3D printing system and method with multiple feeding mechanisms

Abstract

The present application provides a 3D printing system and method with multiple feeding mechanisms. The 3D printing system includes: multiple feeding mechanisms, different feeding mechanisms among the multiple feeding mechanisms have different adjustable ranges of material conveying flow rates; a print head for performing 3D printing using the flowable materials output by the multiple feeding mechanisms; and a control part for selecting a corresponding feeding mechanism from the multiple feeding mechanisms to convey materials according to the requirements of the part to be printed for the range of variation of the material conveying flow rate during the printing of the same object. The use of multiple feeding mechanisms with different adjustable ranges of material conveying flow rates to cooperate in conveying materials can reduce the difficulty of implementing each feeding mechanism.

Description

[0001] This application claims priority to Chinese patent application No. 202010699424.7, filed on July 20, 2020, and entitled “3D printing system and method”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of 3D printing, and in particular to a 3D printing system and method with a multi-feeding mechanism. Background Art

[0003] 3D printing technologies based on material extrusion, such as fused deposition molding (FDM) technology, usually require that the material be first transported to the print head (or extrusion head) of the 3D printing system through a feeding mechanism, and then the material is extruded from the extrusion port (or outlet) of the print head, so that the material is gradually deposited on the work platform to finally form a 3D printed product.

[0004] In traditional 3D printing systems, a single feeding mechanism is usually used to transport the same material. However, in some application scenarios, the 3D printing system requires the material transport flow rate of the feeding mechanism to be able to vary within a large range, which is difficult to achieve with a single feeding mechanism. Summary of the invention

[0005] The present application provides a 3D printing system and method with a multi-feeding mechanism.

[0006] In a first aspect, a 3D printing system with multiple feeding mechanisms is provided, comprising: a plurality of feeding mechanisms, different feeding mechanisms among the plurality of feeding mechanisms have different adjustable ranges of material conveying flow rates; a print head for performing 3D printing using flowable materials output by the plurality of feeding mechanisms; and a control part for selecting a corresponding feeding mechanism from the plurality of feeding mechanisms to convey materials according to the requirements of the part to be printed for the range of variation of the material conveying flow rate during the process of printing the same object.

[0007] In a second aspect, a 3D printing method is provided, which is applied to a 3D printing system, wherein the 3D printing system includes multiple feeding mechanisms, and the adjustable ranges of material conveying flow rates of the multiple feeding mechanisms are different; the 3D printing method includes: in the process of printing the same object, according to the requirements of the part to be printed for the range of variation of the material conveying flow rate, selecting a corresponding feeding mechanism from the multiple feeding mechanisms to convey the material.

[0008] Compared with using a single feeding mechanism, using multiple feeding mechanisms with different adjustable ranges of material conveying flow rates to cooperate in conveying materials can reduce the difficulty of implementing each feeding mechanism. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 Schematic diagram of the structure of a traditional 3D printing system.

[0010] Figure 2 A schematic structural diagram of a 3D printing system provided in the first embodiment of the present application.

[0011] Figure 3 A schematic structural diagram of another 3D printing system provided for the first embodiment of the present application.

[0012] Figure 4 A schematic structural diagram of another 3D printing system provided for the first embodiment of the present application.

[0013] Figure 5 A schematic structural diagram of another 3D printing system provided for the first embodiment of the present application.

[0014] Figure 6 A schematic structural diagram of another 3D printing system provided for the first embodiment of the present application.

[0015] Figure 7 A schematic structural diagram of another 3D printing system provided for the first embodiment of the present application.

[0016] Figure 8 A schematic flowchart of a 3D printing method provided for the second embodiment of the present application. DETAILED DESCRIPTION

[0017] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0018] Figure 1 It is a schematic diagram of the structure of the traditional 3D printing system. Figure 1 As shown, the 3D printing system 10 includes a feeding mechanism 40 and a print head 30. The feeding mechanism 40 is used to transport materials, and the print head 30 is used to perform 3D printing using the materials output by the feeding mechanism 40.

[0019] Figure 1 The direction indicated by the arrow in the figure is the conveying direction (or flow direction) of the material in the 3D printing system 10. Figure 1As can be seen from the direction indicated by the middle arrow, the feeding mechanism 40 delivers the flowable material to the print head 30, and then the print head 30 extrude the material from the extrusion port 31, so that the material is gradually deposited on the working platform 20, and finally a 3D printed product is formed.

[0020] In some application scenarios, the material conveying flow rate of the feeding mechanism 40 needs to be able to vary within a large range. For example, when printing an object, the 3D printing system 10 usually needs to adjust the material extrusion flow rate of the print head 30 according to actual needs to adjust the printing efficiency of the 3D printing system 10. In order to match the change in printing efficiency, the material conveying flow rate of the feeding mechanism 40 needs to be adjusted accordingly. When the printing efficiency of the 3D printing system 10 varies within a large range, the material conveying flow rate of the feeding mechanism 40 also needs to vary within a large range.

[0021] For example, the print head 30 can use an extrusion port 31 that can support disposable surface forming (i.e., the length of the extrusion port can change with the change of the cross-sectional contour line of the part to be printed, and the relevant description can be found in WO2018 / 205149 A1, WO2020 / 087359 A1, etc.). This print head extrusion port has a one-dimensional strip feature, that is, the length of the extrusion port in one dimension is much greater than its length in another dimension, and the extrusion port can change its length in the one-dimensional direction as the cross-sectional contour of the part to be printed changes, thereby forming a variable-length narrow slot extrusion port, so that the material filling of the entire cross section can be completed on the current forming layer by a unidirectional movement along the cross-sectional contour of the current forming layer. The 3D printing method with this extrusion port feature is generally referred to as "fused sheet deposition 3D printing" (FSD for short). Therefore, for FSD, the material conveying flow rate of the feeding mechanism 40 needs to vary within a large range.

[0022] However, in conventional 3D printing technology, the feeding mechanism 40 is usually only a single feeding mechanism, such as only a single screw feeding mechanism. Considering that the adjustable range of the material conveying flow rate of a single feeding mechanism is limited, when the material conveying flow rate of the feeding mechanism 40 needs to vary within a larger range, it is difficult to achieve this with a single feeding mechanism.

[0023] In order to solve this problem, the present application abandons the method of using a single feeding mechanism to transport materials to the print head in the traditional 3D printing system, and chooses to use multiple feeding mechanisms with different adjustable ranges of material transport flow rates to transport materials to the print head. When the material transport flow rate of the feeding mechanism needs to be able to vary within a large range, compared with using a single feeding mechanism, using multiple feeding mechanisms with different adjustable ranges of material transport flow rates to transport materials can reduce the difficulty of implementing each feeding mechanism.

[0024] First embodiment:

[0025] Figure 2 A schematic structural diagram of a 3D printing system provided in the first embodiment of the present application.

[0026] like Figure 2 As shown, the 3D printing system 10 includes a plurality of feeding mechanisms 41, a control part 411 and a print head 30. The plurality of feeding mechanisms 41 can be arranged in parallel. At the same time, the adjustable range of the material conveying flow rate of different feeding mechanisms in the plurality of feeding mechanisms 41 is different. The print head 30 is used to perform 3D printing using the flowable materials output by the plurality of feeding mechanisms 41.

[0027] exist Figure 2 In FIG. 1 , the direction indicated by the arrow is the conveying direction (or flow direction) of the material in the 3D printing system 10. Figure 2 As can be seen from the direction indicated by the middle arrow, the material is first transported from the multiple feeding mechanisms 41 to the print head 30 , then extruded through the extrusion port 31 , and finally deposited on the printing platform 20 .

[0028] The material of the material printed by the 3D printing system 10 is not specifically limited in the embodiment of the present application. In some embodiments, the 3D printing system 10 can be used to print plastics and any paste-like materials that can flow and extrude. In some embodiments, the 3D printing system 10 can be used to print metal paste materials (metal paste materials can be formed by adding liquid binders to metal powders), ceramic paste materials (ceramic paste materials can be formed by adding liquid binders to ceramic powders), organic polymer materials, inorganic paste materials (such as cement, gypsum slurry, mud, etc.). In some embodiments, the material that the 3D printing system 10 can be used to print can also be cream, chocolate and other paste foods. More specifically, in some embodiments, the 3D printing system 10 can be used to print materials formed by the following materials: polylactic acid (PLA), acrylonitrile-butadiene-styrene copolymer (ABS), polycarbonate (PC), nylon-6 (PA6), polyphenylene sulfide (PPS), polymethyl methacrylate (PMMA) and polyetheretherketone (PEEK).

[0029] There are many ways to implement the feeding mechanism 41, which is not limited in the present embodiment. For example, the feeding mechanism 41 can be a screw feeding device (screw pump, or screw extruder), or a pneumatic feeding device or a piston feeding device.

[0030] The different feeding mechanisms 41 can be the same type of feeding devices, for example, they can all be screw feeding devices. The different feeding mechanisms 41 can also be different types of feeding devices, for example, some feeding mechanisms 41 are screw feeding devices, and other feeding mechanisms 41 are piston feeding devices.

[0031] The number of print heads 30 may be one, so that multiple feeding mechanisms 41 can deliver materials to the same print head 30 of the 3D printing system. In some embodiments, multiple print heads 30 may be provided corresponding to multiple feeding mechanisms 41, so that multiple feeding mechanisms 41 can deliver materials to different print heads 30 of the 3D printing system respectively. The present application does not specifically limit the number of print heads 30.

[0032] The control part 411 is used to select a corresponding feeding mechanism from multiple feeding mechanisms to convey materials according to the requirements of the part to be printed on the variation range of the material conveying flow rate during the process of printing the same object (such as the same part).

[0033] Multiple feeding mechanisms 41 can work simultaneously or in different time periods. Multiple feeding mechanisms 41 can print different parts (or different structures) of the same object, such as printing different parts (or different regions) in the same layer. For example, a feeding mechanism with a lower adjustable range of material delivery flow rate can be used to print fine structures of an object with high precision; a feeding mechanism with a higher adjustable range of material delivery flow rate can be used to print thick and large structures of an object with high efficiency.

[0034] Compared with using a single feeding mechanism, using multiple feeding mechanisms with different adjustable ranges of material conveying flow rates to cooperate in conveying materials can reduce the difficulty of implementing each feeding mechanism.

[0035] Below, an example is given to illustrate the practical application effect of this solution.

[0036] Considering that it is difficult for a single feeding mechanism to have an adjustable range of material conveying flow rate of 1 to 10,000 times, in order to make the printing efficiency of the 3D printing system have an adjustable range of 1 to 10,000 times, two feeding mechanisms with different adjustable ranges of material conveying flow rates can be used to convey materials to the print head. For example, assuming that the material conveying flow rate needs to be between 1 and 10,000 mm 3 / s, two feeding mechanisms can be set: the first feeding mechanism and the second feeding mechanism. The adjustable range of the material conveying flow rate of the first feeding mechanism is 1 to 100 mm3 / s, the adjustable range of the material conveying flow rate of the second feeding mechanism is 100~10000mm 3 / s. It can be seen that the two feeding mechanisms cooperate with each other to meet the material conveying flow rate requirements of 1-10000mm 3 / s, but the two feeding mechanisms each only need to satisfy that the material conveying flow rate is adjustable within the range of 1 to 100 times, and does not need to be adjustable within the range of 1 to 10000 times, thereby simplifying the difficulty of realizing the feeding mechanism.

[0037] The embodiment of the present application does not specifically limit the setting method of the adjustable range of the material conveying flow rate of the multiple feeding mechanisms 41. For example, the multiple feeding mechanisms 41 include a first feeding mechanism and a second feeding mechanism. The adjustable range of the material conveying flow rate of the first feeding mechanism is [Q1, Q2], and the adjustable range of the material conveying flow rate of the second feeding mechanism is [Q3, Q4], wherein Q1, Q2, Q3, and Q4 are all positive numbers, and Q1 is less than Q3, Q4 is greater than Q2, and Q2 is greater than Q3. In other words, the adjustable range of the material conveying flow rate of the first feeding mechanism is smaller than the adjustable range of the material conveying flow rate of the second feeding mechanism, and the two ranges at least partially overlap. In this way, the first feeding mechanism and the second feeding mechanism cooperate with each other to achieve continuous adjustment of the material conveying flow rate within a larger range (i.e., [Q1, Q4]).

[0038] Optionally, in some embodiments, the control part 411 can be used to: when the demand of the part to be printed for the range of variation of the material conveying flow rate is less than Q3, control the first feeding mechanism to feed material; when the demand of the part to be printed for the range of variation of the material conveying flow rate is greater than Q2, control the second feeding mechanism to feed material; when the demand of the part to be printed for the range of variation of the material conveying flow rate is between Q2 and Q3, control the first feeding mechanism to feed material or the second feeding mechanism to feed material.

[0039] Optionally, in some embodiments, the material conveyed by the first feeding mechanism is extruded through a first extrusion port of a print head of the 3D printing system, and the material conveyed by the second feeding mechanism is extruded through a second extrusion port of a print head of the 3D printing system, the widths of the first extrusion port and the second extrusion port are both continuously adjustable, and the thickness of the first extrusion port is less than the thickness of the second extrusion port.

[0040] In this embodiment, the adjustable range of the material conveying flow rate of the first feeding mechanism is smaller than the adjustable range of the material conveying flow rate of the second feeding mechanism, and the first feeding mechanism can be configured with an extrusion port with a smaller thickness (the smaller the thickness of the extrusion port, the higher the printing accuracy of the extrusion port), so that the first feeding mechanism is applied to high-precision printing. In addition, the second feeding mechanism is configured with an extrusion port with a larger thickness (the larger the thickness of the extrusion port, the higher the printing efficiency of the extrusion port), so that the second feeding mechanism is applied to high-efficiency printing.

[0041] In the embodiment where multiple feeding mechanisms 41 deliver materials to the same print head 30, the outlets of the multiple feeding mechanisms 41 are connected. In order to avoid the transmission of materials and pressure between different feeding mechanisms 41, in some embodiments of the present application, reference is made to Figure 3 A one-way valve 42 may be provided between any one of the plurality of feeding mechanisms 41 and the print head 30 .

[0042] like Figure 3 As shown, there may be multiple one-way valves 42, so that each feeding mechanism 41 has a corresponding one-way valve 42. After the material flows out of the feeding mechanism 41, it first flows through the one-way valve 42 and then flows into the print head 30.

[0043] By providing the one-way valve 42 , the problem of material and pressure being transmitted between different feeding mechanisms 41 is effectively prevented, thereby improving the operational stability of the 3D printing system 10 .

[0044] In some embodiments, Figure 4 As shown, the 3D printing system 10 further includes a material flow channel 43. The material flow channel 43 has a structure that allows a flowable material to flow therethrough, and is used to deliver the flowable material output by the plurality of feeding mechanisms 41 to the print head 30. The material flow channel 43 is disposed between the feeding mechanism 41 and the print head 30, and the one-way valve 42 is disposed between the material flow channel 43 and the print head 30.

[0045] In the embodiment where multiple feeding mechanisms 41 deliver materials to the same print head, the control part 411 can also be used to control the multiple feeding mechanisms 41 to work at different times during the process of printing the same article. In other words, the control part 411 controls a certain feeding mechanism to work and can control other feeding mechanisms to stop working. In this way, when a certain feeding mechanism is working, the material delivered by the feeding mechanism can be prevented from leaking through the material channel between other feeding mechanisms and the print head.

[0046] For example, when it is necessary to print a thick portion of a part efficiently, the feeding mechanism with a higher adjustable range of the material conveying flow rate can be controlled to work, thereby printing the thick portion efficiently; when it is necessary to print a local fine portion of a part, the feeding mechanism with a lower adjustable range of the material conveying flow rate can be controlled to work, thereby printing the local fine portion with high precision.

[0047] When different feeding mechanisms work in different time periods, if the feeding mechanism stops for a long time, the material transported by the feeding mechanism will be in a high temperature environment for a long time, and there is a risk of material degradation. In order to avoid this problem, Figure 5As shown, in some embodiments, a corresponding print head 30 can be configured for each of the multiple feeding mechanisms 41, and the multiple feeding mechanisms 41 can be controlled to print different parts of the same object at the same time.

[0048] For example, a feeding mechanism with a higher adjustable range of material conveying flow rate can be controlled to efficiently print the thicker part of a part. At the same time, a feeding mechanism with a lower adjustable range of material conveying flow rate can be controlled to print the finer local part of the part with high precision.

[0049] In some embodiments, the plurality of feeding mechanisms 41 may be a plurality of screw feeding devices.

[0050] The screw feeding device can be designed with a single screw or a twin screw. The screw of the screw feeding device can have a single-start thread or a multi-start thread. The screw of the screw feeding device can be a horizontal screw or a vertical screw, and the screw groove of the screw can be of equal depth or variable depth.

[0051] When a screw feeding device is used to convey material to the print head, compared with a single screw feeding device, multiple screw feeding devices with adjustable ranges of different material conveying flow rates can not only reduce the implementation difficulty of each screw feeding device, but also avoid the problems of material degradation and inaccurate temperature control.

[0052] Specifically, in certain application scenarios, when conveying materials, the screw feeding device needs to heat the materials so that the materials are in a flowing state. When a single screw feeding device is used to convey materials to the print head, if the printing efficiency of the 3D printing system is to have a large adjustable range, the screw feeding device needs to have a correspondingly large adjustable range of material conveying flow rate. However, if the adjustable range of the material conveying flow rate of a single screw feeding device is too large, the material will stay in the screw feeding device for too long when the material conveying flow rate is low, increasing the risk of degradation. When the material conveying flow rate is high, the material will stay in the screw feeding device for too short a time and will not be heated enough, making it impossible to accurately control the temperature of the material.

[0053] When multiple screw feeding devices with different material output flow rates are used to transport materials to the print head, a screw feeding device with an appropriate output flow rate can be selected for operation according to actual needs, thereby effectively avoiding the above problems.

[0054] When the screw feeder squeezes the material to the extrusion port, pressure is generated at the extrusion port. Due to the existence of this pressure, the use of the screw feeder will have the problem of backflow or leakage. Backflow means that the material will flow in the opposite direction along the screw groove; leakage means that the material will flow in the gap between the screw and the barrel of the screw feeder in the direction opposite to the extrusion direction.

[0055] To solve this problem, in some embodiments, Figure 6 As shown, the 3D printing system 10 further includes temperature control devices 44, 32. The temperature control devices 44, 32 are used to control the temperature of the screw feeding device 41 and the print head 30, so that the temperature of the print head 30 is higher than the temperature of the material in the screw feeding device 41. This technical solution can effectively reduce the problems of backflow and leakage.

[0056] The following takes a screw feeding device with a single-start thread and a single screw with equal-depth screw grooves as an example to explain the principle by which the above technical solution can avoid leakage and backflow problems. The principles of other types of screws are similar and will not be repeated.

[0057] The extrusion flow rate of the screw feeder can be calculated by the following formula:

[0058]

[0059]

[0060]

[0061] In the formula: Q represents the extrusion flow rate (or flow rate) of the material, D represents the outer diameter of the screw, and H represents the depth of the screw groove. represents the helix angle, n represents the screw speed, P represents the extrusion pressure at the extrusion port 31, and P max It represents the maximum extrusion pressure of the screw, L represents the screw length, δ represents the gap between the screw and the barrel, e represents the normal width of the screw ridge, η represents the viscosity of the material in the screw groove, and η1 represents the viscosity of the material in the gap δ.

[0062] The higher the viscosity of the material in the screw, the higher the values ​​of η and η1. It can be seen from the above formula that the higher the values ​​of η and η1, the lower the ratio of backflow and leakage to the positive flow, and the less obvious the backflow and leakage phenomenon. In addition, backflow and leakage are caused by the existence of extrusion pressure P, and the greater the extrusion pressure P, the more obvious the backflow and leakage. The material at the extrusion port 31 is controlled to have a lower viscosity than the material in the screw feeding device 41. The lower the viscosity of the material, the smaller the extrusion pressure generated by the material at the extrusion port 31, which can also reduce the backflow and leakage phenomenon. The above-mentioned material viscosity difference setting can greatly reduce the backflow and leakage problems of the screw feeding device 41, and even reduce the backflow and leakage to a negligible level compared with the positive flow, so that the screw feeding device 41 can perform accurate metering output. In addition, the inventors also found that reducing the extrusion pressure P of the extrusion port 31 can significantly reduce the power consumption of the screw feeding device 41, thereby reducing the cost of the material conveying system.

[0063] Considering that lower temperature can increase the viscosity of the material, while higher temperature can reduce the viscosity of the material, therefore, by setting the temperature of the print head 30 to be higher than the temperature of the material in the screw feeding device 41 through the temperature control device 44, 32, the problems of backflow and leakage can be effectively reduced, and the power consumption of the screw feeding device 41 can be significantly reduced.

[0064] The temperature control device 44, 32 may include, for example, a first heater 44 and a second heater 32. The first heater 44 is configured to heat the screw feeder 41. The second heater 32 is configured to heat the extrusion port 31. The heating temperature of the second heater 32 is higher than the heating temperature of the first heater 44.

[0065] In some application scenarios, the 3D printing system 10 needs to first convert the solid material into a flowable material, and then transport the flowable material to the print head. In this case, each feeding mechanism 41 needs to continuously complete the conversion of the material from the solid state to the flowable state, and the metering output of the flowable state material to the print head. The inventors found that in this case, if the material conveying flow rate of the feeding mechanism 41 is greatly adjusted, the above two processes (conversion of the material from the solid state to the flowable state and metering output of the flowable state material to the print head) will be difficult to coordinate.

[0066] Take the feeding mechanism 41 as an example of a screw feeding device. The screw feeding device usually includes a feeding section, a melting section (or a compression section) and a metering section. The feeding section is used to receive solid materials, the melting section is used to convert the solid materials into a flowable state, and the metering section is used to quantitatively output the flowable material to the print head. If the flow rate of the material is dynamically changing, then the speed of the screw feeding device will also be dynamically changing. In this way, the pressure, flow rate and temperature of the flowable material output by the melting section will fluctuate. Affected by the fluctuation of the flowable material output by the melting section, it is difficult for the metering section to accurately and quantitatively deliver the material to the print head.

[0067] In order to solve the above problems, the present application assigns the two tasks of material state conversion and material metering output to two different feeding devices, and buffers the material between the two feeding devices to shield the impact of output fluctuations of the first feeding device on the second feeding device.

[0068] Combine the following Figure 7 Provide detailed explanation.

[0069] As shown in FIG7 , the 3D printing system 10 includes: a first feeding device 60, a buffer container 50, a second feeding device 40 and a print head 30. The buffer container 50 is located between the first feeding device 60 and the second feeding device 40. The plurality of feeding mechanisms 41 belong to the second feeding device 40, and the second feeding device 40 can be regarded as a feeding device composed of the plurality of feeding mechanisms 41.

[0070] Figure 7 The direction indicated by the arrow in the figure is the conveying direction of the material (or the flow direction of the material). Figure 7 It can be seen from the direction indicated by the middle arrow that the material flows through the first feeding device 60, the buffer 50, the second feeding device 40 and the print head 30 in sequence.

[0071] The first feeding device 60 is used to convert the solid material into a flowable material (also called a molten material). The buffer container 50 is used to store the flowable material output by the first feeding device 60. The second feeding device 40 is used to transport the flowable material in the buffer container 50 to the print head 30. That is to say, the first feeding device 60 is used to realize the conversion of the material from the solid state to the flowable state, and the second feeding device 40 is used to realize the metering output to the print head.

[0072] There are many ways to implement the first feeding device 60, which is not limited in the present embodiment. For example, the first feeding device 60 can be a screw feeding device (or screw pump, or screw extruder), or a pneumatic feeding device or a piston feeding device.

[0073] The buffer container 50 can isolate the fluctuations of the output of the first feeding device 60 from the adverse effects that may be produced on the second feeding device 40. The fluctuations of the output of the first feeding device 60 include at least one of the following fluctuations: pressure fluctuations, flow fluctuations, and temperature fluctuations. The isolation of the fluctuations of the output of the first feeding device 60 by the buffer container 50 is conducive to the second feeding device 40 being able to precisely control the flow rate of the material.

[0074] Specifically, if the first feeding device 60 is directly connected to the second feeding device 40, in order to achieve high-precision flow rate control at the extrusion port, it is necessary to perform high-precision coordinated flow rate control between the first feeding device 60 and the second feeding device 40. However, when the material extrusion flow rate of the print head 30 needs to change dynamically, the state of the material output by the first feeding device 60 is very unstable. In this case, it is very difficult to achieve high-precision coordination between the first feeding device 60 and the second feeding device 40. Adding a buffer container 50 between the first feeding device 60 and the second feeding device 40 can reduce the requirements for coordinated control between the first feeding device 60 and the second feeding device 40. As a buffer component, the buffer container 50 can smooth out the fluctuations of the output of the first feeding device 60 and ensure that the material is supplied to the subsequent second feeding device 40 in a stable state.

[0075] Due to the existence of the buffer container 50, the difficulty of coordinating the two stages of material state conversion and metering output is reduced, which is conducive to achieving stable metering output of materials.

[0076] The embodiment of the present application does not specifically limit the structure of the print head 30. In some embodiments, the print head 30 may have an extrusion port 31 with a continuously adjustable width.

[0077] At present, extruders with continuously adjustable widths have been used in some advanced 3D printing technologies. Some of these 3D printing systems require the width of the extruder to be controlled so that the width of the extruder changes with the cross-sectional contour of the material filling area (or, so that the width of the extruder matches the length of the cross-sectional contour of the material filling area), thereby achieving ultra-high efficiency printing. The design scheme and control method of such extruders can be found in WO2018 / 205149A1 (it should be noted that the width of the extruder in this application is equivalent to the length of the discharge port in the patent application, and the material filling area is equivalent to the target filling area in the patent application, and the material filling area can be part or all of the area of ​​the layer to be printed). Since the width of the extrusion port 31 will continuously change within a large range, the output flow rate of the feeding device 20 will dynamically change within a large range. The problem of limited adjustable range of the output flow rate of a single feeding device mentioned above, the degradation or inability to accurately control the material temperature when using a screw feeding device, and the difficulty in coordinating between material state conversion and metering output will become more prominent in such systems. Therefore, when using an extrusion port with continuously adjustable width, the 3D printing system 10 provided in the application embodiment can significantly improve the quality of 3D printing compared to traditional 3D printing systems.

[0078] In the above-mentioned 3D printing system 10, the first feeding device 60, the buffer container 50, the second feeding device 40 and the print head 30 can be regarded as four functional sections of the entire 3D printing system 10, and each functional section can perform precise temperature control according to its own needs. For example, the first feeding device 60 can control the temperature to be suitable for the material to be converted from a solid state to a flowable state. The buffer container 50 can control the temperature at a target value, which can be determined according to the operating temperature of the second feeding device 40, for example, it can be slightly higher than the operating temperature of the second feeding device 40. The second feeding device 40 and the print head 30 can be temperature controlled by the temperature difference control method described above.

[0079] Second embodiment:

[0080] The first embodiment is an apparatus embodiment, and the second embodiment is a method embodiment. The description on the apparatus side and the description on the method side correspond to each other, and for the sake of brevity, repeated descriptions are appropriately omitted.

[0081] Figure 8 A schematic flowchart of a 3D printing method provided for the second embodiment of the present application. Figure 8 The method S800 shown can be executed by the 3D printing system 10 mentioned above. The method S800 includes step S810.

[0082] In step S810, during the process of printing the same object, a corresponding feeding mechanism is selected from a plurality of feeding mechanisms to convey the material according to the requirements of the to-be-printed portion on the variation range of the material conveying flow rate.

[0083] In some embodiments, multiple feed mechanisms are used to print different portions of the same layer of an article.

[0084] In some embodiments, the 3D printing system further includes a first feeding device and a second feeding device, a buffer container located between the first feeding device and the second feeding device, and a print head connected to the second feeding device. Step S810 may include: using the first feeding device to convert solid materials into flowable materials; using the buffer container to store the materials output by the first feeding device; using multiple feeding mechanisms to transport the materials in the buffer container to the print head to respectively print different parts of the same object.

[0085] In some embodiments, the multiple feeding mechanisms are multiple screw feeding devices; method S800 may also include: temperature controlling the multiple screw feeding devices and the print head so that the temperature of the print head is higher than the temperature of the materials in the multiple screw feeding devices.

[0086] In some embodiments, multiple feed mechanisms deliver material to the same print head of a 3D printing system.

[0087] In some embodiments, a one-way conduction valve is arranged between any one of the plurality of feeding mechanisms and the print head.

[0088] In some embodiments, a material flow channel is provided between the first feeding mechanism and the print head, and a one-way valve is provided between the material flow channel and the print head.

[0089] In some embodiments, method S800 may further include: controlling multiple feeding mechanisms to work at different times during the process of printing the same object.

[0090] In some embodiments, multiple feeding mechanisms deliver material to different print heads of the 3D printing system.

[0091] In some embodiments, method S800 may further include: controlling multiple feeding mechanisms to work simultaneously during the process of printing the same object.

[0092] In some embodiments, the multiple feeding mechanisms include a first feeding mechanism and a second feeding mechanism, the adjustable range of the material conveying flow rate of the first feeding mechanism is [Q1, Q2], and the adjustable range of the material conveying flow rate of the second feeding mechanism is [Q3, Q4], wherein Q1, Q2, Q3, and Q4 are all positive numbers, and Q1 is less than Q3, Q4 is greater than Q2, and Q2 is greater than Q3.

[0093] In some embodiments, the material conveyed by the first feeding mechanism is extruded through a first extrusion port of a print head of the 3D printing system, and the material conveyed by the second feeding mechanism is extruded through a second extrusion port of a print head of the 3D printing system. The widths of the first extrusion port and the second extrusion port are both continuously adjustable, and the thickness of the first extrusion port is less than the thickness of the second extrusion port.

[0094] In some embodiments, during the process of printing the same object, step S810 includes: when the demand of the to-be-printed part for the range of changes in the material conveying flow rate is less than Q3, controlling the first feeding mechanism to feed; when the demand of the to-be-printed part for the range of changes in the material conveying flow rate is greater than Q2, controlling the second feeding mechanism to feed; when the demand of the to-be-printed part for the range of changes in the material conveying flow rate is between Q2 and Q3, controlling the first feeding mechanism to feed or the second feeding mechanism to feed.

[0095] In some embodiments, the multiple feeding mechanisms are multiple screw feeding devices.

[0096] In some embodiments, the print head has an extrusion orifice with a continuously adjustable width.

[0097] In some embodiments, method S800 may further include: controlling the width of an extrusion port of a print head of the 3D printing system so that the width of the extrusion port changes with the change of a cross-sectional contour line of a material filling area.

[0098] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any other combination. When implemented by software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present invention is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from a website site, computer, server or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (digital subscriber line, DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) mode to another website site, computer, server or data center. The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server or data center that includes one or more available media integrated. The available medium may be a magnetic medium (eg, a floppy disk, a hard disk, a magnetic tape), an optical medium (eg, a digital video disc (DVD)), or a semiconductor medium (eg, a solid state disk (SSD)).

[0099] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0100] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0101] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0102] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0103] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A 3D printing system with a multi-feeding mechanism, characterized in that: include: A plurality of feeding mechanisms, wherein different feeding mechanisms among the plurality of feeding mechanisms have different adjustable ranges of material conveying flow rates; A print head, used for performing 3D printing using the flowable materials output by the multiple feeding mechanisms, and the print head has an extrusion port with a continuously adjustable width; The control part is used to select a corresponding feeding mechanism from multiple feeding mechanisms to convey materials according to the requirements of the part to be printed on the variation range of the material conveying flow rate during the process of printing the same object.

2. The 3D printing system according to claim 1, characterized in that: The multiple feeding mechanisms are used to print different parts in the same layer of the object.

3. The 3D printing system according to claim 1, characterized in that: The 3D printing system comprises a first feeding device and a second feeding device, the plurality of feeding mechanisms belong to the second feeding device, and the 3D printing system further comprises a buffer container located between the first feeding device and the second feeding device; The first feeding device is used to convert solid materials into flowable materials; The buffer container is used to store the material output by the first feeding device; The second feeding device is used to transport the material in the buffer container to the print head.

4. The 3D printing system according to claim 1, characterized in that: The multiple feeding mechanisms are multiple screw feeding devices, and the 3D printing system further includes: A temperature control device is used to control the temperature of the multiple screw feeding devices and the print head so that the temperature of the print head is higher than the temperature of the materials in the multiple screw feeding devices.

5. The 3D printing system according to claim 1, characterized in that: The multiple feeding mechanisms transport materials to the same print head of the 3D printing system.

6. The 3D printing system according to claim 5, characterized in that: A one-way conduction valve is arranged between any one of the plurality of feeding mechanisms and the print head.

7. The 3D printing system according to claim 6, characterized in that: The multiple feeding mechanisms include a first feeding mechanism, a material flow channel is arranged between the first feeding mechanism and the print head, and the one-way guide valve is arranged between the material flow channel and the print head.

8. The 3D printing system according to any one of claims 5 to 7, characterized in that: The control part is also used to control the multiple feeding mechanisms to work at different times during the process of printing the same article.

9. The 3D printing system according to any one of claims 1 to 4, characterized in that: The multiple feeding mechanisms transport materials to different print heads of the 3D printing system.

10. The 3D printing system according to claim 9, characterized in that: The control part is also used to control the multiple feeding mechanisms to work simultaneously during the process of printing the same article.

11. The 3D printing system according to claim 1, characterized in that: The multiple feeding mechanisms include a first feeding mechanism and a second feeding mechanism, the adjustable range of the material conveying flow rate of the first feeding mechanism is [Q1, Q2], and the adjustable range of the material conveying flow rate of the second feeding mechanism is [Q3, Q4], wherein Q1, Q2, Q3, and Q4 are all positive numbers, and Q1 is less than Q3, Q4 is greater than Q2, and Q2 is greater than Q3.

12. The 3D printing system according to claim 11, characterized in that: The material conveyed by the first feeding mechanism is extruded through a first extrusion port of a print head of the 3D printing system, and the material conveyed by the second feeding mechanism is extruded through a second extrusion port of a print head of the 3D printing system. The widths of the first extrusion port and the second extrusion port are both continuously adjustable, and the thickness of the first extrusion port is less than the thickness of the second extrusion port.

13. The 3D printing system according to claim 11, characterized in that: The control part is used to: when the demand of the part to be printed for the range of variation of the material conveying flow rate is less than Q3, control the first feeding mechanism to feed material; when the demand of the part to be printed for the range of variation of the material conveying flow rate is greater than Q2, control the second feeding mechanism to feed material; when the demand of the part to be printed for the range of variation of the material conveying flow rate is between Q2 and Q3, control the first feeding mechanism or the second feeding mechanism to feed material.

14. The 3D printing system according to claim 1, characterized in that: The multiple feeding mechanisms are multiple screw feeding devices.

15. The 3D printing system according to claim 1, characterized in that: Also includes: A control device is used to control the width of the extrusion port of the print head of the 3D printing system so that the width of the extrusion port changes with the change of the cross-sectional contour line of the material filling area.

16. A 3D printing method, characterized in that: The 3D printing method is applied to a 3D printing system, wherein the 3D printing system comprises a plurality of feeding mechanisms and a print head, wherein different feeding mechanisms of the plurality of feeding mechanisms have different adjustable ranges of material conveying flow rates, and the print head has an extrusion port with continuously adjustable width; The 3D printing method comprises: In the process of printing the same object, a corresponding feeding mechanism is selected from multiple feeding mechanisms to convey the material according to the requirements of the part to be printed on the variation range of the material conveying flow rate.

17. The 3D printing method according to claim 16, characterized in that: The multiple feeding mechanisms are used to print different parts in the same layer of the object.

18. The 3D printing method according to claim 16, characterized in that: The 3D printing system further comprises a first feeding device and a second feeding device, a buffer container located between the first feeding device and the second feeding device, the second feeding device is connected to the print head, and the plurality of feeding mechanisms belong to the second feeding device; Using the multiple feeding mechanisms to print different parts of the same object respectively includes: Using the first feeding device to convert the solid material into a flowable material; Using the buffer container to store the material output by the first feeding device; The multiple feeding mechanisms are used to transport the material in the buffer container to the print head, so as to respectively print different parts of the same object.

19. The 3D printing method according to claim 16, characterized in that: The multiple feeding mechanisms are multiple screw feeding devices; The 3D printing method further comprises: The multiple screw feeding devices and the print head are temperature controlled so that the temperature of the print head is higher than the temperature of the materials in the multiple screw feeding devices.

20. The 3D printing method according to any one of claims 16 to 19, characterized in that: The multiple feeding mechanisms transport materials to the same print head of the 3D printing system.

21. The 3D printing method according to claim 20, characterized in that: A one-way conduction valve is arranged between any one of the plurality of feeding mechanisms and the print head.

22. The 3D printing method according to claim 21, characterized in that: The multiple feeding mechanisms include a first feeding mechanism, a material flow channel is arranged between the first feeding mechanism and the print head, and the one-way guide valve is arranged between the material flow channel and the print head.

23. The 3D printing method according to claim 20, characterized in that: The 3D printing method further comprises: During the process of printing the same article, the plurality of feeding mechanisms are controlled to work at different times.

24. The 3D printing method according to any one of claims 16 to 19, characterized in that: The multiple feeding mechanisms transport materials to different print heads of the 3D printing system.

25. The 3D printing method according to claim 24, characterized in that: The 3D printing method further comprises: During the process of printing the same article, the multiple feeding mechanisms are controlled to work simultaneously.

26. The 3D printing method according to claim 16, characterized in that: The multiple feeding mechanisms include a first feeding mechanism and a second feeding mechanism, the adjustable range of the material conveying flow rate of the first feeding mechanism is [Q1, Q2], and the adjustable range of the material conveying flow rate of the second feeding mechanism is [Q3, Q4], wherein Q1, Q2, Q3, and Q4 are all positive numbers, and Q1 is less than Q3, Q4 is greater than Q2, and Q2 is greater than Q3.

27. The 3D printing method according to claim 26, characterized in that: The material conveyed by the first feeding mechanism is extruded through a first extrusion port of a print head of the 3D printing system, and the material conveyed by the second feeding mechanism is extruded through a second extrusion port of a print head of the 3D printing system. The widths of the first extrusion port and the second extrusion port are both continuously adjustable, and the thickness of the first extrusion port is less than the thickness of the second extrusion port.

28. The 3D printing method according to claim 26, characterized in that: In the process of printing the same article, according to the demand of the to-be-printed part for the variation range of the material conveying flow rate, a corresponding feeding mechanism is selected from multiple feeding mechanisms to convey the material, including: when the demand of the to-be-printed part for the variation range of the material conveying flow rate is less than Q3, the first feeding mechanism is controlled to feed the material; when the demand of the to-be-printed part for the variation range of the material conveying flow rate is greater than Q2, the second feeding mechanism is controlled to feed the material; when the demand of the to-be-printed part for the variation range of the material conveying flow rate is between Q2 and Q3, the first feeding mechanism or the second feeding mechanism is controlled to feed the material.

29. The 3D printing method according to claim 16, characterized in that: The multiple feeding mechanisms are multiple screw feeding devices.

30. The 3D printing method according to claim 16, characterized in that: Also includes: The width of the extrusion port of the print head of the 3D printing system is controlled so that the width of the extrusion port changes with the change of the cross-sectional contour line of the material filling area.

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