A multi-material powder bed additive manufacturing device and product preparation method thereof

Abstract

The present invention provides a multi-material powder bed additive manufacturing device and a product preparation method thereof, belonging to the field of laser processing technology, including: a powder bed, a printed area is formed after the powder on a preset track is melted by a laser scanning galvanometer, and a windward side and a leeward side are formed on the contour edge of the printed area; a powder spreading device, located above the powder bed, including: at least two powder droppers for storing different powders; a powder spreading scraper, located on one side of one of the powder droppers, and one side of the powder spreading scraper is the back of the blade, and the other side is the powder scraping surface; two powder suckers, one of which is arranged on the same side as the back of the blade, and the other is arranged on the same side as the powder scraping surface, and the residual powder on the windward side and the leeward side is sucked away by the two powder suckers. The present invention avoids cross contamination between multiple materials and improves the performance of the product after molding.

Description

Technical Field

[0001] The present invention belongs to the technical field of laser processing, and relates to a multi-material powder bed additive manufacturing device, in particular to a multi-material powder bed additive manufacturing device and a product preparation method thereof. Background Art

[0002] Laser powder bed fusion additive manufacturing (hereinafter referred to as powder bed additive manufacturing) is an additive manufacturing method that uses a high-energy beam laser as a heat source to selectively melt powder materials layer by layer to manufacture three-dimensional parts.

[0003] Different from conventional single-material powder bed additive manufacturing, multi-material powder bed additive manufacturing can deposit multiple materials into different positions of the same part in the same forming process, breaking through the performance constraints of a single material and achieving extreme performance and functions through local free regulation of part composition.

[0004] The key technical issue of multi-material powder bed additive manufacturing is the same-layer laying and melting of heterogeneous powder particles. By repeating the "powder laying-melting-powder absorption" steps, the same-layer printing of heterogeneous powder particles can be achieved.

[0005] However, this process has the following problems:

[0006] First, as Figure 1 As shown in the figure, during the powder suction process, the powder at the root of the windward side (facing the powder suction feeding direction) of the printed area can be cleaned up, but the root of the leeward side (opposite to the powder suction feeding direction) of the printed area is difficult to clean up and there is residual powder;

[0007] Second, if Figure 2 As shown in the figure, when the scraper spreads the second powder, the residual powder (powder A) on the leeward side will mix with the newly spread powder (powder B). If the leeward side is the laser melting area, the components of powder A and powder B will be mixed, affecting the thermodynamic properties of the local area.

[0008] Third, the scraper is a commonly used powder spreading tool for powder bed additive manufacturing. During the multi-material powder spreading process, electrostatic force will cause powder particles of different materials to be adsorbed on the scraper surface. These powders will be randomly dispersed to any position in the powder bed as the scraper spreads the powder, affecting the material composition distribution of the entire powder bed. Summary of the invention

[0009] The purpose of the present invention is to address the above-mentioned problems in the existing technology and to propose a multi-material powder bed additive manufacturing device that can remove residual powder at the edge of the contour of the printed area to avoid powder mixing contamination, thereby improving product quality.

[0010] The object of the present invention can be achieved by the following technical solution: A multi-material powder bed additive manufacturing device, comprising:

[0011] The powder bed is used as a carrier for laying powder. When the powder bed is covered with powder to form a powder layer, the upper surface of the powder layer is a forming plane, the lower surface of the powder layer is a powder absorbing plane, and the powder layer is used as a printing area for laser melting. The powder layer on the powder bed is melted on a preset track by a laser scanning galvanometer to form a printed area, and the side of the printed area facing the feeding direction when laying powder is the windward side, and the side of the printed area facing away from the feeding direction when laying powder is the leeward side;

[0012] The powder spreading device is located above the powder bed and includes:

[0013] At least two powder droppers are used as loading containers for different powders, and each powder dropper is provided with a powder dropper opening, wherein the powder dropper opening faces the powder bed, and the powder dropper can reciprocate along the feeding direction when spreading the powder;

[0014] A powder spreading scraper is located on one side of one of the powder droppers, and the powder layer is flattened and compacted along the feeding direction of the powder spreading by the powder spreading scraper, and the side of the powder spreading scraper facing the feeding direction of the powder spreading is the back side of the scraper, and the side of the powder spreading scraper away from the feeding direction of the powder spreading is the powder scraping side;

[0015] Two powder absorbers are provided, one of which is arranged on the same side as the back side of the knife, and the other is arranged on the same side as the powder scraping surface, so that the two powder droppers are located between the powder absorber and the powder spreading scraper arranged on the same side as the powder scraping surface, and the unmelted residual powder between the forming plane and the powder suction plane on the windward side is sucked away by one of the two powder absorbers, and the unmelted residual powder between the forming plane and the powder suction plane on the leeward side is sucked away by the other powder absorber.

[0016] In the above-mentioned multi-material powder bed additive manufacturing equipment, the two powder absorbers work asynchronously. When the powder absorber set on the same side as the back side of the knife is working, the powder absorber set on the same side as the powder scraping surface is not working; when the powder absorber set on the same side as the powder scraping surface is working, the powder absorber set on the same side as the back side of the knife is not working.

[0017] In the above-mentioned multi-material powder bed additive manufacturing equipment, the two powder absorbers are respectively the first powder absorber and the second powder absorber, and the powder absorber arranged on the same side as the back side of the knife is the first powder absorber, and the powder absorber arranged on the same side as the powder scraping surface is the second powder absorber. When the powder layer on the powder bed melts the powder on the preset trajectory through the laser, a printed area is formed on the powder layer, wherein the first powder absorber sucks away the unmelted residual powder between the forming plane and the powder suction plane on the leeward side, and the second powder absorber sucks away the unmelted residual powder between the forming plane and the powder suction plane on the windward side.

[0018] In the above-mentioned multi-material powder bed additive manufacturing equipment, the two ends of the powder spreading feeding direction along the upper edge of the powder bed are respectively the starting end and the ending end. When the powder spreading device moves from the ending end to the starting end, the first powder absorber works to absorb the unmelted residual powder between the forming plane and the powder absorption plane on the leeward side; when the powder spreading device moves from the starting end to the ending end, the second powder absorber works to absorb the unmelted residual powder between the forming plane and the powder absorption plane on the windward side.

[0019] In the above-mentioned multi-material powder bed additive manufacturing equipment, the two powder droppers are respectively the first powder dropper and the second powder dropper, the first powder dropper and the second powder dropper are arranged side by side, and along the feeding direction of the powder are respectively the first powder suction device, the powder spreading scraper, the second powder dropper, the first powder dropper and the second powder suction device, and the first powder suction device, the powder spreading scraper, the second powder dropper, the first powder dropper and the second powder suction device are commonly connected to the slide and move synchronously, wherein the slide and the powder bed are arranged up and down and parallel to each other.

[0020] In the above-mentioned multi-material powder bed additive manufacturing equipment, a powder suction channel is arranged on the powder absorber along the powder suction direction, and the two ends of the powder suction channel are respectively a powder inlet and a powder outlet, and the horizontal height of the end face of the powder inlet is higher than the horizontal height of the forming plane, so that when the powder absorber sucks away the unmelted residual powder between the forming plane and the powder suction plane, the powder inlet on the powder absorber and the residual powder are non-contactly sucked.

[0021] In the above-mentioned multi-material powder bed additive manufacturing equipment, the non-contact powder suction is negative pressure powder suction or electrostatic powder suction. When the non-contact powder suction is negative pressure powder suction, negative pressure can be formed in the powder suction channel, and the unmelted residual powder between the forming plane and the powder suction plane can be sucked into the powder suction channel; when the non-contact powder suction is electrostatic powder suction, an electrostatic field can be formed in the powder suction channel, and the unmelted residual powder between the forming plane and the powder suction plane can be sucked into the powder suction channel.

[0022] The present invention also provides a product preparation method using the multi-material powder bed additive manufacturing equipment, comprising the steps of:

[0023] S1: forming a first powder layer on the powder bed along a feeding direction of the powder by a powder spreading device, wherein the upper surface of the first powder layer is a forming plane, and the lower surface of the first powder layer is a powder absorbing plane;

[0024] S2: melting the powder in the first powder layer on the preset track by means of a laser scanning galvanometer to form a first printed area;

[0025] S3: sucking away the unmelted residual powder in the first powder layer on the leeward side and the windward side by reciprocating movement of the powder spreading device along the feeding direction of the powder spreading;

[0026] S4: forming a second powder layer on the powder bed along the feeding direction of the powder by the powder spreading device, wherein the upper surface of the second powder layer is a forming plane, and the lower surface of the second powder layer is a powder absorbing plane;

[0027] S5: melting the powder in the second powder layer on the preset track by means of a laser scanning galvanometer to form a second printed area;

[0028] S6: sucking away the unmelted residual powder in the second powder layer on the leeward side and the windward side by reciprocating movement of the powder spreading device along the feeding direction of the powder spreading;

[0029] S7: The powder bed moves down as a whole by one printing powder layer thickness;

[0030] S8: Repeat S1 to S7 to complete the preparation of the entire product.

[0031] In the above product preparation method, step S1 comprises:

[0032] S11: the powder spreading device moves from the starting end to the ending end of the powder bed along the feeding direction of the powder spreading. During this process, the powder dropper storing powder A in the two powder droppers works to spread powder A on the surface of the powder bed. At this time, powder A is in a loose state, and the thickness of the first powder layer is 0.5-1.5 mm higher than the forming plane.

[0033] S12: While spreading the powder, use a powder spreading scraper to compact and flatten the powder A to a compacted plane;

[0034] S13: While the powder A is being compacted and scraped, the powder absorber on the same side as the back side of the knife accurately removes the compacted powder A, so that the thickness of the first powder layer is reduced to the forming plane.

[0035] In the above-mentioned product preparation method, in step S2, the side of the first printed area facing the feeding direction when spreading powder is the first windward side, and the side of the first printed area facing away from the feeding direction when spreading powder is the first leeward side, wherein unmelted residual powder is formed on the same side of the first windward side and the first leeward side, respectively.

[0036] In the above product preparation method, step S3 comprises:

[0037] S31: After the first printed area is formed, when the powder spreading device moves from the end end to the starting end of the powder bed, the powder absorber on the same side as the back side of the knife works to remove the unmelted residual powder on the first leeward surface, so that the thickness of the unmelted powder on the first leeward surface is reduced to the powder absorption plane;

[0038] S32: When the powder spreading device moves from the starting end to the ending end of the powder bed, the powder absorber on the same side as the powder scraping surface works to remove the unmelted residual powder on the first windward surface, so that the thickness of the unmelted powder on the first windward surface is reduced to the powder suction plane, thereby completing the removal of the unmelted residual powder in the first powder layer.

[0039] In the above product preparation method, step S4 comprises:

[0040] S41: the powder spreading device moves from the starting end to the ending end of the powder bed along the feeding direction of the powder spreading. During this process, the powder dropper storing powder B in the two powder droppers works to spread powder B on the surface of the powder bed. At this time, powder B is in a loose state, and the thickness of the second powder layer is 0.5-1.5 mm higher than the forming plane.

[0041] S42: While spreading the powder, use a powder spreading scraper to compact and flatten the powder B to a compacted plane;

[0042] S43: While the powder B is being compacted and scraped, the powder absorber on the same side as the back side of the knife in the two powder absorbers accurately removes the compacted powder B, so that the thickness of the second powder layer is reduced to the forming plane.

[0043] In the above-mentioned product preparation method, in step S5, the side of the second printed area facing the feeding direction when spreading powder is the second windward side, and the side of the second printed area facing away from the feeding direction when spreading powder is the second leeward side, wherein unmelted residual powder is formed on the same side of the second windward side and the second leeward side, respectively.

[0044] In the above product preparation method, step S6 comprises:

[0045] S61: After the second printed area is formed, when the powder spreading device moves from the end end to the starting end of the powder bed, the powder absorber on the same side as the back side of the knife works to remove the unmelted residual powder on the second leeward surface, so that the thickness of the unmelted powder on the second leeward surface is reduced to the powder absorption plane;

[0046] S62: When the powder spreading device moves from the starting end to the ending end of the powder bed, the powder absorber on the same side as the powder scraping surface works to remove the unmelted residual powder on the second windward surface, so that the thickness of the unmelted powder on the second windward surface is reduced to the powder absorption plane, thereby completing the removal of the unmelted residual powder in the first powder layer.

[0047] Compared with the prior art, the present invention has the following beneficial effects:

[0048] (1) The multi-material powder bed additive manufacturing equipment provided by the present invention avoids cross contamination between multiple materials and improves the performance of the molded product;

[0049] (2) The two powder absorbers work asynchronously to avoid the unmelted powder on the leeward and windward sides forming dust when the two powder absorbers work synchronously, causing cross-talk and disorder, thus affecting the powder absorption effect;

[0050] (3) Use non-contact powder suction to prevent unmelted residual powder from being adsorbed on the powder inlet end face of the powder absorber or the outer surface of the powder absorber. When the powder absorber is not working or the powder spreading device vibrates during movement, the powder on the powder inlet end face and the powder on the outer surface of the powder absorber will fall onto the powder bed again and mix with other powders, resulting in cross contamination, which will eventually affect the performance of the molded product.

[0051] (4) Two powder droppers, a powder spreading scraper and two powder suckers are placed on the same slide. The movement of the slide drives the two powder droppers, the powder spreading scraper and the two powder suckers to move synchronously, so that powder dropping, leveling and compacting can be carried out simultaneously, thereby improving work efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 It is a schematic diagram of the residual powder area of ​​the powder absorption in the prior art.

[0053] Figure 2 It is a schematic diagram of cross contamination of heterogeneous powders in the prior art.

[0054] Figure 3 It is a structural schematic diagram of a multi-material powder bed additive manufacturing device of the present invention.

[0055] Figure 4 It is a schematic diagram of step S11 in a product preparation method of the present invention.

[0056] Figure 5 It is a schematic diagram of step S12 in a product preparation method of the present invention.

[0057] Figure 6 It is a schematic diagram of step S13 in a product preparation method of the present invention.

[0058] Figure 7 It is a schematic diagram of step S2 in a product preparation method of the present invention.

[0059] Figure 8 It is a schematic diagram of step S31 in a product preparation method of the present invention.

[0060] Fig. 9 It is a schematic diagram of step S32 in a product preparation method of the present invention.

[0061] Fig.10 It is a schematic diagram of step S41 in a product preparation method of the present invention.

[0062] Fig.11 It is a schematic diagram of step S42 in a product preparation method of the present invention.

[0063] Fig.12 It is a schematic diagram of step S43 in a product preparation method of the present invention.

[0064] Fig.13 It is a schematic diagram of step S5 in a product preparation method of the present invention.

[0065] In the figure, 10, powder bed; 11, powder suction plane; 12, forming plane; 13, printed area; 131, windward side; 132, leeward side; 14, compaction plane; 20, powder spreading device; 21, powder spreading scraper; 211, back side of the scraper; 212, powder scraping surface; 22, first powder absorber; 23, second powder absorber; 24, first powder dropper; 25, second powder dropper; 30, laser scanning galvanometer. DETAILED DESCRIPTION

[0066] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

[0067] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0068] In the existing powder spreading equipment, only single-material products can be processed. When the processed products contain two or more materials, the following problems will arise:

[0069] When the powder A on the preset track is melted by the laser scanning galvanometer 30 to form the first printing area, unmelted residual powder will be formed on the leeward side 132 and the windward side 131 of the first printing area. At this time, if the powder B is directly spread on the first printing area, the powder B may be mixed with the residual powder on the leeward side 132 and the windward side 131 of the first printing area, and the second printing area is formed under the action of the laser scanning galvanometer 30. Since the second printing area is a material mixed with powder A and powder B, the performance of the final molded product is affected;

[0070] Therefore, in order to solve the mixing problem of powder A and powder B, a powder absorber is set in the powder spreading device to absorb the unmelted residual powder in the first printing area. However, no matter which side of the powder dropper in the powder spreading device 20 the powder absorber is set on, it can only absorb the residual powder on one side of the leeward side 132 and the windward side 131, but cannot absorb the residual powder on both sides of the leeward side 132 and the windward side 131.

[0071] In addition, the powder that falls from the powder dropper onto the powder bed 10 is loose, and it is impossible to evenly spread the powder on the powder bed 10. Therefore, it is necessary to add a powder scraper 21 to the powder spreading device 20 to flatten and compact the powder on the powder bed 10. However, when the powder scraper 21 flattens and compacts the powder on the powder bed 10, the powder will adhere to the surface of the powder scraper 21. As the powder spreading device 20 moves back and forth, the powder suction device can also suck away the powder that falls from the powder scraper 21 from one direction.

[0072] Therefore, the powder spreading equipment in the prior art cannot accurately and reliably ensure that there will be no cross-contamination of materials.

[0073] like Figures 3 to 13 As shown, the present invention provides a multi-material powder bed additive manufacturing device, comprising:

[0074] The powder bed 10 is used as a carrier for laying powder. When the powder bed 10 is covered with powder to form a powder layer, the lower surface of the powder layer is a powder absorbing plane 11, the upper surface of the powder layer is a forming plane 12, and the powder layer is used as a printing area for laser melting, wherein the powder layer on the powder bed 10 is melted on a preset track by a laser scanning galvanometer 30 to form a printed area 13, the upper and lower sides of the printed area 13 are respectively located flush with the forming plane 12 and the powder absorbing plane 11, and the side of the printed area 13 facing the feeding direction when laying powder is the windward side 131, and the side of the printed area 13 away from the feeding direction when laying powder is the leeward side 132;

[0075] The powder spreading device 20 is located above the powder bed 10 and includes:

[0076] At least two powder droppers are used as loading containers for different powders, and each powder dropper is provided with a powder dropper opening, wherein the powder dropper opening faces the powder bed 10, and the powder dropper can reciprocate along the feeding direction when spreading the powder;

[0077] A powder spreading scraper 21 is located on one side of one of the powder droppers, and the powder layer is flattened and compacted along the feeding direction of the powder spreading by the powder spreading scraper 21, and the side of the powder spreading scraper 21 facing the feeding direction of the powder spreading is the blade back side 211, and the side of the powder spreading scraper 21 away from the feeding direction of the powder spreading is the powder scraping surface 212;

[0078] There are two powder absorbers, one of which is arranged on the same side as the back side 211 of the knife, and the other is arranged on the same side as the powder scraping surface 212, so that the two powder droppers are located between the powder absorber and the powder scraper 21 arranged on the same side as the powder scraping surface 212, and the unmelted residual powder between the forming plane 12 and the powder suction plane 11 on the windward surface 131 is sucked away by one of the two powder absorbers, and the unmelted residual powder between the forming plane 12 and the powder suction plane 11 on the leeward surface 132 is sucked away by the other powder absorber.

[0079] It is worth mentioning that after the printed area 13 is formed on the powder layer, the corresponding powder absorbers are opened in sequence through the reciprocating movement of the powder spreading device 20, so as to absorb the unmelted residual powder on the leeward side 132 and the windward side 131 of the printed area 13. In addition, since the two powder absorbers are on both sides of the powder spreading scraper 21, the powder falling from the powder spreading scraper 21 can be reliably absorbed.

[0080] The invention provides a multi-material powder bed additive manufacturing device, which avoids cross contamination between multiple materials and improves the performance of the product after molding.

[0081] It is further pointed out that the two powder absorbers work asynchronously. When the powder absorber set on the same side as the back side 211 of the knife is working, the powder absorber set on the same side as the powder scraping surface 212 is not working; when the powder absorber set on the same side as the powder scraping surface 212 is working, the powder absorber set on the same side as the back side 211 of the knife is not working.

[0082] In this embodiment, the two powder absorbers work asynchronously to avoid the unmelted powder on the leeward side 132 and the windward side 131 forming dust when the two powder absorbers work synchronously, causing the dust to cross and disorder each other and affect the powder absorption effect.

[0083] In addition, the asynchronous operation of the two powder absorbers means that after the printed area 13 is formed, when the powder spreading device 20 moves along the feeding direction during powder spreading, one of the powder absorbers works to absorb the unmelted residual powder on one of the leeward side 132 or the windward side 131; when the powder spreading device 20 returns, the other powder absorber works to absorb the unmelted residual powder on the other of the leeward side 132 or the windward side 131, thereby ensuring the reliability of powder suction.

[0084] Preferably, a powder suction channel is provided on the powder absorber along the powder suction direction, with the two ends of the powder suction channel being a powder inlet and a powder outlet respectively, and the horizontal height of the end face of the powder inlet is higher than the horizontal height of the forming plane 12, so that when the powder absorber sucks away the unmelted residual powder between the forming plane 12 and the powder suction plane 11, the powder inlet on the powder absorber and the residual powder are non-contactly sucked.

[0085] In this embodiment, non-contact powder suction is adopted to prevent the unmelted residual powder from being adsorbed on the end face of the powder inlet of the powder absorber or the outer surface of the powder absorber. When the powder absorber is not working, or the powder spreading device 20 vibrates during movement, the powder on the end face of the powder inlet and the powder on the outer surface of the powder absorber will fall onto the powder bed 10 again and mix with another powder, resulting in cross contamination, which ultimately affects the performance of the molded product. The non-contact powder suction can better solve the above-mentioned problems, so that the unmelted powder on the powder bed 10 can directly enter the powder suction channel without sticking to the end face of the powder inlet or the outer surface of the powder absorber.

[0086] It is worth mentioning that the non-contact powder suction is negative pressure powder suction or electrostatic powder suction. When the non-contact powder suction is negative pressure powder suction, negative pressure can be formed in the powder suction channel to suck the unmelted residual powder between the forming plane 12 and the powder suction plane 11 into the powder suction channel; when the non-contact powder suction is electrostatic powder suction, an electrostatic field can be formed in the powder suction channel to suck the unmelted residual powder between the forming plane 12 and the powder suction plane 11 into the powder suction channel.

[0087] In this embodiment, it is not limited to the negative pressure powder suction or electrostatic powder suction mentioned above, and other powder suction methods can also be used as long as they can meet the requirements of non-contact powder suction.

[0088] It is further pointed out that the horizontal height of the end face of the powder dropper on the powder dropper is higher than the horizontal height of the end face of the powder inlet on the powder absorber, and the horizontal height of the end face of the powder inlet on the powder absorber is higher than the horizontal height of the end of the powder scraper 21 close to the forming plane 12.

[0089] Preferably, the two powder absorbers are respectively a first powder absorber 22 and a second powder absorber 23, and the powder absorber arranged on the same side as the back side 211 of the knife is the first powder absorber 22, and the powder absorber arranged on the same side as the powder scraping surface 212 is the second powder absorber 23. When the powder layer on the powder bed 10 melts the powder on a preset trajectory through the laser, a printed area 13 is formed on the powder layer, wherein the unmelted residual powder between the forming plane 12 and the powder suction plane 11 on the leeward side 132 is sucked away by the first powder absorber 22, and the unmelted residual powder between the forming plane 12 and the powder suction plane 11 on the windward side 131 is sucked away by the second powder absorber 23.

[0090] It is worth mentioning that the powder suction areas targeted by the first powder absorber 22 and the second powder absorber 23 can be interchangeably set, that is, the first powder absorber 22 can suck away the unmelted residual powder between the forming plane 12 and the powder suction plane 11 on the windward side 131, and the second powder absorber 23 can suck away the unmelted residual powder between the forming plane 12 and the powder suction plane 11 on the leeward side 132.

[0091] However, it is preferred that the first powder absorber 22 absorbs the residual powder on the leeward surface 132, and the second powder absorber 23 absorbs the residual powder on the windward surface 131. The reason for this arrangement is that when the powder spreading device 20 moves along the feeding direction of the powder spreading, the second powder absorber 23 corresponds to the unmelted residual powder on the windward surface 131 before the first powder absorber 22; when the powder spreading device 20 returns, the first powder absorber 22 corresponds to the unmelted residual powder on the leeward surface 132 before the second powder absorber 23, so the unmelted residual powder between the forming plane 12 and the powder suction plane 11 on the leeward surface 132 is sucked away by the first powder absorber 22, and the unmelted residual powder between the forming plane 12 and the powder suction plane 11 on the windward surface 131 is sucked away by the second powder absorber 23.

[0092] When the powder spreading device 20 moves along the feeding direction of the powder spreading, if the unmelted residual powder on the windward surface 131 is sucked away by the first powder absorber 22, the two powder droppers are located in front of the first powder absorber 22 from the moving direction of the powder spreading device 20, resulting in the first powder absorber 22 may cause the unmelted residual powder to float to the two powder droppers when it is working, so that the powder sticks to the outer surface of the powder droppers, and there is a risk of cross-contamination with another powder in the subsequent product processing. Similarly, when the powder spreading device 20 returns, if the unmelted residual powder on the leeward surface 132 is sucked away by the second powder absorber 23, the two powder droppers are still in front of the second powder dropper 25 from the moving direction of the powder spreading device 20, so that the second powder absorber 23 may cause the unmelted residual powder to float to the two powder droppers when it is working, so that the powder sticks to the outer surface of the powder droppers, and there is a risk of cross-contamination with another powder in the subsequent product processing.

[0093] In summary, in order to avoid the risk of cross-contamination of powder, the first powder absorber 22 is used to absorb the unmelted residual powder between the forming plane 12 and the powder absorption plane 11 on the leeward side 132, and the second powder absorber 23 is used to absorb the unmelted residual powder between the forming plane 12 and the powder absorption plane 11 on the windward side 131.

[0094] In other words, the two ends of the powder bed 10 along the feeding direction of the powder are respectively the starting end and the ending end. When the powder spreading device 20 moves from the ending end to the starting end, the first powder absorber 22 works to absorb the unmelted residual powder between the forming plane 12 and the powder suction plane 11 on the leeward side 132; when the powder spreading device 20 moves from the starting end to the ending end, the second powder absorber 23 works to absorb the unmelted residual powder between the forming plane 12 and the powder suction plane 11 on the windward side 131.

[0095] Preferably, the two powder droppers are respectively the first powder dropper 24 and the second powder dropper 25, the first powder dropper 24 and the second powder dropper 25 are arranged side by side, and along the feeding direction of the powder are respectively the first powder suction device 22, the powder spreading scraper 21, the second powder dropper 25, the first powder dropper 24 and the second powder suction device 23, and the first powder suction device 22, the powder spreading scraper 21, the second powder dropper 25, the first powder dropper 24 and the second powder suction device 23 are commonly connected to the slide and move synchronously, wherein the slide and the powder bed 10 are arranged up and down and parallel to each other.

[0096] In this embodiment, two powder droppers, a powder spreading scraper 21 and two powder suckers are arranged together on the same slide. Through the movement of the slide, the two powder droppers, the powder spreading scraper 21 and the two powder suckers are driven to move synchronously, so that powder dropping, leveling and compacting are carried out simultaneously, thereby improving work efficiency.

[0097] The present invention also provides a method for preparing a product using a multi-material powder bed additive manufacturing device, comprising the steps of:

[0098] S1: forming a first powder layer on the powder bed 10 along the feeding direction of the powder by the powder spreading device 20, wherein the upper surface of the first powder layer is the forming plane 12, and the lower surface of the first powder layer is the powder suction plane 11;

[0099] S2: melting the powder in the first powder layer on the preset track by the laser scanning galvanometer 30 to form a first printed area;

[0100] S3: The unmelted residual powder in the first powder layer on the leeward surface 132 and the windward surface 131 is sucked away by the powder spreading device 20 moving back and forth along the feeding direction of the powder spreading;

[0101] S4: forming a second powder layer on the powder bed 10 along the feeding direction of the powder by the powder spreading device 20, wherein the upper surface of the second powder layer is the forming plane 12, and the lower surface of the second powder layer is the powder suction plane 11;

[0102] S5: melting the powder in the second powder layer on the preset track by the laser scanning galvanometer 30 to form a second printed area;

[0103] S6: The unmelted residual powder in the second powder layer on the leeward surface 132 and the windward surface 131 is sucked away by the powder spreading device 20 moving back and forth along the feeding direction of the powder spreading;

[0104] S7: The powder bed 10 moves downward as a whole by a printing powder layer thickness;

[0105] S8: Repeat S1 to S7 to complete the preparation of the entire product.

[0106] Preferably, step S1 comprises:

[0107] S11: the powder spreading device 20 moves from the starting end to the ending end of the powder bed 10 along the feeding direction of the powder spreading. During this process, the powder dropper storing powder A in the two powder droppers works to spread powder A on the surface of the powder bed 10. At this time, the powder A is in a loose state, and the thickness of the first powder layer is higher than the forming plane by 120.5-1.5 mm;

[0108] S12: While spreading the powder, use the powder spreading scraper 21 to compact and flatten the powder A to the compacting plane 14;

[0109] S13: While the powder A is being compacted and scraped, the powder absorber on the same side as the back side 211 of the knife accurately removes the compacted powder A, so that the thickness of the first powder layer is reduced to the forming plane 12.

[0110] Preferably, in step S2, the side of the first printed area facing the feeding direction when spreading powder is a first windward side, and the side of the first printed area facing away from the feeding direction when spreading powder is a first leeward side, wherein unmelted residual powder is formed on the same side of the first windward side and the first leeward side, respectively.

[0111] Preferably, step S3 includes:

[0112] S31: After the first printed area is formed, when the powder spreading device 20 moves from the end end to the starting end of the powder bed 10, the powder absorber on the same side as the back side 211 of the knife works to remove the unmelted residual powder on the first leeward surface, so that the thickness of the unmelted powder on the first leeward surface is reduced to the powder absorption plane 11;

[0113] S32: When the powder spreading device 20 moves from the starting end to the ending end of the powder bed 10, the powder absorber on the same side as the powder scraping surface 212 works to remove the unmelted residual powder on the first windward surface, so that the thickness of the unmelted powder on the first windward surface is reduced to the powder suction plane 11, thereby completing the removal of the unmelted residual powder in the first powder layer.

[0114] Preferably, step S4 comprises:

[0115] S41: the powder spreading device 20 moves from the starting end to the ending end of the powder bed 10 along the feeding direction of the powder spreading. During this process, the powder dropper storing the powder B in the two powder droppers works to spread the powder B on the surface of the powder bed 10. At this time, the powder B is in a loose state, and the thickness of the second powder layer is higher than the forming plane by 120.5-1.5 mm;

[0116] S42: While spreading the powder, use the powder spreading scraper 21 to compact and flatten the powder B to the compacting plane 14;

[0117] S43: While the powder B is being compacted and scraped, the powder absorber on the same side as the back side 211 of the knife accurately removes the compacted powder B, so that the thickness of the second powder layer is reduced to the forming plane 12.

[0118] Preferably, in step S5, the side of the second printed area facing the feeding direction when spreading powder is the second windward side, and the side of the second printed area facing away from the feeding direction when spreading powder is the second leeward side, wherein unmelted residual powder is formed on the same side of the second windward side and the second leeward side, respectively.

[0119] Preferably, step S6 comprises:

[0120] S61: After the second printed area is formed, when the powder spreading device 20 moves from the end end to the starting end of the powder bed 10, the powder absorber on the same side as the back side 211 of the knife works to remove the unmelted residual powder on the second leeward surface, so that the thickness of the unmelted powder on the second leeward surface is reduced to the powder absorption plane 11;

[0121] S62: When the powder spreading device 20 moves from the starting end to the ending end of the powder bed 10, the powder absorber on the same side as the powder scraping surface 212 works to remove the unmelted residual powder on the second windward surface, so that the thickness of the unmelted powder on the second windward surface is reduced to the powder suction plane 11, thereby completing the removal of the unmelted residual powder in the first powder layer.

[0122] In this embodiment, according to the above description, steps S1 to S3 realize the spreading, melting and powder absorption of powder A, and steps S4 to S6 realize the spreading, melting and powder absorption of powder B. Although the materials used are different, the processes are the same. It can be seen that when adding powder C and powder D, it is only necessary to repeat the above steps to form a product made of multiple materials.

[0123] It should be noted that in the present invention, descriptions such as "first", "second", "one", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined. The terms "connected", "fixed", etc. should be understood in a broad sense. For example, "fixed" can be a fixed connection, a detachable connection, or an integral whole; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0124] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0125] The specific embodiments described herein are merely examples of the spirit of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in similar ways, but they will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

Claims

1. A multi-material powder bed additive manufacturing device, characterized in that: include: The powder bed is used as a carrier for laying powder. When the powder bed is covered with powder to form a powder layer, the upper surface of the powder layer is a forming plane, the lower surface of the powder layer is a powder absorbing plane, and the powder layer is used as a printing area for laser melting. The powder layer on the powder bed is melted on a preset track by a laser scanning galvanometer to form a printed area, and the side of the printed area facing the feeding direction when laying powder is the windward side, and the side of the printed area facing away from the feeding direction when laying powder is the leeward side; The powder spreading device is located above the powder bed and includes: At least two powder droppers are used as loading containers for different powders, and each powder dropper is provided with a powder dropper opening, wherein the powder dropper opening faces the powder bed, and the powder dropper can reciprocate along the feeding direction when spreading the powder; A powder spreading scraper is located on one side of one of the powder droppers, and the powder layer is flattened and compacted along the feeding direction of the powder spreading by the powder spreading scraper, and the side of the powder spreading scraper facing the feeding direction of the powder spreading is the back side of the scraper, and the side of the powder spreading scraper away from the feeding direction of the powder spreading is the powder scraping side; Two powder absorbers, one of which is arranged on the same side as the back side of the knife, and the other is arranged on the same side as the powder scraping surface, so that the two powder droppers are located between the powder absorber and the powder spreading scraper arranged on the same side as the powder scraping surface, and the unmelted residual powder between the forming plane and the powder suction plane on the windward side is sucked away by one of the two powder absorbers, and the unmelted residual powder between the forming plane and the powder suction plane on the leeward side is sucked away by the other powder absorber, and the unmelted residual powder in the same powder layer on the leeward side and the windward side is sucked away by the reciprocating movement of the powder spreading device along the feeding direction of the powder spreading.

2. A multi-material powder bed additive manufacturing device according to claim 1, characterized in that: The two powder absorbers work asynchronously. When the powder absorber set on the same side as the back side of the knife is working, the powder absorber set on the same side as the powder scraping surface does not work; when the powder absorber set on the same side as the powder scraping surface is working, the powder absorber set on the same side as the back side of the knife does not work.

3. The multi-material powder bed additive manufacturing equipment according to claim 1, characterized in that: The two powder absorbers are respectively the first powder absorber and the second powder absorber, and the powder absorber arranged on the same side as the back side of the knife is the first powder absorber, and the powder absorber arranged on the same side as the powder scraping surface is the second powder absorber. When the powder layer on the powder bed is melted on a preset track by a laser, a printed area is formed on the powder layer, wherein the first powder absorber sucks away the unmelted residual powder between the forming plane and the powder suction plane on the leeward side, and the second powder absorber sucks away the unmelted residual powder between the forming plane and the powder suction plane on the windward side.

4. The multi-material powder bed additive manufacturing equipment according to claim 3, characterized in that: The two ends of the feeding direction of powder spreading along the upper edge of the powder bed are the starting end and the ending end respectively. When the powder spreading device moves from the ending end to the starting end, the first powder absorber works to absorb the unmelted residual powder between the forming plane and the powder suction plane on the leeward side; when the powder spreading device moves from the starting end to the ending end, the second powder absorber works to absorb the unmelted residual powder between the forming plane and the powder suction plane on the windward side.

5. The multi-material powder bed additive manufacturing equipment according to claim 3, characterized in that: The two powder droppers are respectively the first powder dropper and the second powder dropper, the first powder dropper and the second powder dropper are arranged side by side, and along the feeding direction of the powder are respectively the first powder suction device, the powder spreading scraper, the second powder dropper, the first powder dropper and the second powder suction device, and the first powder suction device, the powder spreading scraper, the second powder dropper, the first powder dropper and the second powder suction device are commonly connected to the slide and move synchronously, wherein the slide and the powder bed are arranged up and down and parallel to each other.

6. A multi-material powder bed additive manufacturing device according to any one of claims 1 to 5, characterized in that: A powder suction channel is arranged on the powder suction device along the powder suction direction, and the two ends of the powder suction channel are respectively a powder inlet and a powder outlet, and the horizontal height of the end face of the powder inlet is higher than the horizontal height of the forming plane, so that when the powder suction device sucks away the unmelted residual powder between the forming plane and the powder suction plane, the powder inlet on the powder suction device and the residual powder are non-contactly sucked.

7. The multi-material powder bed additive manufacturing equipment according to claim 6, characterized in that: The non-contact powder suction is negative pressure powder suction or electrostatic powder suction. When the non-contact powder suction is negative pressure powder suction, negative pressure can be formed in the powder suction channel to suck the unmelted residual powder between the forming plane and the powder suction plane into the powder suction channel; when the non-contact powder suction is electrostatic powder suction, an electrostatic field can be formed in the powder suction channel to suck the unmelted residual powder between the forming plane and the powder suction plane into the powder suction channel.

8. A method for preparing a product using the multi-material powder bed additive manufacturing equipment according to any one of claims 1 to 7, characterized in that: Includes steps: S1: forming a first powder layer on the powder bed along a feeding direction of the powder by a powder spreading device, wherein the upper surface of the first powder layer is a forming plane, and the lower surface of the first powder layer is a powder absorbing plane; S2: melting the powder in the first powder layer on the preset track by means of a laser scanning galvanometer to form a first printed area; S3: sucking away the unmelted residual powder in the first powder layer on the leeward side and the windward side by reciprocating movement of the powder spreading device along the feeding direction of the powder spreading; S4: forming a second powder layer on the powder bed along the feeding direction of the powder by the powder spreading device, wherein the upper surface of the second powder layer is a forming plane, and the lower surface of the second powder layer is a powder absorbing plane; S5: melting the powder in the second powder layer on the preset track by means of a laser scanning galvanometer to form a second printed area; S6: sucking away the unmelted residual powder in the second powder layer on the leeward side and the windward side by reciprocating movement of the powder spreading device along the feeding direction of the powder spreading; S7: The powder bed moves down as a whole by one printing powder layer thickness; S8: Repeat S1 to S7 to complete the preparation of the entire product.

9. The product preparation method according to claim 8, characterized in that: Step S1 includes: S11: the powder spreading device moves from the starting end to the ending end of the powder bed along the feeding direction of the powder spreading. During this process, the powder dropper storing powder A in the two powder droppers works to spread powder A on the surface of the powder bed. At this time, powder A is in a loose state, and the thickness of the first powder layer is 0.5-1.5 mm higher than the forming plane. S12: While spreading the powder, use a powder spreading scraper to compact and flatten the powder A to a compacted plane; S13: While the powder A is being compacted and scraped, the powder absorber on the same side as the back side of the knife accurately removes the compacted powder A, so that the thickness of the first powder layer is reduced to the forming plane.

10. The product preparation method according to claim 8, characterized in that: In step S2, the side of the first printed area facing the feeding direction when spreading powder is called the first windward side, and the side of the first printed area facing away from the feeding direction when spreading powder is called the first leeward side, wherein unmelted residual powder is formed on the same side of the first windward side and the first leeward side respectively.

11. The product preparation method according to claim 10, characterized in that: Step S3 includes: S31: After the first printed area is formed, when the powder spreading device moves from the end end to the starting end of the powder bed, the powder absorber on the same side as the back side of the knife works to remove the unmelted residual powder on the first leeward surface, so that the thickness of the unmelted powder on the first leeward surface is reduced to the powder absorption plane; S32: When the powder spreading device moves from the starting end to the ending end of the powder bed, the powder absorber on the same side as the powder scraping surface works to remove the unmelted residual powder on the first windward surface, so that the thickness of the unmelted powder on the first windward surface is reduced to the powder suction plane, thereby completing the removal of the unmelted residual powder in the first powder layer.

12. The product preparation method according to claim 8, characterized in that: Step S4 includes: S41: the powder spreading device moves from the starting end to the ending end of the powder bed along the feeding direction of the powder spreading. During this process, the powder dropper storing powder B in the two powder droppers works to spread powder B on the surface of the powder bed. At this time, powder B is in a loose state, and the thickness of the second powder layer is 0.5-1.5 mm higher than the forming plane. S42: While spreading the powder, use a powder spreading scraper to compact and flatten the powder B to a compacted plane; S43: While the powder B is being compacted and scraped, the powder absorber on the same side as the back side of the knife in the two powder absorbers accurately removes the compacted powder B, so that the thickness of the second powder layer is reduced to the forming plane.

13. The product preparation method according to claim 8, characterized in that: In step S5, the side of the second printed area facing the feeding direction when spreading powder is the second windward side, and the side of the second printed area facing away from the feeding direction when spreading powder is the second leeward side, wherein unmelted residual powder is formed on the same side of the second windward side and the second leeward side, respectively.

14. The product preparation method according to claim 13, characterized in that: Step S6 includes: S61: After the second printed area is formed, when the powder spreading device moves from the end end to the starting end of the powder bed, the powder absorber on the same side as the back side of the knife works to remove the unmelted residual powder on the second leeward surface, so that the thickness of the unmelted powder on the second leeward surface is reduced to the powder absorption plane; S62: When the powder spreading device moves from the starting end to the ending end of the powder bed, the powder absorber on the same side as the powder scraping surface works to remove the unmelted residual powder on the second windward surface, so that the thickness of the unmelted powder on the second windward surface is reduced to the powder absorption plane, thereby completing the removal of the unmelted residual powder in the first powder layer.

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