3D printing device with multiple rows of extrusion holes and control method thereof

Abstract

The present application provides a 3D printing device with multiple rows of extrusion holes and a control method thereof. The 3D printing device includes: a feeding device; a feeding part connected to the feeding device and having an inlet and an outlet for the material; a discharging part having a first row of extrusion holes and a second row of extrusion holes, both of which can be fluidically connected to the feeding part, and the hole spacing of the first row of extrusion holes is different from the hole spacing of the second row of extrusion holes; a control part, which is used to control the relative movement of the feeding part and the discharging part, so that the first row of extrusion holes or the second row of extrusion holes is fluidically connected to the outlet of the feeding part to extrude a row of filamentary materials at the same time. The extrusion holes in the 3D printing device provided by the present application share the same feeding device and feeding part, so that the structure and control method of the 3D printing device can be simplified. In addition, since the 3D printing device can switch between multiple rows of extrusion holes with different hole spacings, it is convenient to print grid components with different densities.

Description

[0001] This application claims priority to Chinese patent application No. 202011087628.1, filed on October 12, 2020, and entitled “3D printing device and control method thereof”, 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 device with multiple rows of extrusion holes and a control method thereof. Background Art

[0003] Grid components have the advantages of being lightweight, cost-saving, saving raw materials, and having strong load-bearing capacity. Therefore, they are widely used in the industry.

[0004] Since 3D printing devices can easily manufacture mesh components with complex structures, 3D printing devices are widely used in manufacturing mesh components.

[0005] In order to print out mesh components, existing 3D printing devices usually use multiple independent print heads to feed wires simultaneously, where different print heads are responsible for printing different parts of the mesh components. However, such 3D printing devices need to be equipped with corresponding feeding devices and feeding parts for the multiple print heads, resulting in a relatively complex structure and control method of such 3D printing devices. Summary of the invention

[0006] The present application provides a 3D printing device with multiple rows of extrusion holes and a control method thereof, so as to simplify the structure and control method of the 3D printing device.

[0007] In a first aspect, a 3D printing device with multiple rows of extrusion holes is provided, including a feeding device for conveying a flowable material; a feeding portion connected to the feeding device and having an inlet and an outlet for the material; a discharging portion having a first row of extrusion holes and a second row of extrusion holes, both of which can be fluidically connected to the feeding portion, and the hole spacing of the first row of extrusion holes is different from the hole spacing of the second row of extrusion holes; and a control portion for controlling the relative movement of the feeding portion and the discharging portion so that the first row of extrusion holes or the second row of extrusion holes is fluidically connected to the outlet to extrude a row of filamentary materials at the same time.

[0008] In a second aspect, a control method for a 3D printing device having multiple rows of extrusion holes is provided, wherein the 3D printing device comprises: a feeding device for conveying a flowable material; a feeding portion connected to the feeding device and having an inlet and an outlet for the material; and a discharging portion having a first row of extrusion holes and a second row of extrusion holes, both of which are fluidically connected to the feeding portion, and the hole spacing of the first row of extrusion holes is different from the hole spacing of the second row of extrusion holes; the control method comprises: controlling the relative movement of the feeding portion and the discharging portion so that the first row of extrusion holes or the second row of extrusion holes is fluidically connected to the outlet; and controlling a row of extrusion holes that are fluidically connected to the outlet to extrude a row of filamentary materials at the same time.

[0009] The extrusion holes in the 3D printing device with multiple rows of extrusion holes provided by the present application share the same feeding device and feeding part, thereby simplifying the structure and control method of the 3D printing device. In addition, since the 3D printing device can switch between multiple rows of extrusion holes with different hole spacings, it is convenient to print grid components with different densities. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 and Figure 2 Each of them is a cross-sectional view of a 3D printing device provided by an embodiment of the present application.

[0011] Figure 3 It is a cross-sectional view of a 3D printing device provided in another embodiment of the present application.

[0012] Figure 4 It is a side view of the inner and outer sleeve structure provided by one embodiment of the present application.

[0013] Figure 5 It is a cross-sectional view of a 3D printing device provided in yet another embodiment of the present application.

[0014] Figure 6 It is a cross-sectional view of a 3D printing device provided in yet another embodiment of the present application.

[0015] Figure 7 It is a side view of the inner and outer sleeve structure provided by another embodiment of the present application.

[0016] Figure 8 It is a schematic diagram of the structure of a grid component printed by a 3D printing device provided in one embodiment of the present application.

[0017] Fig. 9 It is a schematic structural diagram of a grid component printed by a 3D printing device provided in another embodiment of the present application.

[0018] Fig.10 It is a flow chart of a control method of a 3D printing device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0019] Grid components have the advantages of being lightweight, cost-saving, saving raw materials, and having strong load-bearing capacity. Therefore, they are widely used in the industry.

[0020] Since 3D printing devices can easily manufacture mesh components with complex structures, 3D printing devices are widely used in manufacturing mesh components.

[0021] In order to print out mesh components, existing 3D printing devices usually use multiple independent print heads to feed wires simultaneously, where different print heads are responsible for printing different parts of the mesh components. However, such 3D printing devices need to be equipped with corresponding feeding devices and feeding parts for the multiple print heads, resulting in a relatively complex structure and control method of such 3D printing devices.

[0022] In addition, for some print heads with complex structures, printing grid components is more challenging. For example, the print head can use an extrusion port that can support one-time surface forming (i.e., an extrusion port whose length 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 through 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, it is usually possible to achieve material filling of the entire cross section as a whole, and it is difficult to print grid components.

[0023] In view of the above problems, the present application provides a 3D printing device with a simple structure. The structure of the 3D printing device is described below with reference to the accompanying drawings.

[0024] like Figure 1 and Figure 2 As shown, the 3D printing device 10 includes a feeding device 105 and a material input part 103 .

[0025] The feeding device 105 can be used to convey flowable materials (or molten materials). The type of the feeding device 105 can be selected according to actual needs, for example, it can be a screw feeding device or a hydraulic feeding device.

[0026] The material feeding part 103 may be connected (fluidically connected) to the feeding device 105 . The material feeding part 103 includes an inlet 107 and an outlet 108 for the material. The material feeding part 103 may be used to transport the material provided by the feeding device 105 to the discharge part 101 .

[0027] The discharge portion 101 of the 3D printing device 10 may include a first row of extrusion holes 102 (see Figure 1 ) and a second row of extrusion holes 106 (see Figure 2 ). The material conveyed by the feeding part 103 can be extruded outward through the first row of extrusion holes 102 or the second row of extrusion holes 106 of the discharge part 101, such as being extruded onto a printing platform (not shown in the figure). The first row of extrusion holes 102 and the second row of extrusion holes 106 can be respectively connected to the outlet 108 of the feeding part 103 under different working conditions.

[0028] The material outlet 108 may be a groove. The embodiment of the present application does not impose any particular limitation on the cross-sectional shape of the groove, for example, it may be a narrow and long rectangular groove, or a trapezoid or other shapes.

[0029] The present embodiment does not specifically limit the structure of the discharge portion 101 and the positions of the first row of extrusion holes 102 and the second row of extrusion holes 106 on the discharge portion 101. Figure 3 As shown, the material discharging portion 101 may be a shielding plate, which is arranged outside the material feeding portion 103. The first row of extrusion holes 102 and the second row of extrusion holes 106 may be arranged at different positions of the shielding plate, respectively.

[0030] For example, Figure 4 As shown, the feeding part 103 can be a cylindrical inner cylinder, and the discharging part 101 is a sleeve arranged outside the inner cylinder. The first row of extrusion holes 102 and the second row of extrusion holes 106 can be arranged at different positions of the circumference of the sleeve, and the first row of extrusion holes 102 and the second row of extrusion holes 106 can be arranged along the axis of the sleeve.

[0031] The hole spacing of the first row of extrusion holes 102 is different from the hole spacing of the second row of extrusion holes 106. For example, the hole spacing of the first row of extrusion holes 102 is smaller than the hole spacing of the second row of extrusion holes 106. In other words, the arrangement of the extrusion holes in the first row of extrusion holes 102 is relatively dense, and the arrangement of the extrusion holes in the second row of extrusion holes 106 is relatively sparse. The different densities of the first row of extrusion holes 102 and the second row of extrusion holes 106 enable the two to be used for printing different forms of mesh components.

[0032] The 3D printing device 10 further includes a control unit 104. The control unit 104 can be used to control the first row of extrusion holes 102 or the second row of extrusion holes 106 to be in fluid communication with the outlet 108 of the feeding unit 103, so as to extrude a row of filamentary materials at the same time. Figure 8 (b) When the grid structure has a high density, the first row of extrusion holes 102 with a small hole spacing can be controlled to be fluidically connected to the outlet 108, and the first row of extrusion holes 102 can be used to perform layer-by-layer 3D printing; when printing as shown in FIG. Figure 8 In the case of a grid component with a relatively low density as shown in (a), the second row of extrusion holes 106 with a relatively large hole spacing can be controlled to be fluidically connected to the outlet 108, and the second row of extrusion holes 106 can be used to perform layer-by-layer 3D printing.

[0033] The control part 104 can be controlled in various ways. For example, when the structure of the discharge part 101 is as follows Figure 3 When the shielding plate is provided, the control part 104 can control the shielding plate-shaped material discharging part 101 and the material feeding part 103 to slide relative to each other, so as to select a row of extrusion holes in fluid communication with the outlet 108 of the material feeding part 103 from the first row of extrusion holes 102 and the second row of extrusion holes 106. For another example, when the structure of the material discharging part 101 is as follows Figure 4 When the sleeve is shown, the control part 104 can control the relative rotation of the sleeve-shaped discharge part 101 and the cylindrical feeding part 103 to select a row of extrusion holes from the first row of extrusion holes 102 and the second row of extrusion holes 106 that are fluidically connected to the outlet 108 of the feeding part.

[0034] The extrusion holes in the 3D printing device 10 share the same feeding device and feeding part, so the structure and control method of the 3D printing device 10 can be simplified. In addition, since the 3D printing device 10 can switch between multiple rows of extrusion holes with different hole spacings, grid components with different densities can be easily printed.

[0035] The control part 104 can also be used to control the discharge part 101 and the feed part 103 to move in a first direction (the first direction can be the arrangement direction of the first row of extrusion holes 102 or the length direction of the outlet 108 of the feed part 103, i.e., Figure 1 and Figure 2The relative movement between the discharge portion 101 and the feed portion 103 along the first direction will cause some of the extrusion holes in the first row of extrusion holes 102 that were originally connected to the feed portion outlet 108 to move outside the area where the feed portion outlet 108 is located, thereby being in a blocked state. Therefore, the above control method of the control portion 104 can change the number of extrusion holes in the first row of extrusion holes 102 that are fluidically connected to the feed portion outlet 108. In this way, the 3D printing device 10 can adjust the number of extrusion holes according to the specific structure of the grid component to be printed, thereby improving the flexibility of the 3D printing device 10.

[0036] During the 3D printing process, it is often necessary to pause the printing process. For example, when printing to the edge of the contour of the section, it is necessary to pause the printing process, move the 3D printing device to a new printing starting point, and then continue the subsequent printing process. Since the materials used in 3D printing technology (such as polymer materials) are usually viscoelastic, when the feeding device stops conveying the material, the flow of the material usually does not stop suddenly. At this time, the material will continue to accumulate outside the contour edge of the section to be printed, destroying the contour shape of the printed section and reducing the geometric accuracy of the printed part.

[0037] In order to solve the above problem, in some embodiments, when the first row of extrusion holes 102 is fluidically connected to the outlet 108 of the feed part 103, the control part 104 can control the relative movement of the feed part 103 and the discharge part 101, so that all the extrusion holes in the first row of extrusion holes 102 and the feed part outlet 108 are simultaneously misaligned.

[0038] For example, in Figure 3 In the embodiment shown, the control part 104 can control the shielding plate-shaped discharging part 101 to move from Figure 3 Slide to the position shown in (a) Figure 3 The position shown in (b) causes all the extrusion holes in the first row of extrusion holes 102 and the outlet 108 of the feed portion to be simultaneously misaligned.

[0039] For example, in Figure 4 In the embodiment shown, the control part 104 can control the inner cylindrical feeding part 103 and the sleeve-shaped discharging part 101 to move from Figure 4 (a) is rotated to Figure 4 (b) makes all the extrusion holes of the first row of extrusion holes 102 and the outlet 108 of the feeding part 103 misaligned at the same time.

[0040] like Figure 5As shown, in some embodiments, a third row of extrusion holes 109 may be provided in the outlet 108 of the feeding portion 103. The material in the feeding portion 103 may be extruded to the outside of the feeding portion 103 through the third row of extrusion holes 109. In order to make the third row of extrusion holes 109 better cooperate with both the first row of extrusion holes 102 and the second row of extrusion holes 106, the hole spacing of the third row of extrusion holes 109 may be designed to be less than or equal to the smaller of the hole spacings of the first row of extrusion holes 102 and the second row of extrusion holes 106.

[0041] When the material is extruded through the extrusion hole, the resistance may be very large, and a very high extrusion pressure is required to extrude the material from the extrusion hole at the required rate, which leads to a large structural size and energy consumption of the entire system, reducing the economic efficiency of the 3D printing device. Since the resistance of the material passing through the extrusion hole is proportional to the depth of the extrusion hole, the resistance of the extruded material can be reduced by reducing the depth of the extrusion hole.

[0042] For example, Figure 6 As shown, in some embodiments, a groove 110 can be dug above the third row of extrusion holes 109, so that the channel depth is reduced by a groove depth from the original wall thickness of the feeding part 103, and the depth of the extrusion hole is equal to the distance from the bottom of the groove 110 to the outer surface of the feeding part 103, thereby reducing the depth of the extrusion hole. The present application does not specifically limit the shape and depth of the groove 110, and a selection can be made according to specific circumstances. For example, the groove 110 can be designed as an arc groove.

[0043] For example, Figure 7 As shown, in other embodiments, the thickness of the sleeve-shaped discharge portion 101 at the position corresponding to the extrusion hole can be thinned to reduce the depth of the extrusion hole. Specifically, the cylinder wall at the position of the extrusion hole can be thinned in a certain arc.

[0044] The shape of the sleeve-shaped discharge portion 101 does not have to be cylindrical, and can also be any other shape. Figure 7 The upper portion of the sleeve-shaped discharge portion 101 may be designed as a thick structure to facilitate installation of the heater 111 therein.

[0045] The mesh structure has different shapes for different appearance or structural requirements. This can be achieved by changing the movement of the 3D printing device. Optionally, when printing different layers, the 3D printing device can be deflected at a certain angle. There is no specific limit on the setting of the deflection angle, and it can be any deflection angle. For example, Figure 8 The printing of the grid structure shown is achieved by deflecting the movement direction of the 3D printing device by 90° when printing between layers. Fig. 9The printing of the grid structure shown in (a) is achieved by deflecting the movement direction of the 3D printing device by 45° when printing between layers.

[0046] In addition, in some embodiments, different relative motion modes may be used between the 3D printing device and the printing platform. Fig. 9 (a) shows the structure, the relative motion mode between the 3D printing device and the printing platform is a linear motion mode; Fig. 9 (b) shows the structure, the relative motion mode between the 3D printing device and the printing platform is a linear motion mode combined with a curved motion mode; Fig. 9 In the structure shown in (c), the relative motion mode between the 3D printing device and the printing platform is a pure curve motion mode. The embodiment of the present application has no specific restrictions on the relative motion mode between the 3D printing device and the printing platform, and different motion modes can be freely combined to form a grid component with diverse structures.

[0047] The embodiment of the present application does not specifically limit the shape of the extrusion hole, which can be a square hole or a round hole. The thickness of the printed layer formed by a row of materials will be different if the aperture of the extrusion hole is different. Therefore, the thickness of a single layer of printing can be changed by changing the aperture of the extrusion hole. The embodiment of the present application has different limitations on the specific size of the aperture, which can be set according to actual needs. For example, for precision printing, an aperture of 0.1mm or less can be used to form an ultra-thin printed layer with a single-layer printing thickness of less than 0.1mm; for another example, for high-efficiency printing, an aperture of 1mm or more can be used to form an ultra-thick printed layer with a single-layer printing thickness of more than 1mm.

[0048] The 3D printing device provided in the embodiment of the present application may refer to a 3D printing head or the entire 3D printing system. The control part of the 3D printing device may be implemented by software, hardware or a combination of software and hardware, which is not limited in the embodiment of the present application.

[0049] Combination of the above Figures 1 to 9 , describes in detail the device embodiment of the present application. Fig.10 , describing the method embodiment of the present application. It should be understood that the description of the method embodiment corresponds to the description of the device embodiment, so the parts not described in detail can refer to the previous device embodiment.

[0050] Fig.10: is a schematic flow chart of a control method of a 3D printing device provided in an embodiment of the present application. The 3D printing device comprises: a feeding device for conveying a flowable material; a feeding part connected to the feeding device and having an inlet and an outlet for the material; and a discharging part having a first row of extrusion holes and a second row of extrusion holes, both of which can be fluidically connected to the feeding part, and the hole spacing of the first row of extrusion holes is different from the hole spacing of the second row of extrusion holes. The structure of the 3D printing device can refer to the above description. Fig.10 The control method includes steps S1010 to S1020.

[0051] In step S1010, the feed part and the discharge part are controlled to move relative to each other so that the first row of extrusion holes or the second row of extrusion holes are in fluid communication with the outlet of the feed part. In step S1020, a row of extrusion holes in fluid communication with the outlet of the feed part are controlled to extrude a row of filamentary materials simultaneously.

[0052] Optionally, in some embodiments, when the first row of extrusion holes is connected to the outlet, step S1010 may include: controlling the relative movement of the feed part and the discharge part along a first direction to change the number of extrusion holes in the first row of extrusion holes that are connected to the outlet fluid, wherein the first direction is the arrangement direction of the first row of extrusion holes.

[0053] Optionally, in some embodiments, when the first row of extrusion holes is connected to the outlet of the discharge portion, Fig.10 The method further includes: controlling the relative movement of the feeding part and the discharging part so that the first row of extrusion holes moves out of the area where the outlet is located, so as to simultaneously close the first row of extrusion holes.

[0054] Optionally, in some embodiments, the feeding part is a cylindrical inner cylinder; the discharging part is a sleeve of the inner cylinder, and the first row of extrusion holes and the second row of extrusion holes are arranged along the axial direction of the inner cylinder. Fig.10 The method further includes: controlling the inner cylinder and the sleeve to rotate relative to each other along the axis to control the first row of extrusion holes or the second row of extrusion holes to be in fluid communication with the outlet of the discharge portion.

[0055] Optionally, in some embodiments, the discharge portion is a shielding plate, which is arranged outside the feeding portion and is slidably connected to the feeding portion. Fig.10 The method further includes: controlling the shielding plate and the feeding part to slide relative to each other, so as to control the first row of extrusion holes or the second row of extrusion holes to be in fluid communication with the outlet of the discharge part.

[0056] Optionally, in some embodiments, the 3D printing device further comprises a third row of extrusion holes, located in the outlet of the discharge portion, and the hole spacing of the third row of extrusion holes is less than or equal to the hole spacing of any one of the first row of extrusion holes and the second row of extrusion holes. Fig.10The method further includes: controlling the relative movement of the input portion and the output portion so that the first row of extrusion holes or the second row of extrusion holes are in fluid communication with the third row of extrusion holes.

[0057] Optionally, in some embodiments, the interior of the feeding part has a groove, and the third row of extrusion holes is located below the groove.

Claims

1. A 3D printing device with multiple rows of extrusion holes, It is characterized in that include: A feeding device for conveying flowable materials; A material conveying part, connected to the feeding device, having an inlet and an outlet for the material; a discharge portion, having a first row of extrusion holes and a second row of extrusion holes, both of which are in fluid communication with the feed portion, wherein the hole spacing of the first row of extrusion holes is different from the hole spacing of the second row of extrusion holes; A control part is used to control the relative movement of the feeding part and the discharging part, so that the first row of extrusion holes or the second row of extrusion holes is connected to the outlet fluid to extrude a row of filamentary materials at the same time.

2. The 3D printing device according to claim 1, Features: The control part is also used to control the relative movement of the feeding part and the discharging part along a first direction when the first row of extrusion holes is connected to the outlet, so as to change the number of extrusion holes in the first row of extrusion holes that are connected to the outlet fluid, wherein the first direction is the arrangement direction of the first row of extrusion holes.

3. The 3D printing device according to claim 1, Features: The control part is also used for controlling the relative movement of the feeding part and the discharging part when the first row of extrusion holes is connected to the outlet, so that the first row of extrusion holes moves out of the area where the outlet is located, so as to simultaneously shut off the first row of extrusion holes.

4. The 3D printing device according to claim 1, Features: The feeding part is a cylindrical inner cylinder; The discharge portion is a sleeve of the inner cylinder, and the first row of extrusion holes and the second row of extrusion holes are arranged along the axial direction of the inner cylinder; The control portion is further used to control the inner cylinder and the sleeve to rotate relative to each other along the axis, so as to control the first row of extrusion holes or the second row of extrusion holes to be in fluid communication with the outlet.

5. The 3D printing device according to claim 1, Features: The material discharging part is a shielding plate, which is arranged outside the material feeding part and is slidably connected with the material feeding part; The control part is further used to control the relative sliding of the shielding plate and the feeding part, so as to control the first row of extrusion holes or the second row of extrusion holes to be in fluid communication with the outlet.

6. The 3D printing device according to any one of claims 1 to 5, It is characterized in that Also includes: A third row of extrusion holes is located in the outlet, and a hole spacing of the third row of extrusion holes is less than or equal to a hole spacing of any one of the first row of extrusion holes and the second row of extrusion holes; The control part is used to control the relative movement of the feeding part and the discharging part so that the first row of extrusion holes or the second row of extrusion holes is in fluid communication with the third row of extrusion holes.

7. The 3D printing device according to claim 6, It is characterized in that The feeding part has a groove inside, and the third row of extrusion holes is located below the groove.

8. A control method for a 3D printing device having multiple rows of extrusion holes, It is characterized in that The 3D printing device comprises: A feeding device for conveying flowable materials; A material conveying part, connected to the feeding device, having an inlet and an outlet for the material; a discharge portion, having a first row of extrusion holes and a second row of extrusion holes, both of which are in fluid communication with the feed portion, wherein the hole spacing of the first row of extrusion holes is different from the hole spacing of the second row of extrusion holes; The control method comprises: Controlling the relative movement of the feeding part and the discharging part so that the first row of extrusion holes or the second row of extrusion holes is in fluid communication with the outlet; A row of extrusion holes in fluid communication with the outlet is controlled to extrude a row of filamentary materials simultaneously.

9. The control method according to claim 8, It is characterized in that Also includes: When the first row of extrusion holes is connected to the outlet, the feed portion and the discharge portion are controlled to move relative to each other along a first direction to change the number of extrusion holes in the first row of extrusion holes that are connected to the outlet fluid, wherein the first direction is the arrangement direction of the first row of extrusion holes.

10. The control method according to claim 8, It is characterized in that Also includes: When the first row of extrusion holes is connected to the outlet, the feeding part and the discharging part are controlled to move relative to each other so that the first row of extrusion holes moves out of the area where the outlet is located, so as to simultaneously shut off the first row of extrusion holes.

11. The control method according to claim 8, Features: The feeding part is a cylindrical inner cylinder; The discharge portion is a sleeve of the inner cylinder, and the first row of extrusion holes and the second row of extrusion holes are arranged along the axial direction of the inner cylinder; The controlling the relative movement of the feeding part and the discharging part comprises: The inner cylinder and the sleeve are controlled to rotate relative to each other along the axis to control the first row of extrusion holes or the second row of extrusion holes to be in fluid communication with the outlet.

12. The control method according to claim 8, Features: The material discharging part is a shielding plate, which is arranged outside the material feeding part and is slidably connected with the material feeding part; The controlling the relative movement of the feeding part and the discharging part comprises: The shielding plate and the feeding portion are controlled to slide relative to each other, so as to control the first row of extrusion holes or the second row of extrusion holes to be in fluid communication with the outlet.

13. The control method according to any one of claims 8 to 12, Features: The 3D printing device also includes: A third row of extrusion holes is located in the outlet, and a hole spacing of the third row of extrusion holes is less than or equal to a hole spacing of any one of the first row of extrusion holes and the second row of extrusion holes; The controlling the relative movement of the feeding part and the discharging part comprises: The relative movement of the feeding portion and the discharging portion is controlled so that the first row of extrusion holes or the second row of extrusion holes is in fluid communication with the third row of extrusion holes.

14. The control method according to claim 13, It is characterized in that The feeding part has a groove inside, and the third row of extrusion holes is located below the groove.

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