A multi-material laser powder bed additive manufacturing powder spreading method and powder spreading device

Abstract

The application relates to a multi-material laser powder bed additive manufacturing powder laying method and a powder laying device. The multi-material laser powder bed additive manufacturing powder laying method comprises the following steps: S1, voxelizing a geometric model to be manufactured to obtain a voxelized model; S2, performing transverse slicing on the voxelized model to obtain Q slice layers; S3, calculating the powder volume V corresponding to each voxel grid q ~V 1q ~V Pq ; V 1q ~V Pq is respectively divided by V to calculate the powder feeding times t q ~t 1q ~t Pq corresponding to each voxel grid. The application adopts a voxelization method to process a multi-material geometric three-dimensional model, then performs slicing on the voxelized geometric model, maps the relative positions of the voxel grids to a substrate according to the obtained slice layer information, feeds in a set type of material and a corresponding powder amount at the mapping positions on the substrate, controls the powder laying precision by controlling the size of the voxel grids, increases the multi-material powder laying efficiency, and is convenient for subsequent 3D printing.

Description

Technical Field

[0001] This invention relates to the field of multi-material laser powder bed additive manufacturing technology, and in particular to a powder spreading method and apparatus for multi-material laser powder bed additive manufacturing. Background Technology

[0002] Laser-based powder bed fusion additive manufacturing (LBD) utilizes a laser beam heat source to bond or melt a powder bed layer by layer along a pre-defined trajectory to directly manufacture solid objects. LBD boasts advantages such as a wide range of usable materials (e.g., metals, polymers, ceramics) and the ability to form complex structures, making it widely used in fields such as biomedicine and aerospace. Multi-material powder bed additive manufacturing overcomes the limitation of traditional powder bed additive manufacturing, which can only form single materials. This technology achieves performance enhancement in specific areas by distributing different materials at different locations.

[0003] Traditional multi-material powder coating technology achieves this through localized powder extraction. Specifically, powder is first evenly deposited onto a substrate via a powder hopper, and then leveled using a scraper. When another powder needs to be added, a laser is used to locally melt the existing powder layer, removing excess powder to create a gap. Then, the other powder is evenly deposited onto the substrate via a hopper, and leveled again using a scraper, thus completing the multi-material powder coating for each layer. However, each layer requires these steps, which not only reduces the efficiency of multi-material powder coating and increases the number of steps, but also makes it easy for the various materials to mix after localized extraction, affecting the coating accuracy. Summary of the Invention

[0004] Therefore, it is necessary to provide a multi-material laser powder bed additive manufacturing powder spreading method and device to address the problem of low powder spreading accuracy in existing multi-material powder spreading methods.

[0005] In a first aspect, the present invention proposes a multi-material laser powder bed additive manufacturing powder spreading method, which is used to control the powder feeding and spreading of the powder spreading device; the powder spreading device includes a substrate and a powder feeding mechanism, the powder feeding mechanism is used to feed powder onto the substrate, and the volume of powder fed each time is V;

[0006] The multi-material laser powder bed additive manufacturing powder spreading method includes the following steps:

[0007] S1. Perform voxelization on the geometric model to be manufactured to obtain a voxelized model;

[0008] The geometric model consists of N sub-parts; the nth sub-part is made of the nth material; N≥2, n∈[1,N];

[0009] The voxelization model consists of K voxel lattices; each K voxel lattice contains material information to accommodate the powder spreading requirements of N materials.

[0010] S2. Perform lateral slicing on the voxelized model to obtain Q-layer slices; wherein the thickness of the q-th slice is the same as the thickness of the voxel lattice; q∈[1,Q]; the q-th slice includes P q Individual character;

[0011] S3, Calculate P q The powder volume V corresponding to an individual lattice 1q ~V Pq ;

[0012] V 1q ~V Pq Calculate P by dividing by V respectively q The number of times t is sent to each individual element. 1q ~t Pq ;

[0013] S4. Based on the qth slice layer, the qth layer powder is laid on the substrate;

[0014] S4 includes the following steps:

[0015] P of the qth slice layer q Individual lattice mappings are applied to the substrate;

[0016] Based on the number of powder deliveries t pq To the pth q The powder is fed at the mapped position of the individual lattice on the substrate so that its powder volume reaches the p-th position. q The powder volume V corresponding to an individual lattice pq ;p q ∈[1 q P q ];

[0017] Traversing P q After individual particles are formed, the powder is scraped flat to complete the qth layer of powder spreading;

[0018] S5. Traverse the Q layer slices sequentially from low to high along the longitudinal direction to complete the Q layer powder spreading.

[0019] Secondly, the present invention also proposes a multi-material laser powder bed additive manufacturing powder spreading apparatus, which operates using the multi-material laser powder bed additive manufacturing powder spreading method described in the first aspect. The multi-material laser powder bed additive manufacturing powder spreading apparatus includes:

[0020] Printing platform; define the direction perpendicular to the working surface of the printing platform as the Z direction;

[0021] The substrate in the process is set on the printing platform and can move along the Z direction;

[0022] A dual-axis linear module, which is mounted on the printing platform;

[0023] A powder feeding mechanism, mounted on a dual-axis linear module and moved via the module, to feed powder onto a substrate; and

[0024] The scraper mechanism is mounted on a dual-axis linear module and moves through the dual-axis linear module to scrape the powder on the substrate.

[0025] Powder supply organizations include:

[0026] The mounting base is connected to the dual-axis linear module for movement;

[0027] The hopper is connected to the mounting base; the interior of the hopper is divided into multiple chambers for storing powder materials; the bottom of the hopper has through holes that communicate with the multiple chambers.

[0028] A powder separator is rotatably connected to the bottom of the hopper; the powder separator has multiple feeding channels corresponding to the through holes; the volume of the feeding channels is V.

[0029] The bracket is connected to the mounting base and is rotatably connected to the bottom of the powder selection tray; the bracket has multiple through holes corresponding to the material feeding channel.

[0030] Multiple nozzles are connected to the mounting base; the multiple nozzles correspond to multiple through holes; and

[0031] The transmission mechanism is used to drive the powder classifier to rotate so that the through hole one, the feeding channel and the through hole two are connected or staggered;

[0032] A virtual circle is defined with a line in the Z direction as its axis; multiple through holes 1, multiple feeding channels, and multiple through holes 2 are distributed along the edge of the virtual circle; when one of the through holes 1 is connected to one of the feeding channels, the other through holes 1 are offset from the feeding channels; when one of the feeding channels is connected to one of the through holes 2, the other feeding channels are offset from the through holes 2; when one of the through holes 1 is connected to one of the feeding channels, the feeding channel connected to through hole 1 is offset from through hole 2.

[0033] The beneficial effects of this invention are as follows:

[0034] 1. This invention employs a voxelization method to process multi-material geometric 3D models, followed by slicing the voxelized geometric models. Based on the obtained slice layer information, the relative positions of the voxel grids are mapped onto a substrate, and a set type of material and corresponding powder amount are fed into the mapped positions on the substrate. Compared with the prior art, this not only reduces the efficiency of multi-material powder spreading, but also prevents different materials from mixing after the powder is leveled. By controlling the size of the voxel grids, the powder spreading accuracy is controlled, and the efficiency of multi-material powder spreading is increased, which is convenient for subsequent 3D printing.

[0035] 2. This invention achieves multi-material powder spreading by driving the powder supply mechanism and scraper mechanism with a dual-axis linear module, which reduces the complexity of the multi-material powder spreading device. At the same time, by adjusting the direction and angle of the powder selection plate, different material powders can be selected and supplied, reducing the impact of local powder extraction on the powder layer accuracy. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 This is a flowchart of the multi-material laser powder bed additive manufacturing powder spreading method in Example 1;

[0038] Figure 2 This is a schematic diagram of the powder spreading method in the multi-material laser powder bed additive manufacturing method of Example 1;

[0039] Figure 3 This is a schematic diagram of the overall structure of the multi-material laser powder bed additive manufacturing powder spreading device in Example 2;

[0040] Figure 4 This is a schematic diagram of the printing platform and the dual-axis linear module in Example 2;

[0041] Figure 5 This is a schematic diagram of the scraper mechanism in Embodiment 2;

[0042] Figure 6 This is a schematic diagram of the powder supply mechanism in Example 2;

[0043] Figure 7 This is a schematic diagram of the powder hopper in Example 2;

[0044] Figure 8 This is a schematic diagram of the powder hopper from another angle in Example 2;

[0045] Figure 9 This is a schematic diagram of the powder selection tray in Example 2;

[0046] Figure 10 This is a schematic diagram of the bracket in Example 2;

[0047] Figure 11 This is a schematic diagram of the installation of the powder hopper, powder sorting tray, and bracket in Example 2;

[0048] Figure 12 This is a top view of through hole one, feeding channel and channel two in the initial position in embodiment two;

[0049] Figure 13 This is a schematic diagram showing the position of one of the feeding channels connected to the through hole in Embodiment 2;

[0050] Figure 14 This is a schematic diagram showing the position of one of the feeding channels connected to the second through hole in Embodiment 2;

[0051] Figure 15 This is a schematic diagram of the transmission mechanism in Example 2;

[0052] Figure 16 This is a schematic diagram of the installation structure of the three-chamber powder silo in Example 5;

[0053] Figure 17 This is a top view of through hole one, feeding channel and channel two in the initial position in embodiment five;

[0054] Figure 18 This is a schematic diagram showing the position of the material feeding channel in area A of Example 5 when it is connected to the through hole 1;

[0055] Figure 19 This is a schematic diagram showing the position of the material feeding channel in area A of Example 5 when it is connected to the through hole 2;

[0056] Figure 20 This is a schematic diagram showing the position of the material feeding channel in area C of Example 5 when it is connected to the through hole 1;

[0057] Figure 21 This is a schematic diagram showing the position of the material feeding channel and the through hole 2 in the material C region of Example 5.

[0058] In the diagram: printing platform 1, powder recovery tanks 11 and 13, substrate 12;

[0059] Dual-axis linear module 2, X-axis linear module 21, motor 211, slider 212, ball screw module 213, Y-axis linear module 22;

[0060] Scraper mechanism 3, scraper body 31, connector 32;

[0061] Powder feeding mechanism 4, mounting base 41, bracket 42, annular protrusion II 421, through hole II 422, nozzle 43, powder selection plate 44, guide groove II 441, material discharge channel 442, hopper 45, guide groove I 451, through hole I 452, transmission mechanism 46, transmission shaft 461, drive component I 462, belt 463. Detailed Implementation

[0062] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0063] It should be noted that when a component is said to be "installed on" another component, it can be directly on the other component or it may be in a component that is centered on it. When a component is said to be "set on" another component, it can be directly set on the other component or it may also be in a component that is centered on it. When a component is said to be "fixed to" another component, it can be directly fixed to the other component or it may also be in a component that is centered on it.

[0064] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0065] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "or / and" as used herein includes any and all combinations of one or more of the associated listed items.

[0066] Example 1

[0067] This embodiment provides a multi-material laser powder bed additive manufacturing powder placement method, which controls the powder feeding and placement of a powder placement device. The powder placement device includes a substrate 12 and a powder feeding mechanism 4. The powder feeding mechanism 4 is used to feed powder onto the substrate 12, with a powder volume of V each time. The multi-material laser powder bed additive manufacturing powder placement method includes the following steps:

[0068] S1. The geometric model to be manufactured is voxelized to obtain a voxelized model. The geometric model contains N sub-parts; the nth sub-part is made of the nth material; N≥2, n∈[1,N]. The voxelized model includes K voxel lattices; each K voxel lattice contains material information to accommodate the powder spreading requirements of the N materials.

[0069] In this step, it can be as follows: Figure 1 As shown, the geometric model is constructed using two materials, A and B. This results in a geometric model comprising two sub-parts, one made of material A and the other of material B. The voxelized model consists of K voxel lattices. Each voxel lattice contains material information for either material A or material B, the specific material information being included depending on the relative positions of the geometric sub-parts.

[0070] S2. The voxelized model is slicing laterally to obtain Q-layer slices. The thickness of the q-th slice layer is the same as the thickness of the voxel lattice. The q-th slice layer includes P... q Individual prime. q∈[1,Q].

[0071] S3, Calculate P q The powder volume V corresponding to an individual lattice 1q ~V Pq V 1q ~V Pq Calculate P by dividing by V respectively q The number of times t is sent to each individual element. 1q ~t Pq .

[0072] In this step, the powder volume corresponding to the voxel lattice is calculated based on the size of the voxel lattice. In this embodiment, the voxel lattices are all cubes or cubic structures, so the powder volume is the product of the length, width, and height of the voxel lattice.

[0073] S4. Based on the qth slice layer, the powder layer of the qth layer is laid on the substrate 12.

[0074] S4 includes the following steps:

[0075] P of the qth slice layer q Individual lattice mappings are applied to substrate 12. Based on the number of powder feeds t... pq To the pth q The individual lattice is fed with powder at the mapped position on substrate 12 so that its powder volume reaches the p-th position. q The powder volume V corresponding to an individual lattice pq p q ∈[1 q P q ]. V pq ∈[V 1qV Pq ]. t pq ∈[t 1q , t Pq Traversing P q After individual particles are formed, the powder is scraped flat to complete the qth layer of powder spreading.

[0076] like Figure 2 As shown, using two materials as an example, in the powder coating of the qth layer of substrate 12, material A and material B are distributed horizontally in the same layer. After leveling, a powder coating layer with material A and material B distributed horizontally is formed. Alternatively, material B can be entirely fed into one layer for powder coating, and material A can be entirely fed into the next layer for powder coating, thus forming a powder coating layer with material A and material B distributed vertically. The specific material distribution is determined according to the powder type of different voxel lattices.

[0077] S5. Traverse the Q layer slices sequentially from low to high to complete the Q layer powder spreading, and the entire powder spreading operation is completed.

[0078] Example 2

[0079] Please refer to Figure 3 This embodiment provides a multi-material laser powder bed additive manufacturing powder spreading device, which uses the multi-material laser powder bed additive manufacturing powder spreading method described in Embodiment 1 for powder spreading. The multi-material laser powder bed additive manufacturing powder spreading device includes a printing platform 1, a substrate 12, a dual-axis linear module 2, and a powder supply mechanism 4. For ease of explanation, the two vertical directions on the working surface of the printing platform 1 are defined as the X and Y directions, and the direction perpendicular to the working surface is defined as the Z direction. The Z direction is the direction of gravity.

[0080] Specifically, please refer to Figure 4 The substrate 12 is disposed on the working surface of the printing platform 1 and can move up and down along the Z direction. Two powder recovery tanks 11 and 13 are disposed on the working surface. The two powder recovery tanks 11 and 13 are located on opposite sides of the substrate 12 in the X direction.

[0081] Please refer to this again. Figure 4The dual-axis linear module 2 includes an X-axis linear module 1 21, an X-axis linear module 2, and a Y-axis linear module 22. The X-axis linear modules 1 and 2 are symmetrically mounted at both ends of the working surface of the printing platform 1. The X-axis linear module 1 21 includes a frame 1, a motor 211, a ball screw module 213, and a slider 212. The frame 1 is fixed to the printing platform 1. The ball screw module 213 is mounted on the frame 1 along the X-direction. The motor 211 is fixed to the frame 1 and drives the ball screw in the ball screw module 213 to rotate. The slider 212 is fitted onto the ball screw and moves in the X-direction as the ball screw is driven. The difference between the X-axis linear module 2 and the X-axis linear module 1 21 is that the X-axis linear module 2 does not contain the motor 211, and the ball screw module 213 is replaced with a smooth rod. The guide rod and the ball screw are arranged in parallel, and a second slider is slidably connected to the guide rod. The Y-axis linear module 22 is the same as the X-axis linear module 21, and it is connected to the first slider 212 and the second slider, and is arranged in the Y direction.

[0082] Please refer to Figure 5 The scraper mechanism 3 includes a scraper body 31 and a connector 32. The bottom of the scraper body 31 is in close contact with the printing platform 1, and the length of the scraper body 31 in the Y direction is greater than the length of the substrate 12. That is, when the scraper body 31 moves in the X direction, its scraping path can cover the entire substrate 12. The scraper body 31 is fixed to the slider 2 by the connector 32. The distance between the fixed scraper body 31 and the powder supply mechanism 4 is greater than or equal to the length of the substrate 12 in the X direction. The purpose is to ensure that the scraper body 31 does not come into contact with the powder when the powder supply mechanism 4 feeds powder onto the substrate 12.

[0083] Please refer to Figure 6 The powder supply mechanism 4 is a major design highlight of this invention. In this embodiment, the powder supply mechanism 4 includes a mounting base 41, a hopper 45, a powder selection disc 44, a bracket 42, N nozzles 43, and a transmission mechanism 46. Specifically, the mounting base 41 is C-shaped, and the hopper 45, the powder selection disc 44, and the bracket 42 are all located inside the C-shaped opening. The side of the mounting base 41 away from the opening is fixed to a slider on the Y-axis linear module 22, so that the dual-axis linear module 2 can drive the mounting base 41 to move along the X and Y directions.

[0084] The hopper 45 is fixed inside the mounting base 41. The interior of the hopper 45 is divided into two chambers for storing different powder materials, and a circular guide groove 451 is provided at the bottom of the hopper 45. Figure 7 , Figure 8As shown. To facilitate the description of the relative relationships of the structures below, the circle formed by the guide groove 451 is defined as a virtual circle, and a line segment d is defined along the radius of the virtual circle. In this embodiment, the number of through holes 452 opened at the bottom of the hopper 45 is set to two. Both through holes 452 are located within the guide groove 451 and are symmetrically distributed with respect to the line segment d, which is located on the boundary line between the two chambers. The two through holes 452 are connected to the two chambers respectively.

[0085] The powder selection disc 44 is disc-shaped and is horizontally rotatable and connected to the bottom of the hopper 45. Specifically, as shown... Figure 9 As shown, the top of the powder sorting disk 44 has an annular protrusion along a virtual circle, and the annular protrusion extends into the guide groove 451. At the bottom of the powder sorting disk 44, a guide groove 441 is formed at the position corresponding to the annular protrusion. Two feeding channels 442 are symmetrically formed within the guide groove 441, centered on line segment d. The volume of both feeding channels 442 is V.

[0086] Please refer to Figure 10 The bottom of the bracket 42 is fixed to the mounting base 41, and the top of the bracket 42 also has an annular protrusion 421 along the virtual circle. The annular protrusion 421 extends into the guide groove 441, allowing the powder selection disc 44 to rotate under the clamping of the hopper 45 and the bracket 42. Two through holes 422 are symmetrically formed on the annular protrusion 421 with line segment d as the center. The number of nozzles 43 corresponds to the number of through holes 422. The nozzles 43 are fixed to the mounting base 41, with their tops communicating with the corresponding through holes 422, and the bottom nozzles 43 facing downwards.

[0087] It should be noted that the positions of through hole 452, feeding channel 442, and through hole 422 have special requirements and must meet certain conditions: In this embodiment, for example... Figure 11As shown, in the initial position, the angle between through hole 1 452 and line segment d is 37.5°. The angle between feeding channel 442 and line segment d is 52.5°. The angle between through hole 2 422 and line segment d is 22.5°. When one of the feeding channels 442 rotates to connect with the corresponding through hole 1 452, the other feeding channel 442 will be offset from the other through hole 1 452. Similarly, when one feeding channel 442 connects with one through hole 2 422, the other feeding channel 442 will be offset from the other through hole 2 422. Furthermore, when one feeding channel 442 connects with one through hole 1 452, that feeding channel 442 will not simultaneously connect with through hole 2 422. During powder feeding, the feeding channel 442 first connects to through hole 452, allowing powder from the hopper 45 to enter the feeding channel 442. Then, the powder selection disc 44 rotates, moving the powder-filled feeding channel 442 until it connects to through hole 422, allowing powder to enter. Through hole 422 then connects to nozzle 43, and finally, the powder is delivered to a designated position on the substrate 12 through nozzle 43. Please refer to... Figure 12 , 13 And 14. Figure 12 This is a top-down view of the initial position of the powder spreading device. The right half is the storage area for material A, and the left half is the storage area for material B. Figure 13 In material A area, after the powder selection disc rotates counterclockwise, the feeding channel 442 connects with the through hole 452, allowing material A to enter the feeding channel 442. Then, the counterclockwise rotation continues... Figure 14 As shown, the feeding channel 442 rotates to connect with through hole 422, allowing material A to be fed. While material A is being fed, the feeding channel 442 in the material B area never comes into contact with through hole 452 or through hole 422, thus preventing the two materials from interfering with each other during feeding.

[0088] It should also be noted that in this embodiment, the cross-sectional shape of both through-hole 452 and the feeding channel 442 can be set to a fan shape. The two straight sides of the fan-shaped through-hole form a 15° angle with the center of the virtual circle as the vertex, which is more conducive to feeding when through-hole 452 and feeding channel 442 are connected. Compared with a general circle, the fan shape can have a larger volume V in the same area. Of course, through-hole 452 and feeding channel 442 can also be set to other shapes. The volume V of feeding channel 442 can be calculated according to the volume formula of the corresponding shape, which will not be described in detail here. The side of through-hole 422 near the powder selection plate 44 is set to a fan shape to facilitate docking with feeding channel 442. The side of through-hole 422 near the nozzle is set to a circle to facilitate docking with nozzle 43, ultimately enabling through-hole 422 and nozzle 43 to feed better.

[0089] The transmission mechanism 46 is used to drive the powder classifier 44 to rotate. In this embodiment, the transmission mechanism 46 includes a transmission shaft 461, a drive component 462, and a belt 463. The transmission shaft 461 can be a stepped shaft for easy installation. The transmission shaft 461 is arranged along the Z direction, and its upper and lower ends are rotatably connected to the inner wall of the opening of the mounting base 41, respectively. It should be noted that the transmission shaft 461 is located at the center of the virtual circle, and the transmission shaft 461 is rotatably sleeved with the hopper 45 and the bracket 42, while it is fixedly sleeved with the powder classifier 44 to drive the rotating disk to rotate. Figure 15 The drive component 462 can be a motor, which is fixed on the mounting base 41 and moves together with the mounting base 41. The two ends of the belt 463 are respectively sleeved on the drive shaft 461 and the output shaft of the motor to transmit the power of the drive component 462 to drive the drive shaft 461 to rotate.

[0090] Example 3

[0091] Compared to Embodiment 2, the transmission mechanism 46 in this embodiment can take a different form. Specifically, the transmission mechanism 46 includes a second driving component, a transmission gear, and a gear ring. The second driving component can also be a motor, which is also fixed on the mounting base 41, or it can be installed on the hopper 45. The gear ring has teeth on its outer side and is fixedly sleeved on the outer edge of the powder classifier 44. The transmission gear is fixed on the output shaft of the second driving component and meshes with the gear ring to drive the powder classifier 44 to rotate. Compared with the above embodiment, this transmission mechanism 46 has a more compact structure. Regardless of the structure of the transmission mechanism 46, the control circuit of the first driving component 462 or the second driving component is a conventional control circuit, which will not be described in detail here.

[0092] Example 4

[0093] This embodiment combines the method in Embodiment 1 and the apparatus in Embodiment 2 to completely print a 10×10×10cm size. 3 Taking a 316L / CuSn10 cubic workpiece (length × width × height) as an example, the two materials each occupy half of the distribution area in each layer, which is 5×5×10cm. 3 (Length × Width × Height)

[0094] Step 1: Inject sufficient amounts of 316L stainless steel powder and CuSn10 powder with particle sizes between 20 and 100 μm into the two chambers of the silo 45, respectively.

[0095] Step 2: The geometric model of the 316L / CuSn10 cubic workpiece is voxelized. In the resulting voxelized model, the length, width, and height of each voxel cell are all 0.1 mm. Then, the voxelized model is transversely sliced ​​into multiple slices, each with a thickness of 0.1 mm. The slice information is transmitted to the controller of the powder spreading device via a computer.

[0096] Step 3: Move the substrate 12 downwards along the Z direction by one slice thickness.

[0097] Step 4: The controller of the powder spreading device confirms that the powder material to be dropped at the first voxel mapping position on the substrate 12 is 316L stainless steel powder based on the material distribution information obtained in the slice layer (distribution information includes voxel lattice mapping position, number of powder feedings, etc.), and calculates the number of powder feedings required.

[0098] Step 5: The dual-axis linear module 2 drives the powder supply mechanism 4 to stop at the first voxel lattice mapping position on the substrate 12. Then, the transmission mechanism 46 drives the powder selection disk 44 to rotate, connecting the feeding channel 442 with the chamber containing 316L stainless steel powder, storing the 316L stainless steel powder within the feeding channel 442. The transmission mechanism 46 then drives the powder selection disk 44 back to its initial position.

[0099] Step Six: The transmission mechanism 46 drives the powder selection disk 44 to rotate, so that the feeding channel 442 storing 316L stainless steel powder is connected to the through hole 422. The 316L stainless steel powder is fed onto the base plate 12 through the nozzle 43, and then fed multiple times at this mapped position according to the obtained powder feeding number.

[0100] Step 7: After the powder feeding at the first individual grid mapping position is completed, the dual-axis linear module 2 drives the powder supply mechanism 4 to feed powder along the Y direction at each mapping position until the powder feeding at all mapping positions in an X direction position is completed.

[0101] Step 8: The dual-axis linear module 2 drives the powder supply mechanism 4 to move along the X direction, sequentially traversing all X-direction positions, and completing the powder supply to all voxel lattice mapping positions corresponding to all 316L stainless steel powders in this layer.

[0102] Repeat steps four through eight, replacing the 316L stainless steel powder with CuSn10 powder for powder feeding, until all mapped positions are fed with powder.

[0103] Step 9: The dual-axis linear module 2 moves along the X direction, driving the scraper mechanism 3 to scrape the powder falling on the substrate 12.

[0104] Step 10: The laser beam selectively melts the powder layer located on the substrate 12 according to the set program.

[0105] Step 11: Repeat steps 3 through 10 until the 316L / CuSn10 cubic workpiece is printed.

[0106] Example 5

[0107] Compared with Embodiment 2, the difference in this embodiment is that the hopper 45 in this embodiment is provided with three chambers for storing different powder materials, such as... Figure 16 As shown. Correspondingly, the relative positions of through hole 1 452, feeding channel 442, and through hole 2 422 also need to be adjusted accordingly. Its feeding logic and other structures are basically the same as the multi-material laser powder bed additive manufacturing powder spreading device in Example 2.

[0108] Specifically, please refer to Figure 17 , 18 19, 20, and 21. (For example...) Figure 17 As shown, this is a schematic diagram of the initial position of the three chambers from a top-down view. Let the defined line segment d be set in the vertical direction, then... Figure 17 The upper right corner is the material A storage area, the upper left corner is the material B storage area, and the lower part is the material C storage area. In the material A and material B storage areas, the positions of through-hole 452, the feeding channel 442, and through-hole 422 are the same as the positions of the two chamber holes in Example 2, all symmetrically distributed along line segment d. (For ease of subsequent description and distinction, the through-hole 452, feeding channel 442, and through-hole 422 in the material A area will be referred to as A1, A2, A3, A4, A4, A5, A6, A7, A8, A9, A1, A1, A2, A1, A2, A3, A4, A5, A1, A2, A3, A4, A5, A1, A2, A3, A4, A5, A6, A7, A8, A9, A1, A1, A2, A1, A2, A3, A4, A1, A2, A3, A4, A5 ...4, A5, A1, A2, A3, A4, A5, A4, A5, A4, A5, A4, A5, A4, A5, A6, A7, A8, A1, A2, A3, A4, A5, A4, A5, A4, A5, A6, A7, A8, A1, A2, A3, A4, A bai And A2. The through hole 452, the feeding channel 442 and the through hole 422 in the material B region are respectively referred to as B1, B2, B3, B4, B4, B5 ...6, B7, B8, B9, B9, B9, B9, B9, B9, bai And B2. The through-hole 452, feeding channel 442, and through-hole 422 in material region C are labeled C1, C2, C3, C44, and C452, respectively. bai And C2). C1 in the storage area of ​​material C is located on line segment d, and two C's are opened at the corresponding positions of material C. bai And with two C2s, four nozzles 43 need to be set accordingly. The two C2s... bai respectively with A bai B bai Regarding the symmetrical setting of horizontal lines (horizontal lines with...) Figure 17 (From the perspective of...) The two C2s are set symmetrically with A2 and B2 about the horizontal line, respectively.

[0109] Let's take material A as an example. bai First, rotate counterclockwise to position A1. Material A is temporarily stored at A1. bai Inside, such as Figure 18 As shown. Then continue rotating counter-clockwise, so that A... bai Complete the material cutting by overlapping with A2, such as Figure 19 As shown, at this time, Bbai Keeping it away from B1 and B2 will not interfere with the feeding of material B, while one of C's... bai If it is connected to one of C2, it will not cause material C to be fed.

[0110] If material A is finished being fed, and then another material A is fed, first restore the initial position and repeat the above steps. At this time, because C bai Since it is never connected to C2, it will not affect the unexplained feeding of material C.

[0111] If material A is finished being fed, and then material B is fed next, first restore the initial position, and then make B... bai Connecting B1 and B2 sequentially follows the same principle as feeding material A. During this process, C... bai It was never connected to C1, thus material C was temporarily stored in C1. bai Inside.

[0112] If material A is finished being fed, and material C is then fed next, continue rotating counterclockwise. Figure 20 As shown, C bai Connected to C1, material C falls into C. bai Temporarily stored in A. At this time, A... bai Move it between A2 and B2. Then rotate it clockwise, as follows. Figure 21 As shown, C bai Connected to C2, material C falls into nozzle 43, at which point A bai Returning to point A2 will prevent material A from being fed out unnecessarily. When multiple portions of material C need to be fed, the process will repeat. Figure 20 , Figure 21 The clockwise and counterclockwise movements shown are sufficient.

[0113] In some other embodiments, it may be configured as a four-chamber or more-chamber structure, with a specific design similar to the two-chamber and three-chamber structures, so that only one type of material is added at a time.

[0114] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0115] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for powder bed additive manufacturing of multi-material laser powder bed, characterized in that, It is used to control the powder feeding and powder spreading of the powder spreading device; the powder spreading device includes a substrate and a powder feeding mechanism, the powder feeding mechanism is used to feed powder onto the substrate, and the volume of powder fed each time is V; The multi-material laser powder bed additive manufacturing powder spreading method includes the following steps: S1. Perform voxelization on the geometric model to be manufactured to obtain a voxelized model; The geometric model consists of N sub-parts; the nth sub-part is made of the nth material; N≥2, n∈[1,N]; The voxelization model consists of K voxel lattices; each K voxel lattice contains material information to accommodate the powder spreading requirements of N materials. S2. Perform lateral slicing on the voxelized model to obtain Q-layer slices; wherein the thickness of the q-th slice is the same as the thickness of the voxel lattice; q∈[1,Q]; the q-th slice includes P q Individual character; S3, Calculate P q The powder volume V1 corresponding to the individual element lattice ; V1~ Calculate P by dividing by V respectively q The number of times powder is delivered to an individual unit (t1) ; S4. Based on the qth slice layer, the qth layer powder is laid on the substrate; S4 includes the following steps: P of the qth slice layer q Individual lattice mappings are applied to the substrate; Based on the number of fans sent To the pth q The powder is fed at the mapped position of the individual lattice on the substrate so that its powder volume reaches the p-th position. q Powder volume corresponding to individual lattice ;p q ∈[1, P q ]; Traversing P q After individual particles are formed, the powder is scraped flat to complete the qth layer of powder spreading; S5. Traverse the Q layer slices sequentially from low to high along the longitudinal direction to complete the Q layer powder spreading.

2. The multi-material laser powder bed additive manufacturing powder spreading method according to claim 1, characterized in that, In S4, the method for mapping the position of the q-th slice layer onto the substrate includes the following steps: S41. Coordinate the substrate and the qth slice layer; Wherein, the origin O1 of the substrate is set as one of the corners of the substrate; the origin O2 of the qth slice layer is set as one of the corners of the slice layer; S42. Assign O2 to one of the coordinates on the substrate so that the q-th slice layer is mapped onto the substrate.

3. The multi-material laser powder bed additive manufacturing powder spreading method according to claim 1, characterized in that, Before each layer of powder is applied, the substrate is lowered by one voxel lattice thickness.

4. A multi-material laser powder bed additive manufacturing powder spreading device, characterized in that, It operates using the multi-material laser powder bed additive manufacturing powder spreading method as described in any one of claims 1 to 3; the multi-material laser powder bed additive manufacturing powder spreading apparatus includes: Printing platform; define the direction perpendicular to the working surface of the printing platform as the Z direction; The substrate is set on the printing platform and can move along the Z direction; A dual-axis linear module, which is mounted on the printing platform; A powder feeding mechanism, mounted on a dual-axis linear module and moved via the module, to feed powder onto a substrate; and The scraper mechanism is mounted on a dual-axis linear module and moves through the dual-axis linear module to scrape the powder on the substrate. Powder supply organizations include: The mounting base is connected to the dual-axis linear module for movement; The hopper is connected to the mounting base; the interior of the hopper is divided into multiple chambers for storing powder materials; the bottom of the hopper has through holes that communicate with the multiple chambers. A powder separator is rotatably connected to the bottom of the hopper; the powder separator has multiple feeding channels corresponding to the through holes; the volume of the feeding channels is V. The bracket is connected to the mounting base and is rotatably connected to the bottom of the powder selection tray; the bracket has multiple through holes corresponding to the material feeding channel. Multiple nozzles are connected to the mounting base; the multiple nozzles correspond to multiple through holes; and The transmission mechanism is used to drive the powder classifier to rotate so that the through hole one, the feeding channel and the through hole two are connected or staggered; A virtual circle is defined with a line in the Z direction as its axis; multiple through holes 1, multiple feeding channels, and multiple through holes 2 are distributed along the edge of the virtual circle; when one of the through holes 1 is connected to one of the feeding channels, the other through holes 1 are offset from the feeding channels; when one of the feeding channels is connected to one of the through holes 2, the other feeding channels are offset from the through holes 2; when one of the through holes 1 is connected to one of the feeding channels, the feeding channel connected to through hole 1 is offset from through hole 2.

5. The multi-material laser powder bed additive manufacturing powder spreading device according to claim 4, characterized in that, The bottom of the hopper has a circular guide groove with a virtual circle as its boundary; multiple through holes are located on the guide groove. The top of the powder classifier is provided with an annular protrusion that matches the guide groove 1; the annular protrusion 1 extends into the guide groove 1; the bottom of the powder classifier forms a guide groove 2 at the position corresponding to the annular protrusion 1; multiple material discharge channels are located on the guide groove 2. The top of the bracket is provided with an annular protrusion II that matches the guide groove II; the annular protrusion II extends into the guide groove II; and multiple through holes II are located on the annular protrusion II.

6. The multi-material laser powder bed additive manufacturing powder spreading device according to claim 4, characterized in that, Multiple through holes and multiple feeding channels are all fan-shaped through holes; The two straight sides of the fan-shaped through hole form a 15° angle with the center of the virtual circle as the vertex; The multiple through holes are fan-shaped on the side near the powder sorting disc and circular on the side near the nozzle.

7. The multi-material laser powder bed additive manufacturing powder spreading device according to claim 4, characterized in that, The mounting base is C-shaped; the hopper, classifier, and support are all located inside the mounting base. The transmission mechanism includes: The drive shaft has its two ends rotatably connected to the mounting base; the drive shaft is set along the Z direction and is located at the center of the virtual circle; the drive shaft is rotatably connected to the hopper and the bracket; the drive shaft is fixedly connected to the classifier disc to drive the classifier disc to rotate. Drive component one, which is connected to the mounting base; A belt is used to transmit the rotational motion of a drive component to drive the transmission shaft to rotate.

8. The multi-material laser powder bed additive manufacturing powder spreading device according to claim 4, characterized in that, The transmission mechanism includes: Drive component two is connected to the mounting base; The transmission gear is connected to the output shaft of the second driving component; The gear ring has teeth on its outside; the gear ring is fixedly sleeved on the classifier disc and meshes with the transmission gear to drive the classifier disc to rotate.

9. The multi-material laser powder bed additive manufacturing powder spreading device according to claim 4, characterized in that, The scraper mechanism includes: The scraper body has its bottom in contact with the working surface of the printing platform; The connector has one end connected to the dual-axis linear module for movement in the X direction, and the other end connected to the scraper body. The scraper body moves along a path that covers the substrate in the X direction; The distance between the scraper body and the mounting base is greater than or equal to the length of the substrate in the X direction.

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