipation section 14. Figure 2 and Figure 7 hot end or Figure 5The hot end of the printhead 1a, or the heat dissipation section 14 without heat dissipation fins 142 but with a heat dissipation surface for contact with the heat dissipation surface of the heat dissipation fins on the printhead (e.g., through thermal grease or a thermal pad), transfers heat from the heat dissipation section of the hot end to the heat dissipation fins on the printhead for heat dissipation. When the hot end is installed on the printhead, the heating element 21 can be used to heat the heating section. A first positioning feature 153 may also be provided on the hot end for matching and positioning with the positioning structure or positioning part on the printhead. The hot end may be equipped with a heating element, heat dissipation fins, heat dissipation mechanism, or extruder (filament feeder), and may even be equipped with a cutting mechanism, a connector for connecting circuits, or a circuit board for detection, control, or power supply. The printhead 1 can be movable, for example, the printhead 1 can move relative to the printing platform (not shown), for example... Figure 2 The diagram illustrates that printhead 1 can move along guide rail 81, guide rail 81 can also move along guide rail 81z, or guide rail 81 can move along a Y-axis (a direction perpendicular to guide rails 81 and 81z), as shown below. Figure 7 The track 81y, guide rail 81, and the Y-direction guide rail can also move along guide rail 81z, or refer to... Figure 7 The printhead 1 can also be equipped with a heating element 21 and a wire feeder 71.

[0086] Example 2, as Figure 1a , Figure 2 Left side, Figures 3 to 6a , Figure 7 As shown, the material changing device includes a material changing hub 900, which can retract the printing material in the feeding pipeline and feed another printing material into the feeding pipeline to deliver it to the print head; the material changing hub 900 includes several inlet ports and several outlet ports, for example... Figure 3 The feed ports are 8a, 8b, 8c, 8d, 8e, and 8f, and the discharge ports are 9a and 9b. Each feed port is equipped with a switching mechanism, for example... Figure 3 The switching mechanisms 91, 92, 93, 94, 95, and 96 in the design allow the inlet end of the switching mechanism to be connected to any outlet end by adjusting its state. The inlet end of each switching mechanism is connected to the feed port, and each mechanism has several outlet ends, each adapted and connected to a different discharge port. This allows each feed port to be connected to any discharge port by changing the state of the switching mechanism. It can be seen that this connection between each feed port and any discharge port is simultaneous. For example, if one feed port is connected to a certain discharge port, other feed ports can still be connected to any discharge port (including the aforementioned discharge port).

[0087] The material changing device may also include multiple material sources, such as Figure 3The material sources 731, 732, 733, 734, 735, and 736 are configured, and the number of material sources can be set as needed, as long as there are two or more material sources. The material sources control the conveying direction of the printing material through the material changing hub 900 and convey the printing material to the print head 1 through the feeding pipeline. Each material source conveys its filamentous printing material to the corresponding feed port of the material changing hub 900. The corresponding output port of the material changing hub 900 is connected to the inlet of the corresponding multi-inlet-one-outlet connecting pipe 709. The outlet of the multi-inlet-one-outlet connecting pipe 709 is connected to the hot end of the print head. A remote filament feeder 711 can also be installed on the output manifold of the conveying line that conveys the printing material from each material source to the corresponding feed port to drive the printing material in the material source to be conveyed to the material changing hub 900. As shown in the figure, a material detection sensor 74 can also be installed on the inlet side of the remote filament feeder 711 to detect the presence of printing material in order to determine whether to start or stop the remote filament feeder. Material detection sensors 74 can also be installed at each inlet of the multi-inlet-one-outlet connecting pipe 709 to detect whether the printing material exists at that location or whether the end of the printing material has reached that location.

[0088] The material changing hub 900, as shown in the figure, includes an inlet end group and an outlet end group. The inlet end group includes at least two inlet ports, for example, as illustrated in the figure, it includes four or six inlet ports, such as inlet ports 8a, 8b, 8c, and 8d, and 8e and 8f. The outlet end group includes at least two outlet ports, such as outlet ports 9a and 9b. A switching mechanism connects the inlet end group and the outlet end group. Operation of the switching mechanism allows any inlet port to selectively connect with any outlet port, and simultaneously allows any other inlet port to selectively connect with any other outlet port, and allows any inlet port to be simultaneously connected to any outlet port. For example, when inlet port 8a is connected to outlet port 9a, the remaining inlet ports 8b, 8c, and 8d, as well as 8e and 8f, can also be connected to outlet port 9b. For example, feed ports 8e or 8d can be connected to discharge port 9a, allowing printing material input through feed ports 8a or 8c to be delivered to discharge port 9a, and simultaneously allowing printing material input through feed ports 8d or 8e to be delivered to discharge port 9a. Ideally, the number of feed ports should be greater than or equal to the number of discharge ports. Each feed port is equipped with a corresponding switching mechanism, which has an inlet end and several outlet ends. The inlet end is connected to the feed port of the material changing center, or the inlet end can coincide with the feed port. The outlet ends are used to connect to the discharge ports of the material changing center, for transferring printing material from the switching mechanism to the discharge ports of the material changing center. The inlet end of the switching mechanism refers to the port used to receive the incoming printing material, and the outlet end refers to the port used to discharge the printing material.

[0089] The material changing center can also have more discharge ports, such as Figure 4 , Figure 5, Figure 6a and Figure 7 As shown. Among them. Figure 4 Among them Figure 5 The schematic switching mechanism can have multiple outlets, each connected to a corresponding discharge port via a corresponding output manifold, forming a material switching hub with multiple discharge ports. For example... Figure 5 The switching mechanisms 91, 92, 93 and 94 shown in the diagram each have 3 outlet ends. Each switching mechanism connects the corresponding outlet end and the discharge port through 3 output manifolds. For example, the output manifolds 721, 722 and 723 corresponding to the switching mechanism 91 connect the 3 outlet ends of the switching mechanism 91 to the discharge ports 9a, 9b and 9c respectively, forming a material changing hub with 3 discharge ports.

[0090] In Example 3, each switching mechanism is equipped with a material conveying structure, such as... Figure 1a , Figure 2 , Figure 3 , Figure 5 , Figure 6a and Figure 7 As shown, the feeding structure includes several output manifolds or several feeding channels. The feed section of the feeding structure for receiving printing material is connected to the outlet end of the switching mechanism, and the discharge end of the feeding structure for discharging printing material is connected to each discharge port, for example... Figure 1a The outlet end of the switching mechanism 91 is connected to output manifolds 721 and 722, wherein output manifold 721 is connected to the discharge port 9a of the material changing center, and output manifold 722 is connected to the discharge port 9b of the material changing center.

[0091] Alternatively, the material conveying structure may include a conical channel structure at each discharge port. (See [reference needed]). Figure 3 On the left side of the middle, the port in the channel structure used to receive the printing material is the large end and faces the outlet end of the switching mechanism. The projection of the outlet end of each switching mechanism along the conveying direction of the printing material falls on the port in the channel structure used to receive the printing material. The ports in each channel structure used to discharge the printing material form the discharge ports. Figure 3As shown in the material changing hub 900a, each discharge port (e.g., 9c, 9d, and 9e) is equipped with a channel structure (e.g., 771, 772, or 773). The channel structure is conical, with the larger end facing the outlet of the switching mechanism. The projection of the outlet of each switching mechanism (e.g., 97, 98, or 99) along the material conveying direction falls on the port in the channel structure used to receive the material. The ports in each channel structure used to discharge the material form discharge ports (e.g., 991, 992, and 993). The inlet of each switching mechanism is connected to the feed port (e.g., 8g, 8h, and 8i). For example, the channel structure 771 of discharge port 9c corresponds to the outlet 991 of the switching mechanism, the channel structure 772 of discharge port 9d corresponds to the outlet 992 of the switching mechanism, and the channel structure 773 of discharge port 9e corresponds to the outlet 993 of the switching mechanism.

[0092] The switching mechanism includes a main body (such as a rotating body, a flipping body, a moving body, or a sliding body) and a support body (such as a rotating support body, a flipping support body, a moving support body, or a sliding support body). The main body may have a material feeding channel. The main body can move relative to the support body (e.g., slide or rotate), switching between multiple positions corresponding to various outlet ends. The material feeding channel, which receives the printing material, is connected to the inlet end of the switching mechanism, and the material discharging port is connected to each outlet end of the switching mechanism. Alternatively, a material feeding channel can be provided in the support body, and the inlet end can be connected to the corresponding outlet end through adjustment of the main body.

[0093] Example 4, as Figure 3 As shown on the right, the switching mechanism includes a rotating body and a rotating support for supporting the rotating body to rotate around its own axis. The rotating body has a feeding channel. Along the direction of the printing material feeding, the projection of the port of the feeding channel for receiving the printing material always at least partially overlaps with the projection of the inlet end, or the port of the feeding channel for receiving the printing material is coaxial with the inlet end (the angle between the axes is 0 degrees). The port of the feeding channel for discharging the printing material is spaced apart from the axis of the rotating body. The outlet end of the switching mechanism is circumferentially spaced at corresponding positions on the rotation path of the port of the feeding channel for discharging the printing material. Specifically, Figure 3The material changing hub 900 shown has six feed ports, namely feed ports 8a, 8b, 8c, 8d, 8e, and 8f, and also includes two discharge ports 9a and 9b. A switching mechanism is correspondingly provided downstream of each feed port (in the direction the printing material is conveyed towards the discharge port). The structures of each switching mechanism can be identical. Each feed port is connected to multiple output manifolds through a corresponding switching mechanism. Each output manifold is connected to a discharge port. The feed end of each output manifold is connected to the outlet end of the switching mechanism, or the feed end of each output manifold coincides with the outlet end of the switching mechanism. For example... Figure 3 As shown, each switching mechanism is connected to two output manifolds, one of which is connected to the discharge port 9a, and the other to the discharge port 9b. The switching mechanism allows connection from the feed port to either the feed port or the discharge port. For example... Figure 3 The feed port 8a is connected to the inlet end of the switching mechanism 91. The rotating body 911 of the switching mechanism 91 is provided with a feeding channel 913. The port of the feeding channel for receiving printing material is connected to the inlet end of the switching mechanism 91. The inlet end of the switching mechanism 91 is connected to the feed port 8a. The port of the feeding channel for discharging printing material is set towards the outlet end of the switching mechanism 91. By rotating the rotating body 911 relative to the rotating support 912, the port of the feeding channel for discharging printing material can be aligned with each outlet end of the switching mechanism 91. The outlet end and the inlet end of the switching mechanism 91 can be connected to the rotating support. The support body 912 is fixedly connected. The outlet end of the switching mechanism is respectively connected to or overlaps with the feed ends of the output manifold 721 and the output manifold 722. Thus, the feed port 8a is connected to the output manifold 721 and the output manifold 722 through the switching mechanism 91. The output manifold 721 is connected to the discharge port 9a, and the output manifold 722 is connected to the discharge port 9b. The body 911 of the switching mechanism 91 can achieve the connection between the feed port 8a and one of the output manifold 721 or the output manifold 722 by rotating around its own axis 300, thereby achieving the controllable connection between the feed port 8a and one of the discharge ports 9a and 9b. Figure 3 The rotation axis 300 of the rotating body 911 of the schematic switching mechanism is vertical and located in the drawing. In this case... Figure 3 The port for receiving printing material and the port for discharging printing material shown in the diagram are located on the upper and lower end faces of the rotating body 911. Of course, the port for discharging printing material can also be located on the outer circumference of the rotating body 911.

[0094] Similarly, the feed port 8b can be connected to one of the two output manifolds corresponding to the switching mechanism 92 through switching control, thereby achieving controllable connection between the feed port 8b and one of the discharge ports 9a and 9b; the feed port 8c can be connected to one of the two output manifolds corresponding to the switching mechanism 93 through switching control, thereby achieving controllable connection between the feed port 8c and one of the discharge ports 9a and 9b; the feed port 8d can be connected to one of the two output manifolds corresponding to the switching mechanism 94 through switching control, thereby achieving controllable connection between the feed port 8d and the discharge port 9b. One of the feed port 9a and the discharge port 9b is controllably connected; the feed port 8e can be connected to one of the two output manifolds corresponding to the switching mechanism 95 through switching control, thereby achieving controllable connection between the feed port 8e and one of the discharge ports 9a and 9b; the feed port 8f can be connected to one of the two output manifolds corresponding to the switching mechanism 96 through switching control, thereby achieving controllable connection between the feed port 8f and one of the discharge ports 9a and 9b. The two output manifolds corresponding to each switching mechanism are respectively connected to the discharge ports 9a and 9b. The switching mechanism is equivalent to a one-in-multiple-outlet pipeline connection switching device, that is, the switching mechanism can selectively connect the inlet end to any outlet end. The switching mechanism can achieve connection between the inlet end and any outlet end by changing its state (relative movement of the rotating body and the rotating support body). A material conveying channel can be set within the rotating body or the rotating support. The switching mechanism includes one inlet end and multiple outlet ends. The relative movement between the rotating body and the rotating support allows the material conveying channel to connect the inlet end to any outlet end. The output manifold and the discharge port can be connected by a multi-inlet-one-outlet connecting pipe (pipe connection structure). For example, a multi-inlet-one-outlet connecting pipe 701 is set at discharge port 9a, and a multi-inlet-one-outlet connecting pipe 702 is set at discharge port 9b. The inlet end of the multi-inlet-one-outlet connecting pipe 701 is connected to one outlet end of each switching mechanism, and the inlet end of the multi-inlet-one-outlet connecting pipe 702 is connected to the other outlet end of each switching mechanism. The outlet end of the multi-inlet-one-outlet connecting pipe 701 is connected to discharge port 9a, and the outlet end of the multi-inlet-one-outlet connecting pipe 702 is connected to discharge port 9b. A material detection sensor 74 can also be set at the upstream position (where the printing material is conveyed from the upstream position to the corresponding switching mechanism) and close to the switching mechanism. For example, a material detection sensor 74 can be set at the feeding port or on the printing material conveying line between the feeding port and the corresponding switching mechanism to detect whether the end of the printing material is located at the upstream position of the corresponding switching mechanism.

[0095] Or, in another implementation, such as Figure 7The switching mechanisms 91, 92, and 93 include a rotating body 911 and a rotating support 912 for supporting the rotating body 911 to rotate around its own axis. The rotating body 911 has several material conveying channels 913. The port of the material conveying channel 913 for receiving printing material is located on the first end face of the rotating body 911, and the port of the material conveying channel 913 for discharging printing material is located on the second end face of the rotating body 911. The material conveying channel 913 has several ports for receiving printing material, and all of them are connected to a common port for discharging printing material. The outlet ends of the switching mechanisms are circumferentially spaced at corresponding positions on the rotation path of the common port of the material conveying channel 913 for discharging printing material. When the rotating body 911 moves to multiple positions where the ports of the material conveying channels 913 for receiving printing material are opposite to the inlet end of the switching mechanism, the common port of the material conveying channels 913 for discharging printing material is then opposite to the outlet end of the switching mechanism.

[0096] Or, in yet another implementation, such as Figure 7 The switching mechanisms 91a and 92a include a rotating body 911 and a rotating support 912 for supporting the rotating body 911 to rotate around its own axis. The rotating body 911 has a material conveying channel 913. The port of each material conveying channel 913 for receiving the printing material is located on the first end face of the rotating body 911, and the port of each material conveying channel 913 for discharging the printing material is located on the second end face of the rotating body 911. When the rotating body 911 moves to multiple positions such that the ports of each material conveying channel 913 for receiving the printing material are opposite to the inlet end of the switching mechanism, the ports of each material conveying channel 913 for discharging the printing material are opposite to the outlet ends of the switching mechanism.

[0097] Or, in yet another implementation, such as Figure 7 The switching mechanisms 94, 91b, and 92b include a rotating body 911 and a rotating support 912 for supporting the rotating body 911 to rotate around its own axis. A material conveying channel 913 is provided in the rotating body 911. The port of the material conveying channel 913 for receiving the printing material is located on the first end face of the rotating body, and the port of the material conveying channel 913 for discharging the printing material is located on the second end face of the rotating body. The outlet ends of the switching mechanisms are circumferentially spaced at corresponding positions on the rotational path of the outlet of the material conveying channel for discharging the printing material. The port of the material conveying channel for receiving the printing material is conical, with the larger end facing the inlet end. When the rotating body moves to multiple positions where the port of the material conveying channel for discharging the printing material is opposite to the outlet end of the switching mechanism, the projection of the inlet end of the switching mechanism along the direction of printing material feeding always falls on the port of the material conveying channel for receiving the printing material. Figure 7 The rotation axis of the rotating body 911 of each switching mechanism is approximately perpendicular to the first end face or the second end face (angle 90°), and the angle error is no greater than ±45°.

[0098] Example 5, as Figure 1a The switching mechanisms 93 and 94 in the middle and Figure 5 The switching mechanisms 91, 92, 93, and 94 are included. Each switching mechanism includes a rotating body 911 and a rotating support 912 for supporting the rotating body 911 to rotate around its own axis. A material conveying channel 913 is provided in the rotating body 911. The port for receiving printing material and the port for discharging printing material in the material conveying channel 913 are both located on the outer circumferential surface of the rotating body 911. There are several ports for receiving printing material in the material conveying channel, and all of them are connected to a common port for discharging printing material in the material conveying channel. The outlet end of the switching mechanism is circumferentially spaced at corresponding positions on the rotation path of the common port for discharging printing material in the material conveying channel. When the rotating body moves to multiple positions where the ports for receiving printing material in the material conveying channel are opposite to the inlet end of the switching mechanism, the common port for discharging printing material in the material conveying channel is opposite to the outlet end of the switching mechanism. Figure 1a or Figure 5 The rotation axis of the rotating body 911 of the switching mechanism is indicated by the intersection of the intersecting center lines on each rotating body, that is, the rotation axis is perpendicular to the drawing. Figure 1a The rotating body 911 of the switching mechanism, as illustrated in the diagram, has two ports for receiving printing material and three outlet ports. Figure 6a The rotating body 911 of the switching mechanism shown in the diagram has three ports for receiving printing material and three outlets.

[0099] Alternatively, in one implementation, such as Figure 1aThe switching mechanisms 91 and 92 are included. Each switching mechanism comprises a rotating body 911 and a rotating support 912 supporting the rotating body 911 to rotate around its own axis. The rotating body 911 has several feeding channels 913. Ports for receiving printing material and ports for discharging printing material in the feeding channels 913 are located on the outer circumference of the rotating body 911. When the rotating body 911 moves to multiple positions where the ports for receiving printing material in each feeding channel are opposite to the inlet of the switching mechanism, the ports for discharging printing material in the feeding channels 913... Each port of the printing material is respectively opposite to the outlet end of the switching mechanism; as shown in the figure, there are two material feeding channels 913. The switching mechanism 91 shows that one of the material feeding channels 913 connects the inlet port 8a and the outlet port 9a, and the switching mechanism 91 shows that one of the material feeding channels 913 connects the inlet port 8b and the outlet port 9b. The figure also shows that the port of the other material feeding channel 913 used to discharge printing material can be offset from the port of the aforementioned material feeding channel 913 used to discharge printing material along the axis of rotation of the rotating body 911, as shown by the dotted line in the rotating body 911 in the figure.

[0100] Alternatively, in one implementation, such as Figure 6a The switching mechanisms 93a and 94a include a rotating body 911 and a rotating support 912 for supporting the rotating body 911 to rotate around its own axis. The rotating body 911 has a feeding channel 913. The port for receiving printing material and the port for discharging printing material in the feeding channel 913 are both located on the outer circumferential surface of the rotating body 911. The outlet end of the switching mechanism is circumferentially spaced at corresponding positions on the rotating path of the outlet of the feeding channel 913 for discharging printing material. The port for receiving printing material in the feeding channel 913 is conical, with the larger end facing the inlet end. When the rotating body moves to multiple positions where the port for discharging printing material in the feeding channel is opposite to the outlet end of the switching mechanism, the projection of the inlet end of the switching mechanism along the direction of printing material feeding always falls on the port for receiving printing material in the feeding channel 913.

[0101] Example 6, as Figure 6a The switching mechanisms 93b and 94b include a sliding body 911a and a sliding support 912a for supporting the sliding of the sliding body 911a. The outlet ends of the switching mechanisms are arranged at intervals along the movement trajectory of the sliding body 911a. The sliding body 911a has several material conveying channels 913. When the sliding body moves to multiple positions such that the port in each material conveying channel used to receive the printing material is opposite to the inlet end of the switching mechanism, the port in each material conveying channel used to discharge the printing material is opposite to each outlet end of the switching mechanism.

[0102] Or, such as Figure 6a The switching mechanisms 93 and 94 are included. The switching mechanism includes a sliding body 911a and a sliding support 912a for supporting the sliding of the sliding body 911a. The outlet ends of the switching mechanism are arranged at intervals along the movement trajectory of the sliding body. The sliding body is provided with a material conveying channel 913. The material conveying channel has several ports for receiving the printing material, and all of them are connected to the common port for discharging the printing material. When the sliding body moves to multiple positions such that the ports in the material conveying channel for receiving the printing material are opposite to the inlet end of the switching mechanism, the common port in the material conveying channel for discharging the printing material is opposite to each outlet end of the switching mechanism.

[0103] Alternatively, the switching mechanism includes a sliding body and a sliding support for supporting the sliding of the sliding body; the outlet ends of the switching mechanism are arranged at intervals along the movement trajectory of the sliding body; a material conveying channel is provided on the sliding body, the material conveying channel is conical, and the port in the material conveying channel for receiving the printing material is the larger end and faces the inlet end of the switching mechanism. When the sliding body moves to multiple positions such that the port in the material conveying channel for discharging the printing material is opposite to each outlet end of the switching mechanism, the projection of the inlet end of the switching mechanism along the printing material feeding direction always falls on the port in the material conveying channel for receiving the printing material. Figure 6a The sliding bodies of the switching mechanisms 93, 94, 93b and 94b shown in the diagram can slide left and right in the horizontal direction.

[0104] Or, in another implementation, such as Figure 2The switching mechanisms 91, 92, 93, and 94 include a movable body 911b and a movable support (not shown in the figure) for supporting the movement of the movable body 911b. The outlet ends of the switching mechanisms are arranged at intervals along the movement trajectory of the movable body. The inlet end of the switching mechanism is connected to the movable body 911b via a feed pipe. The movable body 911b can switch between corresponding outlet ends or output manifolds. For example, the movable body 911b of the switching mechanism 91 can switch between the feed ends of output manifolds 725, 726, 727, and 728 for receiving printing material (each feed end can coincide with the corresponding outlet end of the switching mechanism 91). The output manifolds 725, 726, 727, and 728 are connected to the discharge ports 9a, 9b, 9c, and 9d, respectively. A connecting pipe 791 connects the moving body 911b of the switching mechanism 91 to the inlet end of the switching mechanism. The inlet end of the switching mechanism is connected to the corresponding feed port, so that the printing material (filament printing material) can be conveyed from the feed port 8a (which can coincide with the inlet end of the switching mechanism 91) to the switching mechanism 91. The switching mechanism 91 switches between the feed ends of the output manifolds 725, 726, 727 and 72 to realize the switching of the connection between the feed port 8a and the output ports 9a, 9b, 9c and 9d. The moving body 911b can be driven by a motor, servo, or servo motor. The moving path of the moving body 911b can be a straight line or an arc. For example, the moving body 911b can rotate around the axis of the inlet end of the switching mechanism 91. The connecting pipe 791 can also be a material conveying channel set on the moving body 911b. When the line is straight, the connecting pipe 791 can be a flexible hose. The feed ends of the output manifolds 725, 726, 727, and 728 for receiving the printing material (filament printing material) are set at the corresponding positions on the moving path.

[0105] Example 7, as Figure 6aThe switching mechanisms 91, 92, 91a, and 92a in the switching mechanism include a flipping body 911c and a flipping support 912c for supporting the flipping body 911c to rotate around its flipping axis. The flipping support 912c is provided with a material conveying channel 913, which includes a feeding section for receiving printing material and two discharging sections for discharging printing material. The feeding section intersects with the two discharging sections. The flipping body 911c of the switching mechanisms 91 and 92 extends along a direction perpendicular to its rotation axis and is pivotally connected between the two discharging sections. Pivotibly connected to the material conveying channel 913, the flipping bodies 911c of the switching mechanisms 91a and 92b extend in opposite directions perpendicular to their axes of rotation and pivotally connect between the feeding section and the two discharging sections, or pivotally connected to the material conveying channel 913. When the flipping bodies 911c rotate to their respective positions, they block the inlets of the discharging sections other than the inlet of the discharging section corresponding to that position. The port of the feeding section used for the entry of printing material forms the inlet end of the switching mechanism, and the ports of each discharging section used for the discharge of printing material form the outlet end of the switching mechanism. In this case, if... Figure 6a The flipping body 911c of the switching mechanisms 91, 92, 91a and 92a shown can rotate clockwise or counterclockwise along the rotation axis perpendicular to the plane of the drawing. For example, the flipping body 911c can rotate around an axis perpendicular to the axis of the feeding section and / or the axis of the discharging section.

[0106] Alternatively, in one implementation, such as Figure 6a The switching mechanisms 91b and 92b include a rotating body 911 and a rotating support 912 for supporting the rotating body 911 to rotate around its rotation axis 914. The rotating support 912 has a material conveying channel, which includes an infeed section for receiving printing material and multiple outlet sections for discharging printing material. The infeed section intersects with multiple outlet sections. When the rotating body 911 rotates to its corresponding position, it blocks the inlets of all outlet sections except the one corresponding to that position. The port of the infeed section for receiving printing material forms the inlet of the switching mechanism, and the ports of each outlet section for discharging printing material form the outlet of the switching mechanism. In this case, if... Figure 6a The rotating body 911 of the switching mechanisms 91b and 92b shown can rotate clockwise or counterclockwise along a vertical rotation axis 914 located in the drawing. For example, the rotating body 911 can rotate around the axis of the feed section.

[0107] The material changing device of the present invention includes a switching mechanism that can be any one of the switching mechanisms in Embodiments 4 to 7 above, or a combination of two or more switching mechanisms.

[0108] Example 8, as Figure 6a and Figure 7As shown, at least one feed port is configured with two or more switching mechanisms. The switching mechanisms are divided into at least two levels along the conveying direction of the printing material. Each level includes one or more switching mechanisms. In this way, the switching structure forms a cascaded switching mechanism by setting at least two levels, so that the material changing hub can have more discharge ports.

[0109] Alternatively, when the switching mechanism is divided into two levels along the direction of printing material conveying, the inlet end of the switching mechanism in the uppermost level is connected to the feeding port, and the inlet end of the switching mechanism in the lowermost level is connected to the outlet end of the switching mechanism in the uppermost level. The port in the material conveying structure used to receive the printing material is connected to the idle outlet end of each switching mechanism.

[0110] Alternatively, when the switching mechanism is divided into three or more levels along the conveying direction of the printing material, the inlet end of the switching mechanism in the top level is connected to the feeding port, the inlet end of the switching mechanism in the middle level is connected to the outlet end of the switching mechanism in the level above, and the outlet end of the switching mechanism in the middle level is connected to the inlet end of the switching mechanism in the level below. The port in the material conveying structure used to receive the printing material is connected to the idle outlet end of each switching mechanism.

[0111] For example Figure 6a and Figure 7 In the diagram, the switching mechanism 91 corresponding to the feed port 8a has two outlet ends. It forms a cascaded structure with the lower-level switching mechanisms 91a and 91b, meaning the two outlet ends of switching mechanism 91 are connected to the inlet ends of switching mechanisms 91a and 91b respectively. As shown in the diagram, output manifolds 721 and 722 connect the outlet ends of switching mechanism 91 to the inlet ends of the lower-level switching mechanisms 91a and 91b respectively. Switching mechanisms 91a and 91b are... It has two outlet ends. The outlet ends of switching mechanisms 91a and 91b are connected to the discharge ports 9a, 9b, 9c, and 9d, respectively. As shown in the figure, the outlet ends of switching mechanisms 91a and 91b are connected to the discharge ports 9a, 9b, 9c, and 9d respectively through output manifolds 723, 724, 725, and 726. This allows the feed port 8a to be selectively and controllably connected to the four discharge ports 9a, 9b, 9c, and 9d, thus expanding the number of discharge ports. Similarly... Figure 6a and Figure 7 The switching mechanism 92 corresponding to the feed port 8b forms a cascade structure with the lower-level switching mechanisms 92a and 92b, allowing the feed port 8b to be selectively and controllably connected to the four discharge ports 9a, 9b, 9c, and 9d. Similarly... Figure 6aThe switching mechanism 93 corresponding to the feed port 8c forms a cascaded structure with the lower-level switching mechanisms 93a and 93b, allowing the feed port 8c to be selectively and controllably connected to the four discharge ports 9a, 9b, 9c, and 9d. Similarly... Figure 6a The switching mechanism 94 corresponding to the feed port 8d forms a cascade structure with the switching mechanisms 94a and 94b at the lower level, so that the feed port 8d can be selectively and controllably connected to the four discharge ports 9a, 9b, 9c and 9d.

[0112] A cascaded (cascaded structure) switching mechanism can be viewed as a new type of switching mechanism formed by self-nesting and series combination of switching mechanisms. The idle outlet end is the outlet end of the cascaded switching mechanism. An idle outlet end in a switching mechanism refers to an outlet end not used to connect to the inlet end of other switching mechanisms (lower-level switching mechanisms). The inlet end of the top-level switching mechanism is the inlet end of the cascaded switching mechanism. In the material conveying structure, multiple inlet and one outlet connecting pipes (structures) can also be set at the corresponding outlet port to connect the outlet end of the switching mechanism to the outlet port, for example... Figure 3 and Figure 1a The switching hub shown has two discharge ports. Multiple-inlet-one-outlet connecting pipes 701 and 702 can be used to connect the two outlet ends of each switching mechanism to the corresponding discharge port; for example... Figure 5 The material changing hub with three discharge ports shown can use multi-inlet-one-outlet connecting pipes 701, 702, and 703 to connect the three outlet ends of each switching mechanism to the corresponding discharge ports, as shown. Figure 6a and Figure 7 The material changing hub shown has four discharge ports. Multiple inlet and one outlet connecting pipes 701, 702, 703 and 704 can be used to connect the four outlet ends of each switching mechanism to the corresponding discharge ports.

[0113] Example 9: The switching mechanism has several outlets, each adapted and connected to a different discharge port. It can also be described as follows: Assume the material switching hub has *s* inlet ports and *m* outlet ports. When the switching mechanism is arranged in a single layer along the material conveying direction, the switching mechanism enables the switching of the connection lines used to convey the printing material from the inlet ports to the outlet ports. The material switching hub can then include *s* switching mechanisms, each with an inlet port and *m* outlet ports. The inlet port of each switching mechanism is connected to the inlet port of the material switching hub, or the inlet port of each switching mechanism forms the inlet port of the material switching hub, and the outlet port of each switching mechanism is connected to the outlet port of the material switching hub. Alternatively, when the switching mechanism is arranged in multiple layers along the material conveying direction... In a hierarchical arrangement, one outlet of the upper-level switching mechanism is connected to the inlet of the corresponding switching mechanism in the lower level to form a cascaded switching mechanism. The cascaded switching mechanism is used to switch the connection line used to transfer printing material from the feed port to the discharge port. So, s cascaded switching mechanisms are used, and each cascaded switching mechanism has m idle outlets (e.g., outlets not connected to the inlet of the lower level or other switching mechanisms). The inlet of each switching mechanism in the uppermost level is connected to the feed port of the material changing center, or the inlet of each switching mechanism in the uppermost level forms the feed port of the material changing center. The discharge port is connected to the idle outlet of each cascaded switching mechanism. Here, s and m are positive integers greater than or equal to 2.

[0114] Example 10, as follows Figure 8 or Figure 4 As shown, there are two or more material changing centers connected in parallel to form a combined material changing center that can access more material sources.

[0115] Specifically, such as Figure 8 As shown, each material changing hub forms a combined material changing hub. The combined material changing hub may include several multi-inlet-one-outlet connecting pipes. The outlet ends of the multi-inlet-one-outlet connecting pipes respectively form the discharge ports of the combined material changing hub or are respectively connected to the discharge ports of the combined material changing hub. The inlet ends of the multi-inlet-one-outlet connecting pipes are respectively connected to the discharge ports of each material changing hub. The inlet ports of each material changing hub respectively form the inlet ports of the combined material changing hub or are respectively connected to the inlet ports of the combined material changing hub. By changing the state of the switching mechanism, each inlet port of the combined material changing hub can be connected to any discharge port of the combined material changing hub. The discharge ports of the combined material changing hub can be respectively connected to the print head through the feeding pipe.

[0116] Or, such as Figure 4As shown, the multi-inlet / one-outlet connecting pipes of the combined material changing center can also form a cascaded structure. Multiple multi-inlet / one-outlet connecting pipes can be cascaded along the feeding line, which can be considered as a multi-inlet / one-outlet connecting pipe with more inlet ends. Each material changing center (such as 900, 900a, 900b, and 900c, etc.) forms a combined material changing center 9000. The combined material changing center also includes several multi-inlet / one-outlet connecting pipes. These pipes are divided into two levels along the material conveying direction. The outlet end of the multi-inlet / one-outlet connecting pipe 701 at the lowest level forms the outlet port of the combined material changing center (such as 901, 902, 903, and 904) or is connected to the outlet port of the combined material changing center. The outlet end of the multi-inlet / one-outlet connecting pipe 702 at the highest level is connected to one inlet end of a different multi-inlet / one-outlet connecting pipe at the lowest level, for example, through the feeding line. The manifold 722 is connected to the inlet end of the multi-inlet-one-outlet connecting pipe 702 at the top level, which is connected to the outlet port of different material changing centers, for example, through the output manifold 721. The outlet port of each material changing center is connected to the idle inlet end of each multi-inlet-one-outlet connecting pipe. The inlet port of each material changing center forms the inlet port of the combined material changing center or is connected to the inlet port of the combined material changing center. By changing the state of the switching mechanism, each inlet port of the combined material changing center can be connected to any outlet port of the combined material changing center. The outlet port of the combined material changing center is connected to the print head through the feeding pipe.

[0117] Alternatively, the various material changing centers can form a combined material changing center. This combined material changing center also includes several multi-inlet / one-outlet connecting pipes. These multi-inlet / one-outlet connecting pipes are divided into three or more levels along the material conveying direction. The outlet ends of the multi-inlet / one-outlet connecting pipes at the lowest level form the outlet ports of the combined material changing center, or are connected to the outlet ports of the combined material changing center. The outlet ends of the multi-inlet / one-outlet connecting pipes in the middle levels are connected to the inlet ends of different multi-inlet / one-outlet connecting pipes in the next lower level. The inlet end is connected to the outlet end of the multi-inlet-one-outlet connecting pipe in the previous level. The outlet port of the material changing center is connected to the corresponding empty inlet in each multi-inlet-one-outlet connecting pipe. The inlet ports of each material changing center form the inlet ports of the combined material changing center or are connected to the inlet ports of the combined material changing center. By changing the state of the switching mechanism, each inlet port of the combined material changing center can be connected to any outlet port of the combined material changing center. The outlet ports of the combined material changing center are connected to the print head through the feeding pipe.

[0118] Alternatively, the various material changing centers can form a combined material changing center. This combined material changing center also includes several multi-inlet / one-outlet connecting pipes. These multi-inlet / one-outlet connecting pipes are arranged in a single layer along the printing material conveying direction. The number of inlets of the multi-inlet / one-outlet connecting pipes is equal to or greater than the number of material changing centers. This combined material changing center includes n material changing centers, each with m outlet ports, using m multi-inlet / one-outlet connecting pipes. The corresponding outlet port of each material changing center is connected to the inlet end of each multi-inlet / one-outlet connecting pipe, and the outlet end of the multi-inlet / one-outlet connecting pipe is connected to the group of... The discharge ports of the combined material changing hub are connected one-to-one, or the outlet ends of the multi-inlet-one-outlet connecting pipes respectively form the discharge ports of the combined material changing hub. The inlet ports of each material changing hub form the inlet ports of the combined material changing hub, or are respectively connected to the inlet ports of the combined material changing hub. By changing the state of the switching mechanism, each inlet port of the combined material changing hub can be connected to any discharge port of the combined material changing hub. The discharge ports of the combined material changing hub are respectively connected to the print head through the feeding pipe; where m and n are both positive integers greater than or equal to 2.

[0119] Alternatively, the various material changing centers can form a combined material changing center. This combined material changing center also includes several multi-inlet / one-outlet connecting pipes. These multi-inlet / one-outlet connecting pipes are arranged in multiple levels along the material conveying direction. The outlet end of the multi-inlet / one-outlet connecting pipe of the upper level is connected to one inlet end of the multi-inlet / one-outlet connecting pipe of the lower level, forming a cascaded multi-inlet / one-outlet connecting pipe. This combined material changing center includes n material changing centers, each with m outlet ports. Therefore, m cascaded multi-inlet / one-outlet connecting pipes can be used. Each cascaded multi-inlet / one-outlet connecting pipe has n or more idle inlet ports. The corresponding outlet port of each material changing center is connected to this cascaded multi-inlet / one-outlet connecting pipe. The idle inlet end of the connecting pipe, the outlet end of the lowest-level multi-inlet-one-outlet connecting pipe is connected to the outlet port of the combined material changing center, or the outlet end of the lowest-level multi-inlet-one-outlet connecting pipe forms the outlet port of the combined material changing center. The inlet ports of each material changing center form the inlet ports of the combined material changing center or are connected to the inlet ports of the combined material changing center. By changing the state of the switching mechanism, each inlet port of the combined material changing center can be connected to any outlet port of the combined material changing center. The outlet ports of the combined material changing center are connected to the print head through the feeding pipe; where m and n are positive integers greater than or equal to 2.

[0120] For example Figure 8It includes four material changing centers 900, 900a, 900b, and 900c, each equipped with several material sources. The print head 1 is connected to at least one outlet port in each material changing center via a feeding pipe. Alternatively, the material changing centers form a combined material changing center 9000, which also includes several multi-inlet, one-outlet connecting pipes, for example... Figure 8 The system includes multiple inlet and outlet connecting pipes 701 and 702. The outlet ends of these multiple inlet and outlet connecting pipes respectively form the discharge ports of the combined material changing center or are connected to the discharge ports of the combined material changing center. For example, the outlet ends of each multiple inlet and outlet connecting pipe 701 (or 702) respectively form discharge ports 901, 902, 903, and 904 of the combined material changing center 9000. The inlet ends of these multiple inlet and outlet connecting pipes are respectively connected to the discharge ports of each material changing center. For example, discharge port 9a of material changing center 900, discharge port 9a-1 of material changing center 900a, discharge port 9a-2 of material changing center 900b, and discharge port 9a-3 of material changing center 900c are connected to discharge port 901 of the combined material changing center 9000. The discharge port 9b of 900, the discharge port 9b-1 of the material changing hub 900a, the discharge port 9b-2 of the material changing hub 900b, and the discharge port 9b-3 of the material changing hub 900c are connected to the discharge port 902 of the combined material changing hub 9000. The feed ports of each material changing hub form the feed ports of the combined material changing hub or are respectively connected to the feed ports of the combined material changing hub. By changing the state of the switching mechanism, each feed port of the combined material changing hub can be connected to any discharge port of the combined material changing hub. The discharge ports of the combined material changing hub can be connected to the print head through the feeding pipe, for example, they can be connected to the print head 1 through the feeding pipe 72, or to the corresponding inlet end of the multi-inlet-one-outlet connecting pipe on the print head 1.

[0121] Example 11: Based on the material changing hub in the above embodiments, a material changing device can be formed, including the aforementioned material changing hub, a print head, and several material sources; each material source is connected to a respective inlet port of the material changing hub; wherein, one print head is connected to at least two outlet ports of the material changing hub through a feeding pipe, such as... Figure 1a , Figure 3 , Figure 4 , Figure 7 and Figure 8 As shown; or, there are two or more printheads, each of which is connected to at least one discharge port of the material changing center via a feed line, such as... Figure 6a and Figure 5 As shown, where Figure 6a and Figure 5The diagram illustrates that discharge ports 9a and 9b are connected to the print head 1 via various corresponding feed pipes 72, such as the inlet end of the multi-inlet / one-outlet connecting pipe 709 on the print head 1. Figure 6a The discharge ports 9c and 9d are connected to the print head 1a via various corresponding feed pipes 72, such as the inlet end of the multi-inlet / one-outlet connecting pipe 709a on the print head 1a. Figure 5 The discharge port 9c is connected to the print head 1a via a feed tube. Figure 7 The discharge ports 9a, 9b, and 9c of the switching mechanism 900 are all connected to the print head 1. The print head 1 can also be equipped with a multi-inlet / one-outlet connecting pipe 709 with four inlet ends. Of course... Figure 5 The three discharge ports or Figure 6aThe four output ports can all be connected to a single printhead. For example, a three-in-one-out or four-in-one-out connecting pipe can be installed on a single printhead, with the inlet end connected to each output port. Alternatively, printheads 1 and 1a can be combined into one printhead, meaning one printhead can have two hot ends 10 and two multi-in-one-out connecting pipes 709 corresponding to the two hot ends. Alternatively, printheads 1 and 1a can be two printheads on the same printer, or they can be separate printheads on different printers. Each of the multiple material sources corresponds to an inlet port of the material changing center, with each source providing filamentous printing material and conveying it to its corresponding inlet port. Remote filament feeders can also be separately installed to drive and feed each corresponding printing material (filamentous printing material) along its axial direction. This conveys the printing material from the material source to its corresponding inlet port. Alternatively, detection sensors 74 can be installed on the printing material conveying lines between the material source and the corresponding filament feeder 71 to detect whether the end of the printing material has been conveyed to the upstream position of each filament feeder. For example, when printing material is inserted into a certain feed pipe or printing material conveying line, the corresponding detection sensor will be triggered, and then the corresponding filament feeder can be started to drive the printing material along its axial direction. The filament feeder in the figure is only for illustration; any mechanism or solution that can drive the printing material to be fed along its axial direction is acceptable. When the printing material is fed to the inlet end of each switching mechanism in the material changing hub or the corresponding feed port of the material changing hub, the detection sensors installed at the inlet end of the corresponding switching mechanism or the corresponding feed port can be used to detect and determine whether the end of the printing material is located upstream of the corresponding switching mechanism, or at the inlet end of the corresponding switching mechanism, or at the corresponding feed port. Detection sensors can also be installed at the discharge port (such as 9a or 9b, etc.). When the end of the retracted printing material has been retracted past this point, the printing material from another feed port can start to be conveyed to this discharge port. The material detection sensor here can also be used to detect the conveying length of the printing material. Material detection sensors can also be installed at the inlet of the multi-inlet / one-outlet tube structure at the discharge port to determine when the end of the retracted printing material reaches that point, signifying that the printing material has passed through the discharge port. Additionally, feeders can be installed at the discharge ports (such as 9a and 9b), and these feeders can be configured with stronger feeding thrust to facilitate the easier delivery of the filament (filamentous printing material) through the long feed tube to the print head.

[0122] Each material source can provide filamentary printing materials, such as thermoplastic resins like PLA (polylactic acid), PP (polypropylen), PE (polyethylene), ABS (Acrylonitrile Butadiene Styrene), PA (Polyamide) (nylon), PC (Polycarbonate), PS (Polystyrene), PEI (Polyetherimide), PET (Poly(Ethylene Terephthalare)), PEEK (Polyetheretherketone), TPU (Thermoplastic polyurethanes), etc.; or materials of different colors, or elastic materials, such as thermoplastic elastomers (TPE), styrene-butadiene rubber (SBR), and styrene-butadiene rubber (SBS), etc.; or thermoplastic polyurethane (TPU) or thermoplastic vulcanizate (TPV); of course, it can also be thermosetting resins or photopolymerizable resins; or other flowable extruded materials. The filamentous material can also be continuous fiber printing material (or continuous fiber filament), fiber material, metal wire material (such as copper wire), optical fiber material, or other continuous linear material. It can also be resin-preimpregnated continuous fiber material, such as carbon fiber, glass fiber, polyester, aramid, ceramic fiber, boron fiber, or basalt fiber. For example, each material source can be a reel with filamentous printing material wound on it. When the filamentous printing material is fed out, the reel rotates synchronously. When the filamentous printing material is retracted, the reel can rotate synchronously in the opposite direction to rewind the retracted printing material onto the reel. The material source can also be in other forms, as long as it can provide printing material.

[0123] The discharge ports 9a and 9b are connected to the print head via a feeding pipeline, which may include two feeding pipes and a two-in-one-out connecting pipe 709. The discharge ports 9a and 9b are respectively connected to feeding pipes 72, and the two feeding pipes 72 are respectively connected to the two inlets of the two-in-one-out connecting pipe 709. The outlet end of the two-in-one-out connecting pipe 709 is connected to the feed input end of the print head. The two-in-one-out connecting pipe 709 can be fixedly installed on the print head, thus becoming part of the print head. The outlet of the two-in-one-out connecting pipe 709 is connected to the nozzle (extrusion port) of the print head. The print head may include a hot end 10. The printing material fed from the input end of the print head is conveyed to the nozzle 11 via the feeding pipe section and then extruded, for example, extruded onto the printing platform according to a preset printing path. After one layer is printed, the distance between the print head and the platform increases by a preset distance (such as layer thickness) before printing the next layer, thus stacking layers to form a three-dimensional model. Material detection sensors 74 can also be installed at the end of the feed tube 72 near the print head. These sensors detect whether the printing material in the feed tube 72 has been delivered to that location, for example, whether it has been delivered to the inlet of the multi-inlet-one-outlet connecting tube (two-inlet-one-outlet connecting tube) 709. The feed tube 72 can be made of elastic or flexible materials such as polytetrafluoroethylene or other plastics.

[0124] The material changing device can employ the aforementioned material changing hubs, and also includes a print head and several material sources. Each material source is connected to a feed port of the material changing hub, and the print head is connected to at least two discharge ports of the material changing hub via a feeding pipe. The print head may also include at least one hot end or nozzle for extruding printing material, and the material sources are used to supply printing material. Alternatively, two hot ends or nozzles can be provided on the same print head, with a corresponding feeding pipe provided for each hot end or nozzle. Each feeding pipe can also include two feeding pipes connected to the print head, supplying printing material to the two hot ends respectively. When the material changing device includes a material changing hub, the discharge port of the material changing device refers to the discharge port of the material changing hub; when the material changing device does not include a material changing hub, such as... Figure 2 The material changing device that supplies material to print head 1 is shown on the right side. The outlet port of the material changing device refers to the outlet of the multi-inlet-one-outlet connecting pipe 701.

[0125] The multiple feed ports of the material changing center are connected to the corresponding material sources, and the print head is connected to at least two discharge ports of the material changing center through the feeding pipeline.

[0126] The first printing material to be used by the printhead and its corresponding first material source are conveyed by the filament feeder of the first material source to the corresponding first feeding port of the material changing center or to the inlet end of the corresponding first switching mechanism of the material changing center. The corresponding first switching mechanism is controlled to connect the first feeding port with the first discharge port of the material changing center connected to the printhead, so that the first printing material is conveyed to the first discharge port. Under the action of the filament feeder of the first material source, the first printing material is conveyed to the printhead through the first discharge port along the first feeding path in the feeding pipeline, and the printhead performs printing.

[0127] During the printing process of the first printing material, the second printing material to be used next and its corresponding second material source are determined. Under the action of the filament feeder equipped with the second material source, the second printing material is transported to the corresponding second feeding port of the material changing center or to the inlet end of the corresponding second switching mechanism of the material changing center. The corresponding second switching mechanism is controlled to connect the second feeding port with the second discharge port in the material changing center that is connected to the print head, and the second printing material is transported to the second discharge port. Under the action of the filament feeder equipped with the second material source, the second printing material is transported through the second discharge port along the second feeding path in the feeding pipeline to a position near the intersection of the second feeding path and the first feeding path, ready for use.

[0128] After the printing process of the first printing material is completed, the first printing material is cut off at the notch (gap) on the print head or at a position downstream of the printing material conveying direction where the second feeding path intersects with the first feeding path. The first printing material is then pulled back to the position where the first feeding path intersects with the second feeding path in the feeding pipeline or back to a position that no longer obstructs the feeding path of the second printing material, so as to prevent the first printing material from obstructing the second printing material.

[0129] The second printing material is fed into the print head by the filament feeder of the second material source, and the print head prints the second printing material.

[0130] The printhead can be detachably mounted with a hot end, either via a first clamping mechanism or via screws or other fasteners.

[0131] The use of a material changing hub in the material changing device has significant advantages. For example, 1. Regardless of the number of types or quantities of printing media, as long as at least two outlet ports of the material changing hub are connected to a print head, free and rapid switching of any printing media can be achieved. For instance, the material changing hub can have two outlet ports, each connected to the same print head via flexible feeding pipes to supply material to the hot end of the print head. This can be achieved through a two-in-one-out connecting pipe, which greatly simplifies and lightens the print head structure, allowing for free switching between various printing media and improving printing speed and accuracy. Furthermore, the material cutting... The material switching process is fast. Through the material switching hub, a wider variety of printing materials can be converted into two or more output channels. The material switching hub allows each feed port to be connected to any output port simultaneously. It allows all printing materials connected to the feed ports to be transmitted in any combination with the output ports. One channel can be used for printing by the 3D print head, while the other channel can be used for standby. For example, the printing material to be used in the next step can be selected in advance from a large number of printing materials and switched to another channel in advance, realizing a faster printing material switching process. In addition, the two or more output ports are shared and symmetrical with all feed ports, and the switching process is free and flexible. Alternatively, 2. The feed ports of the feed changer can be connected to different printheads, enabling different printheads to share all feed sources and to transfer various combinations of feed materials to multiple printheads. Furthermore, it allows for free and rapid switching of any number of feed materials with only two printheads. Moreover, it allows one printhead to print while the other switches feed materials simultaneously, further improving printing speed or reducing printing time spent on feed material switching. For example, the feed changer has two feed ports, each connected to a separate printhead. By having the two printheads print alternately, with one printhead in printing mode and the other in feed material switching / standby mode, free and rapid switching of any number of feed materials and printing of any feed material can be achieved. Additionally, it can provide feed materials to printheads belonging to different printers, allowing different printers to share feed materials connected to the feed changer. This facilitates centralized feed material management, reduces feed material reuse when printing with multiple printers, and lowers costs. Alternatively, 3. It is easier to expand the types or quantities of printing materials. Since the printing materials to be switched have been pre-switched by the material switching center and delivered to the pipeline near the print head, such as being switched to the inlet of the two-in-one-out connecting pipe on the print head for later use, the distance between the material source (such as the material tray) and the print head has almost no impact on the printing material switching speed. Therefore, it is easier to place the material source as needed. For example, it can be placed in a space with more space far away from the print head, so that more material sources can be set up. Multiple material switching centers can also be connected in parallel to realize the connection of more material sources and use for switching.Alternatively, 4. The printing material switching process is easily automated and highly reliable. For example, the switching mechanism does not need to move the feeding pipe during printing material switching. The switching mechanism's body is simply moved (sliding) or rotated (turning) relative to the support body at the corresponding outlet positions via a power device (such as a motor, servo motor, or solenoid valve) to switch the printing material delivery line. The printing material switching process is fast, stable, and reliable. Furthermore, it facilitates modular design of each switching mechanism or material changing center, simplifying design and development, as well as maintenance and replacement. Alternatively, the flexible feeding pipe does not need to be moved during printing material switching, allowing for fast and reliable switching. Alternatively, the material changing center is small and compact, easily automatable. Alternatively, it is easier to expand the number of printing material delivery pipes because each switching mechanism is independent and does not interfere with each other, making it easier to increase the number of inlet ports.

[0132] It enables more thorough and faster replacement of printing materials. For example, the printing material on the print head can be switched using a material switching device with a material switching center and / or the hot end of the print head can be switched accordingly using a tool holder or other methods. This allows for rapid printing of the next material, with fast material switching speed and material saving.

[0133] A 3D printing system with material changing capabilities may also include a heat exchange end mechanism, wherein,

[0134] The heat exchanger mechanism may include a tool holder 50 for detachably mounting the heat exchanger, and the printhead and the tool holder may switch the heat exchanger between two states.

[0135] The feed changing device is used to connect to the print head and switch the printing material, or the feed changing device is used to connect to the print head and switch the printing material, and also to connect to the tool holder and switch the printing material.

[0136] The cutting mechanism is used to cut the printing material on the print head, or the cutting mechanism is used to cut the printing material on the print head and the printing material on the tool holder;

[0137] And / or,

[0138] The heat exchange end mechanism includes a clamping component movably connected to the print head or tool holder. The clamping component can be adjusted to clamp the heat end onto the print head or tool holder, and can also release the clamping of the heat end.

[0139] And / or, the heat exchange end mechanism includes a first defining structure such that the hot end is mounted to or removed from the print head in a direction generally perpendicular to or in the direction generally along the feed line of the hot end; the first defining structure includes a first clamping mechanism and / or a first positioning mechanism, the first clamping mechanism including a clamping element movably connected to the print head;

[0140] And / or,

[0141] The heat exchange end mechanism includes a gripping mechanism 33, which can be used to grip the hot end for installation on the print head or to remove the hot end from the print head; in addition, the gripping mechanism can be set on the tool head or tool seat, or the tool head or tool seat can also include a lever 58 (including an upper lever 582 or a lower lever 581), which can move the locking member on the print head or tool seat to open the locking member;

[0142] And / or,

[0143] The heat exchange end mechanism includes a lever 58 (including an upper lever 582 or a lower lever 581) and a clamping member movably connected to the print head. The clamping member is provided with a lever part. The clamping member can clamp the heat end to the print head by adjusting the lever part. The lever part can move the lever part on the clamping member to release the clamping of the heat end by adjusting the clamping member.

[0144] Replacing the hot end can solve the problems in existing technologies where a large amount of printing material remains in the nozzle or hot end of the printhead after replacing the filamentary printing material, requiring the residual printing material to be squeezed out before printing the next type of printing material, resulting in wasted printing material, increased printing time, and reduced printing efficiency. It can also solve the problem of slow color switching when using multiple nozzles on the printhead to print multiple materials or colors, which poses a significant challenge for accurate and fast printing that requires color jumps. Furthermore, it can solve the problems of system complexity, large size, low repeatability of nozzles in different printheads after replacement, poor bonding between parts printed by different printheads, and a significant impact on printing success rate when using printhead replacement to print multiple materials or colors.

[0145] In existing technologies, after replacing the filamentary printing material, a significant amount of printing material remains in the nozzles or hot end of the printhead. To avoid printing errors, this residual material in the hot end needs to be extruded, for example, into a waste area or a dedicated waste disposal unit, before printing the next material. This wastes a large amount of printing material and significantly increases printing time, reducing printing efficiency. By switching the hot end of the printhead, for example, ensuring that the printing material in the hot end is the same as that in the printhead, it is unnecessary to extrude the residual material in the hot end. Furthermore, automatic hot end switching between the printhead and the tool holder allows for faster switching, and the hot end is simpler in structure than the printhead. The positioning after switching is more precise, and the repeatability after switching the hot end is high, which improves printing accuracy and stability. This also solves the problem of difficulty in achieving accurate and rapid color transitions when using multiple nozzles on the printhead to print multiple materials or colors. It may also address the issues of system complexity, large size, and low repeatability of nozzle changes when switching printheads, which significantly impacts printing success rates.

[0146] Example 12, Figure 1a , Figures 2 to 4 , Figure 6a and Figure 7 As illustrated, a 3D printing system with material changing capabilities may also include a tool holder 50, on which the hot end 10 can be detachably mounted. The print head 1 and the tool holder 50 can switch the hot end 10 between them; that is, the hot end 10 can be switched from being mounted on the print head 1 to being mounted on the tool holder 50, or vice versa. Figure 2 and Figure 7 The diagram illustrates the state where the hot end 10 is installed on the printhead 1. Hot ends 10 are also installed on tool holders 50a, 50b, and 50c, while tool holder 50d is idle and has no hot end 10 installed. The feed changing device can also be connected to the tool holder 50 to switch printing materials, where switching refers to replacing the first printing material delivered to the tool holder with a second printing material. The cutting mechanism 59 can also be used to cut the printing material on the tool holder 50. The first printing material delivered to the tool holder 50 is cut by the cutting mechanism 59, and then the feed changing device switches the second printing material to the tool holder 50. The feed changing device can also be connected to the tool holder via a feeding pipe to deliver printing material to the tool holder and can also be used to switch printing materials on the tool holder.

[0147] The material changing device can also be used to switch the printing material on the tool holder, such as... Figure 2 , Figure 3 , Figure 4 or Figure 7 As shown. For example Figure 2The schematic diagram shows that the material changing hub 900 has four discharge ports, each of which is connected to a corresponding tool holder via a feeding pipe 72. Figure 3 The schematic diagram shows that the material changing hub 900a has three discharge ports, each connected to a corresponding tool holder via a feeding pipe 72. The switching hub allows for the switching of the printing material connected to the tool holder. Additionally, Figure 4 and Figure 7 It also shows that the material changing center 900 can be connected to the print head and the tool set at the same time. Figure 4 The discharge ports 901 and 902 of the medium-combination material changing hub 9000 are connected to tool groups 50A and 50B respectively through the feeding pipe 72, while the discharge ports 903 and 904 are connected to the print head 1 respectively through the feeding pipe 72. Figure 7 The feed ports 9a, 9b, and 9c of the feed changer hub 900d are connected to the print head via feed lines, while feed port 9d is connected to the tool holder 50a via a feed line. This allows all feed sources to be shared between the print head and the tool holder through switching. Figure 1a , Figures 2 to 6a , Figure 7 and Figure 8 Any of the feed change centers can be used to switch the printhead and tool holder for the same printhead, and the printhead and tool holder can alternately share the same printhead by switching.

[0148] The cutting mechanism 59 is also used to cut the printing material on the tool holder, for example... Figure 2 A cutting blade can be installed at the corresponding position of each tool holder to cut the printing material on each tool holder. A feeding pipe can also be connected to each tool holder to deliver the printing material to the hot end of the tool holder. When it is necessary to switch the hot end, the printing material connected to the tool holder or the hot end can be cut by the cutting mechanism.

[0149] The heat dissipation surface of the heat dissipation section 14 at the hot end can also be used to contact the heat dissipation surface of the heat dissipation fins on the tool holder (e.g., through thermal grease or a thermal pad) to conduct heat from the heat dissipation section at the hot end to the heat dissipation fins on the tool holder for heat dissipation. When the hot end is installed on the tool holder, the tool holder can be equipped with a heating element 51 to heat the heating section. The positioning structure or positioning element on the tool holder can also match and position with the first positioning feature 153 on the hot end.

[0150] Example 13: The 3D printing system with material changing function may further include a tool holder. For example, at least two tool holders may be provided, and when the print head is provided with a hot end, at least one of the tool holders may not have a hot end. The print head and the tool holders are movable relative to each other, allowing the hot end on the print head to be switched onto the tool holder, and vice versa. The switching of the printing material and the switching of the hot end of the print head and / or tool holder can be performed in parallel, serially, or partially in parallel. Specifically, as shown in the figure... Figure 14b , Figure 14p and Figure 15 As shown, the hot end 10 can be mounted onto or removed from the print head 1 along a first direction. The hot end 10 mounted on the print head 1 is limited along a second direction, wherein the second direction is angled to the first direction, for example, the first direction and the second direction are perpendicular to each other. Figure 14b As shown, the first direction is the Y-axis direction, and the second direction is the X-axis direction. Figure 15 The diagram illustrates that the first and second directions are angled together. The hot end 10 can be mounted onto or removed from the tool holder 50 along the second direction. The hot end mounted on the tool holder 50 is limited along the first direction. The print head 1 and the tool holder 50 can move relative to each other, allowing the hot end 10 on the print head 1 to be switched onto the tool holder 50, and vice versa. The first direction and the second direction can be interchanged; for example, the first direction can be the X-axis and the second direction the Y-axis, depending on the spatial arrangement of the tool holder and print head. The first direction also includes a first positive direction and a first negative direction, which are opposite in direction. The second direction also includes a second positive direction and a second negative direction, which are also opposite in direction.

[0151] The number of tool holders 50 can be multiple (which can also be understood as multiple hot ends being installed on a single tool holder). These tool holders 50 (from the perspective of installing hot ends, this can also be understood as the position or structure of the hot ends on the tool holder) can be arranged along a second direction or a direction perpendicular to the first direction. One of the tool holders (the position or structure of the hot end on the tool holder) or the print head may not have a hot end installed. That is, when a hot end is installed on the print head, at least one of the tool holders may not have a hot end installed, i.e., it may be in an idle state. When no hot end is installed on the print head, all of the tool holders may have hot ends installed, or some may be in an idle state. The specific number of tool holders 50 can be determined by the amount of printing material that needs to be replaced on the print head 1, the size of the 3D printer frame, or other factors or application requirements. The number of print heads can also be multiple. For example, multiple print heads can be arranged parallel to the second direction or perpendicular to the first direction. These multiple print heads can move independently or be interconnected as a single structure.

[0152] For example, a tool holder assembly may include a first tool holder and a second tool holder, wherein the first tool holder has a first hot end mounted on it, and the second tool holder is idle; the print head and the tool holder are movable relative to each other; when the print head and the first tool holder move relative to each other to a corresponding switching position, the hot end on the first tool holder is switched to the print head; when the print head and the second tool holder move relative to each other to a corresponding switching position, the hot end on the print head can be switched to the second tool holder. A detection sensor may also be provided on the tool holder to detect whether the hot end is mounted on the tool holder.

[0153] like Figure 14b and Figure 15 As shown, each tool holder 50 has a first switching position A and a second switching position C. The print head 1 can move relative to the tool holder 50 to either the first switching position A or the second switching position C. If the print head 1 moves to the first switching position A and then the print head 1 and the corresponding tool holder begin to move relative to each other, the hot end can be switched and installed onto the tool holder 50. If the print head 1 moves to the second switching position C and then the print head 1 and the corresponding tool holder begin to move relative to each other, the hot end on the tool holder 50 can be switched and installed onto the print head 1. It should be noted that the first switching position A and the second switching position C can be interchanged. That is, if the print head 1 moves to the second switching position C and then the print head 1 and the corresponding tool holder begin to move relative to each other, the hot end can be switched and installed onto the tool holder 50. If the print head 1 moves to the first switching position A and then the print head 1 and the corresponding tool holder begin to move relative to each other, the hot end on the tool holder 50 (e.g., 50A) can be switched and installed onto the print head 1. For example, ... Figure 14b The tool holder on the left side of the middle is mirrored vertically.

[0154] like Figure 14b As shown, when the hot end 10 on the printhead 1 is switched and installed on the tool holder 50, the printhead 1 and the tool holder 50 move relative to each other, causing the printhead 1 to sequentially pass through the first switching position A, the relay position T, the corresponding hot end installation position B on the tool holder 50A, and the second switching position C of the tool holder 50A, thereby completing the switch of the hot end on the printhead 1 to the tool holder 50A; or, the printhead 1 and the tool holder 50 move relative to each other, causing the tool holder 50A to sequentially pass through the first switching position AA, the relay position TT, the corresponding hot end installation position BB on the printhead, and the second switching position CC of the printhead 1, thereby completing the switch of the hot end on the printhead 1 to the tool holder 50A. When switching the hot end on the tool holder to the print head, the print head and tool holder move relative to each other, causing the print head 1 to sequentially pass through the second switching position C of the tool holder 50A, the corresponding hot end mounting position B on the tool holder 50A, the relay position T, and the first switching position A of the tool holder 50A, thus completing the switching of the hot end on the tool holder 50A to the print head 1; or, the print head and tool holder move relative to each other, causing the tool holder 50A to sequentially pass through the second switching position CC of the print head, the corresponding hot end mounting position BB on the print head 1, the relay position TT, and the first switching position AA of the print head, thus completing the switching of the hot end on the tool holder 50A to the print head 1. For example, specifically... Figure 14b As shown, the print head 1 and the tool holder 50A move relative to each other, causing the print head 1 to move relative to the tool holder 50A from its first switching position A along a first direction that is relatively close to the tool holder 50A, and then relative to the tool holder 50A along a second direction that is relatively close to the mounting position B of the corresponding hot end 10 on the tool holder 50A, until it reaches the mounting position B of the corresponding hot end 10 on the tool holder 50A. Then, it moves relative to the tool holder 50A along a first direction that is relatively away from the tool holder 50A until it reaches the second switching position C of the tool holder 50A, thus realizing the switching and mounting of the hot end 10 on the print head 1 onto the tool holder 50A. The printhead 1 and the tool holder 50A move relative to each other, causing the printhead 1 to move relative to the tool holder 50A from the second switching position C along the first direction relative to the tool holder 50A, to the mounting position B of the corresponding hot end 10 on the tool holder 50A, and then move relative to the tool holder 50A from the second direction relative to the mounting position B of the corresponding hot end 10 on the tool holder 50A, and then move relative to the tool holder 50A from the first direction relative to the tool holder 50A to the first switching position A, so that the hot end 10 on the tool holder 50A is switched and installed on the printhead 1. Figure 14b Tool holder 50A in the middle can be regarded as Figure 14a , Figures 14c to 14L Tool holder 50.

[0155] like Figure 14pAs shown, the left side contains printheads 1A and 1B, and the right side contains tool holder 50. Figure 14p Position AA is the first switching position of printhead 1A, and position CC is the second switching position of printhead 1A. If tool holder 50 reaches the first switching position AA of printhead 1A (which can be achieved by moving printhead 1A and / or tool holder 50), then printhead 1A and tool holder 50 move relative to each other (which can be achieved by moving printhead 1A and / or tool holder 50) so that tool holder 50 reaches the position BB on printhead 1A corresponding to the position where the hot end is installed, or first passes through the intermediate position TT of the printhead and then reaches the position BB on the corresponding printhead where the hot end is installed, and then moves from position BB to position CC to realize the transfer of hot end 10 from tool holder 50 to position CC. 0. Switch to printhead 1A; if printhead 1A has a hot end 10 but tool holder 50 does not, tool holder 50 can first reach the second switching position CC of printhead 1 (achieved by moving printhead 1A and / or tool holder 50), then printhead 1A and tool holder 50 move relative to each other (achieved by moving printhead 1A and / or tool holder 50) so that tool holder 50 reaches the position BB on printhead 1A corresponding to the installation of the hot end, and then moves from position BB to position AA, or from position BB to position TT and then to position AA, thereby switching the hot end 10 from printhead 1A to tool holder 50. Additionally, by... Figure 14p It can also be seen that when printhead 1A reaches the first switching position A of tool holder 50, it is equivalent to tool holder 50 reaching the first switching position AA of printhead 1A. Similarly, when printhead 1A reaches the second switching position C of tool holder 50, it is equivalent to tool holder 50 reaching the second switching position CC of printhead 1A. The position B of the hot end of tool holder 50 corresponds to the position BB of tool holder 50 reaching the hot end of printhead 1A. The relay position T of printhead 1A reaching tool holder 50 corresponds to the relay position TT of tool holder 50 reaching printhead 1A. The tool holder can also be slidably set along the navigation, or the tool holder can also move on the corresponding plane (such as the XY plane or YZ plane). A filament feeder or feeding line can also be set on the tool holder. For example, the filament feeder can be used to transfer the printing material in the feeding line to the hot end in the tool holder, extruding the residual printing material in the hot end and replacing it with the printing material in the feeding line, so that the printing material in the hot end is the printing material to be used in the next step when switching the hot end with the printhead. The tool holder can be configured with multiple hot ends, or multiple hot ends can be installed on a single tool holder assembly. Similarly, the printhead can also be configured with multiple hot ends, or multiple hot ends can be installed on a single printhead. Furthermore, the first and second directions are opposite to each other, meaning they can be interchanged. Figure 14p The printhead 1A in the figure can be regarded as the printhead 1 in other figures.

[0156] Figure 12a It can be regarded as Figures 14a to 14c and Figure 14eThe diagram shows a three-dimensional structure of the print head 1 in the 3D printing system. Figure 13a and Figure 13b It can be regarded as Figures 14a to 14c and Figure 14e A three-dimensional structural diagram of the tool holder 50 of the 3D printing system shown. Figure 12b It can be regarded as Figures 14a to 14c and Figure 14e A three-dimensional structural diagram of the hot end 10 of the 3D printing system shown.

[0157] based on Figure 14b For example, Figure 14c and Figure 14e ,as well as Figure 14d and Figure 14L This illustrates the state of printhead 1 in the first switching position A of tool holder 50 (or 50A in 14b). When the hot end 10 is switched from printhead 1 to tool holder 50, printhead 1 and tool holder 50 move relative to each other, causing printhead 1 to move from the first switching position A to the relay position T, as shown below. Figure 14f and Figure 14g As shown, at this time, the hot end 10 on the print head 1 pushes the second heating element 51 (second clamping mechanism) to move the second heating element 51 along the first direction and compress the third elastic element 541; then the print head moves from the relay position T to the mounting position B of the corresponding hot end on the tool holder, as shown. Figure 14h and Figure 14i As shown, the limiting mechanism (such as the limiting member 53) on the tool holder limits the hot end 10; then the print head moves from position B to the second switching position C, as shown. Figure 14j and Figure 14k As shown, the hot end 10 remains on the tool holder 50, and the second heating element 51 is reset under the action of the third elastic element 541. The second heating element 51 is in contact with the first heating surface 151 of the heating block 15 of the hot end 10. Figure 14m to Figure 14o This illustrates printhead 1 after the hot end 10 has been removed. Conversely, when the hot end 10 is switched from the tool holder 50 to the printhead 1, the printhead 1 and the tool holder 50 move relative to each other, causing the printhead 1 to move from the second switching position C to the corresponding hot end mounting position B on the tool holder, as shown below. Figure 14h and Figure 14i As shown, the first clamping mechanism is clamped and matched with the hot end 10. For example, the first swinging pressure rod 31 is clamped onto the heating section of the hot end 10, the upper pressure member 41 is clamped onto the heat dissipation section of the hot end 10, the tool seat heating member 51 can be pushed open, and the second heat dissipation fin 52 may be pushed open. Of course, the positioning features on the hot end 10 can also be matched and combined with the positioning part on the print head. Then the print head moves from the mounting position B on the tool seat corresponding to the hot end to the relay position T, such as... Figure 14f and Figure 14gAs shown, the positioning hole 155 of the hot end 10 disengages from the positioning member 53 of the tool holder, and the print head 1 moves from the relay position T to the first switching position A, as... Figure 14c and Figure 14e as well as Figure 14d As shown, the hot end 10 is detached from the tool holder and attached to the print head 1.

[0158] The size or diameter of the extrusion port of each of the switching hot ends may be different, the shape of the extrusion port of the hot ends may be different, the material of the hot ends or the extrusion port may be different, or the structure of each hot end may be different.

[0159] Example 14, as Figure 2 As shown, the tool holder 50 is equipped with a gripping mechanism 33, which is used to grip the hot end 10 and move it towards the print head 1 or the tool holder 50, so as to complete the switching of the hot end 10 from the print head 1 to the tool holder 50 or from the tool holder 50 to the print head 1. For example Figure 2 The diagram shows four tool holders, namely 50a, 50b, 50c and 50d. Each tool holder can also be equipped with a gripping mechanism 33, which can be used to grip the hot end and move it between the print head and the tool holder.

[0160] Furthermore, such as Figure 9a and Figure 9b , Figures 10a to 10c As shown, the gripping mechanism 33 on the tool holder can be telescopically adjusted relative to the tool holder 50. For example, the gripping mechanism 33 can be telescopically adjusted relative to the body of the tool holder 50d along the Y-axis direction. Figure 9a The tool holder 50d in the middle does not have a hot end, and the gripping mechanism 33 is in the retracted state. The gripping mechanism 33 includes a pair of clamping members with an adjustable clamping distance. By adjusting the clamping distance, the pair of clamping members can clamp the corresponding hot end. The tool holder can also be provided with a positioning member 53 and a tool holder lower clamping mechanism 532. The positioning member 53 can be used to position the hot end installed on the tool holder, and the lower clamping mechanism 532 is used to fix the hot end to the tool holder. A tool holder heating member 51 can be provided to heat the hot end installed on the tool holder. Specifically, the lower clamping mechanism 532 of the tool holder 50d (the specific structure of the lower clamping mechanism will be described in subsequent embodiments) is in the open state. When the print head 1 moves to the corresponding switching position of the tool holder 50d, the lower clamping mechanism 30 of the print head 1 releases the clamping of the hot end 10, and the gripping mechanism 33 on the tool holder 50d extends to clamp the hot end 10 on the print head 1 through the clamping members and then moves it towards the tool holder 50d. Figure 9b This illustrates the mid-movement state. When the hot end 10 moves onto the tool holder 50d, the first positioning feature 153 on the hot end 10 can be matched and positioned with the positioning element 53 on the tool holder 50d.

[0161] Or, such as Figures 10a to 10c As shown, the gripping mechanism 33 on the tool holder 50 is telescopically adjustable relative to the tool holder 50. The gripping mechanism 33 includes a clamping member that can rotate around a rotation axis. The clamping member is connected to a driving mechanism, which can drive the clamping member to rotate around the rotation axis to clamp or release the corresponding hot end; and / or, the gripping mechanism 33 on the tool holder 50 includes a pair of clamping members. The end of the clamping member near the hot end is provided with a gripping head, and the hot end is provided with a groove corresponding to the gripping head. Specifically, the lever 58 provided on the tool holder can be inserted into the lever 39, thereby levering the lower clamping mechanism 30 outwards to expose the hot end 10. At the same time, the extended gripping mechanism 33 can clamp the hot end 10. Figure 10b As shown, the gripping mechanism 33 includes two swing arms that can rotate around their respective corresponding pivots 331. A driving mechanism, such as an electromagnetic coil 332 (or any other structure capable of driving the two swing arms to swing), can be provided on the side of the pivots 331 away from the print head to drive the two swing arms to swing around their respective pivots. For example, when the electromagnetic coil 332 drives the connection points of the two swing arms to move away from each other, the gripping heads of the gripping hot ends on the side of the pivots relative to their respective pivots closer to the print head can move closer to each other, clamping the heating block of the hot end, thereby clamping the hot end. For example, grooves can also be provided on the left and right sides of the heating block of the hot end so that the gripping heads can be embedded therein to reliably grip the hot end. Then, the pusher 58 and the gripping mechanism 33 retract towards the tool seat, gripping the hot end 10 and moving it away from the print head 1. At the same time, since the pusher 58 has left the pusher part 39 on the lower clamping mechanism 30, the plate of the lower clamping mechanism 30 returns to the opposite moving clamping state under the action of the reset elastic member 305. Figure 10c This illustrates the mid-process state of the hot end being grasped and moved by the grasping mechanism 33.

[0162] Alternatively, the tool holder 50 may also be equipped with an upper gripping mechanism 33a for gripping the heat dissipation section at the hot end; such as Figure 10aAs shown, a gripping mechanism 33a can also be provided on the tool holder to grip the heat dissipation section of the hot end 10. For example, similar to the gripping mechanism 33, two swinging pairs that can swing around their respective axes can be set to clamp the tubular heat dissipation section, making the switching process of the hot end 10 more stable. If each tool holder is equipped with a gripping mechanism 33 (or even further, each with an upper gripping mechanism 33a), then after the gripping mechanism 33 grips and moves the hot end 10 to the tool holder, the gripping mechanism 33 can be used as a clamping mechanism for the hot end on the tool holder. That is, the gripping mechanism 33 can keep the hot end 10 on the tool holder in a clamped state at all times, for example, always clamping the heating section of the hot end, and can also forcefully make the heating surface (first heating surface) of the heating section abut against the laterally open heating surface (third heating surface) of the heating element 51 on the tool holder. Furthermore, the upper gripping mechanism 33a also always clamps the heat dissipation section of the hot end, and can also forcefully make the heat dissipation surface of the heating section abut against the heat dissipation surface of the heat dissipation fins 22 on the tool holder. Of course, the hot end 10 can also cooperate with the positioning element 53 on the tool holder for positioning. An upper clamping mechanism 40 can also be provided, and similarly, an upper actuating part 39a can be provided to facilitate the actuation of the upper actuating element 582.

[0163] In this embodiment, the gripping mechanism 33 can be extended or retracted relative to the tool holder 50 by a drive mechanism mounted on the tool holder 50. This drive mechanism can be a drive cylinder, pneumatic cylinder, hydraulic cylinder, lead screw, or synchronous belt mechanism, etc., and can also be guided by a guide rail, enabling the gripping mechanism 33 to extend or retract relative to the tool holder 50. Additionally, the lever 58 can be an upper lever 582 and / or a lower lever 581.

[0164] Example 15, as follows Figures 11a to 11g As shown, another hot-end switching structure is illustrated, in which... Figures 11a to 11d The switching structure is displayed in three dimensions from different angles and states. The 3D printing system of the present invention also includes a tool head 6a that can move along a second guide rail 81b. The second guide rail 81b is arranged along the arrangement direction of the tool holders 50. The tool head 6a can move to the corresponding position of each tool holder 50. The tool head 6a includes a gripping mechanism 33, which is used to grip the hot end 10 and move the hot end 10 towards the print head 1 or the tool holder 50 to complete the switching of the hot end from the print head to the tool holder or from the tool holder to the print head.

[0165] The tool holder assembly 50 includes multiple tool holders, such as seven tool holders shown in the figure. These tool holders are arranged parallel to the X-axis or the guide rail 81b. Assuming each tool holder has the same structure, the tool holder assembly 50 also includes a tool head 6a, which can move along the guide rail 81b, allowing the tool head 6a to reach the corresponding position on each tool holder. Figure 11bThe diagram shows that tool head 6a is located at the corresponding position of the third tool holder from the left, and this tool holder does not have a hot end 10, while all other tool holders have a hot end 10. Meanwhile, Figure 11b The diagram shows that printhead 1 is located on the side of the tool holder away from toolhead 6a, and is also located at the corresponding switching position of the tool holder.

[0166] Or, such as Figures 11a to 11g As shown, the gripping mechanism 33 on the tool head 6a is telescopically adjustable relative to the tool holder. The gripping mechanism 33 on the tool head 6a includes a rotatable long rod structure. The end of the long rod structure has a transverse protrusion 333 perpendicular to the direction of the long rod structure. Correspondingly, as... Figure 11f and Figure 11g As shown, two elongated holes 157 and a transverse hole 156 are also correspondingly provided on the hot end 10. The pressing step 158 can be positioned between the two elongated holes 157. Ideally, the axis of the elongated hole 157 of the hot end 10 is perpendicular to the axis of the feeding pipe of the hot end. The feeding pipe of the hot end is located on the side away from the elongated hole 157 or away from the pressing step 158 relative to the transverse hole 156. This structure is more conducive to concentrating the structures related to gripping or clamping on one side of the feeding pipe, which is beneficial to simplifying the structure of the hot end and reducing its size. The hot end 10 is provided with an elongated hole 157 facing the tool holder 50 and a transverse hole 156 perpendicular to the axis of the elongated hole 157. The transverse hole 156 is connected to the elongated hole 157. The long rod structure can extend into the elongated hole 157. Then, by rotating the long rod structure, the transverse convex structure 333 extends into the transverse hole 156, thereby clamping the hot end 10. Specifically, when the axis of the transverse convex structure 333 of the gripping mechanism 33 is approximately parallel to the long axis of the elongated hole 157, the transverse convex structure 333 of the gripping mechanism 33 can penetrate into the elongated hole 157. When it reaches the transverse hole 156, the long rod part of the gripping mechanism 33 drives the transverse convex structure 333 to rotate. If it rotates 90 degrees, the transverse convex part 333 penetrates into the transverse hole 156 and clamps the hot end.

[0167] Or, such as Figures 11a to 11gAs shown, the gripping mechanism 33 on the tool head 6a includes a rotatable long rod structure and an actuator 641 drivenly connected to the long rod structure. The actuator 641 drives the long rod structure to rotate. The end of the long rod structure is provided with a transverse protrusion 333 perpendicular to the direction of the long rod structure. The hot end 10 is provided with an elongated hole 157 facing the tool seat 50 and a transverse hole 156 perpendicular to the axis of the elongated hole 157. The transverse hole 156 communicates with the elongated hole 157, and the long rod structure can extend into the elongated hole 157, thereby rotating. The long rod structure allows the transverse convex structure 333 to extend into the transverse hole 156, thus clamping the hot end 10. For example, the output shaft of the actuator 641 drives a gear, which in turn drives a gear fixed to the gripping mechanism 33, causing the gripping mechanism 33 to rotate. Ideally, two gripping mechanisms 33 can be provided, with both gripping mechanisms 33 simultaneously clamping the hot end 10. This ensures that the hot end 10 is reliably and stably clamped and reduces the force on the print head during the gripping mechanism 33's grasping or releasing of the hot end. For example... Figure 11e The gear on the output shaft of the actuator 641 simultaneously drives the gears on the two gripping mechanisms 33 to rotate, and the rotation directions of the two gripping mechanisms 33 can be the same or opposite.

[0168] Alternatively, the gripping mechanism on the tool head includes a pair of grippers with an adjustable clamping distance, which can be adjusted to clamp the corresponding hot ends; the gripping mechanism 33 on the tool head 6a can also be... Figure 9a , 9b The gripping mechanism shown.

[0169] Alternatively, the gripping mechanism on the tool head includes a pair of clamping members, each of which can rotate about its own rotation axis. A drive mechanism connects the pair of clamping members, which drives them to rotate about their respective rotation axes, thereby clamping or releasing the corresponding hot end. The gripping mechanism 33 on the tool head 6a can also employ... Figures 10a to 10c The gripping mechanism shown.

[0170] Or, such as Figures 11a to 11gAs shown, the tool head 6a also includes a lever 58, which is a long rod structure with a lever structure 583 at its end. For example, the lever structure 583 can be a flat plate-like structure similar to the end of a screwdriver, or it can be other shapes, as long as it can rotate the lower clamping mechanism 30 and / or the upper clamping mechanism 40 on the print head. The first clamping mechanism of the print head (the lower clamping mechanism 30) is provided with a lever part 39 that matches the lever structure 583. When the lever structure 583 matches the lever part 39 (for example, in the figure, the lever structure 583 can extend into the groove-shaped lever part 39), it can drive the first clamping mechanism to rotate, thereby clamping or releasing the hot end of the print head. Of course, the lever part 39 can also be other shapes, such as a protruding structure, while the lever structure 582 can be a corresponding matching groove structure.

[0171] Or, such as Figures 11a to 11g As shown, the tool head 6a also includes a lever 58, which is a long rod structure. The tool head 6a also includes an actuator 642 that is driven to connect with the long rod structure. The actuator 642 is used to drive the long rod structure to rotate.

[0172] Or, such as Figure 11e As shown, the tool head 6a also includes two levers 58. One lever is used to open or close the lower clamping mechanism 30 of the print head, and the other lever is used to open or close the upper clamping mechanism 40 of the print head. The two levers 58 can be driven simultaneously by an actuator 642; for example, they can be driven to rotate separately through gear transmission. The tool head also includes levers and a tool head base. The gripping mechanism and levers can both be mounted on the tool head base. The tool head base can move along the first guide rail connected to the tool head, driving the gripping mechanism and levers to move together for telescopic adjustment.

[0173] The aforementioned gripping mechanism 33 and lever 58 can be mounted on the tool head base 65. For example, drive mechanisms 641 and 642 can be fixedly connected to the tool head base 65, and the gripping mechanism 33 and lever 58 can rotate relative to the tool head base 65. The tool head base 65 can move along the first guide rail 81a, driving drive mechanisms 641 and 642, gripping mechanism 33, and lever 58 to move together along the first guide rail 81a. For example, the tool head base 65 can be driven by a lead screw 66 to move along the guide rail 81a to achieve telescopic adjustment. The lead screw 66 is rotated by an actuator 643, and the actuator 643 can be fixedly connected to the guide rail 81a. Figure 11a For ease of display, the tool head base 65 of the tool head 6a is shown as transparent.

[0174] The dial 58 on tool head 6a can also be 10a to Figure 10cThe actuator 642 of the dial 58 shown may be omitted in this case, allowing the dial 58 to be fixedly connected to the tool head base 65. Alternatively, the dial 58 on the tool head 6a can also be used for tossing (rotation). Figure 9a The lower clamping mechanism 30 shown, for example, in the lower clamping mechanism 30 shown in 9a, has a connecting structure that matches the lever 58, allowing the end of the lever 58 to engage with this connecting structure to rotate the lower clamping mechanism 30. If the heat dissipation section on the hot end 10 is provided with heat dissipation fins, the upper clamping mechanism 40 on the print head, the lever 58 above the tool head, etc., may be omitted. Ideally, the moving direction of the gripping mechanism 33 is perpendicular to the Z-axis, or perpendicular to the axis of the feed pipe of the hot end, or perpendicular to the normal to the surface of the printing platform. The error is less than ±40°. Alternatively, the moving direction (extension adjustment direction) of the gripping mechanism 33 can be set at an angle to the Z-axis. This allows the gripping mechanism 33 to move away from the print head when the gripping hot end moves away from the print head, and conversely, to move closer to the print head when the gripping mechanism 33 moves closer to the print platform. For example, when the gripping mechanism 33 is installed on the print head, the Z-axis height of the hot end is exactly at the preset state.

[0175] Combination Figures 11a to 11dThe first guide rail 81a can move along the second guide rail 81b, thereby driving the gripping mechanism 33 and the lever 58 on the tool head to move to the corresponding position of the corresponding tool seat. The first guide rail 81a and the second guide rail 81b are preferably set perpendicularly. For example, the second guide rail 81b can be set along the X-axis and the first guide rail 81a can be set along the Y-axis. To move the hot end from the tool holder to the print head, the first guide rail 81a carries the entire tool head 6 along the second guide rail 81b to the corresponding position on the target tool holder. The print head 1 also moves to the corresponding switching position on the tool holder. Then, the tool head base 65 moves along the first guide rail 81a toward the hot end on the tool holder. The gripping mechanism 33 clamps the hot end; for example, the transverse protrusion 333 of the gripping mechanism 33 is inserted into the elongated hole 157 of the hot end and, after rotation, is locked onto the transverse surface of the transverse hole 156. Then, the tool head base 65 moves along the first guide rail 81a toward the print head (extension adjustment), carrying the hot end with it. At the same time, the lever 58 is also carried along. Moving towards the print head, since there is no hot end on the print head, the lower clamping mechanism 30 on the print head is currently in the open state, and the upper clamping mechanism 40 is also in the open state. The hot end is carried and installed onto the print head by the gripping mechanism of the tool holder. The first positioning feature on the hot end cooperates with the positioning structure on the print head for positioning. At the same time, the lever 58 is also connected to the lower clamping mechanism 30, and can also be connected to the upper clamping mechanism 40. Then, the lever 58 rotates to move the lower clamping mechanism 30 to clamp the heating block of the hot end onto the print head. The upper lever 58 can also be rotated to move the upper clamping mechanism 40 to press the heat dissipation section of the hot end against the side-open heat dissipation surface on the heat dissipation fin 22. Then the gripping mechanism 33 releases its clamping state from the hot end. For example, the gripping mechanism 33 rotates so that the transverse convex structure 333 aligns with the long axis of the elongated hole 157, causing the gripping mechanism 33 to release its clamping state from the hot end. Then the tool head base 65 moves back along the guide rail 81a, causing the gripping mechanism 33 and the pusher 58 to move away from the print head and return to the side of the tool seat away from the print head. In this way, the tool head 6a can move along the second guide rail 81b to the corresponding position of other tool seats.

[0176] If the hot end switches from the printhead to the tool holder, the printhead moves to the corresponding switching position on the right-hand tool holder, and the tool head 6a also moves along the second guide rail 81b to the corresponding position on the tool holder. The tool head base 65 moves along the first guide rail 81a towards the printhead until the gripping mechanism 33 clamps the hot end on the printhead. For example, the transverse convex structure 333 of the gripping mechanism extends into the elongated hole of the hot end, and then rotates approximately 90 degrees so that the transverse convex structure 333 is locked onto the stepped surface within the transverse hole 156. The lever 58 also engages with the lower or upper clamping mechanism on the printhead. Then, the lever 58 opens the lower clamping mechanism, for example, by rotating the lower clamping mechanism 30 to release the heating block of the hot end. Similarly, the upper lever 58 can also move the upper clamping mechanism 40 so that the upper clamping mechanism 40 contacts the heat source. The heat dissipation section of the end is locked. Then, the tool head base 56 moves back away from the print head along the first guide rail 81a. The gripping mechanism 33 carries the hot end 10 away from the print head and moves towards the tool seat. The heating block 15 pushes open the elastic clip structure 543 until it is installed on the corresponding tool seat and is pressed by the elastic clip structure 543 to make the heating block of the heating block abut against the heating surface on the tool seat. At the same time, the first positioning feature on the heating block also cooperates with the positioning structure on the tool seat to form a positioning, restricting the up and down movement of the hot end. Then, the gripping mechanism 33 releases the gripping state of the hot end. For example, the gripping mechanism 33 rotates so that the transverse convex structure 333 corresponds to the long axis of the elongated hole 157, releasing the gripping state of the hot end. Then, the tool head 6 continues to move back away from the hot end along the guide rail 81a until it moves to the side of the tool seat away from the print head.

[0177] Alternatively, the tool holder and tool head can also move along the Z-axis or along the direction in which the print head extrudes the printing material;

[0178] Alternatively, it may include two tool heads, namely a first tool head (such as tool head 6a) and a second tool head (such as tool head 6b). When the first tool head switches the hot end of the print head to the first tool seat, the second tool head can move to the corresponding position of the second tool seat. When the print head moves to the second tool seat, the second tool head can be used to switch the hot end on the second tool seat to the print head.

[0179] Alternatively, it may include two tool heads, each tool holder including a tool holder base and a first guide rail (such as guide rail 81a), the tool holder base being movable along the first guide rail, and the drive mechanisms of the two tool heads for driving the tool holder base to move along the first guide rail being respectively arranged on opposite sides of their respective gripping mechanisms.

[0180] To expedite the automatic switching process of the hot end, an additional toolhead 6b can be added, such as... Figures 11a to 11bAs shown, tool head 6b has the same function as tool head 6a and can also move along guide rail 81b. Thus, while tool head 6a is switching the hot end from the print head to the tool holder, tool head 6b can first move to the corresponding position of the tool holder where the next hot end will be used, allowing the gripping mechanism 33 on tool head 6b to hold the next hot end in place, waiting for the print head to come and perform the hot end switching. This improves the switching speed. Ideally, tool head 6b and tool head 6a have a mirror-symmetric structure, meaning that the gripping mechanism 33 or lever 58 on tool head 6a and the gripping mechanism 33 or lever 58 on tool head 6b are both located on the side closer to each other, while the driving mechanism that drives the tool head base 65 to move along the guide rail 81a, such as the lead screw 66 and the corresponding actuator 643, are located on the side further away from each other. This allows the gripping mechanism or lever of tool head 6b and tool head 6a to be as close to each other as possible, which is beneficial for arranging tool holders close to each other. More tool holders can be set in certain length ranges, which is beneficial for installing more hot ends and realizing more hot end switching.

[0181] Alternatively, the tool head includes a tool head base that can move (telescopically adjust) along a first guide rail 81a. The first guide rail can move along a second guide rail (guide rail 81b), which is connected to a fourth guide rail 81 on which the print head slides. Alternatively, the second guide rail can move along a third guide rail, which is connected to the fourth guide rail on which the print head slides. The first guide rail is perpendicular to the second, third, or fourth guide rail, and the third guide rail is perpendicular to the fourth, first, or second guide rail. The print head 1 can move along guide rail 81.

[0182] Additionally, the second guide rail 81b can also move along the third guide rail 81c, which is set along the Z-axis. This allows adjustment of the relative position of the tool holder assembly 50 to the print head 1 along the Z-axis. After switching, the tool holder assembly 50 can move upwards along the Z-axis along the third guide rail 81c, moving the hot ends on the tool holder away from the printing platform 89, thus preventing interference between the hot ends on the tool holder and the model being printed on the printing platform. When switching the hot ends is required, the tool holder assembly 50 can move downwards along the third guide rail 81c to a position where the hot ends on the tool holder and the hot ends on the print head are at the same height. This structure is specifically designed for gantry-type 3D printed parts, or other cases where the tool holder assembly is located directly above the printing platform 89. The third guide rail 81c can be fixedly connected to the fourth guide rail 81.

[0183] Example 16: The printhead includes a first limiting structure that can limit the hot end in a second direction; the tool holder includes a second limiting structure that can limit the hot end in a first direction; wherein, the first limiting structure includes a first clamping mechanism that can clamp the hot end in a first direction; and / or the first limiting structure includes a first positioning mechanism that can limit the hot end in a second direction; and / or the second limiting structure includes a second clamping mechanism that can clamp the hot end in a second direction; and / or the second limiting structure includes a second positioning mechanism that can limit the hot end in a first direction. Further, as... Figure 12a As shown, the first clamping mechanism of the first limiting structure includes a clamping member movably connected to the print head, and / or the second clamping mechanism of the second limiting structure includes a clamping member movably connected to the tool holder. The clamping member can be adjusted to press against the hot end to achieve clamping of the hot end, and can also be separated from the hot end to release the clamping of the hot end; wherein,

[0184] The clamping element is rotatably mounted on the print head or tool holder. One end of the clamping element can rotate around the rotating connection to press against the hot end or rotate to separate from the hot end; Reference Figure 2 , Figure 3 , Figure 7 , Figure 9a , Figure 9b or Figure 17b The lower clamping mechanism 30 or clamping element of the print head 1 is shown for fixing the hot end 10 to the print head 1 or the tool holder 50.

[0185] Alternatively, in another preferred embodiment, the clamping member is movable along the second direction and / or the clamping member is movable along the first direction and is disposed on the tool holder, and the clamping member can be moved and adjusted to press the hot end or separate from the hot end.

[0186] Alternatively, in yet another preferred embodiment, such as Figure 11g As shown, the first clamping mechanism includes a lower clamping mechanism 30, which includes a clamping member. This clamping member is an eccentric shaft structure, comprising a connecting shaft 301 and a stepped shaft 304 connected to the connecting shaft 301. The axis of the stepped shaft 304 has an eccentric gap with the axis of the connecting shaft 301. The connecting shaft 301 is rotatably mounted on the print head. The hot end has an inwardly recessed pressing step 158 corresponding to the stepped shaft 304. Rotation of the stepped shaft allows it to press against the pressing step to clamp the hot end, or to move away from the pressing step to release the clamping of the hot end. Specifically, Figure 11gThe diagram illustrates a printhead structure including a lower clamping mechanism 30, which is an eccentric shaft structure. The shaft 301 is inserted into a hole 191 on the printhead. The hole 191 can be located on the heating element 21. An elastic retaining ring 309 is positioned within an annular groove on the shaft 301, preventing the lower clamping mechanism 30 from being pulled out of the hole 191. A stepped shaft 304, eccentrically positioned to the shaft 301, has a gap between its axis and the shaft 301. By rotating the lower clamping mechanism 30, when the axis of the stepped shaft 304 faces the hot end 10, it presses the heating block 15 of the hot end against the laterally open section on the heating element 21. The heating surface (second heating surface) 211, along with a recessed area on the heating block 15 corresponding to the clamping mechanism 30, forms a pressing step 158. The step surface of the step shaft 304 can also press against the pressing step 158, preventing the hot end 10 from moving out in the horizontal direction parallel to the heating surface 211. Conversely, when the step shaft 304 rotates to a region where its axis is not facing the hot end 10, for example, when the step shaft 304 rotates to a region where its axis is far from the hot end 10, the step shaft 304 can leave the heating block 15 of the hot end, releasing the clamping state on the hot end. Simultaneously, the heating block is also provided with a first positioning feature 153, which can match the positioning structure 23 on the print head, preventing the hot end from moving in the vertical direction. The positioning structure 23 can be provided on the heating element 21. A clamping mechanism 40 can also be provided, including a shaft 401 and an eccentric stepped shaft 404 disposed on the shaft 401. A pressure block 45 can also be provided. The shaft 401 is inserted into a hole 192 in the print head, and the hole 192 can be disposed on the heat dissipation fins 22. The axis of the stepped shaft 404 is spaced from the axis of the shaft 401. The stepped shaft 404 is embedded in a long groove 451 on the pressure plate 45. When the drive shaft 401 and the stepped shaft 404 rotate, the stepped shaft 404 will drive the pressure plate 45 to move left and right. For example, when the axis of the stepped shaft 404 moves to the side closer to the hot end relative to the axis of the shaft 401, the pressure plate 45 is pushed against the heat dissipation section of the hot end and the heat dissipation surface 221 on the heat dissipation fins 22. Conversely, when the axis of the stepped shaft 404 moves to a region not located on the side closer to the hot end relative to the axis of the shaft 401, for example, when the axis of the stepped shaft 404 moves to the side farther away from the hot end relative to the axis of the shaft 401, the pressure plate 45 is pushed away from the heat dissipation section of the hot end 10.

[0187] Or, such as Figure 12a , Figure 14a ,or Figure 8As shown, the clamping component is a first swinging pressure rod 31. The middle part of the first swinging pressure rod 31 is rotatably mounted on the print head or tool holder via a first rotating shaft 301. A first elastic element 241 is connected to the end of the first swinging pressure rod 31 away from the hot end 10. The first elastic element 241 applies a spring force to the corresponding end of the first swinging pressure rod 31, causing the first swinging pressure rod to rotate around the first rotating shaft 301. Consequently, the end of the first swinging pressure rod near the hot end presses against the hot end along a first direction and / or a second direction. The first swinging pressure rod 31 is provided corresponding to the heating section 12 of the hot end 10. There can be two first swinging pressure rods 31, which are respectively pressed against the upper and lower parts of the heating section 12 of the hot end 10. Further, the first rotating shaft 301 is provided along a third direction, which can be perpendicular to the first direction and the second direction.

[0188] The end of the first swing pressure rod 31 installed on the print head facing the tool seat 50 may also be provided with a slope. The slope can make it easy to install the hot end 10 onto the print head 1. When the hot end 10 moves relative to the print head 1 along the first direction, the end side of the hot end 10 contacts the slope of the end of the first swing pressure rod 31 facing the tool seat 50. The hot end 10 can slide into the corresponding part between the first swing pressure rod 31 and the print head 1 through the guidance of the slope. During the installation of the hot end 10, the elastic force of the first elastic element 241 is overcome, and the first swing pressure rod 31 rotates around the first rotating shaft 301, so that one end of it opens to allow the hot end 10 to enter. Conversely, when the hot end 10 moves relative to the print head 1 in the direction away from the print head 1 along the first direction, the hot end 10 can overcome the clamping force of the first swinging lever 31 and be removed from the print head 1. After the hot end 10 is removed, the first elastic element 241 pushes the first swinging lever 31 to rotate around the first rotating shaft 301, so that the end of the first swinging lever 31 facing the tool holder 50 continues to rotate. The end of the first swinging lever 31 can be in contact with the corresponding surface of the print head 1, or be limited as... Figure 14c As shown, the swing limiting structure 272 provided on the print head 1, for example, is set on the swing path of the first swing pressure rod 31 along the elastic force of the first elastic member 241. When the hot end 10 is not installed on the print head 1, the first swing pressure rod 31 continues to swing in the pressing direction under the action of the first elastic member 241 until it is limited by the swing limiting structure 272, so that the end of the first swing pressure rod 31 maintains a certain distance from the opposite structure (such as the heating element) of the print head 1, so that the hot end can be reinstalled later. The swing limiting structure 272 can be set on the base 27 of the print head 1. The base 27 has a through hole corresponding to the first swing pressure rod 31. The end of the first swing pressure rod 31 passes through the through hole and is connected to the first elastic member 241. The other end of the first elastic member 241 is connected to the corresponding part of the base 27. Figure 14cAs shown, the printhead 1 also includes a base 27. For example, the hot end 10 can be clamped between the first swinging pressure rod 31 and the base 27. For example, the first elastic element 241 can be a cylindrical compression spring, which is supported and connected between the corresponding parts of the printhead base 27 and the first swinging pressure rod 31. Figure 12a As shown, the middle part of the first swing pressure rod 31 is rotatably mounted on the printing base 27 via the first rotating shaft 301.

[0189] Figure 14d and Figure 14L The diagram illustrates the fourth swing pressure rod 532 installed on the tool holder 50. The fourth swing pressure rod 532 rotates around the shaft 301, and the elastic force of the third elastic element 541 presses the fourth swing pressure rod 532 against the hot end 10, thus clamping the hot end onto the tool holder 50.

[0190] Or, such as Figure 14d As shown, the clamping component on the print head is a second swing rod 31b. One end of the second swing rod 31b is rotatably mounted on the print head 1 on the side opposite the hot end 10 and away from the tool holder 50 via a second rotating shaft 302. The end of the second swing rod 31b presses against the side of the hot end facing the tool holder. A swing rod actuating part 39 is provided on the second swing rod 31b. A lowering part 581 is provided on the tool holder 50 corresponding to the swing rod actuating part 39. Alternatively, the clamping component is a second swing rod, one end of which is rotatably mounted on the tool holder on the side opposite the hot end and away from the print head via a second rotating shaft. The end of the second swing rod presses against the side of the hot end facing the print head. A swing rod actuating part 39 is provided on the second swing rod. The print head is equipped with a rocker arm actuation part, and a corresponding actuating element is provided on the rocker arm actuation part. When the print head and the tool holder move relative to each other in a first direction, the actuating element cooperates with the rocker arm actuation part. When the print head and the tool holder move relative to each other in a second direction, the actuating element can actuate the rocker arm actuation part, thereby driving the second rocker arm to rotate, causing the end of the second rocker arm to separate from the hot end or causing the end of the second rocker arm to press against the hot end. The end of the second rocker arm 31b may also be provided with a stop part, which is a protrusion (clamping part) 311. The outer surface of the protrusion 311 is preferably an arc-shaped surface. The protrusion 311 presses against the surface of the hot end 10 facing the side that can move outward (such as the side facing the tool holder 50). Further, the rocker arm actuation part 39 is a shaft member, and the lower actuating element 581 is provided with an actuating groove 5811. When the print head moves from the first switching position A of the tool holder to the intermediate position T of the tool holder, the shaft member can move into the actuating groove 5811.

[0191] Or, such as Figure 17aAs shown, the clamping component is a lower pressure plate 32, which is movable along the second direction and mounted on the print head 1. The lower pressure plate 32 has a pressure plate actuating part 39, and the tool holder 50 has a corresponding lower actuating part 581. Alternatively, the clamping component is a lower pressure plate, which is movable along the second direction and mounted on the tool holder. The lower pressure plate has a pressure plate actuating part, and the print head has a corresponding actuating part. When the print head and the tool holder move relative to each other along the first direction, the actuating part cooperates with the pressure plate actuating part. When the print head and the tool holder move relative to each other along the second direction, the actuating part can actuate the pressure plate actuating part, thereby moving the lower pressure plate to separate the end of the lower pressure plate from the hot end or to press the hot end against the lower pressure plate. Further, the pressure plate actuating part 39 can be a hole or groove, and the lower actuating part 581 can be a corresponding matching shaft, or the pressure plate actuating part 39 is a shaft, and the lower actuating part 581 is a matching hole or groove. Additionally, as... Figure 14L As shown, the pressure plate 32 on the print head 1 can be the heating assembly 21.

[0192] Or, such as Figure 17b As shown, the clamping component is a lower pressure plate 32. One end of the lower pressure plate 32 is rotatably mounted on the print head 1 on the side opposite the hot end 10 and close to the tool seat 50 via a third rotating shaft 303. The axis of the third rotating shaft 303 is set along the first direction. The lower pressure plate 32 is provided with a pressure plate actuating part 39, and the tool seat 50 is provided with a lower actuating part 58 corresponding to the pressure plate actuating part 39. Alternatively, the clamping component is a lower pressure plate. One end of the lower pressure plate is rotatably mounted on the tool seat on the side opposite the hot end and close to the print head via a third rotating shaft. The axis of the third rotating shaft is set along the first direction. The lower pressure plate is provided with a pressure plate actuating part, and the print head is provided with a lower actuating part corresponding to the pressure plate actuating part. When the print head and the tool seat move relative to each other along the first direction, the lower actuating part cooperates with the pressure plate actuating part. When the print head and the tool seat move relative to each other along the second direction, the lower actuating part can actuate the pressure plate actuating part, thereby driving the lower pressure plate to rotate so that the end of the lower pressure plate separates from the hot end or presses the end of the lower pressure plate against the hot end.

[0193] Or, such as Figure 12b and Figure 12a As shown, a boss (or groove) 154 is provided on the hot end 10; the clamping element is a first swinging pressure rod 31, the middle part of which is rotatably mounted on the print head or tool holder via a first rotating shaft 301. A corresponding abutment is provided on the first swinging pressure rod 31 corresponding to the boss (or groove) 154. When the first swinging pressure rod presses the hot end, the abutment contacts the inclined side of the boss or groove, thus clamping the hot end by the first swinging pressure rod. Figure 14c As shown, the abutment portion is a protrusion 311, and the outer surface of the protrusion 311 is preferably an arc-shaped surface. The protrusion 311 presses against the side of the boss (or groove) 154 on the heating section 12, which can more reliably clamp the hot end 10. Figure 14jAs shown, the abutment part can also be a roller 314, which is rotatably mounted on the first swing pressure rod 31. The rotation of the roller 314 can reduce friction and wear during hot-end replacement. Furthermore, Figure 14j The diagram also illustrates that the first heating element 21, corresponding to the first swing pressure rod, can also be mounted on (another) swing pressure rod and can rotate around the pivot 302. In this way, when the hot end 10 is installed on the print head, the hot end 10 can be clamped on both sides simultaneously. Moreover, the elastically movable first heating element 21 is also easier to attach to the heating section of the hot end, which is conducive to the rapid transfer of heat to the hot end through heat conduction.

[0194] Alternatively, the tool holder is equipped with a gripping mechanism and a lever. The gripping mechanism and the lever can move simultaneously toward the print head. The lever releases the first clamping mechanism on the print head, causing the clamping mechanism to loosen its clamping state on the hot end of the print head. The gripping mechanism then clamps the hot end of the print head.

[0195] Alternatively, two pressure plates are provided on both sides of the hot end of the print head, and two levers are provided on the tool holder corresponding to the two pressure plates respectively. When the print head and the tool holder move relative to each other, the two levers simultaneously move in opposite directions and push the two pressure plates apart, so that the ends of the pressure plates separate from the hot end of the print head or press the pressure plates against the hot end. In this way, the force on the print head is balanced along the movement direction of the pressure plates or in the direction perpendicular to the extension and retraction adjustment of the levers during the pushing process, reducing the force on the print head; the two pressure plates can also rotate or swing around their respective axes (see reference). Figure 17b );

[0196] The relative movement of the printhead and the tool holder includes the printhead moving relative to the tool holder, or the tool holder moving relative to the printhead, or the printhead and the tool holder moving simultaneously.

[0197] like Figure 17a , Figure 17b , Figure 14m , Figure 14d , Figure 14L or Figures 11a to 11g The diagram illustrates that a toggle part can also be provided on the clamping component, and an elastic element can also be provided to apply an elastic force to the clamping component, causing the clamping component to swing or move in the direction of the hot end being installed; when the hot end is to be removed or installed, the print head moves to the corresponding position of the toggle part, and through the relative movement of the print head and the toggle part, the toggle part pushes the toggle part of the clamping component, causing the clamping component to be pushed open against the force of the elastic element;

[0198] Alternatively, a drive mechanism can also be provided. Figure 17a , Figure 17b , Figure 14m , Figure 14d and Figure 14L(Not shown in the image) is used to drive the dial. When it is not necessary to remove or install the hot end, the drive mechanism drives the dial to move to the retracted state. When it is necessary to remove or install the hot end, the drive mechanism drives the dial to move to extend.

[0199] Alternatively, a drive mechanism can also be provided. Figure 17a , Figure 17b , Figure 14m , Figure 14d and Figure 14L (not shown in the image) is used to drive the dialing component. When it is necessary to remove or install the hot end, the drive mechanism drives the dialing component to move and move the dialing part on the clamping component.

[0200] Alternatively, it may include a detection sensor 61 for detecting whether the clamping component is properly clamped;

[0201] Or, such as Figure 1c The illustration also includes a latching lever, which can swing around a second pivot on the print head, and a clamping element can swing around a first pivot on the print head; the latching lever is the next lever 34, the clamping element is the first swinging pressure lever 31, the second pivot is the second shaft 302, and the first pivot is the first shaft 301; or, the latching lever is the previous lever 44, the clamping element is the upper pressure element 41, the second pivot is shaft 402, and the first pivot is shaft 401; wherein, the included angle between the first pivot and the second pivot is 0 degrees, with an error not exceeding ±40°, and the first pivot and the second pivot are respectively located at the hot end 1. The two sides of the hot end 10 or the latching swing rod 34 and the clamping member 31 are respectively set on both sides of the hot end 10. The clamping member can swing towards the hot end 10 to press the hot end 10 against the print head. The latching swing rod can swing towards the hot end or the clamping member to clamp the clamping member. The clamping member can be a swing rod, a swing plate or a heating element, or a heat dissipation fin that is movably installed on the print head. An upper locking part 413 can also be set on the upper pressing member 41 to facilitate the upper swing rod 44 to be locked onto the upper pressing member 41, or a locking part 313 can be set on the first swing pressing rod 31 to facilitate the next swing rod 34 to be locked onto the first swing pressing rod 31.

[0202] Or, such as Figure 6b The illustration also includes a latching lever rotatably mounted on the print head. The latching lever is the next lever 34, and the clamping member is the first swing pressure lever 31. The axis of the rotating shaft (second shaft 302) of the latching lever is at a 90-degree angle with the axis of the feeding pipe of the hot end or with the axis of the rotating shaft (first shaft 301) of the clamping member, with an error of no more than ±45°. The axis of the rotating shaft (first shaft 301) of the clamping member is at a 0-degree angle with the axis of the feeding pipe of the hot end 10, with an error of no more than ±40°. When the clamping member rotates to the position above (in front) of the hot end 10, it presses the hot end 10 against the print head. When the latching lever 34 rotates to the position above (in front) of the clamping member, it presses the clamping member and the hot end 10 against the print head.

[0203] Or, such as Figure 14d The illustration also includes an elastic element 241, and a clamping element is a second swing pressure rod 31b. The rotating shaft (second shaft 302) of the clamping element is located on one side of the print head relative to the rear of the hot end 10. The clamping element is provided with a clamping part (protrusion 311) for clamping the hot end 10. The clamping part is located on the side relative to the front of the hot end or away from the rotating shaft 302. The elastic element 241 applies a spring force to the clamping element, causing the clamping element to swing towards the hot end 10 to clamp the hot end 10.

[0204] Or, such as Figure 17a The diagram also includes an elastic element 241 and a clamping element, which is a lower pressure plate 32. The clamping element is located on the side (front) away from the print head relative to the hot end 10. The clamping element can move relative to the hot end 10 or the print head. The elastic element 241 is used to apply elastic force to the clamping element so that the clamping element moves towards the hot end and clamps the hot end 10.

[0205] Alternatively, the clamping component may be a heating element or a heat dissipation fin;

[0206] Or, such as Figure 17a , Figure 17b , Figure 14m , Figure 14d , Figure 14L or Figures 11a to 11g The diagram also includes an elastic element 241, which applies a force to the clamping element, causing the clamping element to move or swing toward the mounting hot end 10. The clamping element is provided with a toggle part (including a toggle part 39 or an upper toggle part 39a).

[0207] Or, such as Figure 1b The clamping member is the first swinging pressure rod 31, and also includes a corresponding clamping part (clamping part 313). For example, the clamping part is located on the heating assembly 21 or on the side of the heating assembly 21 away from the first swinging pressure rod 31. Alternatively, the clamping member is the upper pressure member 41, and also includes a corresponding clamping part (upper clamping part 413). For example, the upper clamping part 413 is located on the heat dissipation fin 22. The clamping member is rotatably mounted on the print head. The rotating shaft (first shaft 301) of the clamping member and the clamping part 313 are respectively located on both sides of the hot end 10, or the rotating shaft (shaft 401) of the clamping member and the clamping part (upper clamping part 413) are respectively located on both sides of the hot end 10. When the hot end 10 is mounted on the print head, the clamping member swings towards the hot end 10 or the clamping part and clamps itself onto the clamping part, so that the clamping member presses against the hot end 10 against or is mounted on the print head accordingly.

[0208] Or, such as Figure 12a , Figure 12b , Figure 14c , Figure 14f , Figure 14j , Figure 14m , Figure 14n or Figure 14oThe illustration also includes an elastic element 241 and a first swinging pressure rod 31 as the clamping element. The clamping element is rotatably mounted on the print head. The hot end 10 is provided with a protrusion or groove structure, such as the boss (or groove) 154 shown in Figure 12b. The clamping element is provided with a stop part 311, which is a structure or roller 314 adapted to the protrusion or groove structure on the hot end. The elastic force of the elastic element causes the clamping element to swing towards the hot end. When the clamping element presses the hot end, the stop part is in contact with the inclined side of one side of the protrusion or groove structure, so that the clamping element clamps the hot end to the print head.

[0209] Or, such as Figure 6c The print head includes a heating element 21 for heating the hot end 10. The heating section 12 of the hot end 10 is a cylindrical structure. The heating element 21 includes a heating seat. The heating surface 211 of the heating seat is a circular hole structure that mates with the heating section 12. The hot end 10 is mounted on the print head along the axial direction of the feed pipe of the hot end 10 or removed from the print head.

[0210] The relative movement of the printhead and the dial includes the printhead moving relative to the dial, or the dial moving relative to the printhead, or the printhead and the dial moving simultaneously.

[0211] Figures 10a to 10c The diagram illustrates a lower clamping mechanism 30 and an upper clamping mechanism 40 on the print head. The lower clamping mechanism 30 is a movable pressure plate. When the pressure plate is moved to the hot end 10, it can press the hot end against the print head or the heating element 21 on the print head. Movable pressure plates can be provided on both sides of the print head. When the two pressure plates move towards each other, they press the hot end against the print head. When the two pressure plates move away from each other, they release the clamping state on the hot end. For example, a toggle part 39 can be provided on the pressure plate. The toggle part 39 is shown as a groove structure. A toggle member 58 is provided on the tool holder. When it is necessary to switch the hot end, for example, when the hot end is switched from the print head to the tool holder, the print head first moves to the corresponding switching position on the tool holder. Then, the toggle member 58 can extend and be inserted into the toggle part 39. The toggle member 58 can move the plate of the lower clamping mechanism 30 outward in a moving direction. For example, the end of the toggle member can be sloped. As it is inserted into the toggle part 39, the slope will push the plate of the lower clamping mechanism 30 outward, thereby exposing the hot end 10. At the same time, the extended gripping mechanism 33 can hold the hot end 10. Figure 10bThe diagram illustrates that the gripping mechanism 33 includes two swing arms that can rotate around their respective axes 331. A drive mechanism, such as an electromagnetic coil 332, can be provided on the side of the swing arm away from the print head relative to the axes 331 to drive the two swing arms to swing around their respective axes. For example, when the electromagnetic coil 58 drives the connection points of the two swing arms to move away from each other, the gripping heads of the gripping hot ends on the side of the swing arms closest to the print head relative to their respective axes can move closer together, clamping the heating block of the hot end and thus holding the hot end in place. For example, grooves can be provided on the left and right sides of the heating block of the hot end so that the gripping bucket can be embedded therein to reliably grip the hot end. Then, the lever 58 and the gripping mechanism 33 retract towards the tool holder, gripping the hot end 10 and moving it away from the print head 1. Simultaneously, as the lever 58 moves away from the lever part 39 on the lower clamping mechanism 33, the flat plate returns to its opposite moving and clamping state under the action of the reset elastic member 305. Figure 10c This illustrates the mid-process state of the hot end being grasped and moved by the gripping mechanism 33. Similarly, an upper clamping mechanism 40 can also be provided on the print head 1, and an upper lever 582 can be provided on the tool holder to open or close the upper clamping mechanism 40. The clamping and opening methods of the upper clamping mechanism 40 can be the same as those of the lower clamping mechanism, except that the translating plate of the upper clamping mechanism 40 clamps the heat dissipation section of the hot end. For example, if the heat dissipation section is a round tube, the upper clamping mechanism 40 can bring the round tube-shaped heat dissipation section against the matching heat dissipation surface of the heat dissipation fins 22 on the tool holder. An upper gripping mechanism 33a can also be provided on the tool holder to grip the position of the heat dissipation section of the hot end 10. For example, similar to the gripping mechanism 33, two swinging pairs that can swing around their respective axes can be provided to clamp the tubular heat dissipation section, making the switching process of the hot end 10 smoother. If each tool holder is equipped with a gripping mechanism 33 (or even further, each is equipped with an upper gripping mechanism 33a), then after the gripping mechanism 33 grips the hot end 10 and moves it to the tool holder, the gripping mechanism 33 can be regarded as a clamping mechanism for the hot end on the tool holder. That is, the gripping mechanism 33 can keep the hot end 10 located on the tool holder in a clamped state at all times. For example, it can always clamp the heating section of the hot end, and can also forcefully make the heating surface of the heating section abut against the heating surface of the heating element 51 on the tool holder. Furthermore, the upper gripping mechanism 33a also always clamps the heat dissipation section of the hot end, and can also forcefully make the heat dissipation surface of the heating section abut against the heat dissipation surface of the heat dissipation fins 22 on the tool holder. Of course, the hot end 10 can also cooperate with the positioning element 53 on the tool holder for positioning.

[0212] Example 17: Both the printhead and the tool holder have positioning mechanisms, and corresponding positioning features are provided on the hot end.

[0213] The hot end is provided with a second positioning feature extending along a second direction; the second positioning mechanism on the tool holder includes a positioning element 53 corresponding to and matching the second positioning feature, and the positioning element also extends along the second direction; such as Figure 15 , Figure 14L , Figure 7 , Figure 11f , Figure 13a , Figure 14a , Figure 14c , Figure 14d , Figure 14f , Figure 14h As shown in the figure.

[0214] When the tool holder and the print head move relative to each other along the second direction, the positioning element and the second positioning feature can cooperate to limit the hot end along the first direction, or the positioning element and the second positioning feature can move away from each other to release the limitation on the hot end along the first direction.

[0215] And / or,

[0216] like Figure 12b As shown, a first positioning feature 153 that can extend along a first direction is provided on the hot end, such as... Figure 14m , Figure 14n , Figure 14L , Figure 17a , Figure 17b As shown, the first positioning mechanism on the print head includes a positioning part 23 or a lateral positioning part 231 or a heating surface on the heating element 21 that corresponds to and matches the first positioning feature. The positioning part 23 can extend along the first direction; or as shown... Figure 6c The circular heating surface 211 of the heating element 21 on the printhead forms a first positioning mechanism for the cylindrical heating section 12 of the hot end 10, ensuring that the hot end 10 can only be installed or removed along its axial direction (Z-direction or vertical direction). Simultaneously, the first positioning feature 153 further limits the positioning of the hot end along its axial direction. Other figures illustrate this. Figure 1b , Figure 1c , Figure 6b The locking parts shown in the diagram, or Figure 2 , Figure 9b , Figure 10a , Figure 11g , Figure 14m , Figure 14n , Figure 17b The positioning part 23 and the clamping part, or Figure 14nThe lateral positioning part 231 in the middle limits the hot end 10 to be installed onto the print head or removed from the print head only in the axial direction perpendicular to the hot end. The first positioning mechanism or positioning part 23 is used to accurately position the hot end 10 to ensure the repeatability of the position of its extrusion port 11 after the hot end 10 is replaced; when the hot end is installed onto the print head, the positioning part 23 cooperates with the first positioning feature 153 to position the hot end 10 in a third direction perpendicular to the first direction and the second direction or in the axial direction of the hot end's feed pipe and / or the second direction.

[0217] The positioning element on the tool holder 50 can be a positioning post 53 extending in a second direction, and the second positioning feature on the hot end 10 can be a positioning hole 155 extending in a second direction. When the hot end 10 is installed on the tool holder 50, the positioning post 53 is inserted into the positioning hole 155, thereby limiting the hot end 10 on the tool holder 50. The second positioning mechanism may also include the limiting groove 55. The positioning element on the tool holder 50 is the limiting groove 55, which includes a groove segment extending in a second direction and a notch or passage extending in a first direction, the notch or passage communicating with the groove segment; or, the second positioning feature on the hot end 10 can be a heat dissipation section 14 of the hot end, and the limiting groove 55 is adapted to the heat dissipation section 14. When the hot end 10 is installed on the tool holder 50, the heat dissipation section 14 is engaged in the limiting groove 55, thereby limiting the hot end 10 on the tool holder 50. The positioning element of the tool holder can have both a positioning pin 53 and a limiting groove 55. Alternatively, the positioning element on the tool holder can have only a positioning pin (positioning element 53) or only a limiting groove 55. For example... Figure 14c As shown, the positioning element on tool holder 50 is positioning pin 53. (As indicated...) Figure 14d As shown, the positioning element 53 on the tool holder 50 is a positioning plate extending along the second direction. Figure 14d The position of the middle positioning plate (positioning element 53) can be interchanged with the position of the fourth swing pressure rod (tool seat lower clamping mechanism 532) relative to the vertical mirror position between the two, and after the transformation, it can be as follows: Figure 14L As shown. When Figure 14d The heated end is installed onto the tool holder, and the positioning element 532 is positioned by abutting against one side surface of the heated end 10. Figure 14L As shown, the positioning plate (positioning element 532) can also be a second heating element 51. Another heating element 51 can be provided on the side of the tool holder adjacent to the positioning element 53, or another heating element 51 can be provided on the fourth swing pressure rod (tool holder lower clamping mechanism 532) on the side opposite to the positioning element 53. Figure 17aAs shown, the positioning element 53 on the tool holder 50 is a positioning plate extending along the second direction, and the second positioning feature on the hot end 10 is a corresponding positioning groove or surface extending along the second direction. When the hot end 10 is installed on the tool holder 50, the positioning plate is inserted into the positioning groove or pressed against the corresponding surface, thereby limiting the hot end 10 on the tool holder 50. Figure 17b As shown, the positioning element on the tool holder 50 includes a positioning pin (not shown in the figure, but can be referenced). Figure 14f The positioning element 53 and the limiting groove 55 are provided on the hot end 10. A positioning hole 155 is provided on the hot end 10 corresponding to the positioning post. The positioning element on the tool holder can also be an edge extending in a second direction, and the second positioning feature on the hot end is a boss extending in a second direction. When the hot end is installed on the tool holder, the boss overlaps with the edge to limit the hot end. The positioning element on the tool holder includes one or more of the following: positioning plate, positioning post, edge, and limiting groove. Correspondingly, the second positioning feature on the hot end is one or more of the following: positioning groove, positioning hole, boss, and heat dissipation section.

[0218] In embodiment eighteen, a heating element may also be provided on the print head and / or tool holder for heating the heating section of the hot end. A first heating element 21 is mounted on the print head and / or a second heating element 51 is mounted on the tool holder. The first heating element 21 and / or the second heating element 51 may also have a laterally open heating surface. Figure 12a and Figure 12b As shown, the printhead 1 has a first heating element 21 corresponding to the heating section 12 of the hot end 10, which is used to heat the heating section 12. For example, the first heating element 21 can be disposed opposite to the first clamping mechanism on the printhead 1. The first clamping mechanism presses the heating section 12 of the hot end 10 against the first heating element 21, so that the heating section 12 is in close contact with the first heating element 21. Further, a heating block 15 is disposed on the heating section 12. The side of the heating block 15 facing the first heating element 21 forms a first heating surface 151. The first heating surface 151 can be parallel to a first direction with an error of no more than ±40° or no more than ±45°. When the hot end 10 is installed on the printhead 1, the first heating surface 151 can be in contact with the first heating element 21, that is, in contact with the second heating surface on the first heating element 21. Furthermore, the first heating element 21 can be made of ceramic heating elements, heating rods, or induction coils, which can heat the hot end through heat conduction or through electromagnetic induction. When heating the heating section 12 of the hot end 10 through electromagnetic induction, the heating section 12 does not need to be in contact with the first heating element 12. A temperature sensor can also be provided on the first heating element 21 to detect the temperature of the first heating element 21 and / or the hot end. Furthermore, a thermally conductive medium, such as thermal grease, thermal pad, or other thermally conductive medium, can be provided on the surface of the first heating element 21 that is in contact with the heating block 15 on the hot end 10 to reduce the thermal resistance of heating or heat dissipation through heat conduction.

[0219] like Figure 12a As shown, the first heating element 21 is disposed on the printing substrate 27. The hot end 10 is placed between the first heating element 21 and the first swinging pressure rod 31. The first swinging pressure rod 31 presses the heating block 15 of the hot end 10 so that the heating block 15 is in close contact with the first heating element 21, thereby heating the heating block 15 through the first heating element 21. Figure 14c As shown, the first heating element 21 can be disposed on the base 27. The first heating element 21 includes a first portion that is in contact with the first heating surface of the hot end 10 and a second portion connected to the first portion. The second portion is in contact with the end face of the hot end 10 near the printhead. A first heater 63-1 and a third heater 63-3 are disposed on the side of the first and second portions away from the hot end. The first heater 63-1 and the third heater 63-3 are ceramic heating plates or heating rods. The first heating element 21 can heat the first heating surface of the hot end 10 and the end face of the hot end near the printhead. When an electromagnetic induction heating coil is disposed within the first heating element 21 to heat the heating section 12 through electromagnetic induction, the first heating element 21 may be in contact with the hot end 10 or may not require direct contact. Figure 17b As shown, the first heating element 21 has a heating surface that matches the heating surface of the hot end 10, preferably a flat surface. Similarly, the first heating element 21 can also be a ceramic heating plate, a heating rod, or an induction coil to heat the heating block 15 of the hot end 10 mounted on the printhead. The first heating element 21 can be used to heat the printing material that needs to be heated and melted in the hot end before it is extruded from the extrusion port of the hot end. For printing material that does not need to be heated and melted before extrusion, the first heating element may not be necessary.

[0220] Similarly, the tool holder can also be equipped with a heating element to heat the hot end mounted on the tool holder, such as... Figure 13a and Figure 13b As shown, a second heating element 51 is provided on the tool holder 50 corresponding to the heating section 12 of the hot end 10. The second heating element 51 is used to heat the heating section 12. When the hot end 10 is mounted on the tool holder 50 by the second limiting mechanism, the second heating element 51 is in contact with the heating section 12. Figures 11a to 11g , Figure 7 , Figure 9a , Figure 10c Figure 13g Figure 14c , Figure 14d , Figure 14j As shown, a second heating element 51 can also be provided on each tool holder to heat the heating section of the hot end mounted thereon, or a heat dissipation fin 22 can be provided to dissipate heat from the heat dissipation section of the hot end mounted thereon. A temperature detection element 212 can also be provided on the heating element 21 on the print head to detect the temperature of the heating block of the hot end.

[0221] By installing a second heating element 51 on the tool holder 50, the hot end 10 can be preheated. That is, when the print head 1 needs to use a particular hot end, the tool holder 50 first heats that hot end to a preset temperature, achieving preheating before switching the hot end 10. This ensures that the temperature of the hot end 10 has reached the preset value before it is transferred from the tool holder to the print head 1. Thus, when the hot end is switched from the tool holder to the print head, the time spent heating the hot end by the print head is reduced, or the hot end can be switched to the print head at the required printing temperature for direct printing. This greatly improves printing efficiency after switching hot ends and reduces the time spent switching hot ends and maintaining the temperature of the newly installed hot end on the print head.

[0222] The second heating element 51 is provided with a third heating surface. When the hot end 10 is installed on the tool holder 50, the first heating surface 151 of the heating block 15 on the heating section 12 of the hot end 10 is in contact with the third heating surface. The first heating surface 151 can be parallel to the first direction with an error of no more than ±40° and no more than ±45°. The heating block 15 is provided with a first heating surface 151, which can be in contact with the first heating element 21 on the print head 1 and also with the second heating element 51 on the tool holder 50, so that the heating block 15 has only one heating surface. This allows both the print head and the tool holder to be in contact with the first heating surface 151 of the hot end. For heating by conduction, this reduces the number of heating surfaces on the hot end, simplifies the hot end structure, and allows the remaining surfaces of the heating block 15 to be insulated to slow down the heat dissipation rate of the remaining surfaces, making it easier to insulate the hot end, improve the heating speed, and reduce power consumption.

[0223] The second heating element 51 can be heated by means of ceramic heating element, heating rod or induction coil, etc., and can heat the hot end installed on the tool holder by means of heat conduction or electromagnetic induction. Similarly, a heat-conducting medium, such as thermal grease, thermal pad or other heat-conducting medium, can be provided on the surface of the second heating element 51 that is in contact with the heating block 15 on the hot end 10.

[0224] Furthermore, the first heating element can be fixedly connected to the print head or flexibly connected to the print head; similarly, the second heating element can be fixedly connected to the tool holder or flexibly connected to the tool holder. Figure 14j The first heating element 21 is oscillatingly connected to the print head via a rotating shaft 302. Figure 14L The first heating element 21 shown is slidably connected to the print head 1, and the movable first heating element 21 can also serve as a first clamping mechanism. Figure 12a , Figure 13a and Figure 13bAs shown, the second heating element 51 on the tool holder 50 can move along the first direction. A third elastic element 541 (spring) is provided between the second heating element 51 and the corresponding part of the tool holder 50. The third elastic element 541 applies a force to the second heating element 51 so that the second heating element 51 is in contact with the hot end 10. The second heating element 51 can also be rotatably connected to the tool holder. The movably connected second heating element 51 can also serve as a second clamping mechanism.

[0225] like Figure 14c and 14d As shown, a second heater 63-2, which is a ceramic heating element or heating rod, can be provided on the second heating element 51. The second heating element 51 can heat the first heating surface of the hot end 10. Additionally, to ensure a tight fit between the hot end mounted on the tool holder and the second heating element 51, a spring 243 connected to the base 57 can be provided. The spring force acting on the hot end mounted on the tool holder pushes the hot end against the second heating element 51. Similarly, Figure 14L A spring 243 can also be installed on the print head, connected to the print head base 27. The elastic force it provides pushes the hot end mounted on the print head against the first heating element 21. The second heating element 51 can adopt an electromagnetic induction heating technology. The second heating element 51 is equipped with an electromagnetic induction coil, which induction heats the heating block of the hot end 10. The second heating element 51 can be fixed on the bracket 57. In the case of electromagnetic induction heating, the hot end does not need to be in contact with the heating element (such as 21 or 51). The heating block on the hot end 10 can be matched with the first heating element on the print head. Alternatively, a fourth heating surface can be added to the hot end. The first and fourth heating surfaces are positioned opposite each other. When the hot end 10 is installed on the print head 1, the laterally open second heating surface of the first heating element 21 is in contact with the first heating surface. When the hot end 10 is installed on the tool holder 50, the third heating surface of the second heating element 51 is in contact with the fourth heating surface. In this way, the hot end can also be heated by heat conduction on the tool holder. The first heating surface is perpendicular to the first direction, with an error of no more than ±40° or no more than ±45°. Figure 17b The hot end shown also has a first heating surface 151 and a fourth heating surface, the fourth heating surface being the second surface 152 on the hot end 10. When the hot end 10 is installed on the print head 1, the second heating surface (the side-open heating surface) of the first heating element 21 is in contact with the first heating surface. When the hot end 10 is installed on the tool holder 50, the second heating element 51 (e.g., set on...) is... Figure 17b The third heating surface of the lower pressure plate 32 is in contact with the fourth heating surface, and the first heating surface is perpendicular to the first direction with an error of no more than ±40° or no more than ±45°.

[0226] Depend on Figure 14c , Figure 14f , Figure 14h , Figure 14j , Figure 14m and Figure 14n As can be seen, a shielding part 271 corresponding to the heating section 12 can also be provided on the print head 1 or tool holder 50 to enhance the heat preservation of the heating section 12. The shielding part 271 shields the heating section mounted on the hot end of the print head, reducing heat loss to the surrounding air and minimizing the heat dissipation of the heating section from the surrounding airflow. Figure 14c , Figure 14f , Figure 14h , Figure 14j , Figure 14m and Figure 14n It can be illustrated that there may also be a gap 273 between the shielding part 271 and the hot end along the second direction. The gap 273 allows the positioning member on the tool seat to extend into it. Moreover, when the print head and the tool seat move relative to each other along the second direction or the X-axis direction, the gap 273 can also ensure that the print head does not interfere with the tool seat.

[0227] Additionally, a heating element can be installed on the hot end 10. For example, it can be electrically connected to the circuitry on the print head via a connector to power the heating element on the hot end 10 and control its heating temperature. Heat dissipation fins can also be installed on the heat dissipation section of the hot end 10, such as... Figure 2 and Figure 7 As shown, the third heat dissipation fin 142 is disposed on the heat dissipation section of the hot end 10 to dissipate heat from the feeding pipe that feeds material to the extrusion port 11. With the third heat dissipation fin 142 disposed on the hot end 10, heat dissipation fins are not required on the print head 1 and the tool holder 50, simplifying their structure. Magnets or magnetic materials can also be disposed on the third heat dissipation fin 142 to facilitate attraction and fixation with corresponding magnetic materials or magnets on the print head or tool holder. Alternatively, the heat dissipation fin 142 may not be necessary on the hot end; corresponding heat dissipation fins or heat dissipation mechanisms can be disposed on the print head or tool holder.

[0228] In Example 19, heat dissipation fins or heat dissipation mechanisms may be provided on the print head and / or tool holder to dissipate heat from the heat dissipation section of the hot end.

[0229] like Figure 12a and Figure 2 As shown in Figure b, the printhead 1 is provided with a first heat dissipation fin 22 that is in contact with the heat dissipation section 14 of the hot end 10 mounted on the printhead 1. The first heat dissipation fin 22 can be in direct contact with the heat dissipation section 14 or can be provided with thermal grease, thermal pad or other thermal medium in between for heat dissipation.

[0230] Furthermore, such as Figure 14m , Figure 14n and Figure 14kAs shown, the first heat dissipation fin 22 on the print head 1 has a second heat dissipation surface 221 that is open to the side. The first clamping mechanism includes an adjustable upper clamping mechanism 40 that is provided corresponding to the first heat dissipation fin 22. The upper clamping mechanism 40 can be adjusted to press the heat dissipation section 14 of the hot end installed on the print head 1 so that the heat dissipation section 14 is in contact with the second open heat dissipation surface of the first heat dissipation fin 22. Figure 6c As shown, the heat dissipation surface 221 on the heat dissipation fin 22 is a side-closed heat dissipation surface, and the heating surface 211 on the heating element 21 is a side-closed heating surface.

[0231] In a preferred embodiment, the upper clamping mechanism 40 is rotatably mounted on the print head 1. The upper clamping mechanism 40 can rotate around the rotating connection to press the heat dissipation section 14 against the first heat dissipation fin 22, thereby making the heat dissipation section 14 and the first heat dissipation fin 22 in contact. When no hot end is installed on the print head 1, the upper clamping mechanism 40 abuts against a limiting structure mounted on the print head.

[0232] In another preferred embodiment, the upper clamping mechanism 40 is movable along the second direction and is disposed on the print head 1. By moving and adjusting the upper clamping mechanism 40, the upper clamping mechanism 40 can press the heat dissipation section 14 so that the heat dissipation section 14 is in contact with the first heat dissipation fin 22. When no hot end is installed on the print head, the upper clamping mechanism 40 abuts against a limiting structure disposed on the print head.

[0233] like Figure 12a and Figure 14e As shown, the upper clamping mechanism 40 is an upper pressing member 41. The upper pressing member 41, as illustrated in the figure, is a swinging fin, meaning it is a heat dissipation fin movably mounted to the print head. This upper pressing member 41 is rotatably mounted on the print head 1 via a fourth rotating shaft 401. A second elastic member 242 is provided on the fourth rotating shaft 401. This second elastic member 242 drives the upper pressing member 41 to rotate and press against the heat dissipation section 14, so that the heat dissipation section 14 comes into contact with the first heat dissipation fin 22. By pressing the heat dissipation section 14 at the hot end against the second heat dissipation surface 221 of the first heat dissipation fin 22, the heat dissipation end 10 can be more reliably fixed, and the heat conduction between the heat dissipation section 14 and the heat dissipation fin 22 can be enhanced. Preferably, the second elastic member 242 is a coil spring, which can drive the upper pressing member 41 to swing around the fourth rotating shaft 401. Furthermore, the heat dissipation section 14 of the hot end 10 can be tubular or cylindrical, with matching grooves formed on the corresponding side of the first heat dissipation fin 22. When the hot end 10 is installed onto the print head 1, the heat dissipation section 14 snaps into the groove, and the inner wall of the groove forms a laterally open second heat dissipation surface 221 for contact with the heat dissipation section 14. Figure 14eAs shown, when the hot end 10 is installed on the print head 1, the end of the upper pressure member 41 presses against the heat dissipation section 14, so that the heat dissipation section 14 is in contact with the first heat dissipation fin 22. When there is no hot end 10 on the print head 1, the end of the upper pressure member 41 can be in contact with the part of the first heat dissipation fin 22 near the second heat dissipation surface 221, and the part of the first heat dissipation fin 22 near the second heat dissipation surface 221 can be used as a limiting mechanism. An inclined surface can be provided on the side of the upper pressure member 41 near the hot end insertion or removal (the side near the tool holder 50), with the opening widening outward. This inclined surface can serve as a guide to facilitate the sliding of the heat dissipation section 14 between the upper pressure member 41 and the first heat dissipation fin 22. The upper pressure member 41 can also be a heat dissipation fin, which can also have a heat dissipation function. The part of the upper pressure member 41 that is in contact with the heat dissipation section 14 of the hot end 10 has an arc shape that matches the heat dissipation section, so as to make it fit tightly on the heat dissipation section 14.

[0234] like Figure 17a As shown, the upper clamping mechanism is an upper pressure plate 42, which is movable along the second direction and mounted on the print head 1. The upper pressure plate 42 has an upper actuating part 39a, and the tool holder 50 has an upper actuating member 582 corresponding to the upper actuating part 39a. When the print head 1 and the tool holder 50 move relative to each other along the first direction, the upper actuating member 582 engages with the upper actuating part 39a. When the print head 1 and the tool holder 50 move relative to each other along the second direction, the upper actuating member 582 can actuate the upper actuating part 39a, thereby moving the upper pressure plate 42 to separate it from the heat dissipation section 14 or to press the upper pressure plate 42 against the heat dissipation section 14. Further, the upper actuating part 39a can be a hole or groove, and the upper actuating member 582 can be a corresponding matching shaft, or the upper actuating part 39a can be a shaft, and the upper actuating member 582 can be a matching hole or groove. Taking an example where the upper pusher 582 is a shaft and the upper pusher part 39a is a hole, when the print head 1 moves relative to the tool holder 50, causing the print head 1 to move from the first switching position A to the relay position T, the upper pusher 582 is inserted into the upper pusher part 39a. When the print head 1 moves from the relay position T to the corresponding hot end mounting position B on the tool holder, the upper pusher 582, along with the upper pusher part 39a, moves away from the hot end 10, causing the upper pressure plate 42 to separate from the hot end 10, thus releasing the restriction on the hot end 10. When the print head moves from the corresponding hot end mounting position B on the tool holder to the second switching position C, the hot end 10 is replaced and mounted on the tool holder 50 from the print head 1. Conversely, the hot end 10 can be switched from the tool holder 50 to the print head 1. The above movement process can also be achieved by moving the tool holder.

[0235] In addition, the upper pressure plate 42 can also be rotatably connected to the print head. The upper pressure plate 42 is rotatably mounted on the print head 1 via a fifth rotating shaft. The upper pressure plate 42 is provided with a toggle part 39, and the tool holder 50 is provided with an upper toggle member 582 corresponding to the toggle part 39. When the print head 1 and the tool holder 50 move relative to each other along the first direction, the upper toggle member 582 cooperates with the toggle part 39. When the print head 1 and the tool holder 50 move relative to each other along the second direction, the upper toggle member 582 can toggle the toggle part 39, thereby driving the upper pressure plate 42 to rotate so that the upper pressure plate 42 separates from the heat dissipation section 14 or presses the heat dissipation section 14 with the upper pressure plate 42. Furthermore, the actuating part 39 can be a shaft member, and the upper actuating member 582 is provided with an upper actuating groove 5821. When the print head moves from the first switching position A of the tool holder to the intermediate position T of the tool holder, the shaft member can move into the upper actuating groove 5821. When the print head moves relative to the tool holder, causing the print head to move from the intermediate position T to the corresponding hot end mounting position B of the tool holder, the actuating part 39 is actuated by the upper actuating member 582, and the upper pressure plate 42 will rotate clockwise around the fifth rotating shaft, releasing the clamping state of the hot end. Then, the print head moves from the corresponding hot end mounting position B of the tool holder to the second switching position C, and the hot end is switched from the print head to the tool holder. The above movement sequence can be reversed to transfer the hot end from the tool holder to the print head. The above movement process can also be achieved by moving the tool holder.

[0236] like Figure 17a As shown, the printhead 1 is provided with a first heat dissipation fin 22. The side of the first heat dissipation fin 22 facing the mounting hot end (the side facing the tool holder 50) is a laterally open second heat dissipation surface 221. The second heat dissipation surface 221 can be a plane, and a matching plane is provided on the heat dissipation section of the hot end 10. For example, a heat dissipation block 16 can be provided on the heat dissipation section, and a plane heat dissipation surface 161 can be provided on the heat dissipation block 16. When the hot end is mounted on the printhead, the heat dissipation surface 161 is in contact with the second heat dissipation surface 221, which can be used for heat conduction. A first magnetic element 441 can also be provided on the second heat dissipation surface 221, and a corresponding second magnetic element 442 can be provided on the heat dissipation block 16. The first magnetic element 441 and the second magnetic element 442 can attract the heat dissipation block 16 to be in contact with the second heat dissipation surface 221. Of course, the plane heat dissipation surface 161 does not have to be provided on a dedicated heat dissipation block 16, and can be formed directly on the heat dissipation section 14. For example, the heat dissipation section 14 of the hot end can be made of a rectangular tube on the outside.

[0237] The aforementioned first heat dissipation fin 22 can be fixedly connected to the print head, for example, fixed to the base 27. Alternatively, the first heat dissipation fin 22 can be elastically or movably connected to the print head, allowing it to better contact the heat dissipation section of the hot end. Figure 6b , 14k , Figure 14n and Figure 14oAs shown, the first heat dissipation fin can also be flexibly connected to the print head. For example, the first heat dissipation fin may include a left first heat dissipation fin 22a and a right first heat dissipation fin 22b. The left first heat dissipation fin 22a and the right first heat dissipation fin 22b can be rotatably connected to the print head, for example, on the base 27 of the print head, respectively, via a fourth rotating shaft 401 and a fifth rotating shaft 403. The left first heat dissipation fin 22a and the right first heat dissipation fin 22b are respectively provided with a laterally open second heat dissipation surface 221 at the corresponding positions of the heat dissipation section of the hot end. Second elastic members 242 can be respectively provided, and each second elastic member 242 provides elastic force to rotate the left first heat dissipation fin 22a and the right first heat dissipation fin 22b in a direction closer to each other on the side where the hot end is installed. Preferably, the fourth rotating shaft 401 and the fifth rotating shaft 403 are located at a position on the print head where the hot end is installed (such as the axis of the feed pipe of the hot end) and parallel to the plane of the second direction. More preferably, they are located on the side away from the hot end. When no hot end is installed, the left first heat dissipation fin 22a and the right first heat dissipation fin 22b abut against each other and are limited, or are limited by their respective corresponding limiting structures. When a hot end is installed, the second heat dissipation surface 221 of the left first heat dissipation fin 22a and the right first heat dissipation fin 22b respectively abut against the heat dissipation section of the hot end. Of course, the left first heat dissipation fin 22a and the right first heat dissipation fin 22b do not necessarily have to be connected to the print head in a way that rotates around various corresponding axes. Instead, they can be translatably mounted on the print head in a second direction. Elastic elements can be provided separately, or a tension spring can be provided between them to provide elastic force to bring the left first heat dissipation fin 22a and the right first heat dissipation fin 22b closer to each other. This eliminates the need for an upper clamping mechanism, or for the left first heat dissipation fin 22a and the right first heat dissipation fin 22b to act as upper clamping mechanisms for each other. Furthermore, since the first heat dissipation fins are flexibly connected to the print head, it makes it easier and more reliable for the first heat dissipation fins (left first heat dissipation fin 22a and right first heat dissipation fin 22b) to abut against the heat dissipation section of the hot end. This avoids the problem that the heat dissipation section 14 and the heating section 12 cannot reliably abut against the first heat dissipation fin and the first heating element on the print head at the same time due to dimensional errors of the hot end or the print head. Guide slopes 225 are provided on the side of the left first heat dissipation fin 22a and the right first heat dissipation fin 22b facing the hot end for installation and removal. The two guide slopes 225 form an opening shape that is larger on the outside and smaller on the inside, which facilitates the heat dissipation section 14 of the hot end to push and separate the left first heat dissipation fin 22a and the right first heat dissipation fin 22b when it is installed from the outside, so as to install the hot end onto the print head. At the same time, when the hot end is removed from the print head, it can also guide the left first heat dissipation fin 22a and the right first heat dissipation fin 22b to gradually approach each other to avoid collision.

[0238] The aforementioned printhead can also be a tool holder, that is, the aforementioned first heat dissipation fin 22 and upper clamping mechanism can also be the heat dissipation fin (second heat dissipation fin) and clamping element (second clamping mechanism) on the tool holder. Additionally, as... Figure 13a and Figure 13bThis diagram illustrates a specific structure of a heat dissipation fin on a tool holder, for a second heat dissipation fin 52 that contacts the heat dissipation section 14 of the hot end 10 mounted on the tool holder 50. A first or second clamping mechanism may include a rotatable second heat dissipation fin 52, which is rotatably mounted on the base 57 of the tool holder 50 via a sixth rotating shaft 501. It also includes a fourth elastic member 542, which applies a force to the second heat dissipation fin 52 to cause it to rotate towards the hot end 10 or the print head 1. When the hot end 10 is not mounted on the tool holder 50, [the mechanism] combines [the following components]. Figure 14e As shown, the second heat dissipation fin 52 abuts against a limiting structure 522 provided on the tool holder 50 to prevent the second heat dissipation fin 52 from rotating excessively. Figure 13a and Figure 13b If we consider it as a printhead, then the second heat sink 52 can be regarded as the first heat sink 22.

[0239] The fourth elastic element 542 can be sleeved on the sixth rotating shaft 501. This fourth elastic element 542 can be a coil spring. A mounting frame corresponding to the second heat dissipation fin 52 can also be provided on the base 57 of the tool holder 50. One end of the coil spring is connected to the side frame corresponding to the mounting frame, and the other end is connected to the portion of the second heat dissipation fin 52 away from the sixth rotating shaft 501. The fourth elastic element can also be a cylindrical compression spring, pushing or pulling the second heat dissipation fin to rotate. A limiting groove 55 can also be provided on the mounting frame. Alternatively, the second heat dissipation fin 52 on the tool holder can also be moved horizontally by a cylindrical spring providing elastic force, thus compressing the cylindrical spring to move the second heat dissipation fin 52 away from the print head. A laterally open third heat dissipation surface 521 is formed on the second heat dissipation fin 52, which is in contact with the heat dissipation section 14 of the hot end 10. Figure 4 a and Figure 4 b, when switching the hot end 10 onto the tool holder 50, combined with Figure 14e and Figure 14g As shown, the relative movement of printhead 1 and tool holder 50 causes the printhead to move from the first switching position A to the relay position T. The corresponding part of printhead 1 pushes the second heat dissipation fin 52, and then combines... Figure 14i As shown, the print head moves from relay position T to the corresponding hot end mounting position B on tool holder 50, and then combines... Figure 14k As shown, the print head moves from position B to the second switching position C, with the hot end 10 remaining on the tool holder 50. When the print head 1 leaves the tool holder 50, the second heat dissipation fin 52, under the action of the fourth elastic member 542, comes into close contact with the heat dissipation section 14 on the hot end 10. The second clamping mechanism, including the second heat dissipation fin 52, is used to press the heat dissipation section of the hot end onto the tool holder.

[0240] like Figure 17bAs shown, the tool holder 50 is provided with a second heat dissipation fin 52 corresponding to the heat dissipation section 14. The second positioning mechanism may also include a limiting groove 55 provided on the second heat dissipation fin 52 for limiting the heat dissipation section 14. By using the limiting groove 55 to clamp the heat dissipation section 14 on the hot end 10 or the heat dissipation block 16 provided on the heat dissipation section 14, the hot end 10 can be limited on the tool holder 50. Further, the first heat dissipation fin 22 may be provided with a clearance groove 2211 on the second heat dissipation surface 221 for avoiding the limiting groove 22. The second heat dissipation fin 52 can be fixedly connected to the tool holder.

[0241] A first heat dissipation fin is installed on the print head, and a second heat dissipation fin is installed on the tool holder for heat dissipation. This eliminates the need for a separate heat dissipation fin on the hot end, simplifying the hot end structure, reducing its size and weight, and facilitating hot end switching. Furthermore, when the hot end wears out and needs replacement, the heat dissipation fins do not need to be replaced, reducing application costs. Additionally, the heat dissipation fins fixed to the print head or tool holder can provide better heat dissipation. For example, connecting the heat dissipation fins to the body of the print head or tool holder (such as the base or frame) forms a larger heat sink with better heat dissipation capacity. It also allows the heat dissipation fins to contact the coolant for even stronger heat dissipation, enabling multiple heat dissipation methods. Fans or liquid circulation can be installed on the print head or tool holder to dissipate heat from the heat dissipation fins. Figure 16 As shown, a first heat dissipation mechanism may be provided on the heat dissipation section 14 corresponding to the hot end 10 on the printhead 1. This first heat dissipation mechanism is used to dissipate heat from the heat dissipation section. Further, the first heat dissipation mechanism may be a fan, an air duct, or a coolant circulation device. Figure 16 and Figure 6a As shown in the printhead 1 on the left, the first heat dissipation mechanism on the printhead 1 is a coolant circulation device. Coolant 224 flows into the heat dissipation chamber from the inlet 222 and then flows out from the outlet 222. The coolant 224 can dissipate heat from the first heat dissipation fins 22 on the printhead 1, thereby dissipating heat from the heat dissipation section 14 of the hot end 10. The heat dissipation fins on the first heat dissipation fins 222 are in contact with the coolant 224, and the flow of the coolant 224 carries away the heat from the first heat dissipation fins 222. The first heat dissipation fins dissipate heat from the heat dissipation section 14 of the hot end through heat conduction via the second heat dissipation surface 221 that is in contact with the heat dissipation section 14. Similarly, this coolant circulation device can also be installed on the tool holder, where the coolant 224 contacts the second heat dissipation fins 52 and carries away heat through its flow. Figure 17b As shown, the first heat dissipation mechanism provided on the printhead 1 can be a fan 62, which blows air to dissipate heat from the heat dissipation section 14 at the hot end of the printhead 1 and / or the first heat dissipation fins 22 provided on the printhead 1.

[0242] A heat dissipation mechanism can also be provided on the tool holder. A second heat dissipation mechanism is provided on the tool holder 50 corresponding to the heat dissipation section 14 or the second heat dissipation fin 52 of the hot end 10. This second heat dissipation mechanism is used to dissipate heat from the heat dissipation section. Further, the second heat dissipation mechanism can be a fan, an air duct, or a coolant circulation device. For example... Figure 13a In Figure 14, the second heat dissipation mechanism provided on each tool holder 50 is a fan 62, which blows air to dissipate heat from the corresponding heat dissipation section and / or heat dissipation fins of the hot end. A third heat dissipation fin is provided on the hot end 10, and a fan 62 corresponding to the third heat dissipation fin is provided on the tool holder 50. The fan 62 is used to blow air to dissipate heat from the third heat dissipation fin.

[0243] The heat dissipation fins (such as the first heat dissipation fin 22, the left first heat dissipation fin 22a, or the right first heat dissipation fin 22b) can be fixedly or movably connected to the print head;

[0244] Alternatively, it may also include a flexible element, with the first heat dissipation fin movably mounted on the print head; the first heat dissipation fin may be... Figure 12a or Figure 14m Upper pressure component 41 or Figure 13a The second heat dissipation fin 52 in the middle, the first heat dissipation fin can also be Figure 14n , Figure 14o , Figure 14k or Figure 6b The left first heat dissipation fin 22a and / or the right first heat dissipation fin 22b in the printhead have an elastic element that provides a spring force for the first heat dissipation fins to abut against the hot end mounted on the printhead; for example Figure 1c The upper pressure member 41 (not shown in the figure) can also be regarded as the first heat dissipation fin;

[0245] Alternatively, the first heat dissipation fin is movably mounted on the print head. When the hot end 10 is mounted on the print head, the elastic force provided by the corresponding elastic element will cause the side-open heat dissipation surface on the first heat dissipation fin to abut against the heat dissipation surface on the heat dissipation section on the hot end 10.

[0246] Or, refer to Figure 6b , Figure 14k , Figure 14n or Figure 14oIt includes two first heat dissipation fins, namely a left first heat dissipation fin 22a and a right first heat dissipation fin 22b. At least one of the left and right first heat dissipation fins is movably connected to the print head. The left and right first heat dissipation fins are respectively provided with elastic elements (they can share the same elastic element or each can be provided with a separate elastic element). For example, elastic elements 242 of coil springs are respectively sleeved on shafts 401 and 402. Each elastic element 242 acts on the left and right first heat dissipation fins respectively. The left and right first heat dissipation fins can rotate around the corresponding shafts. For example, they can be oscillatingly connected to the print head through shafts 401 and 402 respectively. The elastic elements act on the corresponding left and right first heat dissipation fins respectively to provide elastic force for the left and right first heat dissipation fins to swing towards each other or towards the mounting heat end 10.

[0247] Alternatively, it may include two first heat dissipation fins, namely a left first heat dissipation fin 22a and a right first heat dissipation fin 22b, which are movably connected to the print head. The left and right first heat dissipation fins are respectively provided with laterally open heat dissipation surfaces that match the heat dissipation section 14 of the hot end 10. When the hot end 10 is installed on the print head, the laterally open heat dissipation surfaces are in contact with the heat dissipation section. And / or, guide slopes 225 are respectively provided on the side of the left first heat dissipation fin 22a and the right first heat dissipation fin 22b facing the hot end for installation and removal. The two guide slopes 225 form an opening shape that is larger on the outside and smaller on the inside, so that when the heat dissipation section of the hot end 10 is installed from the outside between the left first heat dissipation fins 22a and the right first heat dissipation fin 22b, the left first heat dissipation fins 22a and the right first heat dissipation fin 22b are pushed apart and then installed on the print head.

[0248] Or, such as Figure 14nAs shown, it includes two first heat dissipation fins, namely a left first heat dissipation fin 22a and a right first heat dissipation fin 22b. The left first heat dissipation fin 22a and / or the right first heat dissipation fin 22b are movably connected to the print head. It also includes a rotatable upper swing arm 44 disposed on the left first heat dissipation fin 22a. The left first heat dissipation fin and / or the right first heat dissipation fin are rotatably disposed on the print head. When the hot end 10 is installed on the print head, the left first heat dissipation fin and / or the right first heat dissipation fin swing towards each other and contact the heat dissipation section of the hot end between them. The upper swing arm 44 can swing towards the right first heat dissipation fin 22b and lock the right first heat dissipation fin 22b, so that the left first heat dissipation fin 22a... The hot fin 22a and the right first heat dissipation fin 22b contact and lock the heat dissipation section of the hot end 10 between them; or, the right first heat dissipation fin 22b is provided with an upper locking part corresponding to the upper swing rod 44, and the left first heat dissipation fin and / or the right first heat dissipation fin are rotatably mounted on the print head. When the hot end is installed on the print head, the left first heat dissipation fin and the right first heat dissipation fin swing towards each other and contact the heat dissipation section of the hot end between them. The upper swing rod 44 can swing towards the right first heat dissipation fin 22b and lock the upper locking part 413 on the right first heat dissipation fin, so that the left first heat dissipation fin and the right first heat dissipation fin contact and lock the heat dissipation section of the hot end between them.

[0249] In embodiment 20, the printhead 1 and / or tool holder 50 may be equipped with a presence sensor 61 for detecting the presence (installation) of the hot end 10, and may also be used to detect whether the clamping component is properly clamped. (See Figure 1.) Figure 4 , Figure 8 , Figure 12a , Figure 13a , Figure 13b , Figures 14a to 14p As shown, the presence or absence of the hot end 10 is detected by the presence sensor 61. Furthermore, the presence sensor 61 can be a contact switch, Hall effect switch, or photoelectric switch, etc., which determines the presence or absence of a hot end by detecting the different states of the print head and tool holder when a hot end is present and when it is absent. Figure 14e and Figure 14k As shown, a presence sensor 61 is provided on the print head 1. This presence sensor 61 is positioned opposite the upper pressure member 41. When a hot end 10 is installed on the print head 1, the swinging motion of the upper pressure member 41 triggers the presence sensor 61, for example, bringing it into contact. When no hot end 10 is installed on the print head 1, the reverse swinging motion of the upper pressure member 41 triggers the presence sensor 61 again, for example, no longer bringing it into contact. This allows the presence sensor 61 to determine whether a hot end 10 is installed on the print head 1 based on different states. Of course, the presence sensor 61 can also determine the presence of a hot end by detecting the state of the first swinging pressure rod 31, or the presence sensor 61 can directly detect the presence of a hot end through the hot end itself. Figure 13a , Figure 13b and Figure 14bAs shown, a presence sensor 61 is provided on the tool holder 50. The presence sensor 61 can be installed on the base 57 of the tool holder 50 and is positioned opposite to the limiting member 531. Figure 4 and Figure 14b The image shows two tool holders, tool holder 50A and tool holder 50B. Tool holder 50A has a presence sensor 61-1, and tool holder 50B has a presence sensor 61-2. Tool holder 50A does not have a heated end. A limiting member 531-1 on tool holder 50A triggers the presence sensor 61-1, for example, by contacting the presence sensor 61-1. The limiting member 531-1 is positioned against the holder 57. Tool holder 50B has a heated end 10. The heated end 10 cooperates with a second heating element 51 to cause the limiting member 531-2 to move in the opposite direction, triggering the presence sensor 61-2. For example, the limiting member 531-2 may not be in contact with the presence sensor 61-2, but may be positioned with a certain distance between it and the holder 57. Similarly, this method of implementing presence sensors can also be used in printheads, such as... Figure 14L As shown, the only difference is that the bracket 57 is replaced by the base 27, and the second heating element 51 is replaced by the first heating element 21. The overall structure is changed from being arranged in the second direction to being arranged along the first direction. This mounting structure of the detection sensor is only for illustrative purposes. The detection sensor can also be installed in other ways, such as directly corresponding to the hot end mounting position, using the hot end to trigger the sensor to achieve detection, etc. The detection sensor can be triggered by the first clamping mechanism of the print head or the second clamping mechanism of the tool holder, or it can be triggered by the hot end, or by other means through the installation and removal process of the hot end.

[0250] Example 21: The printhead includes an extrusion port and a feed pipe for conveying printing material to the extrusion port, wherein the feed pipe has a notch to expose the printing material; wherein,

[0251] During cutting, the print head moves to the cutting position of the cutting mechanism and moves toward the cutting blade of the cutting mechanism so that the cutting blade cuts the printed material at the notch; or the print head moves to the cutting position of the cutting structure and the cutting mechanism or cutting blade moves toward the print head so that the cutting blade cuts the printed material at the notch; or the cutting blade of the cutting mechanism moves to the cutting position of the print head and the print head moves toward the cutting blade so that the cutting blade cuts the printed material at the notch; or the cutting blade of the cutting mechanism moves to the cutting position of the print head and the cutting mechanism or cutting blade moves toward the print head so that the cutting blade cuts the printed material at the notch.

[0252] Alternatively, a cutter and a driver can be installed on the print head. The driver can drive the cutter to cut the printed material at the notch. The driver can be a motor, servo motor, cylinder or hydraulic cylinder, etc. A transmission mechanism can also be set to drive the driver and the cutter, such as a linkage, gear pair or synchronous belt drive, etc.

[0253] Or, such as Figure 6c or Figure 16 As shown, the cutting mechanism includes a contact member 584 and a cutting blade 591 disposed on the print head. The cutting blade 591 can be disposed on a rocker arm or the cutting blade 591 can move along the guide structure. During cutting, the print head moves to the corresponding position of the contact member 584 or the contact member 584 moves to the corresponding position of the print head 1. The relative movement of the print head 1 and the contact member 584 causes the cutting blade to cut the printing material 70 at the notch (gap) 18.

[0254] Alternatively, the cutting mechanism includes a switching structure, which is used to switch or change the cutting blade between the working position and the retracted position. When cutting, the switching structure moves or swings the cutting blade to the working position. After cutting, the switching structure moves or swings the cutting blade to the retracted position.

[0255] Alternatively, the cutting mechanism includes a cutting blade and a protective structure;

[0256] Alternatively, the cutting mechanism is a laser, which emits a laser beam to cut the printing material on the print head;

[0257] Alternatively, the cutting mechanism can also be used to cut the printing material on the tool holder.

[0258] A notch (gap) 18 can also be provided on the feed path of the print head 1 to the hot end, which exposes the print material and can be cut by the cutting mechanism 59. The notch 18 can be provided on the feed path of the hot end 10 to expose the print material for easy cutting by the cutting mechanism. For example, the notch 18 can be provided between the hot end 10 and the filament feeder 71 on the print head.

[0259] refer to Figure 6c and Figure 16 The guiding structure can be a guide rail, a rocker arm, or other structure that can limit the movement of the cutting blade along a preset direction; for example... Figure 6c The cutting blade 691 is shown to be capable of translational movement, for example, movement constrained by a guide structure (not shown), and may be provided with an elastic element 243 (such as a compression spring) to elastically act on the cutting blade 591 in a direction away from the notch 18, or as... Figure 16The cutting blade 591 is mounted on a swing arm, which can swing around an axis 306. An elastic element 243, such as a coil spring sleeved on the axis 306, can also be provided to apply elastic force to the cutting blade 591 in a direction away from the notch 18. When cutting is required, the print head 1 and the contact element 584 move relative to each other; for example, the print head 1 moves towards the contact element 584, causing the contact element 584 to push the cutting blade 591 against the elastic force of the elastic element 243, causing the cutting blade 591 to move towards the notch 18 and cut the printed material 70 at the notch 18. After the print head 1 separates from the contact element 584, the cutting blade 591 can leave the notch 18 under the action of the elastic element 243. The contact element 584 can be mounted on the frame of the 3D printer, connected to the guide rail for the movement of the print head 1, mounted on the actuator, or located elsewhere outside the print head 1.

[0260] The cutting mechanism 59 includes a cutting blade, which can be fixedly connected to the guide rail 81 or to the printer frame. The movement of the print head 1 moves the printing material to the cutting mechanism 59, where the cutting blade cuts the printing material at the notch (gap) on the print head. Alternatively, the cutting mechanism 59 can be mounted on the print head 1, and a drive mechanism (such as a servo motor or electric motor) can be provided to move the blade to cut the printing material at the gap. Figure 6a As shown, a drive mechanism 64 can also be set to move the cutting blade 591 towards the gap of the print head to cut the printing material. Figure 6a The cutting mechanism can be mounted on the guide rail 81, for example, by being fixed to the guide rail 81 via the drive mechanism 64. If the guide rail 81 also moves along the Z direction (perpendicular to the direction greater than the platform), the cutting mechanism can also move along the Z direction, but the print head 1 can move along the guide rail 81. Alternatively... Figure 8 As shown, the cutting blade 591 can be mounted on the guide rail 81y. The guide rail 81y can drive the cutting blade 591 to move along its axial direction. Simultaneously, the guide rail 81y can also move along the guide rail 81x. This allows the cutting blade 591 to move along the XY plane, enabling it to reach the cutting position of the print head 1 and penetrate into the notch (gap) 18 of the print head 1 to cut the printing material. The movable cutting blade can be moved in this manner. Figure 8 The XY track type shown can also be used where the cutting blade is mounted on a swing arm, the length of which can be adjusted for movement within the XY plane, or other methods can be used to drive the cutting blade within the XY plane. This reduces the distance the print head needs to move to cut the printing material, and even allows the cutting blade 591 to move synchronously with the print head 1 while cutting the printing material, greatly improving the efficiency of cutting the printing material and reducing the time spent in the cutting process. The cutting blade 591 of the cutting mechanism 59 can be mounted on the frame of the 3D printed part, fixed to the guide rail of the print head, or movable within the XY plane. A protective structure 592 can also be provided, such as... Figure 2, Figure 7 , Figure 8 , Figure 9a , Figure 10a , Figure 10c or Figure 11c As shown in the diagram or other illustrations depicting a similar cutting mechanism 59, the protective structure 592 extends from the cutting edge of the cutting blade 591 and forms a narrow notch. Ideally, the width of this notch is greater than the diameter of the printing material but less than the diameter of a human finger. This allows the printing material to contact the cutting edge of the cutting blade 591 through the notch for cutting, while the larger diameter of a finger is generally blocked by the protective structure, making it less likely for a person's hand to come into contact with the cutting edge of the cutting blade 591, thus enhancing safety. If the cutting mechanism (e.g., the cutting blade paired with the actuator) is located on the print head, the cutting process can be controlled by the actuator to drive the cutting blade to cut the printed material at the notch 18, or the cutting blade can be located on the print head and move elastically toward the notch 18. When not cutting, the cutting blade leaves the gap. When cutting is required, the print head moves toward the contact part fixed to the printer frame or the guide rail (e.g., guide rail 81), allowing the cutting blade to contact the contact part and push it toward the gap to cut the printed material. After the print head moves away, the cutting blade returns to its retracted state due to the action of the elastic element. If the cutting mechanism (e.g., the cutting blade) is not located on the print head, but is located on the cutting tool holder, the cutting process can be that the print head moves to the cutting tool holder, and then the print head moves toward the cutting blade on the cutting tool holder, or the cutting blade extends or swings toward the print head, allowing the cutting blade to insert into the notch 18 on the print head to cut the printed material. Figure 6a The cutting blade 591 on the right side can be driven by the actuator 64 through a lead screw mechanism or a swing mechanism to extend towards the print head and cut the printing material; for example Figure 11a and Figure 11b The cutting mechanism 59a includes a cutting blade 591 mounted on the output shaft of the actuator 64. The cutting blade can be oscillating to cut the printing material at the notch (gap) of the print head. Either the cutting mechanism 59 or 59a can be retained. If the cutting blade can move along the XY plane, the cutting blade can start moving towards the position of the print head before cutting. When cutting, the cutting blade can move to the corresponding cutting position of the print head, and then the cutting blade moves towards the print head or the print head moves towards the cutting blade, so that the cutting blade inserts into the notch 18 of the print head to cut the printing material. Furthermore, during this process, the print head can continue to move, for example, to maintain a normal printing process, while the cutting blade can move synchronously with the print head and perform the cutting process synchronously.

[0261] like Figure 10a and Figure 10cAs shown, the cutting mechanism 59 may also include a buffer and detection structure. For example, the cutting mechanism is equipped with a sensor 610 for detecting the displacement or force of the cutting blade during the cutting process. Figure 10a When the cutting blade 591 experiences excessive force, exceeding the elastic force of the elastic element 541, the cutting blade may overcome the elastic force of the elastic element 541 and move away from the print head along the direction of the force or along the direction defined by the guide structure 503. This movement may trigger the sensor 610. For example, the trigger element 611 can move along with the cutting blade until it triggers the sensor 610. The sensor 610 can be a limit switch, photoelectric switch, or Hall sensor, or it can be a force sensor that directly detects the force on the cutting blade during cutting. During normal cutting, the force on the cutting blade is small and will not cause the cutting blade to shift or trigger the sensor 610. Additionally, the cutting mechanism 59 includes a switching structure, which is used to switch or change the cutting blade between the working position and the retracted position. When cutting, the switching structure moves or swings the cutting blade to the working position; after cutting, the switching structure moves or swings the cutting blade to the retracted position. Figure 10a and Figure 10c As illustrated, the cutting blade 591 of the cutting mechanism 59 is mounted on the connecting part 504, which is located on the output shaft of the drive mechanism 64. The drive mechanism can drive the cutting blade 591 to swing via the connecting part 504, which is shown to swing vertically (through the Z-axis plane) (or around the horizontal axis). When cutting is required, the drive mechanism 64 drives the connecting part 504 to swing to the extended state (working position). Figure 10a As shown, this allows the cutting blade 591 to enter the reachable area or printing area of ​​the print head 1, facilitating the movement of the print head to the cutting position of the cutting mechanism. When cutting is not required, the drive mechanism 64 causes the connecting part 504 to swing to the retracted state (retracted position), as shown. Figure 10c As shown, this allows the cutter to move away from the reachable area or printing area of ​​printhead 1, thus avoiding interference between the printhead and the cutter that limits the printable range of the printhead and increasing the size of the printable model. By swinging vertically, or by swinging the cutter around a horizontal axis perpendicular to the direction of movement of the printhead and the cutter, the cutter can penetrate deeply into the printing area when switched to the working position, and when switched to the retracted state, the cutter can not only move out of the printing area, but also the cutter and the swing arm are vertically positioned, occupying little space.

[0262] like Figures 3 to 5As shown, both the output ports 9a and 9b are connected to the same printhead. For example, output ports 9a and 9b are connected to feed tubes 72a and 72b, respectively. Feed tubes 72a and 72b are connected to the two inlets of a multi-inlet-one-outlet connecting pipe 709, which can be installed on the printhead. The outlet of the multi-inlet-one-outlet connecting pipe 709 faces the hot end 10 of the printhead and communicates with the nozzle 11 on the printhead. A filament feeder 71 can also be installed between the multi-inlet-one-outlet connecting pipe 709 and the hot end 10. For example, the filament feeder 71 is located upstream of the hot end 10 relative to the printing material transport path. The outlet of the aforementioned multi-inlet-one-outlet connecting pipe 709 communicates with the inlet of the filament feeder 71. The filament feeder 71 is used to enhance the driving force or speed of the printing material towards the hot end 10 or the nozzle 11, and can be used to more accurately deliver the printing material to the hot end 10. A notch (gap, slit, or notch) can also be provided between the filament feeder 71 and the hot end 10. This gap can be used by the cutting mechanism 59 (such as a cutting blade) to cut the printing material according to instructions. The multi-inlet / one-outlet connecting pipe 709 does not necessarily need to be located on the print head. For example, the outlet end of the multi-inlet / one-outlet connecting pipe 709 can be connected to one end of the feed pipe, and the other end of the feed pipe can be connected to the feed port (corresponding hot end) on the print head. That is, the outlet end of the multi-inlet / one-outlet connecting pipe 709 can also be connected to the print head via the feed pipe. The multi-inlet / one-outlet connecting pipe 709 can be fixed along with the wires connected to the print head, or fixed to the frame of the print head or the guide rail for print head movement. This helps to reduce the weight of the print head and simplify its structure. The filament feeder 71 can be fixed to the print head or to the outlet end of the multi-inlet / one-outlet connecting pipe (two-inlet / one-outlet connecting pipe) 709.

[0263] Alternatively, a wire feeder can be installed at the discharge port of the switching mechanism, such as... Figure 6a As shown, for example, filament feeders 71 can be installed at discharge ports 9a and 9b, and also at discharge ports 9c and 9d. The filament feeders at the discharge ports can serve as a common feeder for the printing material fed into each feed port of the switching mechanism. These feeders can be more powerful, facilitating the transport of printing material over longer distances or at faster feed rates. This allows for compact structures or less powerful drive forces at the remote filament feeders corresponding to each feed port of the material changing hub, thus saving on the overall cost of the material changing hub or device and reducing its overall size. For harder printing materials or continuous fiber types, filament feeders on the print head are not necessary; other filament feeders on the printing material transport line can be used to feed the printing material to the print head for printing.

[0264] In another preferred embodiment, Figures 3 to 5 The printhead and tool holder shown can also be referenced. Figure 9a, Figure 9b , Figure 10a , Figure 10b , Figure 10c And Figure 10d, and Figure 12, Figure 13a and Figure 13b The printhead 1 can be detachably fitted with the hot end 10. The figure shows the printhead with the hot end 10 installed. The printhead can also be equipped with a heating element 21 for contacting the heating section 12 on the hot end 10 or the heating surface on the heating block 15 on the heating section 12 for heating. Alternatively, the heating element 22 can be electromagnetic induction type, such as a heating induction coil, to heat the hot end 10 by inducing current (forming eddy currents) in the heating section 12 of the hot end 10 in a non-contact manner. A filament feeder 71 can also be provided. The figure shows that the print head 1 also includes a lower clamping mechanism 30 for fixing the hot end 10 to the print head 1 or for pressing the heating surface of the heating block 15 of the hot end 10 against the heating surface 211 of the heating element 21 on the print head. The print head 1 is also provided with a positioning structure 23 for accurately positioning the hot end 10 to ensure the repeatability of the position of its extrusion port 11 after the hot end 10 is replaced. An upper clamping mechanism 40 may also be provided to fix the heat dissipation section of the hot end to the print head or to reliably abut the heat dissipation surface of the heat dissipation section against the heat dissipation surface on the print head, so as to facilitate the heat transfer of the hot end to the heat dissipation fins on the print head for heat dissipation. The printhead 1 may also include heat dissipation fins 22, which have open heat dissipation surfaces 221 for contacting the heat dissipation surfaces on the heat dissipation sections 14 of the hot end 10 for heat dissipation. A clamping mechanism 40 may also be provided on the printhead to press the heat dissipation sections 14 of the hot end 10 against the heat dissipation surfaces 221 of the heat dissipation fins 22 on the printhead. That is, in this embodiment, instead of heat dissipation fins, a heat dissipation surface is provided on the heat dissipation section 14 for contact with the heat dissipation surfaces of the heat dissipation fins on the printhead or tool holder (e.g., through thermal grease or a thermal pad) to conduct heat from the heat dissipation section of the hot end to the heat dissipation fins on the printhead or tool holder for heat dissipation. The laterally open heat dissipation surface is such that the normal to the heat dissipation surface is approximately perpendicular (90 degrees) to the axis of the feed line of the hot end 10, with an error of less than ±40°. A filament feeder 71 may be installed on the printhead to drive the filamentous printing material to feed along its axial direction, for example... Figures 2 to 9a As shown, two rollers can be arranged parallel to each other, with the printing material positioned between them. The axes of the rollers are perpendicular to the axis of the printing material. The rotation of the two rollers drives the feeding of the printing material. Alternatively, as shown... Figure 10a The diagram shows three rollers arranged in parallel around the printing material, with the roller axes parallel to the printing material axis. Only one roller has a threaded protrusion that contacts the printing material to drive it axially. Alternatively, other methods can be used to drive the printing material axially. (See Figure 1 and...) Figure 8As shown, a sensor 61 (detection sensor) can also be installed on the print head to detect whether the hot end 10 is installed on the print head. The figure illustrates that the print head 1 can move along the guide rail 81, and the guide rail 81 can also move along the guide rail 81y, so that the print head 1 can move along the XY plane, or the print head 1 and the printing platform (not shown) can move relative to each other, or the print head can also be mounted on a swing arm and move along an arc trajectory, or the swing arm can also move along the guide rail 81 or 81y. Figure 6a The printhead 1 uses liquid cooling, that is, heat dissipation fins 22 are set on the printhead 1 at the position corresponding to the heat dissipation section of the hot end 10. The heat dissipation fins 22 are placed in the coolant 224. The heat is carried away by the heat dissipation section of the hot end 10 to the heat dissipation fins 22 through the circulation of the coolant inlet 222 and the coolant outlet 223. In this structure, the heat dissipation section of the hot end 10 has a heat dissipation surface in contact with the heat dissipation surface on the heat dissipation fins 22 (direct contact or contact through thermal grease or thermal pad, etc.) for heat conduction and heat dissipation. Figure 5 The heat dissipation fins 22 on the printhead 1 shown in the diagram are located on the printhead rather than on the hot end 10. The hot end 10 of the printhead 1a has heat dissipation fins 142, meaning the heat dissipation fins 22 on the printhead 1 are essentially located on the heat dissipation section of the hot end 10. The printhead 1 can be equipped with a multi-inlet / one-outlet connecting pipe 709. The outlet end of the multi-inlet / one-outlet connecting pipe 709 faces the hot end of the printhead, and the inlet ends can be connected to the corresponding outlet ports of the material changing hub (which can be a combined material changing hub) via feed pipes. The diagram shows the multi-inlet / one-outlet connecting pipe 709 having two inlet ends, but it can also have more, such as three or four inlet ends. The heat dissipation fins and heating element can be movably connected to the printhead or tool holder, and the heat dissipation mechanism can also be movably connected to the printhead or tool holder. The heating element can be movably mounted on the printhead or tool holder, or it can be fixedly mounted on the printhead or tool holder.

[0265] The tool holder assembly 50 may include at least two tool holders, as illustrated in the figure, possibly including tool holders 50a, 50b, 50c, and 50d, or may include more tool holders, such as 50e, 50f, and 50g. The tool holders can be detachably mounted with the hot end 10. Each tool holder may be provided with a heat dissipation fin 22, which has a laterally open heat dissipation surface 221 for contacting the heat dissipation surface of the heat dissipation section 14 on the hot end 10 for heat dissipation. It may also include a tool holder heating element 51 for contacting the heating section 12 on the hot end 10 or the heating surface on the heating block 15 for heating. Alternatively, the tool holder heating element 51 may be inductive, such as a heating induction coil, to heat the heating section 12 of the hot end 10 in a non-contact manner. Figure 3 , Figure 9a and Figure 9b Hot ends 10 are installed on tool holders 50a, 50b, and 50c respectively, while tool holder 50d is idle as it does not have a hot end 10 installed. Figure 1a The diagram shows tool holder 50g in an idle state without a hot end installed, while tool holders 50a, 50b, 50c, 50d, 50e, and 50f are each equipped with a hot end 10. Figure 3 , Figure 7 , Figure 9a and Figure 9b ,as well as Figure 10a , Figure 10b and Figure 10c Each tool holder shown may also be equipped with a gripping mechanism 33 for gripping the hot end and moving it between the print head and the tool holder. The tool holder may also be equipped with a positioning member 53 and a lower clamping mechanism 532. The positioning member 53 may be used to position the hot end installed on the tool holder, and the lower clamping mechanism 532 may be used to fix the hot end to the tool holder. An upper clamping mechanism may also be provided on the tool holder to fix the heat dissipation section of the hot end to the hot end or to reliably abut the heat dissipation surface of the heat dissipation section against the heat dissipation surface of the heat dissipation fins on the tool holder.

[0266] For example, a tool holder assembly may include a first tool holder and a second tool holder, wherein the first tool holder has a first hot end mounted on it, and the second tool holder is idle; the print head and the tool holder are movable relative to each other; when the print head and the first tool holder are moved relative to each other to a corresponding switching position, the hot end on the first tool holder is switched to the print head; when the print head and the second tool holder are moved relative to each other to a corresponding switching position, the hot end on the print head can be switched to the second tool holder. A detection sensor may also be provided on the tool holder to detect whether the hot end is mounted on the tool holder.

[0267] Figure 9a and Figure 9b The illustrated tool holders include 50a, 50b, 50c, and 50d, each with the same structure. These four tool holders are arranged sequentially along the X-axis. Taking tool holder 50d as an example, the tool holder body can also be equipped with heat dissipation fins 22 and a tool holder heating element 51. For example, the laterally open heating surface of the heating element 51 shown in the diagram is parallel to the X-axis or approximately perpendicular to the Y-axis. The laterally open heating surface of the heating element 21 on the printhead 1 is also approximately parallel to the heating surface on the tool holder. A gripping mechanism 33 is provided on the tool holder. The gripping mechanism 33 can be used to grip and move the hot end 10 from the tool holder to the printhead or from the printhead to the tool holder. For example, the gripping mechanism 33 can be telescopically adjusted relative to the body of tool 50d along the Y-axis. Figure 9a The tool holder 9d is shown in the diagram without a hot end, the gripping mechanism 33 is in the retracted state, and the lower clamping mechanism 532 of the tool holder 50d is in the open state. For example, the clamping mechanism 532 includes a rotatable swing plate, which, by rotation, can press the hot end 10 against the body of the tool holder (e.g., Figure 9a(Regarding the state of the lower clamping mechanism on tool holders 50a, 50b, and 50c), rotating the swing plate in the reverse direction can disengage the swing plate from the hot end, such as... Figure 9a The lower clamping mechanism 532 of the middle tool holder 50d is shown. Figure 9b The illustration shows that when the printhead 1 moves to the corresponding switching position on the tool holder 50d, the lower clamping mechanism 30 on the printhead 1 releases its clamping on the hot end 10. The gripping mechanism 33 on the tool holder 50d extends and clamps the hot end 10 on the printhead 1 before moving it towards the tool holder 50d. The illustration shows the state when it has moved halfway. When the hot end 10 moves onto the tool holder 50d, the first positioning feature 153 on the hot end 10 can match and position with the positioning element 53 on the hot tool holder. See also: Figures 10a to 10c The gripping mechanism 33 shown in the figure may consist of two clamping mechanisms that can open and close in the left and right directions, clamping the hot end in the middle in the left and right directions and then moving the hot end. Figure 9b The state shown can also be the intermediate state during the switching of the hot end from the tool holder to the print head 1.

[0268] The various embodiments of the present invention can be adjusted or combined with each other according to specific applications.

[0269] This invention also provides a material changing method for a 3D printing system, which is described below.

[0270] The material changing method of the 3D printing system of the present invention includes the following steps: cutting the first printing material on the print head using a cutting mechanism; switching the printing material on the print head using a material changing device; and continuing printing using the print head. The step "switching the hot end of the print head using a heat exchange end mechanism" can also be performed before, after, or simultaneously with the step "switching the printing material on the print head using a material changing device".

[0271] like Figure 18a As shown, in step one, the first printing material is cut off at the gap above the hot end of the print head, as in step 102.

[0272] Step two, the process of switching printing materials (steps A1 and A2), is to retract the first printing material on the print head to a position outside the print head that is sufficient to clear the feed path of the print head; the next step is to feed the second printing material to be used into the inlet position of the hot end of the print head.

[0273] The step of switching the hot end of the printhead (step B) involves using a heat exchange mechanism to switch the hot end of the printhead. For example, the heat exchange mechanism may include a tool holder, which can be used to switch the hot end. Specifically, the first hot end on the printhead can be switched to the first tool holder, and the second hot end on the second tool holder can be switched to the printhead. Alternatively, a first clamping mechanism or a gripping mechanism can be used. Before the step of switching the hot end of the printhead, the distance between the printhead and the printing platform can be increased, for example, to a second distance (step 111). After the step of switching the hot end of the printhead, the distance between the printhead and the printing platform can be decreased, for example, to a first distance, wherein the second distance is greater than the first distance.

[0274] Figure 18b This illustrates another method for switching printing media.

[0275] Step 1: Cut the first printing material at the gap above the hot end of the print head, as in step 102;

[0276] Step two, proceed with the material replacement process, as in steps A1 and A2;

[0277] Perform the heat exchange end process, such as steps B1, B2, B3 and B4;

[0278] These two steps can be performed in parallel, sequentially, or partially in parallel.

[0279] The process of changing printing media includes,

[0280] Step A1: The first print material on the print head is retracted to a position outside the print head sufficient to clear the feed path of the print head;

[0281] Step A2: The second printing material is fed into the inlet position of the hot end (first hot end or second hot end) of the print head;

[0282] The heat exchange process includes,

[0283] Step B1: The print head moves to the switching position of the first tool holder corresponding to the first hot end of the print head (for switching the hot end from the print head to the tool holder), for example, the first switching position of the first tool holder;

[0284] Step B2: The first hot end of the print head switches to the first tool holder;

[0285] Step B3: The print head moves to the switching position of the second tool holder corresponding to the second hot end to be used in the next step (used to switch the hot end from the tool holder to the print head), for example, the second switching position of the second tool holder;

[0286] Step B4: The second hot end on the second tool holder switches to the print head;

[0287] The heat exchange end step and the printing material replacement step overlap in time, and step B2 is performed after step one is completed, while step B1 can be performed before, after or simultaneously with step one.

[0288] For the same tool holder, the first switching position and the second switching position can be different or the same.

[0289] It may also include the following steps: Step 101 may be performed before step one (i.e., step 102): the first printing material on the print head is retracted to a preset length; or, Step 103 may be performed before step A1: the first printing material on the print head presses the broken end of the printing material in the first hot end into the hot end; or, Step 106 may be performed after step A2: the print head moves to the waste extrusion area and extrudes a preset length of printing material; or, Step 107 may be performed after step A2: the next step will be a pre-preparation process for the printing material; or, Step 111 may be performed before step B1: the distance between the print head and the printing platform is increased to a second distance; or, Step 117 may be performed after step B4: the distance between the print head and the printing platform is decreased to a first distance; or, Step 115 may be performed before step B4: the second hot end on the second tool holder is heated to a preset temperature.

[0290] Furthermore, this requires assessing the time required to heat to the preset temperature based on the heating curve of the heating element on the tool holder and the ambient temperature. This allows the heating of the hot end to begin before the hot end is replaced, ensuring that the hot end is heated to the preset temperature before or when it is replaced on the print head.

[0291] Furthermore, in step one, the print head moves to the cutting tool holder to cut the printing material. The cutting tool holder has a cutting blade. The printing material in the gap between the print head and the cutting tool holder is moved towards the cutting blade on the cutting tool holder to cut the printing material by moving the print head relative to the cutting tool holder. Alternatively, the printing material is cut by moving the cutting blade on the cutting tool holder toward the print head. Step B1 is performed after step one.

[0292] A cutting blade can also be set on the first tool holder. After step B1 is completed, the cutting blade on the first tool holder will cut the first printing material, and then step B2 will be completed.

[0293] During the hot-end switching process, the gap between the printing platform and the print head can be slightly increased. For example, the printing platform can be moved slightly downwards, or the print head can be moved to an area without a printed model or to an area outside the layer pattern of the current printed layer. This is to prevent the extrusion nozzle (nozzle) of the hot end from scraping the printed model or the printing material on the hot end from dripping onto the model during the hot-end switching process. In one specific embodiment of the invention, before the second printing material is fed into the print head, the first printing material cut off on the print head is pulled back to a set position.

[0294] Alternatively, the second printhead can be fed to a preset position near the printhead before the first printhead is cut off;

[0295] Alternatively, the step of moving the printhead to the tool holder where the hot end is not set may be performed before, after, or simultaneously with the step of cutting the first print material on the printhead.

[0296] Alternatively, before cutting the first print material on the print head, the first print material on the print head is pulled back by a preset length; or, after cutting the first print material on the print head, the first print material is driven to feed towards the hot end by a preset length, and the cut end of the first print material is used to press the cut-off print material in the hot end of the print head into the hot end, and then the cut first print material on the print head is pulled back to the set position.

[0297] Alternatively, after feeding the second printing material into the print head, move the print head to the waste extrusion zone to extrude a preset length of printing material;

[0298] Alternatively, after feeding the second printing material into the print head, the next printing material to be used can be pre-loaded into a designated location;

[0299] Alternatively, increase the spacing between the printhead and the print platform to a second spacing before moving the printhead to the tool holder where the hot end is not set;

[0300] Alternatively, after switching the hot end on the tool holder to the print head, reduce the distance between the print head and the print platform to the first distance.

[0301] Alternatively, during the hot end switching process, the printing platform can be moved down a certain distance, or the print head can be moved to an area without a printing pattern, or the print head can be moved to an area outside the layer pattern of the current printing layer.

[0302] Alternatively, heat the hot end of the tool holder to a preset temperature before switching the hot end on the print head;

[0303] Alternatively, before switching the hot end on the tool holder to the print head, the next print material to be used can be fed to the hot end through the feed line connected to the tool holder, and the residual print material in the hot end can be squeezed out and replaced with the next print material to be used, or the empty hot end can be filled with the next print material to be used.

[0304] Alternatively, the switching of the printhead material and the switching of the hot end can be performed in parallel, serially, or partially in parallel.

[0305] In one specific embodiment of the present invention, in the step of cutting the first printing material on the print head, the print head is moved to the cutting position of the cutting mechanism, which is provided with a cutting blade. The first printing material at the notch of the print head is moved toward the cutting blade by the movement of the print head relative to the cutting blade to cut the first printing material, or the first printing material at the notch of the print head is cut by the movement of the cutting blade toward the print head.

[0306] Alternatively, in the step of cutting the first print material on the print head, the cutting blade of the cutting mechanism is driven by the actuator to move to the corresponding cutting position on the print head, and then the cutting blade moves toward the notch of the print head or the print head moves toward the cutting blade to cut the print material.

[0307] Alternatively, in the step of cutting the first print material on the print head, while the print head is printing, the cutting blade of the cutting mechanism is driven by the actuator to move to the corresponding cutting position on the print head. The cutting blade moves synchronously with the print head, and at the same time, the cutting blade moves toward the notch of the print head to cut the print material.

[0308] Alternatively, the cutting mechanism may be equipped with sensors to detect the displacement or force applied to the cutting blade during the cutting process;

[0309] Alternatively, in the step of cutting the first print material on the print head, when cutting is to be performed, the cutting blade of the cutting mechanism is driven by the transformation structure to move (such as move or swing) to the working position, and after the cutting is completed, the cutting blade is driven by the transformation structure to move back to the retracted position.

[0310] Alternatively, a cutter can be installed on the tool holder, and the first printhead can be cut off by the cutter on the tool holder when the printhead is moved to the tool holder where no hot end is set.

[0311] Alternatively, in the step of "using the heat exchanger mechanism to switch the hot end of the print head;", the print head is moved to the switching position of the tool holder without a hot end, and the hot end of the print head is switched and installed on the tool holder without a hot end; the print head is moved to the switching position of the tool holder with a hot end installed, and the hot end on the tool holder is switched and installed on the print head to complete the hot end switching.

[0312] Alternatively, in the step of "using a material changing device to switch the printing material on the print head;", the first printing material is drawn back by the first material source or by the first remote filament feeder so that the first printing material is drawn back to the inlet of the multi-inlet-one-outlet connecting pipe, or the first printing material is further drawn back to avoid the path for conveying other printing materials, and then the second remote filament feeder conveys the second printing material from the second material source to the print head.

[0313] Alternatively, in the step of "switching the printing material on the print head using a material changing device," the print head is connected to at least two outlet ports of the material changing hub via a feeding pipe. During the printing process of the first printing material, the second printing material to be used in the next step and its corresponding second material source are determined. The second printing material is transported to the corresponding second inlet port of the material changing hub or to the inlet end of the corresponding second switching mechanism of the material changing hub using the filament feeder equipped with the second material source. The corresponding second switching mechanism is controlled to connect the second inlet port with the second outlet port of the material changing hub connected to the print head, and the second printing material is transported to the second outlet port. Under the action of the filament feeder, the second printing material is conveyed through the second discharge port along the second feeding path in the feeding pipeline to a position near the intersection of the second feeding path and the first feeding path, ready for use; after the printing process of the first printing material in the current step is completed, the first printing material is cut off at the notch on the print head, and the first printing material is pulled back to the position where the first feeding path and the second feeding path intersect in the feeding pipeline or pulled back to a position that no longer obstructs the feeding path of the second printing material, so as to prevent the first printing material from obstructing the second printing material; under the action of the filament feeder equipped with the second material source, the second printing material is conveyed to the print head, and the print head performs printing of the second printing material;

[0314] Alternatively, the heat exchanger mechanism includes a tool holder and a tool head. The tool holder includes a first tool holder and a second tool holder, and the tool head includes a first tool head or a first tool head and a second tool head. In the step of "switching the hot end of the print head using the heat exchanger mechanism," the print head is moved to the switching position of the first tool holder where no hot end is installed. The first tool head is used to remove the first hot end from the print head and switch it onto the first tool holder. The print head is then moved to the second tool holder, and the second tool head or the first tool head is used to switch the second hot end on the second tool holder onto the print head. Figures 11a to 11gThe print head first moves to the switching position of the first tool holder where no hot end is installed. The first tool head also moves to the corresponding position of the first tool holder. The first tool head extends and retracts towards the print head to clamp the first hot end on the print head, and then extends and retracts towards the first tool holder to switch the first hot end onto the first tool holder. Then the print head moves to the second tool holder. The second tool head or the first tool head clamps the second hot end on the second tool holder and extends and retracts towards the print head to switch the second hot end onto the print head.

[0315] Furthermore, based on such Figure 2 The printing material changing process of the shown material changing system involves retracting the first printing material from a first material source (e.g., material source 731) or retracting the first printing material from a first remote filament feeder to the inlet of the multi-inlet-one-outlet connecting pipe 701 (e.g., detected by the material detection sensor 74 at that location) or further retracting it to avoid the path for conveying other printing materials to the print head; then the second remote filament feeder conveys the printing material from the second material source to the print head.

[0316] In one specific embodiment of the present invention, reference is made to... Figure 1a , Figure 3 , Figure 4 , Figure 7 or Figure 8 The material changing process of the material changing system shown includes a printhead 1. The material changing device includes a material changing hub, which includes several inlet ports and several outlet ports. Each inlet port is provided with a switching mechanism. The inlet end of the switching mechanism is connected to the inlet port, and the outlet end of the switching mechanism has several outlets, which are adapted and connected to each outlet port, so that each inlet port can be connected to any outlet port by changing the state of the switching mechanism. The printhead is connected to at least two outlet ports of the material changing hub through a feeding pipe.

[0317] The process of switching the printing material on the print head includes the following steps:

[0318] The first printing material to be used in the current step of the printhead and its corresponding first material source are determined. Under the conveying of the filament feeder equipped with the first material source, the first printing material is conveyed to the corresponding first feeding port of the material changing center or to the inlet end of the corresponding first switching mechanism of the material changing center. The corresponding first switching mechanism is controlled to connect the first feeding port with the first discharge port in the material changing center that is connected to the printhead, so that the first printing material is conveyed to the first discharge port. Under the action of the filament feeder equipped with the first material source, the first printing material is conveyed to the printhead through the first discharge port along the first feeding path in the feeding pipeline, and the printhead performs printing.

[0319] During the printing process of the first printing material, the second printing material to be used in the next step and its corresponding second material source are determined. Under the action of the filament feeder equipped with the second material source, the second printing material is transported to the corresponding second feeding port of the material changing center or to the inlet end of the corresponding second switching mechanism of the material changing center. The corresponding second switching mechanism is controlled to connect the second feeding port with the second discharge port in the material changing center that is connected to the print head, and the second printing material is transported to the second discharge port. Under the action of the filament feeder equipped with the second material source, the second printing material is transported through the second discharge port along the second feeding path in the feeding pipeline to a position near the intersection of the second feeding path and the first feeding path, ready for use.

[0320] After the printing process of the first printing material in the current step is completed, the first printing material is cut off at the notch (gap) on the print head or at a position downstream of the printing material conveying direction where the second feeding path intersects with the first feeding path. The first printing material is then pulled back to the position where the first feeding path intersects with the second feeding path in the feeding pipeline or back to a position that no longer obstructs the feeding path of the second printing material (such as the inlet of the multi-inlet and one-outlet connecting pipe on the print head) to prevent the first printing material from obstructing the second printing material.

[0321] The second printing material is fed into the print head by the filament feeder of the second material source, and the print head prints the second printing material.

[0322] In one specific embodiment of the present invention, reference is made to... Figure 5 or Figure 6a As shown, the material changing device includes a material changing hub, which includes several inlet ports and several outlet ports. Each inlet port is provided with a switching mechanism. The inlet end of the switching mechanism is connected to the inlet port, and the outlet end of the switching mechanism has several outlets, which are adapted and connected to each outlet port, so that each inlet port can be connected to any outlet port by changing the state of the switching mechanism. There are two or more printheads, and each printhead is connected to at least one outlet port of the material changing hub through a feeding pipe.

[0323] The process of switching the printing material on the printhead includes the following steps:

[0324] The first print head (e.g., print head 1), the first printing material, and its corresponding first material source are determined for the current step. Under the action of the filament feeder equipped with the first material source, the first printing material is transported to the corresponding first feed port of the material changing center or to the inlet end of the corresponding first switching mechanism of the material changing center. The corresponding first switching mechanism is controlled to connect the first feed port with the first discharge port in the material changing center that is connected to the first print head. Then, under the action of the filament feeder equipped with the first material source, the first printing material is transported to the first print head through the first discharge port and along the first feeding path in the feeding pipeline. The first print head then performs printing.

[0325] During the printing process of the first printing material, the second print head (such as print head 1a), the second printing material, and its corresponding second material source to be used in the next step are determined. Then, under the action of the filament feeder equipped with the second material source, the second printing material is transported to the corresponding second feeding port of the material changing center or to the inlet end of the corresponding second switching mechanism of the material changing center. The corresponding second switching mechanism is controlled to connect the second feeding port with the second discharge port in the material changing center that is connected to the second print head. Under the action of the filament feeder equipped with the second material source, the second printing material is transported to the second print head through the second discharge port and along the second feeding path of the feeding pipeline, ready for use.

[0326] After the first printing process is completed, the first print head is moved out of the printing area, and then the second print head is moved into the printing area to print the second printing material; or, the first print head and the second print head print simultaneously in the printing area.

[0327] The present invention has been described in detail above with reference to the accompanying drawings and embodiments. Those skilled in the art can make various modifications to the present invention based on the above description. Therefore, certain details in the embodiments should not be construed as limiting the present invention, and the scope of protection of the present invention shall be defined by the appended claims.

Claims

1. A 3D printing system with a refilling function, characterized in that, The 3D printing system with the material changing function comprises a printing head, a material changing device, a hot end and a cutting mechanism. The printing head is detachably mounted on the hot end. The material changing device is used to connect with the printing head and realize the switching of printing material. The cutting mechanism is used to cut off the printing material on the printing head.

2. The 3D printing system with refilling function according to claim 1, wherein, The material changing device comprises a material changing hub, the material changing hub comprises a plurality of material inlet ports and a plurality of material outlet ports, each material inlet port is respectively provided with a switching mechanism, the inlet end of the switching mechanism is connected with the material inlet port, the outlet end of the switching mechanism is a plurality of and respectively connected with each material outlet port, so as to make each material inlet port be able to be connected with any material outlet port by changing the state of the switching mechanism.

3. The 3D printing system with the refilling function according to claim 2, wherein, Each switching mechanism is provided with a material conveying structure, the material conveying structure comprises a plurality of output manifolds or a plurality of material conveying channels; the material conveying structure is used to receive the material inlet end of the printing material and is connected with the outlet end of the switching mechanism, and the material outlet end of the material conveying structure is connected with each material outlet port; or, Each material outlet port is provided with a channel structure, the channel structure is tapered, the port for receiving the printing material into the channel structure is the large end and faces the outlet end of the switching mechanism, the projection of the outlet end of each switching mechanism along the conveying direction of the printing material falls in the port for receiving the printing material in the channel structure, and the port for discharging the printing material in each channel structure forms the material outlet port.

4. The 3D printing system with the material changing function according to claim 2, wherein The switching mechanism is one or a combination of the following, The switching mechanism comprises a rotating body and a rotating support body for supporting the rotating body to rotate around its own axis; the rotating body is provided with a material conveying channel, and in the direction of the printing material inlet, the projection of the port for receiving the printing material into the material conveying channel always at least partially overlaps with the projection of the inlet end; The port for discharging the printing material of the material conveying channel is arranged at a distance from the axis of the rotating body; the outlet end of the switching mechanism is arranged at a corresponding position on the rotating path of the port for discharging the printing material of the material conveying channel; or, The switching mechanism comprises a rotating body and a rotating support body for supporting the rotating body to rotate around its own axis; a feeding channel is formed in the rotating body, and the port for receiving printing material into the feeding channel and the port for discharging printing material from the feeding channel are both arranged on the outer circumferential surface of the rotating body; the port for receiving printing material into the feeding channel has a plurality of ports, and all of the ports are in communication with the common port for discharging printing material; the outlet end of the switching mechanism is arranged at corresponding positions on the rotating path of the common port for discharging printing material of the feeding channel; when the rotating body moves to a plurality of positions respectively so that each port for receiving printing material into the feeding channel is opposite to the inlet end of the switching mechanism, the common port for discharging printing material of the feeding channel is opposite to the outlet end of the switching mechanism one by one; or, The switching mechanism comprises a rotating body and a rotating support body for supporting the rotating body to rotate around its own axis; a plurality of feeding channels are formed in the rotating body, and the port for receiving printing material into the feeding channel and the port for discharging printing material from the feeding channel are both arranged on the outer circumferential surface of the rotating body; when the rotating body moves to a plurality of positions respectively so that each port for receiving printing material into the feeding channel is opposite to the inlet end of the switching mechanism, each port for discharging printing material of the feeding channel is opposite to the outlet end of the switching mechanism one by one; or, The switching mechanism comprises a rotating body and a rotating support body for supporting the rotating body to rotate around its own axis; a feeding channel is formed in the rotating body, and the port for receiving printing material into the feeding channel and the port for discharging printing material from the feeding channel are both arranged on the outer circumferential surface of the rotating body, the outlet end of the switching mechanism is arranged at corresponding positions on the rotating path of the outlet for discharging printing material of the feeding channel, the port for receiving printing material into the feeding channel is tapered, the port for receiving printing material into the feeding channel is large and faces the inlet end; when the rotating body moves to a plurality of positions respectively so that each port for discharging printing material from the feeding channel is opposite to the outlet end of the switching mechanism, the projection of the inlet end of the switching mechanism in the direction of printing material feeding always falls in the port for receiving printing material of the feeding channel; or, The switching mechanism comprises a sliding body and a sliding support body for supporting the sliding body to slide; the outlet end of the switching mechanism is arranged along the movement track of the sliding body; a plurality of feeding channels are formed in the sliding body, and when the sliding body moves to a plurality of positions respectively so that each port for receiving printing material into the feeding channel is opposite to the inlet end of the switching mechanism, each port for discharging printing material of the feeding channel is opposite to each outlet end of the switching mechanism one by one; or, The switching mechanism comprises a sliding body and a sliding support body for supporting the sliding of the sliding body; the outlet ends of the switching mechanism are arranged along the movement track of the sliding body; the sliding body is provided with a material conveying channel; the ports for receiving the printing material into the material conveying channel are provided with a plurality of ports, and the common port for discharging the printing material from the material conveying channel is in communication with the ports; when the sliding body moves to a plurality of positions in which the ports for receiving the printing material into the material conveying channel are opposite to the inlet ends of the switching mechanism, the common port for discharging the printing material from the material conveying channel is opposite to the outlet ends of the switching mechanism; or, The switching mechanism comprises a sliding body and a sliding support body for supporting the sliding of the sliding body; the outlet ends of the switching mechanism are arranged along the movement track of the sliding body; the sliding body is provided with a material conveying channel; the material conveying channel is tapered; the port for receiving the printing material into the material conveying channel is the large end and faces the inlet end of the switching mechanism; when the sliding body moves to a plurality of positions in which the ports for discharging the printing material from the material conveying channel are opposite to the outlet ends of the switching mechanism, the projection of the inlet end of the switching mechanism along the printing material feeding direction always falls in the port for receiving the printing material into the material conveying channel; or, The switching mechanism comprises a moving body and a moving support body for supporting the movement of the moving body; the outlet ends of the switching mechanism are arranged along the movement track of the moving body; wherein the inlet end of the switching mechanism is connected with the moving body through a connecting pipe; or, The switching mechanism comprises a flipping body and a flipping support body for supporting the rotation of the flipping body around the flipping axis thereof; the flipping support body is provided with a material conveying channel; the material conveying channel comprises a feeding section for receiving the printing material into and two discharging sections for discharging the printing material; the feeding section is connected with the two discharging sections; the flipping body is pivotally connected between the two discharging sections or between the feeding section and the two discharging sections; or the flipping body can rotate around an axis perpendicular to the axis of the feeding section and / or the axis of the discharging section; the port for receiving the printing material into the feeding section forms the inlet end of the switching mechanism; the ports for discharging the printing material from the discharging sections form the outlet ends of the switching mechanism; or, The switching mechanism comprises a flipping body and a flipping support body for supporting the rotation of the flipping body around the flipping axis thereof; the flipping support body is provided with a material conveying channel; the material conveying channel comprises a feeding section for receiving the printing material into and two discharging sections for discharging the printing material; the feeding section is connected with the two discharging sections; the flipping body is pivotally connected between the two discharging sections or between the feeding section and the two discharging sections; or the flipping body can rotate around an axis perpendicular to the axis of the feeding section and / or the axis of the discharging section; the port for receiving the printing material into the feeding section forms the inlet end of the switching mechanism; the ports for discharging the printing material from the discharging sections form the outlet ends of the switching mechanism; or, The switching mechanism comprises a rotating body and a rotating support body, the rotating support body is provided with a material conveying channel, the material conveying channel comprises a feeding section for receiving printing material and a plurality of discharging sections for discharging printing material, the feeding section intersects with the plurality of discharging sections, the rotating body is rotatably arranged on the rotating support body around a rotating axis, or the rotating body is rotatable around the axis of the feeding section, when the rotating body rotates to a corresponding position, the inlets of the discharging sections other than the discharging section corresponding to the position are shielded, the port of the feeding section for receiving printing material forms the inlet end of the switching mechanism, and the ports of the discharging sections for discharging printing material respectively form the outlet ends of the switching mechanism; or The switching mechanism comprises a rotating body and a rotating support body for supporting the rotating body to rotate around its own axis; the rotating body is provided with a plurality of material conveying channels, the ports of the material conveying channels for receiving printing material are arranged on the first end face of the rotating body, and the ports of the material conveying channels for discharging printing material are arranged on the second end face of the rotating body; the ports of the material conveying channels for receiving printing material are a plurality of ports and are all in communication with the common ports of the material conveying channels for discharging printing material; the outlet ends of the switching mechanism are arranged at corresponding positions on the rotating path of the common ports of the material conveying channels for discharging printing material in a circumferential direction; when the rotating body moves to a plurality of positions respectively so that the ports of the material conveying channels for receiving printing material are opposite to the inlet end of the switching mechanism, the common ports of the material conveying channels for discharging printing material are opposite to the outlet ends of the switching mechanism one by one; or The switching mechanism comprises a rotating body and a rotating support body for supporting the rotating body to rotate around its own axis; the rotating body is provided with a material conveying channel, the ports of the material conveying channels for receiving printing material are arranged on the first end face of the rotating body, and the ports of the material conveying channels for discharging printing material are arranged on the second end face of the rotating body; when the rotating body moves to a plurality of positions respectively so that the ports of the material conveying channels for receiving printing material are opposite to the inlet end of the switching mechanism, the ports of the material conveying channels for discharging printing material are opposite to the outlet ends of the switching mechanism one by one; or The switching mechanism comprises a rotating body and a rotating support body for supporting the rotating body to rotate around its own axis; a material conveying channel is formed in the rotating body, an inlet port for receiving printing material is arranged on a first end surface of the rotating body, an outlet port for discharging printing material is arranged on a second end surface of the rotating body, outlet ends of the switching mechanism are arranged at corresponding positions on a rotating path of the outlet port for discharging printing material of the material conveying channel in a circumferential direction, the inlet port for receiving printing material of the material conveying channel is tapered, the inlet port for receiving printing material of the material conveying channel is large at the end and faces the inlet end; when the rotating body moves to a plurality of positions at which the outlet port for discharging printing material of the material conveying channel is opposite to the outlet ends of the switching mechanism, respectively, a projection of the inlet end of the switching mechanism in the direction of printing material feeding always falls in the inlet port for receiving printing material of the material conveying channel. 5.The 3D printing system with refueling function of claim 3, wherein, At least one of the feeding ports is provided with two or more switching mechanisms, the switching mechanisms are divided into at least two levels in the conveying direction of the printing material, and each level comprises one or more switching mechanisms; Alternatively, When the switching mechanisms are divided into two levels in the conveying direction of the printing material, the inlet end of the switching mechanism in the uppermost level is connected to the feeding port, the inlet end of the switching mechanism in the lowermost level is connected to the outlet end of the switching mechanism in the uppermost level, and the inlet port for receiving printing material in the material conveying structure is connected to the idle outlet end of each switching mechanism, respectively; or When the switching mechanisms are divided into three or more levels in the conveying direction of the printing material, the inlet end of the switching mechanism in the uppermost level is connected to the feeding port, the inlet end of the switching mechanism in the intermediate level is connected to the outlet end of the switching mechanism in the upper level, the outlet end of the switching mechanism in the intermediate level is connected to the inlet end of the switching mechanism in the lower level, and the inlet port for receiving printing material in the material conveying structure is connected to the idle outlet end of each switching mechanism, respectively.

6. The 3D printing system with material changing function as described in claim 2, characterized in that, a The material changing hub has s feeding ports and m discharge ports; the outlet ends of the switching mechanisms are a plurality of and are connected to the discharge ports in adaptation, respectively, wherein When the switching mechanisms are arranged in one level in the conveying direction of the printing material, the switching of the communication line for conveying printing material from the feeding port to the discharge port is realized by the switching mechanism, then the material changing hub can comprise s switching mechanisms, each switching mechanism comprises one inlet end and m outlet ends, the inlet end of each switching mechanism is connected to the feeding port of the material changing hub in correspondence or the inlet end of each switching mechanism forms the feeding port of the material changing hub, and the outlet end of each switching mechanism is connected to the discharge port of the material changing hub in correspondence; or When the switching mechanisms are arranged in multiple levels along the conveying direction of the printing material, an outlet end of a switching mechanism in an upper level is connected to an inlet end of a corresponding switching mechanism in a lower level to form a cascaded switching mechanism, and the switching of the communication line from the feeding port to the discharging port for conveying the printing material is realized through the cascaded switching mechanism, then s cascaded switching mechanisms are adopted, each of which has m idle outlet ends, the inlet end of each switching mechanism in the uppermost level is connected to the feeding port of the material switching hub or forms the feeding port of the material switching hub, and the discharging port is connected to the idle outlet end of each cascaded switching mechanism, wherein s and m are positive integers greater than or equal to 2.

7. The 3D printing system with refilling function according to claim 2, characterized in that, characterized in that: The material switching device further comprises a plurality of material sources, each of which is connected to a corresponding feeding port of the material switching hub; wherein The printing head is connected to at least two discharging ports of the material switching hub through a feeding pipeline; Alternatively, the printing head has two or more, and each of the printing heads is connected to at least one discharging port of the material switching hub through a feeding pipeline; Alternatively, the material switching device is further used for switching the printing material for the tool seat, and at least one discharging port of the material switching device is connected to a corresponding tool seat for conveying the printing material to the tool seat; Alternatively, the material switching device further comprises a remote material feeder arranged corresponding to the material source, which is used for conveying the printing material to the material switching hub through the feeding pipeline; Alternatively, a material feeder is arranged on the feeding pipeline between the material switching device and the extrusion port of the printing head, which is used for conveying the printing material to the extrusion port of the printing head; Alternatively, the switching of the printing material and the switching of the hot end can be performed in parallel, in series or partially in parallel; Alternatively, a material detection sensor is arranged on the printing material conveying line, which is used for detecting whether the printing material exists on the corresponding conveying line.

8. The 3D printing system with a material switching function according to claim 7, wherein The material switching device comprises a plurality of material switching hubs, each of which is configured with a plurality of material sources, wherein The printing head is connected to at least one discharging port of each of the material switching hubs through a feeding pipeline; or Each of the material switching hubs forms a combined material switching hub, the combined material switching hub further comprises a plurality of multi-inlet and single-outlet connecting pipes, the outlet ends of the plurality of multi-inlet and single-outlet connecting pipes form or are connected to the discharging ports of the combined material switching hub, the inlet ends of the plurality of multi-inlet and single-outlet connecting pipes are connected to the discharging ports of each of the material switching hubs, the feeding ports of each of the material switching hubs form or are connected to the feeding ports of the combined material switching hub, each of the feeding ports of the combined material switching hub can be connected to any of the discharging ports of the combined material switching hub by changing the state of the switching mechanism, and the discharging ports of the combined material switching hub are connected to the printing head through a feeding pipeline; or Each of the material exchange hubs forms a combined material exchange hub, the combined material exchange hub further comprises a plurality of multi-in-one-out connecting pipes, the plurality of multi-in-one-out connecting pipes are divided into two levels along the conveying direction of the printing material, the outlet ends of the multi-in-one-out connecting pipes in the lowermost level form or are connected to the outlet ports of the combined material exchange hub respectively, the outlet ends of the multi-in-one-out connecting pipes in the uppermost level are connected to the inlet ends of different multi-in-one-out connecting pipes in the lowermost level respectively, the outlet ports of each of the material exchange hubs are connected to the idle inlet ends of the multi-in-one-out connecting pipes respectively, the inlet ports of each of the material exchange hubs form or are connected to the inlet ports of the combined material exchange hub respectively, each of the inlet ports of the combined material exchange hub can be connected to any of the outlet ports of the combined material exchange hub by changing the state of the switching mechanism, and the outlet ports of the combined material exchange hub are connected to the print head through the feeding pipeline respectively; or Each of the material exchange hubs forms a combined material exchange hub, the combined material exchange hub further comprises a plurality of multi-in-one-out connecting pipes, the plurality of multi-in-one-out connecting pipes are divided into three or more levels along the conveying direction of the printing material, the outlet ends of the multi-in-one-out connecting pipes in the lowermost level form or are connected to the outlet ports of the combined material exchange hub respectively, the outlet ends of the multi-in-one-out connecting pipes in the intermediate levels are connected to the inlet ends of different multi-in-one-out connecting pipes in the next level respectively, the inlet ends of the multi-in-one-out connecting pipes in the intermediate levels are connected to the outlet ends of the multi-in-one-out connecting pipes in the previous level, the outlet ports of each of the material exchange hubs are connected to the idle inlets of the multi-in-one-out connecting pipes respectively, the inlet ports of each of the material exchange hubs form or are connected to the inlet ports of the combined material exchange hub respectively, each of the inlet ports of the combined material exchange hub can be connected to any of the outlet ports of the combined material exchange hub by changing the state of the switching mechanism, and the outlet ports of the combined material exchange hub are connected to the print head through the feeding pipeline respectively; or Each of the material replacement hubs forms a combined material replacement hub, the combined material replacement hub further comprises a plurality of multi-input-and-single-output connecting pipes, the plurality of multi-input-and-single-output connecting pipes are arranged in a plurality of levels along the conveying direction of the printing material, the number of inlets of the multi-input-and-single-output connecting pipes is equal to or greater than the number of the material replacement hubs, the combined material replacement hub comprises n material replacement hubs, each material replacement hub has m material outlet ports, m multi-input-and-single-output connecting pipes are used, the corresponding material outlet ports of each material replacement hub are respectively connected to the inlet ends of the multi-input-and-single-output connecting pipes, the outlet ends of the multi-input-and-single-output connecting pipes are respectively connected to the material outlet ports of the combined material replacement hub or form the material outlet ports of the combined material replacement hub, the material inlet ports of each of the material replacement hubs form or are respectively connected to the material inlet ports of the combined material replacement hub, each of the material inlet ports of the combined material replacement hub can be connected to any of the material outlet ports of the combined material replacement hub by changing the state of the switching mechanism, and the material outlet ports of the combined material replacement hub are respectively connected to the print head through the feeding pipeline; wherein m and n are positive integers greater than or equal to 2; or Each of the material replacement hubs forms a combined material replacement hub, the combined material replacement hub further comprises a plurality of multi-input-and-single-output connecting pipes, the plurality of multi-input-and-single-output connecting pipes are arranged in a plurality of levels along the conveying direction of the printing material, the outlet ends of the multi-input-and-single-output connecting pipes of a previous level are connected to an inlet end of the multi-input-and-single-output connecting pipes of a next level to form cascaded multi-input-and-single-output connecting pipes, the combined material replacement hub comprises n material replacement hubs, each material replacement hub has m material outlet ports, m cascaded multi-input-and-single-output connecting pipes can be used, each cascaded multi-input-and-single-output connecting pipe has n idle or more than n inlets, the corresponding material outlet ports of each material replacement hub are respectively connected to the idle inlets of the cascaded multi-input-and-single-output connecting pipes, the outlet ends of the multi-input-and-single-output connecting pipes of the lowest level are connected to the material outlet ports of the combined material replacement hub or form the material outlet ports of the combined material replacement hub, the material inlet ports of each of the material replacement hubs form or are respectively connected to the material inlet ports of the combined material replacement hub, each of the material inlet ports of the combined material replacement hub can be connected to any of the material outlet ports of the combined material replacement hub by changing the state of the switching mechanism, and the material outlet ports of the combined material replacement hub are respectively connected to the print head through the feeding pipeline; wherein m and n are positive integers greater than or equal to 2.

9. The 3D printing system of claim 2, wherein, The plurality of material inlet ports of the material replacement hub are respectively connected to corresponding material sources, and the print head is connected to at least two material outlet ports of the material replacement hub through the feeding pipeline. The first printing material currently used by the printing head and its corresponding first material source are transported to the corresponding first feeding port of the material switching hub or to the inlet end of the corresponding first switching mechanism of the material switching hub under the transport of the feeding device equipped with the first material source; the corresponding first switching mechanism is controlled to operate so that the first feeding port is connected to the first discharging port in the material switching hub connected to the printing head, and the first printing material is transported to the first discharging port, and the first printing material is transported along the first feeding path in the feeding pipeline through the first discharging port under the action of the feeding device equipped with the first material source, and the printing head performs printing; During the printing of the first printing material, the second printing material to be used next and its corresponding second material source are determined, and the second printing material is transported to the corresponding second feeding port of the material switching hub or to the inlet end of the corresponding second switching mechanism of the material switching hub under the action of the feeding device equipped with the second material source; the corresponding second switching mechanism is controlled to operate so that the second feeding port is connected to the second discharging port in the material switching hub connected to the printing head, and the second printing material is transported to the second discharging port, and the second printing material is transported along the second feeding path in the feeding pipeline through the second discharging port under the action of the feeding device equipped with the second material source, and the second printing material is transported to a position close to the intersection of the second feeding path and the first feeding path; After the current printing process of the first printing material is completed, the first printing material is cut off at the gap on the printing head or at a position downstream of the intersection of the second feeding path and the first feeding path in the direction of printing material transport, and the first printing material is drawn back to a position at which the first feeding path and the second feeding path intersect in the feeding pipeline or to a position that no longer blocks the feeding path of the second printing material, so as to prevent the first printing material from blocking the second printing material; The second printing material is transported into the printing head under the action of the feeding device equipped with the second material source, and the printing head performs printing of the second printing material. 10.The 3D printing system with refueling function of claim 1, wherein, Further comprising a heat exchange end mechanism, wherein The heat exchange end mechanism comprises a tool seat for detachably mounting the heat end, and the printing head and the tool seat can switch the heat end therebetween, The material switching device is used to be connected to the printing head and to realize switching of the printing material, or the material switching device is used to be connected to the printing head and to realize switching of the printing material and to be connected to the tool seat and to realize switching of the printing material, The cutting mechanism is used to cut the printing material on the printing head, or the cutting mechanism is used to cut the printing material on the printing head and the printing material on the tool seat; and / or The heat exchange end mechanism comprises a clamping member movably connected to the printing head or the tool seat, and the clamping member can clamp the heat end to the printing head or the tool seat through movable adjustment and can also release the clamping of the heat end. ​ And / or, the heat exchange end mechanism comprises a first limiting structure, so that the heat end is mounted on or detached from the print head along a direction perpendicular to the feeding pipe of the heat end or along a direction along the feeding pipe of the heat end; the first limiting structure can comprise a clamping member movably connected to the print head and / or a first positioning mechanism; And / or, the heat exchange end mechanism comprises a grabbing mechanism, which can be used to mount or detach the heat end on or from the print head; And / or, The heat exchange end mechanism comprises a poking member and a clamping member movably connected to the print head, the clamping member is provided with a poking part, and the clamping member can clamp the heat end to the print head through movable adjustment; the poking member can poke the poking part on the clamping member to make the clamping member move to release the clamping of the heat end.

11. The 3D printing system with a material replacement function according to claim 10, wherein The tool seat is provided with at least two, and at least one of the tool seats is not provided with a heat end when the print head is provided with a heat end; wherein The print head and the tool seat can be relatively moved, so that the heat end on the print head can be mounted on the tool seat and the heat end on the tool seat can be mounted on the print head through relative movement; Or, the tool seat is provided with a grabbing mechanism, which is used to grab the heat end and move the heat end to the print head or the tool seat to complete the switching of the heat end from the print head to the tool seat or the switching of the heat end from the tool seat to the print head; Or, further comprising a tool head movable along a second guide rail, the second guide rail is arranged along the arrangement direction of the tool seat, the tool head can be moved to the corresponding position of each tool seat, the tool head comprises a grabbing mechanism, which is used to grab the heat end and move the heat end to the print head or the tool seat to complete the switching of the heat end from the print head to the tool seat or the switching of the heat end from the tool seat to the print head; Or, the tool head can further comprise a poking member, which can open the clamping member on the print head or the tool seat. Or, the tool seat is connected with a feeding pipe, and a feeder is arranged on the conveying line of the print material in the feeding pipe, the feeder conveys the print material in the feeding pipe into the corresponding heat end in the tool seat, extrudes the residual print material in the heat end, and replaces the print material in the feeding pipe, so that the print material in the heat end is the print material to be used in the next step or fills the empty heat end with the print material to be used in the next step when the heat end is switched with the print head; and / or, the material replacement device is also used for switching the print material of the tool seat; The switching of the print material and the switching of the heat end of the print head and / or the tool seat can be performed in parallel, in series or partially in parallel.

12. The 3D printing system with refilling function according to claim 11, characterized in that, The grabbing mechanism on the tool seat can be adjusted in extension and retraction relative to the tool seat, the grabbing mechanism comprises a pair of clamping members with adjustable clamping distance, and the pair of clamping members can clamp the corresponding heat end by adjusting the clamping distance; Or, the tool seat is provided with a grabbing mechanism which is telescopic relative to the tool seat, the grabbing mechanism comprises a clamping piece which is rotatable around a rotation axis, and the clamping piece is connected with a driving mechanism which can drive the clamping piece to rotate around the rotation axis and thereby clamps or releases the corresponding hot end; and / or, the grabbing mechanism comprises a pair of clamping pieces, and one end of the clamping piece close to the hot end is provided with a grabbing head, and the hot end is provided with a groove corresponding to the grabbing head; Or, the tool seat is further provided with an upper grabbing mechanism for grabbing the heat dissipation section of the hot end; Or, the tool head is further provided with a printing platform, and the telescopic adjustment direction of the grabbing mechanism is arranged at an angle with the Z axis or the axis of the feeding pipe of the hot end, so that when the grabbing mechanism clamps the hot end and moves away from the printing head, the grabbing mechanism clamps the hot end and also moves away from the printing platform; when the grabbing mechanism clamps the hot end and moves towards the printing head, the grabbing mechanism clamps the hot end and also moves towards the printing platform; Or, the tool head is further provided with a tool head; Or, the hot end can be mounted on or removed from the printing head along a first direction, and the hot end mounted on the printing head is limited in a second direction; the hot end can be mounted on or removed from the tool seat along the second direction, and the hot end mounted on the tool seat is limited in the first direction; wherein the second direction is arranged at an angle with the first direction; Or, the printing head and the tool seat are relatively moved so that the printing head passes through a first switching position, a mounting position of the hot end on the tool seat and a second switching position in sequence, thereby realizing switching and mounting the hot end on the printing head to the tool seat or switching and mounting the hot end on the tool seat to the printing head; Or, the printing head and the tool seat are relatively moved so that the printing head passes through a second switching position, a mounting position of the hot end on the tool seat and a first switching position in sequence, thereby realizing switching and mounting the hot end on the tool seat to the printing head or switching and mounting the hot end on the printing head to the tool seat; Or, A relay position is arranged near the first switching position and the mounting position of the hot end on the tool seat; the printing head and the tool seat are relatively moved so that the printing head passes through the first switching position, the relay position, the mounting position of the hot end on the tool seat and the second switching position in sequence, thereby realizing switching and mounting the hot end on the printing head to the tool seat or switching and mounting the hot end on the tool seat to the printing head; Or, a relay position is arranged near the first switching position and the mounting position of the hot end on the tool seat, and the relative movement of the print head and the tool seat is such that the print head passes through the first switching position, the mounting position of the hot end on the tool seat, the relay position and the first switching position in sequence, so as to realize the switching mounting of the hot end on the tool seat to the print head or the switching mounting of the hot end on the print head to the tool seat. Or, The relative movement of the print head and the tool seat is such that the print head passes through the first switching position of the tool seat, moves relatively close to the tool seat in a first direction, then moves relatively close to the mounting position of the hot end on the tool seat in a second direction, reaches the mounting position of the hot end on the tool seat, then moves relatively away from the tool seat in the first direction and reaches the second switching position of the tool seat, so as to realize the switching mounting of the hot end on the print head to the tool seat or the switching mounting of the hot end on the tool seat to the print head. Or, the relative movement of the print head and the tool seat is such that the print head passes through the first switching position of the tool seat, moves relatively close to the tool seat in a first direction, reaches the mounting position of the hot end on the tool seat, then moves relatively away from the mounting position of the hot end on the tool seat in a second direction, and then moves relatively away from the tool seat in the first direction and reaches the second switching position, so as to realize the switching mounting of the hot end on the tool seat to the print head or the switching mounting of the hot end on the print head to the tool seat. Or, the relative movement of the print head and the tool seat is such that the print head passes through the first switching position, the second switching position, the mounting position of the hot end on the tool seat and the first switching position in sequence, so as to realize the switching mounting of the hot end on the tool seat to the print head or the switching mounting of the hot end on the print head to the tool seat. Or, a relay position is arranged near the first switching position and the mounting position of the hot end on the tool seat, and the relative movement of the print head and the tool seat is such that the print head passes through the first switching position, the mounting position of the hot end on the tool seat, the relay position and the first switching position in sequence, so as to realize the switching mounting of the hot end on the tool seat to the print head or the switching mounting of the hot end on the print head to the tool seat. And / or, The direction of the relative movement of the print head and the tool seat and / or the first direction and / or the second direction is in the XY plane or perpendicular to the Z axis or perpendicular to the axis of the feeding pipe of the hot end or perpendicular to the axis of the extrusion port of the print head or perpendicular to the normal of the surface of the print platform for carrying the extrusion printing material of the print head, with an error of not more than ±45°. The relative movement of the print head and the tool seat includes movement of the print head relative to the tool seat, or movement of the tool seat relative to the print head, or simultaneous movement of the print head and the tool seat.

13. The 3D printing system with refilling function according to claim 11, wherein, The print head comprises a first limiting structure for limiting the hot end in the second direction, and the tool seat comprises a second limiting structure for limiting the hot end in the first direction. The first limiting structure comprises a first clamping mechanism for clamping the hot end in the first direction; and / or The first limiting structure comprises a first positioning mechanism for limiting the hot end in the second direction; and / or The second limiting structure comprises a second clamping mechanism for clamping the hot end in the second direction; and / or The second limiting structure comprises a second positioning mechanism for limiting the hot end in the first direction. The first clamping mechanism of the first limiting structure comprises a clamping piece movably connected to the print head, and / or the second clamping mechanism of the second limiting structure comprises a clamping piece movably connected to the tool seat. The clamping piece can be pressed against the hot end by movable adjustment to clamp the hot end, and can also be separated from the hot end to release the clamping of the hot end.

14. The 3D printing system of claim 10 or 13, wherein The clamping piece is rotatably arranged on the print head or the tool seat, and one end of the clamping piece can rotate around a rotating connection to press on the hot end or to separate from the hot end; Alternatively, the clamping piece is movably arranged on the print head in the second direction and / or the clamping piece is movably arranged on the tool seat in the first direction, and the clamping piece can be pressed against the hot end or separated from the hot end by movement adjustment; Alternatively, the clamping piece is an eccentric shaft structure, the eccentric shaft structure comprises a connecting shaft and a stepped shaft connected to the connecting shaft, the axis of the stepped shaft and the axis of the connecting shaft have a spacing, the connecting shaft is rotatably arranged on the print head, the hot end corresponds to the stepped shaft and is provided with a pressing step, the stepped shaft is rotated to press on the pressing step to press the hot end or to separate from the pressing step to release the clamping of the hot end; Alternatively, the clamping piece is a first swing pressing rod, the middle part of the first swing pressing rod is rotatably arranged on the print head or the tool seat through a first rotating shaft, one end of the first swing pressing rod away from the hot end is connected with a first elastic piece, the first elastic piece applies an elastic force to the corresponding end of the first swing pressing rod to make the first swing pressing rod rotate around the first rotating shaft, and then one end of the first swing pressing rod close to the hot end presses the hot end in the first direction and / or the second direction. Or, the clamping member is a second swing pressure rod, one end of the second swing pressure rod is rotatably arranged on the printing head on a side away from the hot end and away from the tool seat through a second rotating shaft, the end of the second swing pressure rod is pressed on a side of the hot end towards the tool seat, a swing lever actuating part is arranged on the second swing pressure rod, and a tool seat actuating part is arranged on the tool seat corresponding to the swing lever actuating part. Or, the clamping member is a second swing pressure rod, one end of the second swing pressure rod is rotatably arranged on the tool seat on a side away from the hot end and away from the printing head through a second rotating shaft, the end of the second swing pressure rod is pressed on a side of the hot end towards the printing head, a swing lever actuating part is arranged on the second swing pressure rod, and a printing head actuating part is arranged on the printing head corresponding to the swing lever actuating part. When the printing head and the tool seat relatively move along the first direction, the tool seat actuating part cooperates with the swing lever actuating part, when the printing head and the tool seat relatively move along the second direction, the tool seat actuating part can actuate the swing lever actuating part, thereby driving the second swing pressure rod to rotate, so that the end of the second swing pressure rod is separated from the hot end or the end of the second swing pressure rod presses the hot end, wherein the relative movement of the printing head and the tool seat includes that the printing head moves relative to the tool seat, or the tool seat moves relative to the printing head, or the printing head and the tool seat simultaneously move. Or, the clamping member is a lower pressing plate, the lower pressing plate is arranged on the printing head and can move along the second direction, a pressing plate actuating part is arranged on the lower pressing plate, and a tool seat actuating part is arranged on the tool seat corresponding to the pressing plate actuating part. Or, the clamping member is a lower pressing plate, the lower pressing plate is arranged on the tool seat and can move along the second direction, a pressing plate actuating part is arranged on the lower pressing plate, and a printing head actuating part is arranged on the printing head corresponding to the pressing plate actuating part. When the printing head and the tool seat relatively move along the first direction, the tool seat actuating part cooperates with the pressing plate actuating part, when the printing head and the tool seat relatively move along the second direction, the tool seat actuating part can actuate the pressing plate actuating part, thereby driving the lower pressing plate to move, so that the end of the lower pressing plate is separated from the hot end or the lower pressing plate presses the hot end, wherein the relative movement of the printing head and the tool seat includes that the printing head moves relative to the tool seat, or the tool seat moves relative to the printing head, or the printing head and the tool seat simultaneously move. Or, the clamping member is a lower pressing plate, one end of the lower pressing plate is rotatably arranged on the print head or the tool seat relative to the hot end close to the tool seat through a third rotating shaft, the axis of the third rotating shaft is arranged along the first direction, the lower pressing plate is provided with a pressing plate poking part, and the tool seat is provided with a lower poking member corresponding to the pressing plate poking part. Or, the tool seat is provided with a grabbing mechanism and a poking member, the grabbing mechanism and the poking member can simultaneously move towards the print head, the poking member pokes away the first clamping mechanism on the print head, so that the clamping member releases the clamping state of the hot end on the print head, and the grabbing mechanism clamps the hot end on the print head. Or, the print head is provided with two lower pressing plates on both sides of the hot end, and the tool seat is provided with two poking members corresponding to the two lower pressing plates respectively, when the print head and the tool seat relatively move, the two poking members simultaneously poke and move away the two lower pressing plates in the same direction or opposite directions, so that the end of the lower pressing plate is separated from the hot end on the print head or the lower pressing plate presses the hot end. Or, the tool seat is provided with a second heat dissipation fin, and the second heat dissipation fin has a third heat dissipation surface which is a laterally open heat dissipation surface. Or, the print head is provided with a first heat dissipation mechanism and / or the tool seat is provided with a second heat dissipation mechanism, and the first heat dissipation mechanism and / or the second heat dissipation mechanism is a fan, an air supply pipe or a cooling liquid circulating device. ​ Or, the first heating element is installed on the print head and / or the second heating element is installed on the tool seat, and the first heating element and / or the second heating element is a ceramic heating sheet, a heating rod or an induction coil; Or, the first heating element is installed on the print head and / or the second heating element is installed on the tool seat, and the first heating element and / or the second heating element has a laterally open heating surface; Or, the second heating element is provided on the tool seat and can move in the first direction or swing about an axis perpendicular to the first direction and / or the second direction or an axis parallel to the Z axis, and a third elastic element is further provided between the second heating element and a corresponding part on the tool seat, and the third elastic element exerts a force on the second heating element to make the second heating element be located at a position close to the hot end; Or, the print head or the tool seat comprises a detection sensor for detecting whether the clamping element is clamped in place; or, The second positioning mechanism on the tool seat comprises a rotatable second heat dissipation fin, and further comprises a fourth elastic element, and the fourth elastic element exerts a force on the second heat dissipation fin to make the second heat dissipation fin rotate towards the direction of the hot end or the print head; when the hot end is not installed on the tool seat, the second heat dissipation fin abuts against a limiting structure provided on the tool seat; Or, the tool seat is provided with a second heat dissipation fin corresponding to the heat dissipation section, and the second positioning mechanism comprises a limiting groove provided on the second heat dissipation fin for limiting the heat dissipation section; Or, the tool seat is provided with a second heat dissipation mechanism corresponding to the heat dissipation section of the hot end, and the second heat dissipation mechanism is used for heat dissipation of the heat dissipation section; Or, the tool seat is provided with a second heating element corresponding to the heating section of the hot end, and the second heating element is used for heating the heating section, and the second heating element is fixedly connected to the tool seat or movably connected to the tool seat; Or, the tool seat is provided with a second heat dissipation fin, the second heat dissipation fin has a third heat dissipation surface, the heat dissipation section of the hot end installed on the tool seat has a first heat dissipation surface, the first heat dissipation surface abuts against the third heat dissipation surface, and the second heat dissipation fin is fixedly connected to the tool seat or movably connected to the tool seat; Or, the hot end comprises an extrusion port, a heating section, a throat section and a heat dissipation section in sequence, the print head or the tool seat is provided with a shielding part corresponding to the heating section, and the shielding part is used for strengthening heat preservation of the heating section; Or, the hot end comprises an extrusion port, a heating section, a throat section and a heat dissipation section in sequence, the tool seat is provided with a positioning element, and the print head is provided with a shielding part corresponding to the heating section, and the shielding part and the hot end can further have an empty gap in the second direction, and the empty gap can allow the positioning element on the tool seat to extend in. Or, the hot end comprises in sequence an extrusion port, a heating section, a throat section and a heat dissipation section, the heating section is provided with a first heating surface, the print head is provided with a first heating member, the first heating member is provided with a second heating surface; or the tool holder is provided with a second heating member, the second heating member is provided with a third heating surface, the second clamping mechanism comprises the second heating member or the third heating surface, or the first clamping mechanism comprises the first heating member or the second heating surface, when the hot end is mounted on the print head, the first heating surface is attached to the second heating surface, when the hot end is mounted on the tool holder, the first heating surface is attached to the third heating surface, the first heating surface is parallel to the first direction, and the error is not more than ±45°; Or, the hot end comprises in sequence an extrusion port, a heating section, a throat section and a heat dissipation section, the heating section is provided with a first heating surface and a fourth heating surface, the first heating member on the print head is provided with a second heating surface, the tool holder is provided with a second heating member, the second heating member is provided with a third heating surface, the second clamping mechanism comprises the second heating member or the third heating surface, the first heating surface and the fourth heating surface are oppositely arranged, when the hot end is mounted on the print head, the first heating surface is attached to or oppositely arranged with the second heating surface, when the hot end is mounted on the tool holder, the fourth heating surface is attached to or oppositely arranged with the third heating surface, the first heating surface is perpendicular to the first direction, and the error is not more than ±45°.

15. The 3D printing system of claim 10 or 13, wherein, the hot end is provided with a second positioning feature extending along a second direction; the second positioning mechanism on the tool holder comprises a positioning member corresponding to the second positioning feature, the positioning member also extends along the second direction; when the tool holder and the print head move relative to each other along the second direction, the positioning member and the second positioning feature can cooperate to limit the hot end in the first direction, or the positioning member and the second positioning feature move away to release the limitation of the hot end in the first direction; and / or the hot end is provided with a first positioning feature extending along a first direction, the first positioning mechanism on the print head comprises a positioning part corresponding to the first positioning feature, the positioning part also extends along the first direction; when the hot end is mounted on the print head, the positioning part cooperates with the first positioning feature to position the hot end in a third direction perpendicular to the first direction and the second direction, or in the axial direction of the feeding pipe of the hot end and / or the second direction.

16. The 3D printing system of claim 1 or 10, wherein, The hot end comprises, in sequence, an extrusion port, a heating section, a throat section and a heat dissipation section, the heat dissipation section of the hot end on the print head is provided with a first heat dissipation mechanism for dissipating heat from the heat dissipation section, and / or the heating section of the hot end on the print head is provided with a first heating element for heating the heating section, the first heating element being fixedly connected to the print head or movably connected to the print head; or, The hot end comprises, in sequence, an extrusion port, a heating section, a throat section and a heat dissipation section, the heat dissipation section being provided with third heat dissipation fins; or The print head is provided with a first heating element, the first heating element being movable in a second direction or being swingable about an axis perpendicular to the first direction and / or the second direction or an axis parallel to the Z axis, a fifth elastic element being further provided between the first heating element and a corresponding part on the print head, the fifth elastic element exerting a force on the first heating element to enable the first heating element to be located at a position in contact with the hot end; or The hot end is provided with a heating element, heat dissipation fins, a heat dissipation mechanism, a wire feeder, a pipe joint, a feeding pipe or a circuit connector; Or, further comprising a pushing element, the clamping element being provided with a pushing part, the clamping element being provided with an elastic element to exert an elastic force on the clamping element to enable the clamping element to swing or move in a direction of installing the hot end; when the hot end is to be dismounted or installed, the print head is moved to a corresponding position of the pushing element, through relative movement of the print head and the pushing element, the pushing element pushes the pushing part of the clamping element, so that the clamping element is pushed away against the elastic force of the elastic element; wherein the relative movement of the print head and the pushing element includes movement of the print head relative to the pushing element, movement of the pushing element relative to the print head or simultaneous movement of the print head and the pushing element; Or, further comprising a pushing element and a driving mechanism, the clamping element being provided with a pushing part, the driving mechanism being used to drive the pushing element, when the hot end is not to be dismounted or installed, the driving mechanism drives the pushing element to move to a retracted state, when the hot end is to be dismounted or installed, the driving mechanism drives the pushing element to move to an extended state; Or, further comprising a pushing element and a driving mechanism, the clamping element being provided with a pushing part, the driving mechanism being used to drive the pushing element, when the hot end is to be dismounted or installed, the driving mechanism drives the pushing element to move to push the pushing part of the clamping element; Or, further comprising a clamping buckle swing lever, the clamping buckle swing lever being swingable about a second pivot shaft on the print head, the clamping element being swingable about a first pivot shaft on the print head, an included angle between the first pivot shaft and the second pivot shaft being 0 degrees, an error being not more than ±40°, the first pivot shaft and the second pivot shaft being respectively arranged on two sides of the hot end or the clamping buckle swing lever and the clamping element being respectively arranged on two sides of the hot end, the clamping element being swingable towards the hot end to press the hot end against the print head, the clamping buckle swing lever being swingable towards the hot end or the clamping element to clamp the clamping element. Or, further comprising a buckle swing lever rotatably mounted on the print head, an axis of rotation of the buckle swing lever being at an angle of 90 degrees, with an error of no more than ±45°, with an axis of the feeding pipe of the hot end or with an axis of rotation of the clamping piece, an angle between the axis of rotation of the clamping piece and the axis of the feeding pipe of the hot end being 0 degrees, with an error of no more than ±40°, the clamping piece being pressed against the print head when being rotated to an upper position of the hot end, the buckle swing lever being pressed against the clamping piece and the hot end when being rotated to an upper position of the clamping piece; Or, further comprising an elastic piece, an axis of rotation of the clamping piece being arranged on a side of the print head opposite to a rear side of the hot end, the clamping piece being provided with a clamping part for clamping the hot end, the clamping part being arranged on a side opposite to a front side of the hot end or away from the axis of rotation, the elastic piece applying an elastic force to the clamping piece so that the clamping piece swings towards the hot end to clamp the hot end; Or, further comprising an elastic piece, the clamping piece being arranged on a side away from the print head relative to the hot end, the clamping piece being movable relative to the hot end or the print head, the elastic piece being used to apply an elastic force to the clamping piece so that the clamping piece moves towards the hot end to clamp the hot end; Or, the clamping piece is a heating piece or a heat dissipation fin; Or, further comprising an elastic piece, the elastic piece applying a force to the clamping piece so that the clamping piece moves or swings towards a direction of mounting the hot end, the clamping piece being provided with a pushing part; Or, the clamping piece is rotatably mounted on the print head, further comprising a clamping part corresponding to the clamping piece, an axis of rotation of the clamping piece and the clamping part being arranged on two sides of the hot end respectively, the clamping piece swinging towards the hot end or the clamping part and clamping to the clamping part when the hot end is mounted on the print head, so that the clamping piece is pressed against the hot end and is correspondingly mounted on the print head; Or, further comprising an elastic piece, the clamping piece being rotatably mounted on the print head, the hot end being provided with a protruding part or a groove structure, the clamping piece being provided with an abutting part, the abutting part being a structure or a roller matched with the protruding part or the groove structure, the elastic piece applying an elastic force to the clamping piece to swing towards the hot end, when the clamping piece is pressed against the hot end, the abutting part is matched with an inclined side of one side of the protruding part or the groove structure, so that the clamping piece clamps the hot end to the print head; Or, the hot end sequentially comprises an extrusion port, a heating section, a throat section and a heat dissipation section, the print head comprises a heating piece for heating the hot end, the heating section of the hot end is a cylindrical structure, the heating piece comprises a heating seat, a heating surface of the heating seat is a circular hole structure matched with the heating section, the hot end is mounted on or detached from the print head along an axis of the feeding pipe of the hot end.

17. The 3D printing system of claim 1 or 10, wherein The hot end comprises in sequence an extrusion port, a heating section, a throat section and a heat dissipation section; the print head is provided with a first heat dissipation fin and a first heating element, wherein, The first heat dissipation fin is fixedly connected to or movably connected to the print head; or, The first heat dissipation fin has a second heat dissipation surface which is a laterally open heat dissipation surface; or, The first heat dissipation fin has a second heat dissipation surface, and the heat dissipation section of the hot end mounted on the print head has a first heat dissipation surface which is in contact with the second heat dissipation surface, Or, further comprising an elastic member, the first heat dissipation fin is movably mounted on the print head, and the elastic member provides a spring force for the first heat dissipation fin to abut against the print head in a direction in which the hot end is mounted on the print head; Or, further comprising that the first heat dissipation fin is movably mounted on the print head, and when the hot end is mounted on the print head, a spring force provided by the corresponding elastic member abuts the laterally open heat dissipation surface of the first heat dissipation fin against the heat dissipation surface of the heat dissipation section on the hot end; Or, comprising two first heat dissipation fins, i.e., a left first heat dissipation fin and a right first heat dissipation fin, the left first heat dissipation fin and the right first heat dissipation fin are movably connected to the print head respectively; the left first heat dissipation fin and the right first heat dissipation fin are respectively provided with an elastic member, and the left first heat dissipation fin and the right first heat dissipation fin are respectively rotatable about a corresponding rotation shaft, and the elastic member respectively provides a spring force for the left first heat dissipation fin and the right first heat dissipation fin to swing towards each other or in a direction in which the hot end is mounted; Or, comprising two first heat dissipation fins, i.e., a left first heat dissipation fin and a right first heat dissipation fin, the left first heat dissipation fin and / or the right first heat dissipation fin is movably connected to the print head, the left first heat dissipation fin and the right first heat dissipation fin are respectively provided with a laterally open heat dissipation surface matched with the heat dissipation section, when the hot end is mounted on the print head, the laterally open heat dissipation surface is in contact with the heat dissipation section, and / or, a guide inclined surface is arranged on a side of the left first heat dissipation fin and the right first heat dissipation fin facing the hot end in a mounting and removing direction, the two guide inclined surfaces form an opening shape with an outer side larger than an inner side, facilitating the hot end to be mounted on the print head by pushing away the left first heat dissipation fin and the right first heat dissipation fin from the outside when the hot end is mounted on the print head; and / or, when the hot end is not mounted, the left first heat dissipation fin and the right first heat dissipation fin abut against each other to be limited or are respectively limited by a corresponding limiting structure. Or, the first heat dissipation fins include two first heat dissipation fins, i.e., a left first heat dissipation fin and a right first heat dissipation fin, the left first heat dissipation fin and / or the right first heat dissipation fin is movably connected to the print head, and a swing lever is rotatably arranged on the left first heat dissipation fin, the right first heat dissipation fin is provided with an upper clamping part corresponding to the swing lever, the left first heat dissipation fin and / or the right first heat dissipation fin is rotatably arranged on the print head, when the hot end is mounted on the print head, the left first heat dissipation fin and the right first heat dissipation fin swing towards each other and contact the heat dissipation section of the hot end therebetween, the swing lever can swing towards the right first heat dissipation fin and clamp the upper clamping part on the right first heat dissipation fin, so that the left first heat dissipation fin and the right first heat dissipation fin clamp the heat dissipation section of the hot end therebetween; Or, the first heat dissipation fins include two first heat dissipation fins, i.e., a left first heat dissipation fin and a right first heat dissipation fin, the left first heat dissipation fin and / or the right first heat dissipation fin is movably connected to the print head, and a swing lever is rotatably arranged on the left first heat dissipation fin, the right first heat dissipation fin is provided with an upper clamping part corresponding to the swing lever, the left first heat dissipation fin and / or the right first heat dissipation fin is rotatably arranged on the print head, when the hot end is mounted on the print head, the left first heat dissipation fin and the right first heat dissipation fin swing towards each other and contact the heat dissipation section of the hot end therebetween, the swing lever can swing towards the right first heat dissipation fin and clamp the upper clamping part on the right first heat dissipation fin, so that the left first heat dissipation fin and the right first heat dissipation fin clamp the heat dissipation section of the hot end therebetween; Or, the first heating member is movably mounted on the print head, when the hot end is mounted on the print head, the first heating member is abutted against the heating surface on the heating section of the hot end by the elastic force provided by the corresponding elastic member; Or, the first heat dissipation fin on the print head has a laterally open second heat dissipation surface, and the first clamping mechanism includes an upper clamping mechanism movably arranged corresponding to the first heat dissipation fin, the upper clamping mechanism is movably adjusted to press the heat dissipation section of the hot end mounted on the print head to make the heat dissipation section abut against the laterally open heat dissipation surface of the first heat dissipation fin; The upper clamping mechanism is rotatably arranged on the print head, the upper clamping mechanism is rotatable around the rotation connection to press the heat dissipation section against the first heat dissipation fin, so that the heat dissipation section abuts against the first heat dissipation fin, when the hot end is not mounted on the print head, the upper clamping mechanism abuts against a limiting structure arranged on the print head; Or, the upper clamping mechanism is movably arranged on the print head along a second direction, the upper clamping mechanism is moved to press the heat dissipation section, so that the heat dissipation section abuts against the first heat dissipation fin, when the hot end is not mounted on the print head, the upper clamping mechanism abuts against a limiting structure arranged on the print head.

18. The 3D printing system of claim 17, wherein The upper clamping mechanism is a swing fin, the swing fin is rotatably arranged on the print head through a fourth rotating shaft, a second elastic member is arranged on the fourth rotating shaft, the second elastic member drives the swing fin to rotate and press against the heat dissipation section, so that the heat dissipation section is attached to the first heat dissipation fin; Or, the tool seat is further included, the upper clamping mechanism is an upper pressing plate, the upper pressing plate is arranged on the print head and is movable along a second direction, an upper driving part is arranged on the upper pressing plate, the tool seat is provided with an upper driving member corresponding to the upper driving part, when the print head and the tool seat are relatively moved along a first direction, the upper driving member is matched with the upper driving part, when the print head and the tool seat are relatively moved along a second direction, the upper driving member can drive the upper driving part, and then the upper pressing plate is moved to separate the upper pressing plate from the heat dissipation section or to press the heat dissipation section by the upper pressing plate; Or, the tool seat is further included, the upper clamping mechanism is an upper pressing plate, the upper pressing plate is rotatably arranged on the print head through a fifth rotating shaft, a driving part is arranged on the upper pressing plate, the tool seat is provided with an upper driving member corresponding to the driving part, when the print head and the tool seat are relatively moved along a first direction, the upper driving member is matched with the driving part, when the print head and the tool seat are relatively moved along a second direction, the upper driving member can drive the driving part, and then the upper pressing plate is rotated to separate the upper pressing plate from the heat dissipation section or to press the heat dissipation section by the upper pressing plate.

19. The 3D printing system of claim 11, wherein, The grabbing mechanism on the tool head is adjustable in extension and retraction relative to the tool seat, the grabbing mechanism on the tool head comprises a rotatable long rod structure, an end of the long rod structure is provided with a transverse protruding structure perpendicular to the direction of the long rod structure, the hot end is provided with a long hole facing the tool seat and a transverse hole perpendicular to the axis of the long hole, the transverse hole is communicated with the long hole, the long rod structure can be extended into the long hole, and then the transverse protruding structure is extended into the transverse hole by rotating the long rod structure, so that the hot end is clamped; Or, the grabbing mechanism on the tool head comprises a rotatable long rod structure and an actuating mechanism drivingly connected with the long rod structure, the actuating mechanism is used for driving the long rod structure to rotate, an end of the long rod structure is provided with a transverse protruding structure perpendicular to the direction of the long rod structure, the hot end is provided with a long hole facing the tool seat and a transverse hole perpendicular to the axis of the long hole, the transverse hole is communicated with the long hole, the long rod structure can be extended into the long hole, and then the transverse protruding structure is extended into the transverse hole by rotating the long rod structure, so that the hot end is clamped; Or, the grabbing mechanism on the tool head comprises a pair of clamping members with adjustable clamping spacing, the pair of clamping members can clamp the corresponding hot end by adjusting the clamping spacing. Alternatively, the grabbing mechanism on the tool head comprises a pair of clamps, each of which is rotatable around a respective rotation axis, and a driving mechanism is connected to the pair of clamps to drive the pair of clamps to rotate around the respective rotation axes and thereby clamp or unclamp the corresponding hot end; Alternatively, the tool head further comprises a poking member in the form of a long rod with a poking structure at one end, and the first clamping mechanism of the print head is provided with a poking part matched with the poking structure, so that the poking structure and the poking part are matched to drive the first clamping mechanism to rotate and clamp or unclamp the hot end on the print head; Alternatively, the tool head further comprises a poking member in the form of a long rod, and the tool head further comprises an execution mechanism drivingly connected to the long rod to drive the long rod to rotate; Alternatively, the tool head further comprises two poking members, one for the opening or clamping of the lower clamping mechanism of the print head, and the other for the opening or clamping of the upper clamping mechanism of the print head, and the two poking members are simultaneously driven by one execution mechanism; The tool head further comprises a poking member and a tool head base, and the grabbing mechanism and the poking member are both arranged on the tool head base, which is movable along a first guide rail connected to the tool head to drive the grabbing mechanism and the poking member to move together for telescopic adjustment; Alternatively, the tool seat and the tool head are movable along the Z-axis direction or the direction of the extrusion of the print material by the print head; Alternatively, the tool head comprises two tool heads, i.e., a first tool head and a second tool head, and when the first tool head is used to switch the hot end on the print head to the first tool seat, the second tool head is movable to the corresponding position of the second tool seat, and after the print head is moved to the second tool seat, the second tool head is used to switch the hot end on the second tool seat to the print head; Alternatively, the tool head comprises two tool heads, and each tool seat comprises a tool seat base and a first guide rail, and the tool seat base is movable along the first guide rail, and the driving mechanisms of the two tool heads for driving the tool seat bases to move along the first guide rails are arranged on the sides away from each other with respect to the respective grabbing mechanisms; Alternatively, the tool head comprises a tool head base movable along a first guide rail, the first guide rail is movable along a second guide rail, the second guide rail is connected to a fourth guide rail on which the print head slides, or the second guide rail is movable along a third guide rail, the third guide rail is connected to the fourth guide rail on which the print head slides, wherein the first guide rail is perpendicular to the second guide rail or the fourth guide rail, and the third guide rail is perpendicular to the fourth guide rail or the first guide rail or the second guide rail.

20. The 3D printing system of claim 1, wherein, The print head comprises a material conveying pipeline conveying print material to the extrusion port of the hot end, and the material conveying pipeline is provided with a notch to expose the print material; In the cutting process, the print head moves to the cutting position of the cutting mechanism, the print head moves towards the cutting knife of the cutting mechanism, so that the cutting knife cuts the print material at the notch; or the print head moves to the cutting position of the cutting mechanism, the cutting mechanism or the cutting knife moves towards the print head, so that the cutting knife cuts the print material at the notch; or the cutting knife of the cutting mechanism moves to the cutting position of the print head, the print head moves towards the cutting knife, so that the cutting knife cuts the print material at the notch; or the cutting knife of the cutting mechanism moves to the cutting position of the print head, the cutting mechanism or the cutting knife moves towards the print head, so that the cutting knife cuts the print material at the notch. Or, A cutting knife and a driver are arranged on the print head, and the driver can drive the cutting knife to cut the print material at the notch. Or, The cutting mechanism includes a touch piece and a cutting knife arranged on the print head, the cutting knife is arranged on a swing rod or the cutting knife can move along a guide structure, in the cutting process, the print head moves to the corresponding position of the touch piece or the touch piece moves to the corresponding position of the print head, through the relative movement of the print head and the touch piece, the touch piece pushes the cutting knife to cut the print material at the notch. Or, The cutting mechanism includes a conversion structure for switching or transforming the cutting knife between a working position and a retracted position, when cutting, the conversion structure drives the cutting knife to move or swing to the working position, after cutting is completed, the conversion structure drives the cutting knife to move or swing to the retracted position. Or, The cutting mechanism includes a cutting knife and a protection structure. Or, The cutting mechanism is a laser, and the print material on the print head is cut by emitting a laser beam by the laser.

21. A method of changing material for a 3D printing system, the method comprising: The method includes the following steps: Cutting the first print material on the print head by using the cutting mechanism; Switching the print material on the print head by using the material switching device; Continuing to print by using the print head.

22. The material switching method of the 3D printing system according to claim 21, wherein, The heat end switching mechanism is used to switch the heat end on the print head before, after or simultaneously with the step of switching the print material on the print head by using the material switching device; Before the second print material is sent to the print head, the cut first print material on the print head is pulled back to a set position; Or, before the first print material on the print head is cut, the second print material is transmitted to a preset position close to the print head; Or, the heat end switching mechanism includes a tool seat, and the step of moving the print head to the tool seat without the heat end is performed before, after or simultaneously with the step of cutting the first print material on the print head. ​ Or, before cutting off the first printing material on the print head, the first printing material on the print head is retracted by a preset length; or, after cutting off the first printing material on the print head, the first printing material is driven to feed by a preset length in the direction of the hot end, the end of the cut-off first printing material is used to press the broken end of the printing material in the hot end on the print head into the hot end, and then the cut-off first printing material on the print head is retracted to the set position; Or, after the second printing material is sent to the print head, the print head is moved to the waste extrusion area to extrude a preset length of printing material; Or, after the second printing material is sent to the print head, the printing material to be used in the next step is sent to the designated position in advance; Or, the hot end switching mechanism includes a tool seat, before moving the print head to the tool seat without a hot end, the distance between the print head and the printing platform is increased to the second distance; Or, the hot end switching mechanism includes a tool seat, after switching and installing the hot end on the tool seat to the print head, the distance between the print head and the printing platform is reduced to the first distance; Or, during the hot end switching process, the printing platform is moved downward by a certain distance, or the print head is moved to an area without a printed model, or the print head is moved to an area outside the layer pattern of the current printing layer; Or, the hot end switching mechanism includes a tool seat, before switching and installing the hot end on the tool seat to the print head, the hot end on the tool seat is heated to a preset temperature; Or, the hot end switching mechanism includes a tool seat, before switching and installing the hot end on the tool seat to the print head, the printing material to be used in the next step is transferred to the hot end through the feeding pipe connected to the tool seat, and the residual printing material in the hot end is replaced by the printing material to be used in the next step or the empty hot end is filled with the printing material to be used in the next step; Or, the hot end switching mechanism includes a tool seat, before moving the print head to the tool seat without a hot end, the first printing material is cut off by the cutting knife on the tool seat; Or, the hot end switching mechanism includes a tool seat, in the step of "switching the hot end on the print head by using the hot end switching mechanism", the print head is moved to the switching position of the tool seat without a hot end, the hot end on the print head is switched and installed to the tool seat without a hot end, the print head is moved to the switching position of the tool seat with a hot end, and the hot end on the tool seat is switched and installed to the print head to complete the switching of the hot end; Or, the hot end switching mechanism includes a tool seat and a tool head, the tool seat includes a first tool seat and a second tool seat, and the tool head includes a first tool head or a first tool head and a second tool head, in the step of "switching the hot end on the print head by using the hot end switching mechanism", the print head is moved to the switching position of the first tool seat without a hot end, the first hot end on the print head is clamped and switched to the first tool seat by using the first tool head, the print head is moved to the second tool seat, and the second hot end on the second tool seat is switched to the print head by using the second tool head or the first tool head. Alternatively, the switching of the printing material on the print head and the switching of the hot end can be performed in parallel, in series or partially in parallel.

23. The method of claim 21, wherein the 3D printing system is a powder bed fusion system. In the step of cutting off the first printing material on the print head, the print head is moved to a cutting position of the cutting mechanism, a cutting knife is arranged at the cutting position of the cutting mechanism, the first printing material at the gap of the print head is moved to the cutting knife by moving the print head relative to the cutting knife to cut off the first printing material or the cutting knife is moved towards the gap of the print head to cut off the first printing material; Alternatively, in the step of cutting off the first printing material on the print head, the cutting knife of the cutting mechanism is driven by an actuator to move to the corresponding cutting position of the print head, then the cutting knife is moved towards the gap of the print head or the print head is moved towards the cutting knife to cut off the printing material; Alternatively, in the step of cutting off the first printing material on the print head, the print head remains in the printing process, the cutting knife of the cutting mechanism is driven by an actuator to move to the corresponding cutting position of the print head, the cutting knife remains synchronous with the print head, and the cutting knife is moved towards the gap of the print head to cut off the printing material; Alternatively, the cutting mechanism is provided with a sensor for detecting the displacement or force of the cutting knife during cutting; Alternatively, in the step of cutting off the first printing material on the print head, the cutting knife of the cutting mechanism is moved to the working position by the transformation structure when cutting is to be performed, and the cutting knife is moved to the retracted position by the transformation structure after cutting is completed; Alternatively, in the step of switching the printing material on the print head by using the material switching device, the first printing material is drawn back by the first material source or the first remote wire feeder to draw the first printing material to the inlet of the multi-inlet and outlet connecting pipe, or the first printing material is further drawn back to avoid the passage of the transmission of other printing materials, and then the second remote wire feeder transmits the second printing material of the second material source to the print head; Alternatively, in the step of switching the printing material on the print head by using the material switching device, the print head is connected to at least two outlet ports of the material switching hub through the feeding pipe, in the printing process of the first printing material, the second printing material to be used in the next step and the corresponding second material source are determined, the second printing material is delivered to the corresponding second inlet port of the material switching hub or to the inlet of the corresponding second switching mechanism of the material switching hub by using the wire feeder of the second material source, the corresponding second switching mechanism is controlled to act so that the second inlet port is connected to the second outlet port of the material switching hub connected to the print head, the second printing material is delivered to the second outlet port, and the second printing material is delivered to the position close to the intersection of the second feeding path and the first feeding path in the feeding pipe through the second outlet port under the action of the wire feeder of the second material source for standby use; After the printing process of the first printing material in the current step is completed, the first printing material is cut off at the notch on the print head, and the first printing material is pulled back to a position where the first feeding path and the second feeding path intersect or to a position where the feeding path of the second printing material is no longer blocked, to prevent the first printing material from blocking the second printing material; under the action of the wire feeder provided by the second material source, the second printing material is transported into the print head, and the print head performs printing on the second printing material.

24. A material changing method for a 3D printing system, characterized in that, The material changing device comprises a material changing hub, the material changing hub comprises a plurality of feeding ports and a plurality of discharging ports, each feeding port is respectively provided with a switching mechanism, the inlet end of the switching mechanism is connected with the feeding port, and the outlet end of the switching mechanism has a plurality of outlet ends and is respectively connected with each discharging port in a matched manner, so that each feeding port can be connected with any discharging port by changing the state of the switching mechanism, and the print head is connected with at least two discharging ports of the material changing hub through a feeding pipe; In the step of switching the printing material on the print head, the following steps are included: The first printing material to be used in the current step of the print head and the corresponding first material source are determined, the first printing material is transported to the corresponding first feeding port of the material changing hub or to the inlet end of the corresponding first switching mechanism of the material changing hub under the transportation of the wire feeder provided by the first material source, the corresponding first switching mechanism is controlled to act so that the first feeding port is connected with the first discharging port in the material changing hub connected with the print head, the first printing material is transported to the first discharging port, and the first printing material is transported to the print head along the first feeding path in the feeding pipe through the first discharging port under the action of the wire feeder provided by the first material source, and the print head performs printing; In the printing process of the first printing material, the second printing material to be used in the next step and the corresponding second material source are determined, the second printing material is transported to the corresponding second feeding port of the material changing hub or to the inlet end of the corresponding second switching mechanism of the material changing hub under the action of the wire feeder provided by the second material source, the corresponding second switching mechanism is controlled to act so that the second feeding port is connected with the second discharging port in the material changing hub connected with the print head, the second printing material is transported to the second discharging port, and the second printing material is transported to a position close to the intersection of the second feeding path and the first feeding path through the second discharging port under the action of the wire feeder provided by the second material source. After the printing process of the first printing material in the current step is completed, the first printing material is cut off at the notch on the print head or at a position downstream of the position where the first feeding path and the second feeding path intersect in the printing material conveying direction, and the first printing material is drawn back to the position where the first feeding path and the second feeding path intersect in the feeding pipe or to the position where the feeding path of the second printing material is no longer blocked, so as to prevent the first printing material from blocking the second printing material; The second printing material is conveyed into the print head under the action of the filament feeder of the second material source, and the print head performs printing on the second printing material.

25. A material changing method of a 3D printing system, characterized in that, The material changing device comprises a material changing hub, the material changing hub comprises a plurality of feeding ports and a plurality of discharging ports, each feeding port is respectively provided with a switching mechanism, the inlet end of the switching mechanism is connected with the feeding port, and the outlet end of the switching mechanism has a plurality of outlet ends and is respectively connected with each discharging port in a matched manner, so that each feeding port can be connected with any discharging port by changing the state of the switching mechanism, each print head is connected with at least one discharging port of the material changing hub through a feeding pipe; In the step of switching the printing material on the print head, the following steps are included: The first print head, the first printing material and the corresponding first material source required in the current step are determined, the first printing material is conveyed to the corresponding first feeding port of the material changing hub or to the inlet end of the corresponding first switching mechanism under the action of the filament feeder of the first material source, the corresponding first switching mechanism is controlled to act so that the first feeding port is connected with the first discharging port in the material changing hub connected with the first print head, and then the first printing material is conveyed to the first print head through the first discharging port and along the first feeding path in the feeding pipe under the action of the filament feeder of the first material source, and the first print head performs printing; In the printing process of the first printing material, the second print head, the second printing material and the corresponding second material source to be used in the next step are determined, the second printing material is conveyed to the corresponding second feeding port of the material changing hub or to the inlet end of the corresponding second switching mechanism under the action of the filament feeder of the second material source, the corresponding second switching mechanism is controlled to act so that the second feeding port is connected with the second discharging port in the material changing hub connected with the second print head, and then the second printing material is conveyed to the second print head through the second discharging port and along the second feeding path in the feeding pipe under the action of the filament feeder of the second material source; After the printing process of the first printing material is completed, the first print head is moved out of the printing area, and then the second print head is moved into the printing area to perform printing on the second printing material; or the first print head and the second print head perform printing in the printing area at the same time.

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