Material conveying device, 3D printing system and feeding method

Abstract

The application provides a material conveying device, a 3D printing system and a feeding method applied to the 3D printing system. The material conveying device comprises: a material flow channel, which is adapted to be installed between a feeding device and a printing head of the 3D printing system, and is used for conveying flowable material output by the feeding device to the printing head, wherein the material flow channel has a variable volume; and a control part, which is connected with the material flow channel, and is used for adjusting the volume of the material flow channel in the process of conveying material by the material flow channel. Due to the existence of the material flow channel with the variable volume, the 3D printing system can more flexibly control the conveying process of the material by adjusting the volume of the material flow channel in the process of conveying the material to the printing head.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of 3D printing, in particular, to a material conveying device, a 3D printing system and a feeding method applied to the 3D printing system. BACKGROUND

[0002] The 3D printing technology based on material extrusion, such as the fused deposition molding (FDM) technology, generally needs to firstly convey the material to the printing head (or extrusion head) of the 3D printing system, and then extrude the material from the discharge port (or extrusion port) of the printing head, so as to gradually deposit the material on the working platform, and finally form a 3D printed product. SUMMARY

[0003] The present application provides a material conveying device, a 3D printing system and a feeding method applied to the 3D printing system, which can improve the controllability of the material conveying process.

[0004] In one aspect, a material conveying device is provided, comprising: a material flow channel adapted to be installed between a feeding device and a printing head of a 3D printing system, for conveying the flowable material output by the feeding device to the printing head, the material flow channel having a variable volume; a control part connected to the material flow channel, for adjusting the volume of the material flow channel during the conveying process of the material flow channel.

[0005] In another aspect, a 3D printing system is provided, comprising: a feeding device for outputting flowable material; a printing head for 3D printing by using the flowable material output by the feeding device; a material flow channel located between the feeding device and the printing head, for conveying the flowable material output by the feeding device to the printing head, the material flow channel having a variable volume; a control part connected to the material flow channel, for adjusting the volume of the material flow channel during the conveying process of the material flow channel.

[0006] In yet another aspect, a feeding method applied to a 3D printing system is provided, comprising: conveying flowable material to a printing head by using a material flow channel; adjusting the volume of the material flow channel during the conveying process of the material flow channel.

[0007] Due to the existence of the material flow channel with a variable volume, the conveying process of the material can be more flexibly controlled by adjusting the volume of the material flow channel during the conveying process of the material to the printing head. BRIEF DESCRIPTION OF DRAWINGS

[0008] Figure 1 Fig. 1 is a structural schematic diagram of a conventional 3D printing system.

[0009] Figure 2 A schematic view of a material conveying device according to a first embodiment of the present application.

[0010] Figure 3 A schematic view of a material flow channel with variable length according to the first embodiment.

[0011] Figure 4 A schematic view of a material flow channel with variable width according to the first embodiment. Figure 3 A cross-sectional view of the material flow channel from one viewing direction.

[0012] Figure 5 A cross-sectional view of the material flow channel from another viewing direction. Figure 3 An exploded view of the material flow channel.

[0013] Figure 6 A schematic view of a material flow channel with variable width according to another implementation of the first embodiment.

[0014] Figure 7 A cross-sectional view of the material flow channel from one viewing direction. Figure 6 A cross-sectional view of the material flow channel from another viewing direction.

[0015] Figure 8 A cross-sectional view of the material flow channel from another viewing direction. Figure 6 An exploded view of the material flow channel.

[0016] Figure 9 A schematic view of a material flow channel with variable width according to another implementation of the first embodiment. Figure 6

[0017] A cross-sectional view of the material flow channel from one viewing direction. Figure 10

[0018] A cross-sectional view of the material flow channel from another viewing direction. Figure 11 Figure 10 A cross-sectional view of the material flow channel from another viewing direction.

[0019] Figure 12 Figure 11 A schematic view of a material conveying device according to the first embodiment with a heating device.

[0020] Figure 13 A schematic view of a 3D printing system according to a second embodiment of the present application.

[0021] Figure 14 A schematic view of another 3D printing system according to the second embodiment of the present application.

[0022] Figure 15 A schematic view of a second material feeding device according to the second embodiment of the present application.

[0023] Figure 16 A schematic view of a second material feeding device according to the second embodiment of the present application. ​​

[0024] Figure 17 A schematic diagram of another 3D printing system provided for the second embodiment.

[0025] Figure 18 A schematic diagram of another 3D printing system provided for the second embodiment.

[0026] Figure 19 A schematic flow chart of a feeding method provided for the third embodiment. DETAILED DESCRIPTION

[0027] In a conventional material-extrusion-based 3D printing technology, referring to Figure 1 , a 3D printing system 10 includes a feeding device 20 and a printing head 30. In Figure 1 , the direction indicated by the arrow is the conveying direction of the material in the 3D printing system 10. As can be seen from the direction indicated by the arrow in Figure 1 , the feeding device 20 conveys the flowable material to the printing head 30, and then the printing head 30 extrudes the material through an extrusion port 31, so that the material is gradually deposited on a work platform 40, and finally forms a 3D printed product.

[0028] In the conventional 3D printing technology, the feeding device 20 and the printing head 30 are usually connected together through a material flow channel with a fixed volume. However, in the process of conveying the material to the printing head 30, the material extrusion flow rate of the 3D printing head can be variable, which can cause different flow rates of the material to pass through the material flow channel at different times, and the entire material conveying process is not controllable. The uncontrollability of the material conveying process can cause many problems, for example, when the material extrusion changes greatly, the temperature or pressure of the material conveyed to the printing head of the 3D printing system can fluctuate significantly.

[0029] In order to improve the controllability of the material conveying process, the present application adds a material channel with variable volume in the 3D printing system, so that in the process of conveying the material to the printing head, the 3D printing system can flexibly control the conveying process of the material by adjusting the volume of the material flow channel.

[0030] First embodiment:

[0031] The first embodiment of the present application is a material conveying device embodiment, which is suitable for use in a 3D printing system.

[0032] As shown in Figure 2 , the material conveying device 50 includes a material flow channel 51 with variable volume and a control part 52, the control part 52 is connected with the material flow channel 51, and is used to adjust the volume of the material flow channel 51 in the process of conveying the material by the material flow channel 51.

[0033] The material flow channel 51 has a structure allowing flowable material to flow therethrough, and has a variable volume. The material flow channel 51 can be implemented in many ways, and embodiments of the present application do not limit the material flow channel 51. For example, the material flow channel 51 can be a material flow channel having a variable length (the direction in which the material flows in the material flow channel 51 is the length direction of the material flow channel 51, and the dimension of the material flow channel 51 in this direction is the length of the material flow channel 51), so that the volume of the material flow channel 51 can be changed by changing the length of the material flow channel 51. For example, the material flow channel 51 can also be a material flow channel having a variable width (the dimension in the direction perpendicular to the length direction), so that the volume of the material flow channel 51 can be changed by changing the width of the material flow channel 51.

[0034] The material flow channel 51 can be installed, for example, between the feeding device 20 and the print head 30 of the 3D printing system as shown in Figure 1 to deliver the flowable material output by the feeding device 20 to the print head 30.

[0035] The feeding device 20 can be a screw-type feeding device (or screw pump, or screw extruder), or a pneumatic feeding device or a piston-type feeding device, and embodiments of the present application do not limit the specific form of the feeding device 20.

[0036] Due to the presence of the material flow channel 51 having a variable volume, the feeding device 20 can more flexibly control the delivery process of the material by adjusting the volume of the material flow channel 51 during the delivery of the material to the print head 30.

[0037] In some embodiments, the material flow channel 51 can be a material flow channel having a variable length, so that the control portion 52 can adjust the volume of the material flow channel 51 by changing the length of the material flow channel 51.

[0038] There are many ways to achieve a variable length of the material flow channel 51, and embodiments of the present application do not specifically limit how to achieve a variable length of the material flow channel 51. A possible implementation is given below in conjunction with the drawings.

[0039] As shown in Figures 3 to 5 , the material flow channel 51 includes a first portion 511 and a second portion 512.

[0040] The second portion 512 is the main portion of the material flow channel 51, and has a passage 5121 passing through the second portion 512, through which the material flow channel 51 delivers the material. Figure 4 The direction indicated by the arrow is the direction of the material flowing through the passage 5121, that is, the direction in which the material flows in the material flow channel 51, which is the length direction of the material flow channel 51.

[0041] The first part 511 is inserted into the channel 5121, sealingly engages with the inner wall of the channel 5121, and is slidable along the length direction of the material flow channel 51. The first part 511 is provided with a hole 5111, so that the material can flow out of the channel 5121 through the hole 5111.

[0042] From Figure 4 the direction of the arrow in FIG. 5, it can be seen that the material flows into the channel 5121 from the end of the channel 5121 away from the first part 511, and flows out of the hole 5111. Obviously, in some embodiments, the material can also flow into the hole 5111, and flow out of the end of the channel 5121 away from the first part 511.

[0043] During the flow of the material through the material flow channel 51, the control part can change the length of the material flow channel 51 by controlling the sliding of the first part 511 relative to the second part 512, so as to change the volume of the material flow channel 51.

[0044] Considering that the end of the material flow channel 51 needs to be connected to other parts of the 3D printing system, changing the length of the material flow channel 51 will cause the position of the end of the material flow channel 51 to move, which is not conducive to the connection of the material flow channel 51 to other parts of the 3D printing system.

[0045] Therefore, in some embodiments, the material flow channel 51 can also be provided as a material flow channel with variable width, so that the control part 52 can adjust the volume of the material flow channel 51 by changing the width of the material flow channel 51.

[0046] There are many ways to achieve the variable width of the material flow channel 51, and the embodiments of the present application do not make specific limitations on how to achieve the variable width of the material flow channel 51.

[0047] In some embodiments, referring to Figures 6 to 9 , the material flow channel 51 has a first part 511 and a second part 512 defining the volume of the material flow channel 51, and the first part 511 is slidably connected to the second part 512 along the width direction of the material flow channel 51. The control part 512 is configured to control the sliding of the first part 511 relative to the second part 512 to change the width of the material flow channel 51.

[0048] The second part 512 can be the main part of the material flow channel 51, and the second part 512 can be provided with a channel 5121 for conveying the material. Figure 5 The direction of the arrow in FIG. 5 is the direction of the flow of the material in the channel 5121, i.e. the length direction of the material flow channel 51.

[0049] The first part 511 can be a movable slider, for example, embedded in the second part 512 and slidable along the width direction of the material flow path 51. The end face of the first part 511 placed in the channel 5121 constitutes part of the side wall of the channel 5121.

[0050] In this way, the control part 52 can change the width of the material flow path 51 by controlling the sliding of the first part 511 relative to the second part 512.

[0051] Some material flow paths 51 can have a relatively low height, and the first part 511 needs to be thin, which can result in low strength of the first part 511 and easy damage after long-time sliding. In order to improve the strength of the first part 511, in some embodiments, the contact part of the first part and the second part can be complementary stepped. The following will be described in detail with reference to Figures 10 to 12 to this embodiment.

[0052] Reference Figures 10 to 12 , the material flow path 51 includes a first part 511 and a second part 512, and the first part 511 is slidably embedded in the second part 512. A first step 5112 is arranged on one side face of the first part 511, and a second step 5122 is arranged on the face of the second part 512 in contact with the first step 5112. The first step 5112, the second step 5122, the face of the first part 511 provided with the first step 5112, and the face of the second part 512 provided with the second step 5122 together enclose a channel 5121. The material flow path 51 transports materials through the channel 5121.

[0053] Figure 11 The direction indicated by the arrow is the direction of the flow of materials in the channel 5121, i.e. the length direction of the material flow path.

[0054] The control part 52 can change the width of the material flow path by controlling the sliding of the first part 511 relative to the second part 512, thereby changing the distance between the first step 5112 and the second step 5122.

[0055] When the materials flow through the material flow path 51 at a constant flow rate, increasing the volume of the material flow path 51 will increase the time required for the materials to flow through the material flow path 51, and conversely, reducing the volume of the material flow path 51 will reduce the time required for the materials to flow through the material flow path 51.

[0056] Therefore, in some embodiments, the control part 52 can control the time of the materials flowing through the material flow path 51 by adjusting the volume of the material flow path 51, thereby controlling the delivery process of the materials.

[0057] Since the flow rate of the material in the material flow channel 51 also affects the time required for the material to flow through the material flow channel 51, when adjusting the time required for the material to flow through the material flow channel 51, the influence of the flow rate of the material in the material flow channel 51 needs to be considered.

[0058] Therefore, in some embodiments, the control part 52 can be used to adjust the volume of the material flow channel 51, so that the volume of the material flow channel 51 matches the flow rate of the material in the material flow channel 51.

[0059] That is, the volume of the material flow channel 51 has a certain matching relationship with the flow rate of the material in the material flow channel 51, so that the control part 52 can adjust the volume of the material flow channel 51 according to the flow rate of the material in the material flow channel 51.

[0060] For example, the matching relationship can be that the volume of the material flow channel 51 increases as the flow rate of the material in the material flow channel 51 increases, and decreases as the flow rate of the material in the material flow channel 51 decreases; or the volume of the material flow channel 51 decreases as the flow rate of the material in the material flow channel 51 increases, and increases as the flow rate of the material in the material flow channel 51 decreases. The matching relationship between the volume of the material flow channel 51 and the flow rate of the material in the material flow channel 51 is not limited in the embodiments of the present application.

[0061] Adjusting the volume of the material flow channel 51 according to the flow rate of the material in the material flow channel 51 can more accurately control the time required for the material to flow through the material flow channel 51.

[0062] In some embodiments, the control of the control part 52 is such that when the flow rate of the material in the material flow channel 51 increases, the volume of the material flow channel 51 increases; and when the flow rate of the material in the material flow channel 51 decreases, the volume of the material flow channel 51 decreases. In this way, the influence of the change in the flow rate of the material on the time required for the material to flow through the material flow channel 51 can be smoothed out, and the fluctuation of the time required for the material to flow through the material flow channel 51 can be reduced.

[0063] In some embodiments, the control of the control part is such that the volume of the material flow channel 51 is proportional to the flow rate of the material in the material flow channel 51.

[0064] Specifically, when the flow rate of the material in the material flow channel 51 increases or decreases by a certain proportion, the control part 52 controls the volume of the material flow channel 51 to increase or decrease by the same proportion.

[0065] For example, the volume of the material flow channel 51 is proportional to the flow rate of the material in the material flow channel 51, so that when the flow rate of the material in the material flow channel 51 increases or decreases by a certain proportion, the volume of the material flow channel 51 also increases or decreases by the same proportion. Figures 6 to 9For example, referring to the material flow channel 51 shown in the figure, when the flow rate of the material in the material flow channel 51 changes in a range of 1 to 10 times, the control part 52 can control the first part 511 to slide so that the width of the material flow channel 51 also changes correspondingly in a range of 1 to 10 times. For example, when the flow rate of the material in the material flow channel 51 increases from 1 times to 3 times, the control part 52 also correspondingly adjusts the width of the material flow channel 51 from 1 times to 3 times; when the flow rate of the material in the material flow channel 51 decreases from 3 times to 2 times, the control part 52 also correspondingly adjusts the width of the material flow channel 51 from 3 times to 2 times.

[0066] In this way, the materials with different flow rates can all flow through the material flow channel 51 in substantially the same length of time.

[0067] In some embodiments, the control of the control part 52 is such that the materials with different flow rates in the material flow channel 51 all pass through the material flow channel 51 within a preset time range. Alternatively, the control of the control part 52 is such that the materials with different flow rates in the material flow channel 51 all pass through the material flow channel 51 in substantially the same time.

[0068] It should be understood that the specific value of the preset time range can be set according to actual needs, and the embodiments of the present application do not make specific limitations thereto.

[0069] In some embodiments, the material flow channel 51 is configured to receive the material from the feeding device 20; and the control of the control part 52 is such that the volume of the material flow channel 51 matches the output rate of the material from the feeding device 20.

[0070] In some embodiments, the 3D printing system 10 further comprises a heating device configured to heat the material in the material flow channel 51.

[0071] The heating device can be a heating pipe or a heating sheet. It can be arranged outside the material flow channel 51 or arranged inside the material flow channel 51. The specific form and arrangement position of the heating device are not limited in the embodiments of the present application.

[0072] For example, referring to Figure 13 The heating device can be a plurality of heating pipes 53 embedded in the second part 512 of the material flow channel 51. The plurality of heating pipes 53 can be arranged in parallel along the length direction of the material flow channel 51 to heat the material when the material flow channel 51 conveys the material.

[0073] Since the time required for the material to flow through the material flow channel 51 can be changed by adjusting the volume of the material flow channel 51, after the heating device is arranged, the heating time of the material flow channel 51 for the material can be controlled by adjusting the volume of the material flow channel 51.

[0074] For example, when the material flows through the material flow channel 51 at different flow rates, the volume of the material flow channel 51 can be controlled so that the material at different flow rates can flow through the material flow channel 51 in similar time, so as to obtain similar heating time. In this way, the influence of the change of the flow rate of the material on the temperature of the material can be reduced to a small extent, and the controllability of the material conveying process can be improved.

[0075] Second embodiment:

[0076] A second embodiment of the present application is a 3D printing system in which a material flow channel with variable volume is provided, so that during the conveying of the material to the print head, the 3D printing system can more accurately and flexibly control the material conveying process by adjusting the volume of the material flow channel.

[0077] As shown in Figure 14 , the 3D printing system 10 includes a feeding device 20, a print head 30, a material flow channel 51, and a control part 52. In Figure 10 , the direction indicated by the arrow is the flow (or conveying) direction of the material in the 3D printing system 10. As can be seen from Figure 10 , in the 3D printing system 10, the material can pass through the feeding device 20, the material flow channel 51, and the print head 30 in turn, and finally be deposited on the printing platform 40.

[0078] The material printed by the 3D printing system 10 is not specifically limited in the embodiments of the present application. In some embodiments, the 3D printing system 10 can be used to print plastic and any paste-like material that can flow and be extruded. In some embodiments, the 3D printing system 10 can be used to print metal paste-like material (metal paste-like material can be formed by adding liquid binder to metal powder), ceramic paste-like material (ceramic paste-like material can be formed by adding liquid binder to ceramic powder), organic polymer material, inorganic paste-like material (such as cement, gypsum slurry, mud slurry, etc.). In some embodiments, the material that can be printed by the 3D printing system 10 can also be paste-like food such as cream and chocolate. More specifically, in some embodiments, the 3D printing system 10 can be used to print material formed by polylactic acid (PLA), acrylonitrile-butadiene-styrene copolymer (ABS), polycarbonate (PC), nylon-6 (PA6), polyphenylene sulfide (PPS), polymethyl methacrylate (PMMA), and polyether ether ketone (PEEK).

[0079] The feeding device 20 is configured to output the flowable material. The print head 30 is configured to perform 3D printing using the flowable material output by the feeding device 20. The material flow channel 51 is located between the feeding device 20 and the print head 30, and is configured to deliver the flowable material output by the feeding device 20 to the print head 30. The material flow channel 51 has a variable volume. The control portion 52 is connected to the material flow channel 51, and is configured to adjust the volume of the material flow channel 51 during the delivery of the flowable material by the material flow channel 51.

[0080] The feeding device 20 can be a screw-type feeding device (or screw pump, or screw extruder), or a pneumatic feeding device, or a piston-type feeding device. The specific form of the feeding device 20 is not limited in the embodiments of the present application.

[0081] The material flow channel 51 can have various implementations, and the specific implementation of the material flow channel 51 is not limited in the embodiments of the present application. For the specific implementation of the material flow channel 51, refer to the related description of the first embodiment, which is not repeated here.

[0082] The material flow channel 51 can be the only device for delivering the flowable material between the feeding device 20 and the print head 30, or other devices for delivering the flowable material can also be provided between the feeding device 20 and the print head 30, which is not limited in the embodiments of the present application.

[0083] Due to the presence of the material flow channel with a variable volume, the 3D printing system can control the delivery process of the flowable material by adjusting the volume of the material flow channel, thereby improving the controllability of the delivery process of the flowable material.

[0084] The specific implementation of the material flow channel 51 and the specific control manner of the control portion 52 can refer to the related description of the first embodiment, and the repeated description is appropriately omitted for brevity.

[0085] In some embodiments, the material flow channel 51 is a material flow channel with a variable length, and the control portion 52 is configured to adjust the length of the material flow channel.

[0086] In some embodiments, the material flow channel 51 is a material flow channel with a variable width, and the control portion 52 is configured to adjust the width of the material flow channel.

[0087] In some embodiments, the material flow channel 51 has a first portion and a second portion defining the volume of the material flow channel 51, and the first portion is slidably connected to the second portion along the width direction of the material flow channel. The control portion 52 is configured to control the sliding of the first portion relative to the second portion to change the width of the material flow channel.

[0088] In some embodiments, the contact portions of the first portion and the second portion are complementary stepped.

[0089] In some embodiments, the control part 52 is configured to adjust the volume of the material flow channel 51, so as to control the time for the material to flow through the material flow channel 51.

[0090] In some embodiments, the control part 52 is configured to adjust the volume of the material flow channel 51, so as to match the volume of the material flow channel 51 with the flow rate of the material in the material flow channel 51.

[0091] In some embodiments, the control part 52 is configured to adjust the volume of the material flow channel 51, so as to match the volume of the material flow channel 51 with the flow rate of the material in the material flow channel 51.

[0092] In some embodiments, the control part 52 is configured to adjust the volume of the material flow channel 51, so as to match the volume of the material flow channel 51 with the flow rate of the material in the material flow channel 51.

[0093] In some embodiments, the control part 52 is configured to adjust the volume of the material flow channel 51, so as to match the volume of the material flow channel 51 with the flow rate of the material in the material flow channel 51.

[0094] In some embodiments, the control part 52 is configured to adjust the volume of the material flow channel 51, so as to match the volume of the material flow channel 51 with the flow rate of the material in the material flow channel 51.

[0095] In some embodiments, the 3D printing system 10 further comprises a heating device configured to heat the material in the material flow channel 51.

[0096] In a conventional 3D printing system, there is usually only one feeding device, which needs to continuously complete the conversion of the material from a solid state to a flowable state, and the metering output of the flowable material to the printing head. With the development of 3D printing technology, more and more 3D printing systems require the feeding device to be able to deliver material with dynamically changing flow rate to the printing head. The inventors have found that in such systems, if only one feeding device is used to continuously complete the conversion of the material state and the metering output of the material to the extrusion head, the two processes will be difficult to coordinate.

[0097] Taking a screw-type feeding device as an example, it usually includes a feeding section, a melting section (or a compression section), and a metering section. The feeding section is configured to receive solid material, the melting section is configured to convert the solid material into a flowable state, and the metering section is configured to quantitatively output the flowable material to the printing head. If the flow rate of the material is dynamically changing, the rotation speed of the screw-type 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. Influenced 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 printing head.

[0098] To solve the above problems, the present application allocates the material state conversion and the material metering output to two different feeding devices, and buffers the material between the two feeding devices to shield the influence of the output fluctuation of the first feeding device on the second feeding device.

[0099] The above and other objects, features and advantages of the present application will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: Figure 15 The above and other objects, features and advantages of the present application will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0100] As shown in Fig. 15, the 3D printing system 10 includes a feeding device 20, a buffer device 60, a printing head 30, a material flow channel 51 and a control part 52. The feeding device 20 includes a first feeding device 21 and a second feeding device 22, and the buffer device 60 is located between the first feeding device 21 and the second feeding device 22.

[0101] Figure 15 The direction indicated by the arrow in the figure is the direction of material flow (or material conveying). As can be seen from the direction indicated by the arrow, in the 3D printing system 10, the material can pass through the first feeding device 21, the buffer container 60, the second feeding device 22 and the printing head 30 in turn.

[0102] The first feeding device 21 is used to convert the solid material into flowable material (also referred to as molten material). The buffer container 60 is used to store the flowable material output by the first feeding device 21. The second feeding device 22 is used to convey the flowable material in the buffer container 60 to the printing head 30. That is, the first feeding device 21 is used to realize the conversion of the material from the solid state to the flowable state, and the second feeding device is used to realize the metering output to the printing head.

[0103] The first feeding device 21 can have various implementations, and the embodiments of the present application are not limited in this regard. For example, the first feeding device 20 can be a screw type feeding device (or screw pump, or screw extruder), or a pneumatic feeding device or a piston type feeding device.

[0104] The second feeding device 21 can also have various implementations, and the embodiments of the present application are not limited in this regard. For example, a melt pump (gear pump), a piston pump or a screw type feeding device (also referred to as a screw pump) can be used for feeding.

[0105] The buffer container 60 can isolate the adverse effects that the output fluctuation of the first feeding device 21 can have on the second feeding device 22. The output fluctuation of the first feeding device 21 includes at least one of the following fluctuations: pressure fluctuation, flow fluctuation and temperature fluctuation. The isolation of the output fluctuation of the first feeding device 21 by the buffer container 60 is beneficial to the precise flow rate control of the material by the second feeding device 22.

[0106] Specifically, if the first feeding device 21 is directly connected to the second feeding device 22, high-precision coordinated flow rate control between the first feeding device 21 and the second feeding device 22 is required to achieve high-precision flow rate control at the extrusion outlet. However, when the material extrusion flow rate of the print head 30 needs to be dynamically changed, the state of the material output by the first feeding device 21 is very unstable. In this case, it is very difficult to achieve high-precision coordination between the first feeding device 21 and the second feeding device 22. Adding the buffer container 60 between the first feeding device 21 and the second feeding device 22 can reduce the requirement for coordinated control between the first feeding device 21 and the second feeding device 22. As a buffering component, the buffer container 60 can smooth the fluctuations in the output of the first feeding device 21 and ensure that the material is supplied to the subsequent second feeding device 22 in a stable state.

[0107] Thanks to the presence of the buffer container 60, the difficulty of coordination between the two stages of material state transformation and metering output is reduced, thereby facilitating the stable metering output of the material.

[0108] The material flow channel 51 can be arranged between the first feeding device 21 and the buffer container 60, or between the second feeding device 22 and the print head 30. Of course, the material flow channel 51 can also be arranged between the first feeding device 21 and the buffer container 60 and between the second feeding device 22 and the print head 30, respectively.

[0109] As a material supply section, the first feeding device 21 generally has a relatively large adjustable range of material delivery flow rate. When the material delivery flow rate of the first feeding device 21 changes significantly in a short period of time, it will cause significant fluctuations in the temperature of the material. Although a temperature control unit can be provided in the buffer container 60 to control the temperature of the flowable material stored in the buffer container 60 to smooth the temperature fluctuations of the material output by the first feeding device 21 to a certain extent. However, considering that the buffer container 60 needs to have an overflow function when the material delivery flow rate of the first feeding device 21 is greater than the material delivery flow rate of the second feeding device 22, its volume cannot be too small. Therefore, for materials with low thermal conductivity, the buffer container 60 may not be able to control the material to the set temperature before the material is delivered to the second feeding device 22.

[0110] Arranging the material flow channel 51 with a heating device between the first feeding device 21 and the buffer can better shield temperature fluctuations.

[0111] Specifically, when the material conveying flow rate of the first feeding device 21 changes, the control unit 52 can control the volume of the material flow channel 51 to change, so that regardless of the change in the material conveying flow rate of the first feeding device 21, the material can pass through the material flow channel 51 in a similar time, thereby obtaining a similar heating time. This setting allows the material to have a similar temperature before entering the buffer container, thus better shielding the temperature fluctuation of the material output by the first feeding device 21.

[0112] In some embodiments, the second feeding device 22 may be a screw-type feeding device.

[0113] Screw-type feeding devices can employ a single-screw design or a twin-screw design. The screw of a screw-type feeding device can have a single-start thread or a multi-start thread. The screw of a screw-type feeding device can be a horizontal screw or a vertical screw, and the screw groove can be of uniform depth or varying depth.

[0114] by Figure 16 For example, the screw-type feeding device 22 may include a screw 221. Furthermore, the screw-type feeding device 22 may also include a motor 222 and a reducer 223. The motor 222 can be used to control the rotation of the screw 221. The reducer 223 can be used to match the speeds between the motor 222 and the screw 221.

[0115] When the second feeding device 22 extrudes the material to the extrusion port 31, pressure is generated at the extrusion port 31. Due to this pressure, the screw-type feeding device 22 may experience backflow or leakage. Backflow refers to the material flowing in the opposite direction along the screw groove; leakage refers to the material flowing in the gap between the screw and the barrel in the opposite direction to the screw extrusion direction.

[0116] To solve this problem, such as Figure 16 As shown, the 3D printing system may also include temperature control devices 224, 32.

[0117] Temperature control devices 224 and 32 are used to control the temperature of the screw feeder 22 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 feeder 22.

[0118] This technical solution can effectively reduce backflow and leakage problems, for the reasons explained below.

[0119] The extrusion flow rate of a screw-type feeder can be calculated using the following formula:

[0120] (1)

[0121] Countercurrent / Forward current = (2)

[0122] backflow / forward flow (3)

[0123] wherein Q represents the extrusion flow rate (or flow rate) of the material, D represents the outer diameter of the screw 221, H represents the screw channel depth, φ represents the helix angle, n represents the screw rotation speed, P represents the extrusion pressure at the extrusion outlet 31, P max represents the maximum extrusion pressure of the screw 221, L represents the length of the screw 221, δ represents the gap between the screw 221 and the barrel, e represents the normal width of the screw flight, η represents the viscosity of the material in the screw channel, and η1 represents the viscosity of the material in the gap δ.

[0124] The higher the viscosity of the material in the screw 221, the higher the values of η and η1. As can be seen from the above formula, the higher the values of η and η1, the lower the proportion of backflow and leakage flow relative to forward flow, and the less obvious the backflow and leakage flow phenomenon. In addition, backflow and leakage flow are caused by the existence of the extrusion pressure P of the material at the extrusion outlet 31, and the greater the extrusion pressure P, the more obvious the backflow and leakage flow. The above technical solution controls the material at the extrusion outlet 31 to have a lower viscosity than the material in the screw 221, and the lower the viscosity of the material, the smaller the extrusion pressure of the material at the extrusion outlet 31, which can also reduce the backflow and leakage flow phenomenon. The above difference in material viscosity can greatly reduce the backflow and leakage flow problem of the screw feeder 22, and even reduce the backflow and leakage flow to a negligible degree compared with forward flow, so that the screw feeder 22 can perform accurate metering output. In addition, the inventors have found that reducing the extrusion pressure P of the extrusion outlet 31 can significantly reduce the power consumption of the screw feeder 22, thereby reducing the material conveying cost of the 3D printing system.

[0125] Considering that a lower temperature can increase the viscosity of the material, and a higher temperature can reduce the viscosity of the material, a lower temperature can be set at the screw 221 to increase the viscosity of the material, and a higher temperature can be set at the extrusion outlet 31 to reduce the viscosity of the material at the extrusion outlet 31. Therefore, by setting the temperature of the print head 30 to be higher than the temperature of the material in the screw feeder 22 through the temperature control device 224, 32, the backflow and leakage flow problem can be effectively reduced, and the power consumption of the screw feeder 22 can be significantly reduced.

[0126] The temperature control device 224, 32 can include a first heater 224 and a second heater 32. The first heater 224 is configured to heat the screw 221. The second heater 32 is configured to heat the extrusion outlet 31. The heating temperature of the second heater 32 is higher than the heating temperature of the first heater 224.

[0127] As can be seen from the foregoing explanation, the higher the viscosity of the material at the screw 221 compared to the viscosity of the material at the extrusion port 31, the less significant the backflow and leakage phenomenon. In order to minimize the backflow and leakage phenomenon and thus provide a basis for accurate metering output of the screw feeder 22, the temperature difference between the screw 221 and the extrusion port 31 can be increased as much as possible. This requires that the material at the lower temperature at the outlet position of the screw feeder 22 be heated to a higher temperature during the process of transporting the material from the outlet position of the screw feeder 22 to the extrusion port 31. However, the material transport flow rate of the screw feeder 22 is dynamically changing. When the material transport flow rate of the screw feeder 22 is low, the material will stay at the outlet of the screw feeder 22 to the print head for a long time, and staying at a high temperature for too long will cause the material to face a higher risk of degradation. Conversely, when the material transport flow rate of the screw feeder 22 is high, the long stay time of the material between the outlet of the screw feeder 22 and the print head will be shortened, resulting in insufficient time to heat the material from the low temperature at the outlet of the screw feeder 22 to the predetermined high temperature at the extrusion port 31.

[0128] The provision of the material flow channel 51 with a heating device between the screw feeder 22 and the print head 30 can effectively solve this problem.

[0129] Specifically, during the process of transporting the material from the screw feeder 22 to the print head 31, the control part 52 can control the volume of the material flow channel 51 so that the material can flow through the material flow channel 51 with similar time regardless of the change in the material transport flow rate of the screw feeder 22, thereby obtaining similar heating time. By such arrangement, the influence of the change in the material transport flow rate of the screw feeder 22 on the heating of the material can be reduced to a low level, thereby solving the above problem.

[0130] In some application scenarios, the material transport flow rate of the second feeder 22 needs to change in a large range. For example, when printing an object, the 3D printing system 10 needs to adjust the material extrusion flow rate of the print head 30 according to the actual demand to adjust the printing efficiency of the 3D printing system. In order to match the change in the printing efficiency, the material transport flow rate of the second feeder 22 needs to be adjusted correspondingly. When the printing efficiency of the 3D printing system 10 changes in a large range, the material transport flow rate of the second feeder 22 also needs to change in a large range.

[0131] If the second feeder is only a single feeder, for example, only a single screw feeder, the adjustable range of the material transport flow rate thereof is limited. When the material transport flow rate of the second feeder 22 needs to change in a large range, it is difficult for a single feeder to achieve this.

[0132] To solve this problem, the second feeding device 22 can be configured by a plurality of feeding mechanisms with different adjustable ranges of material delivery flow rates.

[0133] The following will be described in detail Figure 17 The scheme will be described in detail.

[0134] As Figure 17 shown, the 3D printing system 10 and Figure 15 the 3D printing system 10 shown in FIG. 2 are basically the same, with the only difference being the second feeding device 22. For brevity, the same parts will not be described again.

[0135] Referring to Figure 17 , the second feeding device 22 of the 3D printing system 10 includes a plurality of feeding mechanisms 225 (the plurality of feeding mechanisms 225 can be connected in parallel) and a control unit 226.

[0136] The plurality of feeding mechanisms 225 can be used to deliver the same material, and the adjustable ranges of material delivery flow rates of different feeding mechanisms 225 in the plurality of feeding mechanisms 225 are different.

[0137] The plurality of feeding mechanisms 225 can be respectively connected with the buffer container 60, so that the buffer container 60 can respectively deliver materials to the plurality of feeding mechanisms 225.

[0138] The implementation of the feeding mechanism 225 can be various, and the embodiments of the present application are not limited thereto. For example, the feeding mechanism 225 can be a screw feeding device (or screw pump, or screw extruder), or a pneumatic feeding device or a piston feeding device.

[0139] Different feeding mechanisms 225 can be the same type of feeding device, for example, they can all be screw feeding devices. Different feeding mechanisms 225 can also be different types of feeding devices, for example, some feeding mechanisms 225 are screw feeding devices, and the other feeding mechanisms 225 are piston feeding devices.

[0140] There can be only one material flow channel 51 between the feeding device 22 and the print head 30, so that the plurality of feeding mechanisms 225 can deliver materials to the print head 30 through the same material flow channel 51. There can also be a plurality of material flow channels 51 between the second feeding device 22 and the print head 30, so that different feeding mechanisms 225 can deliver materials to the print head 30 through different material flow channels 51. The number of material flow channels 51 between the second feeding device and the print head is not limited in the embodiments of the present application.

[0141] The number of the print heads 30 can be one, so that the plurality of feeding mechanisms 225 can feed the material to the same print head 30 of the 3D printing system. Obviously, in some embodiments, a plurality of print heads 30 can also be provided corresponding to the plurality of feeding mechanisms 225, so that the plurality of feeding mechanisms 225 can feed the material to different print heads 30 of the 3D printing system respectively. The number of the print heads 30 is not specifically limited in the present application.

[0142] The control unit 226 is configured to select a corresponding feeding mechanism from the plurality of feeding mechanisms 225 to feed the material according to the requirement of the variation range of the material feeding flow rate of the part to be printed during the printing of the same object (e.g., the same part).

[0143] The plurality of feeding mechanisms 225 can work simultaneously or in time division. The plurality of feeding mechanisms 225 can print different parts (or different structures) of the same object, such as different parts (or different regions) in the same layer. For example, the feeding mechanism with a lower adjustable range of the material feeding flow rate can be used for high-precision printing of fine structures of the object; and the feeding mechanism with a higher adjustable range of the material feeding flow rate can be used for high-efficiency printing of thick structures of the object.

[0144] Compared with using a single feeding mechanism, using a plurality of feeding mechanisms with different adjustable ranges of the material feeding flow rate to feed the material can reduce the implementation difficulty of each feeding mechanism.

[0145] In the following, an example is given to illustrate the practical application effect of the scheme.

[0146] Considering that a single feeding mechanism is difficult to have an adjustable range of 1-10000 times of the material feeding flow rate, in order to make the printing efficiency of the 3D printing system have an adjustable range of 1-10000 times, two feeding mechanisms with different adjustable ranges of the material feeding flow rate can be used to feed the material to the print head. For example, assuming that the material feeding flow rate needs to be adjustable within 1-10000 mm / s, the second feeding device can be configured to include two feeding mechanisms: a first feeding mechanism and a second feeding mechanism. The adjustable range of the material feeding flow rate of the first feeding mechanism is 1-100 mm / s, and the adjustable range of the material feeding flow rate of the second feeding mechanism is 100-10000 mm / s. Thus, it can be seen that the two feeding mechanisms can cooperate with each other to meet the requirement that the material feeding flow rate needs to be adjustable within 1-10000 mm / s, but each of the two feeding mechanisms only needs to meet the requirement that the material feeding flow rate is adjustable within 1-100 times, and does not need to be adjustable within 1-10000 times, thereby simplifying the implementation difficulty of the feeding mechanism. 3 3 3 3

[0147] ​​​​The application does not limit the setting mode of the adjustable range of the material delivery flow rate of the plurality of material feeding mechanisms 225. For example, the plurality of material feeding mechanisms 225 can include a first material feeding mechanism and a second material feeding mechanism. The adjustable range of the material delivery flow rate of the first material feeding mechanism can be [Q1, Q2], and the adjustable range of the material delivery flow rate of the second material feeding mechanism can be [Q3, Q4], where Q1, Q2, Q3, and Q4 are positive numbers, 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 delivery flow rate of the first material feeding mechanism is smaller than the adjustable range of the material delivery flow rate of the second material feeding mechanism, and the two ranges at least partially overlap. In this way, the first material feeding mechanism and the second material feeding mechanism cooperate with each other to achieve continuous adjustment of the material delivery flow rate in a larger range (i.e., [Q1, Q4]).

[0148] Optionally, in some embodiments, the control unit 226 can be configured to control the first material feeding mechanism to feed when the demand of the part to be printed on the change range of the material delivery flow rate is less than Q3, control the second material feeding mechanism to feed when the demand of the part to be printed on the change range of the material delivery flow rate is greater than Q2, and control the first material feeding mechanism or the second material feeding mechanism to feed when the demand of the part to be printed on the change range of the material delivery flow rate is between Q2 and Q3.

[0149] Optionally, in some embodiments, the material delivered by the first material feeding mechanism is extruded through a first extrusion opening of the print head of the 3D printing system, and the material delivered by the second material feeding mechanism is extruded through a second extrusion opening of the print head of the 3D printing system. The widths of the first extrusion opening and the second extrusion opening are continuously adjustable, and the thickness of the first extrusion opening is smaller than the thickness of the second extrusion opening.

[0150] In this embodiment, the adjustable range of the material delivery flow rate of the first material feeding mechanism is smaller than the adjustable range of the material delivery flow rate of the second material feeding mechanism. Therefore, the first material feeding mechanism can be configured with an extrusion opening having a smaller thickness (the smaller the thickness of the extrusion opening, the higher the printing precision of the extrusion opening), so that the first material feeding mechanism is applied to high-precision printing. In addition, the second material feeding mechanism is configured with an extrusion opening having a larger thickness (the larger the thickness of the extrusion opening, the higher the printing efficiency of the extrusion opening), so that the second material feeding mechanism is applied to high-efficiency printing.

[0151] In the embodiment in which the plurality of material feeding mechanisms 225 deliver material to the same print head 30, in order to avoid the transmission of material and pressure between different material feeding mechanisms 225, in some embodiments of the application, referring again to Figure 17 , a one-way conduction valve 70 can be arranged between any one of the plurality of material feeding mechanisms 225 and the print head 30.

[0152] In the embodiment where multiple feeding mechanisms 225 respectively feed materials to the print head 30 through different material flow channels 51, the one-way valve 70 can be arranged between the feeding mechanism 225 and the material flow channel 51, or arranged between the material flow channel 51 and the print head 30. In the embodiment where multiple feeding mechanisms 225 feed materials to the print head 30 through the same material flow channel 51, the one-way valve 70 is arranged between the feeding mechanism 225 and the material flow channel 51.

[0153] By arranging the one-way valve 70, the materials and pressure are effectively prevented from being transferred between different feeding mechanisms 225, and the stability of the 3D printing system 10 is improved.

[0154] In the embodiment where multiple feeding mechanisms 225 feed materials to the same print head, the control unit 226 can also be configured to control the multiple feeding mechanisms 225 to work at different times during the printing of the same object. In other words, the control unit 226 can control a certain feeding mechanism to work while controlling other feeding mechanisms to stop working. In this way, the materials fed by a certain feeding mechanism can be prevented from leaking through the material channel between the other feeding mechanisms and the print head.

[0155] For example, when a thick part of a part needs to be printed efficiently, a feeding mechanism with a higher adjustable range of material feeding flow rate can be controlled to work, so as to efficiently print the thick part; when a local fine part of the part needs to be printed, a feeding mechanism with a lower adjustable range of material feeding flow rate can be controlled to work, so as to accurately print the local fine part.

[0156] When different feeding mechanisms work at different times, if the feeding mechanism stops working for a long time, the materials fed 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, in some embodiments, as shown in FIG. 6, a corresponding print head 30 can be arranged for each feeding mechanism 225 in the multiple feeding mechanisms 225, and the multiple feeding mechanisms 225 can be controlled to print different parts of the same object at the same time. Figure 18

[0157] For example, a feeding mechanism with a higher adjustable range of material feeding flow rate can be controlled to efficiently print a thick part of a part, while a feeding mechanism with a lower adjustable range of material feeding flow rate can be controlled to accurately print a local fine part of the part.

[0158] In some embodiments, the multiple feeding mechanisms 225 are multiple screw feeding devices.

[0159] ​Compared with a single screw feeder, multiple screw feeders with different adjustable ranges of material delivery flow rates can not only reduce the difficulty of implementation of each screw feeder, but also avoid the problems of material degradation and inaccurate temperature control when the screw feeders are used to deliver material to the print head.

[0160] Specifically, in some application scenarios, the screw feeder needs to heat the material to make it in a flow state when delivering the material. When a single screw feeder is used to deliver material to the print head, if the print efficiency of the 3D printing system needs to have a large adjustable range, the screw feeder needs to correspondingly have a large adjustable range of material delivery flow rate. However, the large adjustable range of material delivery flow rate of a single screw feeder will cause the material to stay in the screw feeder for too long when the material delivery flow rate is low, increasing the risk of degradation, and the material stays in the screw feeder for too short when the material delivery flow rate is high, resulting in insufficient heating, so that the temperature of the material cannot be accurately controlled.

[0161] When multiple screw feeders with different material output flow rates are used to deliver material to the print head, the screw feeder with an appropriate output flow rate can be selected to operate according to actual needs, thereby effectively avoiding the above problems.

[0162] The structure of the print head 30 is not specifically limited in the embodiments of the present application. In some embodiments, the print head 30 can have an extrusion port 31 with a continuously adjustable width.

[0163] At present, the extrusion nozzle with continuously adjustable width has been applied in some advanced 3D printing technologies, and some of these 3D printing systems require the width of the extrusion nozzle to be controlled so that the width of the extrusion nozzle changes with the cross-sectional profile of the material filling area (or so that the width of the extrusion nozzle matches the length of the cross-sectional profile of the material filling area), thereby achieving ultra-high printing efficiency. The design scheme and control method of such an extrusion nozzle can be found in WO2018 / 205149 A1 (it should be noted that the width of the extrusion nozzle in the present application corresponds to the length of the discharge port in the patent application, and the material filling area corresponds to the target filling area in the patent application, which can be part or all of the layer to be printed). Since the width of the extrusion nozzle 31 continuously changes in a large range, the material conveying flow rate of the feeding device 20 dynamically changes in a large range, and the aforementioned coordination difficulties between the material state conversion and the metering output, the temperature fluctuations of the material output by the first feeding device 21, the degradation or insufficient heating of the material conveyed by the second feeding device 22 to the printing port 30, and the limited adjustable range of the material conveying flow rate of a single feeding device are more prominent in such systems, and therefore, when the extrusion nozzle with continuously adjustable width is applied, the 3D printing system 10 provided by the application embodiment can significantly improve the quality of 3D printing compared with traditional 3D printing systems.

[0164] In the above-mentioned 3D printing system 10, the first feeding device 21, the buffer container 60, the second feeding device 22 and the printing head 30 can be regarded as four functional segments of the entire 3D printing system 10, and each functional segment can be accurately temperature-controlled according to its own needs. For example, the first feeding device 21 can be controlled at a temperature suitable for the conversion of the material from a solid state to a flowable state. The buffer container 60 can be controlled at a target temperature, which can be determined according to the working temperature of the second feeding device 21, for example, slightly higher than the working temperature of the second feeding device 21. The second feeding device 21 and the printing head 30 can be temperature-controlled in the differential temperature control mode as described above.

[0165] The material flow channel 51 arranged between the functional segments helps to accurately control the temperature of each functional segment, thereby improving the printing quality of the 3D printing system.

[0166] The above Figure 17 The multi-feeding mechanism scheme is exemplified in detail by taking the example of the second feeding device 22 comprising a plurality of feeding mechanisms 225, but the application scenarios of the multi-feeding mechanism scheme are not limited to Figure 17 the scenarios shown in the figures. For example, in some embodiments, the feeding mechanism 20 in Figure 14 may be replaced by a plurality of feeding mechanisms to directly feed the printing head, thereby eliminating the first feeding device and the buffer container.

[0167] Third embodiment:

[0168] The second embodiment is a device embodiment, and the third embodiment is a method embodiment.

[0169] Figure 19 is a schematic flowchart of a feeding method applied to a 3D printing system according to a third embodiment of the present application. Figure 19 The method S1900 can be performed by the 3D printing system 10 mentioned above. The method S1900 comprises steps S1910 and S1920.

[0170] In step S1910, the flowable material output by the feeding device is delivered to the print head by using a material flow channel with a variable volume.

[0171] In step S1920, the volume of the material flow channel is adjusted during the delivery of the material by the material flow channel.

[0172] In some embodiments, step S1920 can comprise: controlling the time for the material to flow through the material flow channel by adjusting the volume of the material flow channel.

[0173] In some embodiments, step S1920 can comprise: adjusting the volume of the material flow channel such that the volume of the material flow channel matches the flow rate of the material in the material flow channel.

[0174] In some embodiments, step S1920 can comprise: adjusting the volume of the material flow channel such that the volume of the material flow channel becomes larger when the flow rate of the material in the material flow channel increases; and the volume of the material flow channel becomes smaller when the flow rate of the material in the material flow channel decreases.

[0175] In some embodiments, step S1920 can comprise: adjusting the volume of the material flow channel such that the volume of the material flow channel is proportional to the flow rate of the material in the material flow channel; or such that different flow rates of the material in the material flow channel all pass through the material flow channel within a preset time range.

[0176] In some embodiments, step S1920 can comprise: adjusting the volume of the material flow channel such that the volume of the material flow channel matches the rate of the material input into the material flow channel.

[0177] In some embodiments, the material flow channel can be a material flow channel with a variable width; and step S1920 can comprise: adjusting the volume of the material flow channel by adjusting the width of the material flow channel.

[0178] In some embodiments, the material flow channel can have a first portion and a second portion defining a volume of the material flow channel, and the first portion is slidably connected to the second portion along a width direction of the material flow channel; and step S1920 can include: changing the width of the material flow channel by controlling the first portion to slide relative to the second portion, thereby adjusting the volume of the material flow channel.

[0179] In some embodiments, the contact portions of the first portion and the second portion are complementary stepped.

[0180] In some embodiments, the method S1900 can further include: heating the material in the material flow channel.

[0181] In some embodiments, the feeding device includes a first feeding device and a second feeding device, and the 3D printing system further includes a buffer container between the first feeding device and the second feeding device, and the method S1900 can further include: converting the solid material into flowable material by using the first feeding device; storing the material output by the first feeding device by using the buffer container; and delivering the material in the buffer container to the print head by using the second feeding device; wherein the material flow channel is arranged between the first feeding device and the buffer container, and / or the material flow channel is arranged between the second feeding device and the print head.

[0182] In some embodiments, the second feeding device is a screw feeding device, and the method S1900 can further include: controlling the temperature of the screw feeding device and the print head such that the temperature of the print head is higher than the temperature of the material in the screw feeding device.

[0183] In some embodiments, the second feeding device includes a plurality of feeding mechanisms, and the adjustable ranges of the material delivery flow rates of the plurality of feeding mechanisms are different; and the method S1900 further includes: during printing of the same object, selecting a corresponding feeding mechanism from the plurality of feeding mechanisms to deliver material according to the requirement of the to-be-printed part on the change range of the material delivery flow rate.

[0184] In some embodiments, the plurality of feeding mechanisms are used to print different parts in the same layer of the object.

[0185] In some embodiments, the plurality of feeding mechanisms deliver material to the same print head of the 3D printing system.

[0186] In some embodiments, a one-way conduction valve is arranged between any one of the plurality of feeding mechanisms and the print head.

[0187] In some embodiments, the method S1900 further includes: during printing of the same object, controlling the plurality of feeding mechanisms to work at different times.

[0188] In some embodiments, the plurality of feeding mechanisms feed material to different print heads of the 3D printing system.

[0189] In some embodiments, the method S1900 further comprises: controlling the plurality of feeding mechanisms to work simultaneously during printing of the same object.

[0190] In some embodiments, the plurality of feeding mechanisms comprises a first feeding mechanism and a second feeding mechanism, the first feeding mechanism has a range of adjustable material feeding flow rate of [Q1, Q2], the second feeding mechanism has a range of adjustable material feeding flow rate of [Q3, Q4], wherein Q1, Q2, Q3, Q4 are positive numbers, and Q1 is less than Q3, Q4 is greater than Q2, and Q2 is greater than Q3.

[0191] In some embodiments, the material fed by the first feeding mechanism is extruded through a first extrusion opening of a print head of the 3D printing system, the material fed by the second feeding mechanism is extruded through a second extrusion opening of the print head of the 3D printing system, the width of the first extrusion opening and the second extrusion opening are continuously adjustable, and the thickness of the first extrusion opening is less than the thickness of the second extrusion opening.

[0192] In some embodiments, when the requirement of the print head of the 3D printing system for material extrusion flow rate is less than Q3, the first feeding mechanism is controlled to feed; when the requirement of the print head of the 3D printing system for material extrusion flow rate is greater than Q2, the second feeding mechanism is controlled to feed; when the requirement of the print head of the 3D printing system for material extrusion flow rate is between Q2 and Q3, the first feeding mechanism or the second feeding mechanism is controlled to feed.

[0193] In some embodiments, the plurality of feeding mechanisms are a plurality of screw feeding devices.

[0194] In some embodiments, the print head has an extrusion opening with continuously adjustable width.

[0195] In some embodiments, the method S1900 can further comprise: controlling the width of the extrusion opening such that the width of the extrusion opening changes with the change of the cross-sectional profile line of the material filling area.

[0196] In the embodiments described above, all or some of the embodiments can be implemented by software, hardware, firmware or any combination thereof. When implemented by software, all or some of the embodiments can be implemented in the form of a computer program product storing computer program instructions. When the computer program instructions are loaded into and executed by a computer, all or some of the procedures or functions described in the embodiments of the present application are performed. The computer can be a general purpose computer, a special purpose computer, a computer network, or another programmable apparatus. The computer program 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 program instructions can be transmitted from a website, a computer, a server or a data center to another website, computer, server or data center through a wired (for example, coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (for example, infrared, wireless, microwave, etc.) manner. 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, data center, etc. integrated with one or more available media. The available media can be a magnetic medium (for example, floppy disk, hard disk, magnetic tape), an optical medium (for example, digital video disc (DVD)), or a semiconductor medium (for example, solid state disk (SSD)) and the like.

[0197] Those skilled in the art can appreciate that the units and algorithm steps of the examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware or a combination of computer software and electronic hardware. Whether the functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. A skilled person can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0198] In several embodiments provided in the present application, it should be understood that the disclosed system, device and method 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, and actual implementation can have another division manner, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the units shown or discussed can be indirect coupling or communication connection through some interface, device or unit, and can be electrical, mechanical or other forms.

[0199] The units described as separate components may or may not be physically separate, and the components displayed as units may or may not be physical units, that is, may be located in one place, or may be distributed to multiple network units. Part or all of the units can be selected to achieve the purpose of the embodiment of the present application according to actual needs.

[0200] In addition, each functional unit in each embodiment of the present application can be integrated in one processing unit, or each unit can exist physically alone, or two or more units can be integrated in one unit.

[0201] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can easily think of changes or replacements within the technical scope disclosed by the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A 3D printing system, characterized by, include: A feeding device used to output flowable materials; A printhead for 3D printing using flowable material output from the feeding device, the printhead having an extrusion orifice with continuously adjustable width; A material flow channel, located between the feeding device and the print head, is used to transport the flowable material output by the feeding device to the print head. The material flow channel has a variable volume, and there are multiple material flow channels. The control section, connected to the material flow channel, is used to adjust the volume of the material flow channel during the material conveying process.

2. The 3D printing system of claim 1, wherein, The control section is used to adjust the volume of the material flow channel so that the volume of the material flow channel matches the flow rate of the material in the material flow channel.

3. The 3D printing system according to claim 1 or 2, characterized in that The control unit controls the flow rate of the material in the material flow channel to increase the volume of the material flow channel and decrease the volume of the material flow channel when the flow rate of the material in the material flow channel decreases.

4. The 3D printing system of claim 1, wherein, The control unit controls the material flow channel so that its volume is proportional to the flow rate of the material in the material flow channel; or, the control unit controls the material flow channel so that materials with different flow rates pass through the material flow channel within a preset time range.

5. The 3D printing system of claim 1, wherein, The material flow channel is used to receive material from the feeding device; the control unit controls the flow so that the volume of the material flow channel matches the rate at which the feeding device outputs material.

6. The 3D printing system of claim 1, wherein, The material flow channel is a material flow channel with a variable width; the control section is used to adjust the width of the material flow channel.

7. The 3D printing system according to claim 1, characterized in that, The material flow channel has a first portion and a second portion that define the volume of the material flow channel, and the first portion is slidably connected to the second portion along the width direction of the material flow channel; The control section is used to control the sliding of the first section relative to the second section to change the width of the material flow channel.

8. The 3D printing system of claim 7, wherein, The contact portions of the first part and the second part are complementary stepped.

9. The 3D printing system of claim 1, wherein, Also includes: A heating device for heating the material in the material flow channel.

10. The 3D printing system of claim 1, wherein, The feeding device includes a first feeding device and a second feeding device, and the 3D printing system further includes 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 materials output by the first feeding device; the second feeding device is used to transport the materials in the buffer container to the print head. The material flow channel is disposed between the first feeding device and the buffer container, and / or the material flow channel is disposed between the second feeding device and the print head.

11. The 3D printing system of claim 10, wherein, The second feeding device is a screw-type feeding device, and the 3D printing system further includes: A temperature control device is used to control the temperature of the screw-type feeding device and the print head, so that the temperature of the print head is higher than the temperature of the material in the screw-type feeding device.

12. The 3D printing system of claim 10, wherein, The second feeding device includes: Multiple feeding mechanisms, wherein the adjustable range of the material conveying flow rate of the multiple feeding mechanisms is different; The control unit is configured to select a corresponding feeding mechanism from the plurality of feeding mechanisms to feed the material during printing of the same object according to a requirement of a variation range of a material feeding flow rate of a part to be printed.

13. The 3D printing system of claim 12, wherein, The plurality of feeding mechanisms are configured to print different parts in a same layer of the object.

14. The 3D printing system of claim 12, wherein, The plurality of feeding mechanisms feed the material to a same print head of the 3D printing system.

15. The 3D printing system of claim 14, wherein, A one-way valve is arranged between any one of the plurality of feeding mechanisms and the print head.

16. The 3D printing system according to any one of claims 14 or 15, characterized in that, The control unit is further configured to control the plurality of feeding mechanisms to work at different times during printing of the same object.

17. The 3D printing system of claim 12, wherein, The plurality of feeding mechanisms feed the material to different print heads of the 3D printing system.

18. The 3D printing system of claim 17, wherein, The control unit is further configured to control the plurality of feeding mechanisms to work at the same time during printing of the same object.

19. The 3D printing system of claim 12, wherein, The plurality of feeding mechanisms include a first feeding mechanism and a second feeding mechanism, the first feeding mechanism has an adjustable range of a material feeding flow rate of [Q1, Q2], the second feeding mechanism has an adjustable range of a material feeding flow rate of [Q3, Q4], wherein Q1, Q2, Q3, Q4 are positive numbers, Q1 is less than Q3, Q4 is greater than Q2, and Q2 is greater than Q3.

20. The 3D printing system of claim 19, wherein, The material fed by the first feeding mechanism is extruded through a first extrusion opening of a print head of the 3D printing system, the material fed by the second feeding mechanism is extruded through a second extrusion opening of the print head of the 3D printing system, the first extrusion opening and the second extrusion opening have a continuously adjustable width, and the first extrusion opening has a thickness less than that of the second extrusion opening.

21. The 3D printing system of claim 19, wherein, The control unit is configured to control the first feeding mechanism to feed when a requirement of a variation range of a material feeding flow rate of a part to be printed is less than Q3, control the second feeding mechanism to feed when the requirement of the variation range of the material feeding flow rate of the part to be printed is greater than Q2, and control the first feeding mechanism to feed or the second feeding mechanism to feed when the requirement of the variation range of the material feeding flow rate of the part to be printed is between Q2 and Q3.

22. The 3D printing system of claim 12, wherein, The plurality of feeding mechanisms are a plurality of screw feeding devices.

23. The 3D printing system of claim 1, wherein, Further comprising: A control device is configured to control a width of an extrusion opening of a print head of the 3D printing system, so that the width of the extrusion opening changes with a change of a cross-sectional profile line of a material filling area.

24. A method of feeding for a 3D printing system, characterized in that, Further comprising: A material flow channel with a variable volume is used to feed flowable material output by a feeding device to a print head, the print head has an extrusion opening with a continuously adjustable width; The volume of the material flow channel is adjusted during feeding of the material by the material flow channel.

25. The method of claim 24, wherein, The volume of the material flow channel is adjusted during feeding of the material by the material flow channel. The volume of the material flow channel is adjusted so that the volume of the material flow channel matches a flow rate of the material in the material flow channel.

26. The method of claim 24 or 25, wherein, The volume of the material flow channel is adjusted during feeding of the material by the material flow channel. Adjusting the volume of the material flow channel such that the volume of the material flow channel increases when the flow rate of the material in the material flow channel increases, and decreases when the flow rate of the material in the material flow channel decreases.

27. The method of claim 24, wherein, The adjusting of the volume of the material flow channel during the conveying of the material in the material flow channel comprises: Adjusting the volume of the material flow channel such that the volume of the material flow channel is proportional to the flow rate of the material in the material flow channel, or such that different flow rates of the material in the material flow channel all pass through the material flow channel within a preset time range.

28. The method of claim 24, wherein, The adjusting of the volume of the material flow channel during the conveying of the material in the material flow channel comprises: Adjusting the volume of the material flow channel such that the volume of the material flow channel matches the rate of the material input into the material flow channel.

29. The feeding method according to claim 24, wherein The material flow channel is a material flow channel with variable width. The adjusting of the volume of the material flow channel during the conveying of the material in the material flow channel comprises adjusting the volume of the material flow channel by adjusting the width of the material flow channel.

30. The feeding method according to claim 24, wherein The material flow channel has a first part and a second part defining the volume of the material flow channel, and the first part is slidingly connected with the second part along the width direction of the material flow channel. The adjusting of the volume of the material flow channel during the conveying of the material in the material flow channel comprises changing the width of the material flow channel by controlling the sliding of the first part relative to the second part, so as to adjust the volume of the material flow channel.

31. The method of claim 30, wherein, The contact part of the first part and the second part is in a complementary stepped shape.

32. The method of claim 24, wherein, Further comprising: Heating the material in the material flow channel.

33. The method of claim 24, wherein The feeding device comprises a first feeding device and a second feeding device, and the 3D printing system further comprises a buffer container between the first feeding device and the second feeding device, The feeding method comprises: Converting the solid material into flowable material by using the first feeding device; Storing the material output by the first feeding device by using the buffer container; Conveying the material in the buffer container to the print head by using the second feeding device; The material flow channel is arranged between the first feeding device and the buffer container, and / or the material flow channel is arranged between the second feeding device and the print head.

34. The method of claim 33, wherein, The second feeding device is a screw feeding device, The feeding method further comprises: Controlling the temperature of the screw feeding device and the print head such that the temperature of the print head is higher than the temperature of the material in the screw feeding device.

35. The method of claim 33, wherein, The second feeding device comprises a plurality of feeding mechanisms, and the adjustable range of the material conveying flow rate of the plurality of feeding mechanisms is different. The feeding method further comprises: During the printing of the same object, selecting a corresponding feeding mechanism from the plurality of feeding mechanisms to convey the material according to the requirement of the part to be printed on the range of variation of the material conveying flow rate.

36. The method of claim 35, wherein, The multiple feeding mechanisms are used to print different parts of the same layer of the article.

37. The method of claim 35, wherein, The multiple feeding mechanisms deliver materials to the same print head of the 3D printing system.

38. The method of feeding of claim 37, wherein, A one-way valve is provided between any one of the multiple feeding mechanisms and the print head.

39. The method of feeding of any one of claims 37 or 38, wherein, The feeding method further includes: During the printing of the same item, the multiple feeding mechanisms are controlled to operate at different times.

40. The method of claim 35, wherein, The multiple feeding mechanisms deliver materials to different print heads of the 3D printing system.

41. The method of claim 40, wherein, The feeding method further includes: During the printing of the same item, the multiple feeding mechanisms are controlled to work simultaneously.

42. The method of claim 35, wherein, The plurality of 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]. Where 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.

43. The method of claim 42, wherein, The material fed by the first feeding mechanism is extruded through the first extrusion port of the print head of the 3D printing system, and the material fed by the second feeding mechanism is extruded through the second extrusion port of the print head of the 3D printing system. The widths of the first extrusion port and the second extrusion port are continuously adjustable, and the thickness of the first extrusion port is less than the thickness of the second extrusion port.

44. The method of claim 42, wherein, During the printing of the same item, based on the required range of material flow rate variation for the part to be printed, a corresponding feeding mechanism is selected from multiple feeding mechanisms to feed the material, including: when the required material extrusion flow rate of the 3D printing system's print head is less than Q3, controlling the first feeding mechanism to feed the material; when the required material extrusion flow rate of the 3D printing system's print head is greater than Q2, controlling the second feeding mechanism to feed the material; when the required material extrusion flow rate of the 3D printing system's print head is between Q2 and Q3, controlling either the first feeding mechanism or the second feeding mechanism to feed the material.

45. The method of claim 35, wherein, The multiple feeding mechanisms are multiple screw-type feeding devices.

46. The method of claim 24, wherein, Also includes: The width of the extrusion orifice is controlled such that it varies with the cross-sectional profile of the material filling area.

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