Enhanced design method and selective laser melting forming method of porous metal plate

Abstract

The invention belongs to the technical field of advanced manufacturing, and discloses an enhanced design and selective laser melting forming method for a porous metal flat plate, which comprises the following steps: constructing a first enveloping cuboid of a porous metal flat plate model; constructing a second enveloping cuboid in the first enveloping cuboid; a cross plate unit is constructed in the second enveloping cuboid, the cross plate unit comprises at least four plate bodies parallel to the Z axis, and the plate bodies intersect at the center axis of the second enveloping cuboid and extend outwards in a radial mode to be connected with the inner wall of the second enveloping cuboid; designing a hollow area in the center of the plate body to obtain a reinforcing rib plate unit; in the first enveloping cuboid, the reinforcing rib plate units are copied in the Y-axis direction and the Z-axis direction to form reinforcing rib plate array areas; and performing Boolean subtraction on the reinforcing rib plate array area and the porous metal flat plate model to obtain a porous metal area so as to obtain a porous metal flat plate reinforcing model. The porous metal plate with high mechanical property and high sweating and cooling performance can be obtained through the method.

Description

Technical Field

[0001] The present application belongs to the field of advanced manufacturing technology, and specifically relates to an enhanced design of a porous metal plate and a laser selective melting forming method. Background Art

[0002] Active sweating cooling technology with porous metal as carrier is considered to be a key technology to improve the load-bearing and thermal control performance of aerospace equipment and an ideal solution for aircraft to cope with extreme thermal loads. Active sweating cooling technology is the active thermal protection technology with the highest theoretical cooling efficiency, and the preparation of porous metal structures is the key to active sweating cooling technology. Traditional porous metal manufacturing processes mainly include powder sintering, wire mesh weaving, etc., but these traditional manufacturing processes still have obvious limitations, such as the difficulty in accurately controlling pore parameters, poor mechanical properties, and difficulty in forming complex shapes, which are difficult to meet the manufacturing needs of aerospace equipment for active sweating cooling components. Selective Laser Melting (SLM), also known as laser selective melting technology, is an ideal solution for manufacturing porous metal structures. The main methods used are digital modeling and parameter control. The parameter control method can form porous metal structures with micron-level pore sizes suitable for active sweating cooling, but the existing technical solutions generally have the problem of insufficient mechanical properties of porous metal structures and easy cracking during the SLM forming process due to the inability to resist residual stress, which is difficult to meet the requirements of aerospace equipment. Summary of the invention

[0003] In view of the defects of the prior art, the purpose of this application is to provide an enhanced design method and a laser selective melting forming method for a porous metal plate, mainly to solve the problem that the existing porous metal plate cannot have both high mechanical properties and excellent sweating and cooling performance.

[0004] To achieve the above objectives, the present application provides an enhanced design method for a porous metal flat plate, the design method comprising: S1 constructs a first enveloping cuboid of a porous metal plate model; and constructs a second enveloping cuboid in the first enveloping cuboid; S2 constructs a cross plate unit in the second enveloping cuboid, wherein the cross plate unit includes at least four plates parallel to the Z axis, the plates intersect at the central axis of the second enveloping cuboid, and extend radially outward to connect with the inner wall of the second enveloping cuboid; a hollow area is designed in the center of the plate to obtain a reinforcing rib plate unit; S3, within the first enveloping cuboid, duplicating the reinforcing rib unit along the Y-axis direction and the Z-axis direction to form a reinforcing rib array region; S4 performs a Boolean subtraction operation on the reinforcing rib array region and the porous metal plate model to obtain a porous metal region; the reinforcing rib array and the porous metal region together constitute a porous metal plate reinforcement model.

[0005] The enhanced design method provided in the present application does not require complicated processing of the three-dimensional digital model of the porous metal plate. It only requires adding an optimized reinforcing rib array model on the basis of the porous metal plate model. The amount of three-dimensional digital model slicing calculations is greatly reduced, the printing efficiency is improved, and the manufacturing cost is reduced. At the same time, the porous metal plate enhanced model obtained by this design method has greatly improved mechanical properties while taking into account the cooling medium passing performance.

[0006] Furthermore, the positional relationship between the first enveloping cuboid and the second enveloping cuboid satisfies: In the X-axis direction, X 1min ≤X 2min <X 2max ≤X 1max , and |X 1max -X 2max ∣=∣X 1min -X 2min ∣∈[0,2.0mm]; In the Y-axis direction, Y 1min ≤Y 2min <Y 2max ≤Y 1max , and |Y 1min -Y 2min |∈[0,2.0mm]; in the Z-axis direction, Z 1min ≤Z 2min <Z 2max ≤Z 1max , and |Z 1min -Z 2min ∣∈[0,2.0mm]; Among them, X 1max , Y 1max , Z 1max are the maximum coordinate values ​​of the first enveloping cuboid in the X, Y, and Z axis directions, respectively. 1min , Y 1min , Z 1min are the minimum coordinate values ​​of the first enveloping cuboid in the X, Y, and Z axis directions respectively; 2max , Y 2max , Z 2max are the maximum coordinate values ​​of the second envelope cuboid in the X, Y, and Z axis directions, respectively. 2min , Y 2min , Z 2min are the minimum coordinate values ​​of the second enveloping cuboid in the X, Y, and Z axis directions respectively.

[0007] Furthermore, in step S2, the plate cross direction of the reinforcing rib plate unit coincides with the bottom diagonal direction of the second enveloping cuboid.

[0008] Furthermore, in step S2, the plate body thickness of the reinforcing rib plate unit is 0.2 mm to 1.0 mm.

[0009] Furthermore, in step S2, the hollow area is an axisymmetric shape.

[0010] Furthermore, in step S2, the hollow area is elliptical.

[0011] Furthermore, the distance between the hollow area and each side of the rectangular side surface of the plate body where the hollow area is located is the same.

[0012] Furthermore, in step S3, in the X, Y and Z directions, the spacings between the reinforcing rib array area and the first enveloping cuboid are the same.

[0013] According to another aspect of the present application, a laser selective melting forming method for a porous metal plate is also provided, wherein the forming method is performed using a porous metal plate reinforcement model obtained by the reinforcement design method as described in any one of the above, and the forming method comprises: S1, based on the porous metal plate reinforcement model data, setting printing process parameters by partition; S2 performs laser selective melting according to the printing process parameters to obtain a reinforced porous metal flat plate.

[0014] Furthermore, in step S1, the step of setting the printing process parameters by partition is as follows: in the porous metal area, the distance between adjacent laser scanning tracks is set to be greater than the width of the laser cladding line; in the reinforcing rib array area, the distance between adjacent laser scanning tracks is set to be no greater than the width of the laser cladding line.

[0015] Furthermore, the laser scanning interval of the porous metal region is 1.5 to 4 times the width of the corresponding laser cladding line.

[0016] Furthermore, the laser scanning interval of the reinforcing rib array area is 0.5 to 1 times of the corresponding laser cladding line width.

[0017] In general, the above technical solutions conceived by this application have the following beneficial effects compared with the prior art: (1) The enhanced design method provided in the present application only needs to design an optimized reinforcing rib array structure within the porous metal plate model. The reinforcing rib array structure enables the porous metal plate to have excellent mechanical properties. The hollow areas on the porous metal area and the reinforcing rib array structure can jointly ensure that the porous metal plate has high sweating and cooling performance. There is no need to perform complex processing on the three-dimensional digital model of the porous metal plate, so that the porous metal plate can take into account both high mechanical properties and high sweating and cooling performance, further reducing the design difficulty of the three-dimensional digital model of the porous metal plate, greatly reducing the amount of calculation of three-dimensional digital model slicing, and improving printing efficiency.

[0018] (2) The enhanced design method of the present application optimizes key elements such as the geometric features, shape and size, and positional relationship of the enhanced structure. By taking the cross plate as the basic unit of the reinforced structure, adding a hollow area on the plate body, keeping the distance between the hollow area and the rectangular side edge of the plate body the same, and keeping the reinforced structure at the three-dimensional center of the porous metal plate, the uniformity and consistency of each area of ​​the porous metal plate enhanced model is ensured, thereby further improving the stability, load-bearing capacity, and cooling medium penetration capacity of the porous metal plate enhanced model.

[0019] (3) In the laser selective melting forming method provided by this application, since the metal powder material is continuously heated, melted and cooled to solidify, large residual stress will be generated inside the product, and the mechanical properties of the porous metal area on the conventional porous metal plate are poor. These residual stresses will cause the porous metal area to deform or even crack after exceeding the stress limit of the porous metal area, affecting the quality of the porous metal plate. However, this application integrates the porous metal plate model with a special reinforcing rib array structure and uses the laser selective melting forming method to form it in one piece, which can share the residual stress during the printing process, thereby greatly reducing the risk of cracking of the porous metal plate and improving printing stability.

[0020] (4) In the laser selective melting forming method provided in the present application, by specially designing the laser scanning spacing of the porous metal plate area and the corresponding laser cladding line width, and by specially designing the laser scanning spacing of the reinforcing rib array area and the corresponding laser cladding line width, there is no need to perform complex processing of the three-dimensional digital model in the design stage. An enhanced porous metal plate consistent with the design model can be obtained in the laser selective melting forming process, thereby further reducing the difficulty and amount of calculation in the porous metal plate enhancement design stage. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the enhanced design method of the porous metal plate provided in this application; Figure 2 It is a schematic diagram of the first enveloping rectangular parallelepiped structure of the porous metal flat plate model provided in this application; Figure 3 is a schematic diagram of a second envelope cuboid structure provided by the present application; Figure 4 It is a schematic diagram of a cross-plate unit structure constructed in a second enveloping cuboid provided by the present application; Figure 5 It is a schematic diagram of a cross-shaped plate unit provided by the present application, in which an elliptical hollow area is designed on the plate body; Figure 6 It is a schematic diagram of the structure of the reinforcement rib array area provided in this application; Figure 7 It is a schematic diagram of the porous metal flat plate reinforcement model provided in this application; Figure 8 It is a schematic diagram of SLM process parameter settings provided by this application; Fig. 9 This is a schematic diagram of layer-by-layer scanning of the laser scanning path provided in this application.

[0022] In all the drawings, the same figure numbers are used to represent the same elements or structures. The structures corresponding to the digital marks in the drawings are: 1-first enveloping cuboid, 2-second enveloping cuboid, 3-cross plate unit, 4-strengthening rib unit, 5-strengthening rib array area, 6-rectangular projection surface, 7-cross enclosed area, 8-elliptical hollow area, 9-porous metal area, 10-laser scanning track, 11-laser cladding line. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0024] The present application provides an enhanced design method for a porous metal plate, such as Figure 1 As shown, the design method includes the following steps: S1 constructs a first enveloping cuboid 1 of a porous metal plate model; and constructs a second enveloping cuboid 2 in the first enveloping cuboid 1; S2 constructs a cross plate unit 3 in the second enveloping cuboid 2, the cross plate unit 3 includes at least four plates parallel to the Z axis, the plates intersect at the central axis of the second enveloping cuboid 2, and extend outward in a radial shape to connect with the inner wall of the second enveloping cuboid 2; a hollow area is designed in the center of the plate to obtain a reinforcing rib plate unit 4; S3, within the first enveloping cuboid 1, the reinforcing rib unit 4 is replicated along the Y-axis direction and the Z-axis direction to form a reinforcing rib array region 5; S4 performs a Boolean subtraction operation on the reinforcing rib array region 5 and the porous metal plate model to obtain the porous metal region; the reinforcing rib array region and the porous metal region together constitute the porous metal plate reinforcement model.

[0025] The enhanced design method provided in the present application does not require complicated processing of the three-dimensional digital model of the porous metal plate. It only requires adding an optimized reinforcing rib array model on the basis of the porous metal plate model. The amount of three-dimensional digital model slicing calculations is greatly reduced, the printing efficiency is improved, and the manufacturing cost is reduced. At the same time, the porous metal plate enhanced model obtained by this design method has greatly improved mechanical properties while taking into account the cooling medium passing performance.

[0026] In step S1, a porous metal plate model is first designed in CAD software, that is, an original three-dimensional mathematical model of the porous metal plate (hereinafter referred to as the original three-dimensional digital model). The original three-dimensional digital model only needs to design a solid model containing the appearance information of the product, and does not need to additionally design a pore structure. The SLM printing coordinate system is selected as a Cartesian coordinate system, and the length direction of the plate surface of the original three-dimensional digital model is set as the printing construction direction of the SLM, which is parallel to the Z axis, the plate surface thickness direction of the original three-dimensional digital model is parallel to the X axis, and the plate surface width direction of the original three-dimensional digital model is parallel to the Y axis.

[0027] Specifically, the maximum values ​​of the original three-dimensional digital model of the porous metal plate in the X-axis, Y-axis and Z-axis of the SLM printing coordinate system are determined to be X 1max , Y 1max , Z 1max , the minimum values ​​are X 1min , Y 1min , Z 1min .

[0028] (X 1min ,Y 1min ,Z 1min )、(X 1min ,Y 1min ,Z 1max ), (X 1min ,Y 1max ,Z 1min )、(X 1min ,Y 1max ,Z 1max )、(X 1max ,Y 1min ,Z 1min )、(X 1max ,Y 1min ,Z 1max )、(X 1max ,Y 1max ,Z 1min )、(X 1max ,Y 1max,Z 1max ) as the vertex, construct the first enveloping cuboid 1 of the original three-dimensional digital model of the porous metal plate, such as Figure 2 As shown, the length of the first envelope cuboid 1 in the X direction is L1 X , Y direction length L1 Y , Z direction length L1 Z .

[0029] Then, a second enveloping cuboid 2 is set up in the first enveloping cuboid 1, such as Figure 3 As shown, the maximum values ​​of the second envelope cuboid 2 on the X-axis, Y-axis, and Z-axis of the SLM printing coordinate system are X 2max , Y 2max , Z 2max , the minimum values ​​are X 2min , Y 2min , Z 2min .

[0030] More specifically, the positional relationship between the first enveloping cuboid 1 and the second enveloping cuboid 2 satisfies: (1) In the X-axis direction, X 1min ≤X 2min <X 2max ≤X 1max , and |X 1max -X 2max ∣=∣X 1min -X 2min ∣∈[0,2.0mm]; (2) In the Y-axis direction, Y 1min ≤Y 2min <Y 2max ≤Y 1max , and |Y 1min -Y 2min ∣∈[0,2.0mm]; (3) In the Z-axis direction, Z 1min ≤Z 2min <Z 2max ≤Z 1max , and |Z 1min -Z 2min ∣∈[0,2.0mm].

[0031] In step S2, the specific steps of constructing the cross plate unit 3 in the second envelope cuboid 2 constructed above include: Figure 4As shown, in the rectangular projection surface 6 on the XY plane of the second enveloping cuboid 2, two symmetrically distributed and mutually parallel straight line segments are designed on both sides of the diagonal of the rectangular projection surface 6, and the two straight line segments intersect with the edge of the rectangular projection surface to form a hexagonal enclosed area. The spacing between the two straight line segments is between 0.2 mm and 1.0 mm, that is, the plate thickness R of the cross-intersecting plate unit 3 is 0.2 mm to 1.0 mm; then the hexagonal enclosed area 1 is rotated 90° and copied to form a second hexagonal enclosed area, and the cross-intersecting enclosed area 7 formed by the intersection of the two hexagonal enclosed areas is stretched L2 in the Z direction. Z After the length of Figure 4 The three-dimensional cross plate unit 3 is shown in the middle right figure.

[0032] In other embodiments, the aforementioned cross-plate unit can also be designed as a cross-shaped structure with an angle of 45° to the two diagonals of the rectangular projection surface, or designed as an irregular cross-shaped structure with other angles to the two diagonals of the rectangular projection surface. However, the stability of this type of cross-plate reinforcement structure is not as strong as the cross-plate unit designed along the diagonals of the rectangular projection surface, and the mechanical properties are poor.

[0033] The aforementioned cross plate unit 3 actually includes four centrosymmetrical plates, and the edge of each plate is connected to the second enveloping cuboid 2. In this embodiment, the edge of the cross plate unit 3 away from its central axis is a wedge-shaped edge, and the wedge-shaped edge matches the angle between the two side surfaces of the second enveloping cuboid.

[0034] Then, an elliptical hollow area 8 is designed on the rectangular surface where each side of the plate is located, which runs through the plate. Figure 5 As shown, the distances between the four vertices of the elliptical hollow area 8 and the four sides of the rectangular surface where it is located are the same, that is, d1=d2=d3=d4, and the distances are between 0.2mm and 1.0mm; a Boolean subtraction operation is performed on the elliptical hollow area and the cross-plate unit to obtain a reinforced rib plate unit 4 that can take into account both mechanical properties and sweating cooling performance.

[0035] In other embodiments, the hollow area may also be other regular or irregular shapes, such as circular, rectangular, polygonal or special shapes, but the uniformity of the reinforcing rib plate units corresponding to these shapes is not as good as the cross plate with an elliptical hollow area.

[0036] In step S3, within the size range of the first enveloping cuboid 1, the reinforcing rib plate unit in the second enveloping cuboid 2 is copied along the Y-axis direction and the Z-axis direction respectively to form Figure 6 The reinforcing rib array area 5 is a linear array. The width of the reinforcing rib array area 5 in the X-axis direction is L2 X， The length of the Y-axis reinforcement rib array area is L2 Y, the height in the Z-axis direction is L2 Z The spacing between the reinforcing rib array region 5 and the adjacent side surfaces of the first enveloping cuboid 1 in the X direction, the Y direction and the Z direction is the same, specifically within the range of 0 mm to 2.0 mm.

[0037] In step S4, the relative position relationship between the reinforcing rib array area and the first enveloping cuboid 1 is maintained, and the reinforcing rib array area is integrated into the original three-dimensional digital model of the porous metal plate; specifically, a Boolean subtraction operation is performed between the reinforcing rib array area and the original three-dimensional digital model of the porous metal plate to obtain a porous metal area 9 without the reinforcing rib array area (the gray dots in the figure are the pores actually generated in the subsequent printing process). The porous metal area 9 and the reinforcing rib array area 5 together constitute a porous metal plate reinforcement model, which is also used as a printing digital model used in the subsequent SLM process.

[0038] In another embodiment of the present application, a laser selective melting forming method for a porous metal plate is also provided. The forming method is performed using a porous metal plate enhanced printed digital model obtained by the enhanced design method in any of the aforementioned embodiments. The forming method comprises: S1 sets the printing process parameters by partition based on the porous metal plate reinforcement model data; that is, the porous metal plate reinforcement model printing data is input into the SLM device, and the subsequent printing process parameters are set by partition; S2 performs laser selective melting according to the printing process parameters to obtain a reinforced porous metal flat plate.

[0039] In step S1, the steps of setting the printing process parameters by partition are as follows: in the porous metal area 9, the distance H between adjacent laser scanning tracks is set to be greater than the width D of the laser cladding line; in the reinforcing rib array area 5, the distance Hs between adjacent laser scanning tracks is set to be no greater than the width D of the laser cladding line.

[0040] Specifically, the laser scanning pitch of the porous metal region 9 is 1.5 to 4 times the width of the corresponding laser cladding line. The laser scanning pitch of the reinforcing rib array region is 0.5 to 1 times the width of the corresponding laser cladding line.

[0041] In step S2, the thickness of the powder bed pre-laid layer by layer during SLM forming is selected to be within 0.02mm~0.2mm, and the laser scanning path of the porous metal flat plate printing digital model is set to: the laser scanning tracks 10 are parallel to each other in the same powder layer; the laser scanning tracks 10 are fixedly rotated 0°~180° between adjacent powder layers, such as 180°, 90°, 45°, etc., or any angle between any two of the above angle values. According to basic process tests, such as Figure 8As shown, the width D of the laser cladding line 11 is 0.12 mm, so for the porous metal area 9, the laser scanning spacing H is set to 0.3 mm; for the reinforcing rib array area 5, the laser scanning spacing Hs is set to 0.1 mm.

[0042] Specifically, SLM printing is started using commonly used additive manufacturing metal powders such as nickel-based high-temperature alloys, titanium alloys, and aluminum alloys, combined with Fig. 9 As shown, for N powder layers, a pre-set laser scanning path is used to scan layer by layer, so that the reinforcing rib array area 5 is formed into a dense entity, and the porous metal area 9 is formed into a porous structure. By printing layer by layer according to the porous metal flat plate reinforcement model, a porous metal flat plate reinforced product in which the porous structure and the solid reinforcement structure are integrated is obtained.

[0043] The above-mentioned solution of the present application is introduced below through several specific embodiments.

[0044] Example 1 This embodiment provides a SLM forming method for a GH4169 nickel-based high-temperature alloy porous metal flat plate, which specifically includes the following steps: 1) Design the original three-dimensional digital model of the porous metal plate (hereinafter referred to as the original digital model) in the CAD software. The size of the original digital model is 42 mm × 42 mm × 6 mm. The SLM printing coordinate system is selected as the Cartesian coordinate system. The height direction of the original digital model is set as the SLM printing construction direction, which is parallel to the Z axis. The thickness direction of the original digital model is parallel to the X axis, and the length direction of the original digital model is parallel to the Y axis.

[0045] 2) According to the original digital model of the porous metal plate, a first enveloping cuboid 1 of the original three-dimensional digital model of the porous metal plate is constructed in the SLM printing coordinate system. The length of the first enveloping cuboid 1 in the X direction is 6 mm, the length in the Y direction is 42 mm, and the length in the Z direction is 42 mm.

[0046] 3) A second enveloping cuboid 2 is set up inside the first enveloping cuboid 1. The length of the second enveloping cuboid 2 in the X direction is 4 mm, the length in the Y direction is 4 mm, and the length in the Z direction is 8 mm. The positional relationship between the second enveloping cuboid 2 and the first enveloping cuboid 1 in the X-axis direction is |X 1max -X 2max ∣=∣X 1min -X 2min ∣=1mm, the positional relationship with the first enveloping cuboid 1 in the Y-axis direction is ∣Y 1min -Y 2min ∣=1mm, the positional relationship with the first enveloping cuboid 1 in the Z-axis direction is ∣Z 1min -Z 2min ∣=1mm.

[0047] 4) Construct a cross plate unit in the second enveloping cuboid 2, specifically: in the rectangular projection surface on the XY plane of the second enveloping cuboid 2, design two straight line segments parallel to one of the diagonals of the rectangular projection surface and with a spacing of 0.4 mm, the two straight line segments intersect with the edge of the rectangular projection surface to form a hexagonal enclosed area, the hexagonal enclosed area is rotated 90° to form a second hexagonal enclosed area, and the cross shape formed by the two hexagonal enclosed areas is stretched 8 mm in the Z direction to obtain a cross plate unit 3.

[0048] 5) An elliptical hollow shape is designed on the four plates of the cross plate unit 3 that penetrates the plate body; the distance between the four vertices of the ellipse and the four sides of the rectangular surface of the plate body where it is located is 0.5 mm. A Boolean subtraction operation is performed between the elliptical hollow shape and the cross plate unit 3 to obtain a reinforced rib plate unit that can take into account both mechanical properties and sweating cooling performance.

[0049] 6) Within the size range of the first enveloping cuboid 1, the reinforcing rib units in the second enveloping cuboid 2 are replicated along the Y-axis direction and the Z-axis direction to form a reinforcing rib array area, and the spacing between the reinforcing rib array area and the adjacent side surfaces of the first enveloping cuboid 1 in the X-direction, the Y-direction and the Z-direction is 1 mm.

[0050] 7) Maintaining the relative positional relationship between the reinforcing rib array region and the first enveloping cuboid 1, integrating the reinforcing rib array region into the original three-dimensional digital model of the porous metal plate, performing Boolean subtraction operation on the reinforcing rib array region and the original three-dimensional digital model of the porous metal plate, and obtaining a porous metal region without a reinforcing structure; the porous metal region data and the reinforcing rib array region data together constitute the printed digital model of the porous metal plate.

[0051] 8) When SLM forming is selected, the thickness of the pre-laid powder bed layer by layer is 0.05mm, and the laser scanning path of the porous metal flat plate printing digital model is set as follows: the laser scanning tracks in the same powder layer are parallel to each other; the laser scanning tracks between adjacent powder layers are fixedly rotated 90°. According to the basic process test, the width of the laser cladding line is 0.12mm. Therefore, for the porous metal area, the laser scanning spacing is set to 0.3mm; for the reinforcing rib array area, the laser scanning spacing is set to 0.1mm.

[0052] 9) Use GH4169 nickel-based high-temperature alloy to start SLM printing. For each powder layer, a pre-set laser scanning path is used to form a dense entity in the reinforcement rib array area and a porous structure in the porous metal area. After printing layer by layer, a porous metal flat plate reinforced product with porous-solid integrated formation is obtained.

[0053] Example 2 This embodiment provides a SLM forming method for a TA15 titanium alloy porous metal flat plate, which is different from Embodiment 1 in that: In step 1), the original digital model of the porous metal plate is designed in the CAD software, and the size of the original digital model is 20 mm×20 mm×2 mm.

[0054] In step 2), the first envelope cuboid 1 constructed has a length of 2 mm in the X direction, 20 mm in the Y direction, and 20 mm in the Z direction.

[0055] In step 3), the length of the second envelope cuboid 2 in the X direction is 2 mm, the length in the Y direction is 2 mm, and the length in the Z direction is 4 mm. The second envelope cuboid 2 overlaps with the first envelope cuboid 1 in the X-axis direction, and the position relationship with the first envelope cuboid 1 in the Y-axis direction is |Y 1min -Y 2min ∣=0, that is, with Y 1min The side surface where it is located coincides with the side surface where it is located, and the position relationship with the first enveloping cuboid 1 in the Z-axis direction is |Z 1min -Z 2min ∣=0mm, that is, Z 1min The sides overlap.

[0056] In step 4), a cross plate unit 3 is constructed in the second enveloping cuboid 2, specifically: in the rectangular projection surface of the XY plane of the second enveloping cuboid 2, two straight lines parallel to the diagonals of the rectangular projection surface are designed, and the interval between the two straight lines is 0.2 mm, and the hexagonal enclosed area formed by the intersection of the two straight lines and the edge of the rectangular projection surface is rotated 90° to obtain a cross shape, and the cross-shaped enclosed area is stretched by 4 mm in the Z direction to obtain the required cross plate unit 3.

[0057] In step 5), an elliptical hollow shape is designed on the plate body of the cross plate unit 3, and the distance between the vertex of the ellipse and the rectangular surface of the plate body is 0.2 mm, and a reinforced rib plate unit that can take into account both mechanical properties and sweating cooling performance is also obtained.

[0058] In step 6), within the size range of the first enveloping cuboid 1, the reinforcing rib units in the second enveloping cuboid 2 are replicated along the Y-axis direction and the Z-axis direction to form a reinforcing rib array area in a linear array, and each reinforcing rib unit has a length of 2 mm in the Y-axis direction and a height of 4 mm in the Z-axis direction.

[0059] In step 7), the same steps as in Example 1 are repeated to obtain a porous metal region without a reinforcement structure through Boolean subtraction operation; the porous metal region data and the reinforcement rib array region data together constitute a porous metal flat plate printing digital model.

[0060] In step 8), the thickness of the powder bed pre-laid layer by layer during SLM forming is selected to be 0.03mm, and the laser scanning path of the porous metal flat plate printing digital model is set to: the laser scanning tracks in the same powder layer are parallel to each other; the laser scanning tracks between adjacent powder layers are fixedly rotated by 60°. According to the basic process test, the width of the laser cladding line is 0.1mm, so the laser scanning spacing of the porous metal area is set to 0.3mm, and the laser scanning spacing of the reinforcing rib array area is set to 0.1mm; In step 9), TA15 alloy is used to start SLM printing, and finally a porous metal flat plate reinforced product with porous-solid integrated formation is obtained.

[0061] Example 3 This embodiment provides a SLM forming method of an AlSi10Mg aluminum alloy porous metal flat plate, which is different from the previous two embodiments in that: In step 1), an original three-dimensional digital model of the porous metal plate is designed in CAD software, and the size of the original digital model is 100 mm×100 mm×10 mm.

[0062] In step 2), the length of the first envelope cuboid 1 in the X direction is designed to be 10 mm, the length in the Y direction is 100 mm, and the length in the Z direction is 100 mm.

[0063] In step 3), the length of the second enveloping cuboid 2 in the X direction is 6 mm, the length in the Y direction is 6 mm, and the length in the Z direction is 12 mm; the positional relationship between the second enveloping cuboid 2 and the first enveloping cuboid 1 in the X-axis direction is |X 1max -X 2max ∣=∣X 1min -X 2min ∣=2mm, the positional relationship with the first enveloping cuboid 1 in the Y-axis direction is ∣Y 1min -Y 2min ∣=2mm, the positional relationship with the first enveloping cuboid 1 in the Z-axis direction is ∣Z 1min -Z 2min ∣=2mm.

[0064] In step 4), the cross shape constructed along the diagonal direction of the rectangular projection surface of the XY plane in the second envelope cuboid 2 is stretched in the Z direction by a length of 12 mm to form a cross plate unit 3.

[0065] In step 5), an elliptical hollow is designed on each plate of the cross plate unit 3, and the distance between the vertex of the ellipse and the rectangular side edge of the plate body is 0.6 mm. After Boolean subtraction operation is performed on the elliptical hollow shape and the cross plate unit, a reinforced rib plate unit is obtained that can also take into account both mechanical properties and sweating cooling performance.

[0066] In step 6), the reinforcing rib plate units in the second enveloping cuboid 2 are replicated in the Y-axis direction and the Z-axis direction within the size range of the first enveloping cuboid 1 to form a linear array of reinforcing rib plate array areas. The length of each reinforcing rib plate unit in the Y-axis direction is 6 mm, and the height in the Z-axis direction is 12 mm. The spacing between the reinforcing structure and each adjacent side surface of the first enveloping cuboid 1 in the X-direction, the Y-direction, and the Z-direction is 2 mm.

[0067] In step 7), the relative position relationship between the reinforcement structure and the first envelope cuboid 1 is maintained, and the reinforcement rib array region is integrated into the original three-dimensional digital model of the porous metal plate, and a Boolean subtraction operation is performed between the reinforcement rib array region and the original three-dimensional digital model of the porous metal plate to obtain a porous metal region without the reinforcement structure; the porous metal region and the reinforcement rib array region together constitute the printed digital model of the porous metal plate; In step 8), the thickness of the powder bed pre-laid layer by layer during SLM forming is selected to be 0.03mm, and the laser scanning path of the porous metal flat plate printing digital model is set to: the laser scanning tracks in the same powder layer are parallel to each other, and the laser scanning tracks between adjacent powder layers are fixedly rotated 45°. According to the basic process test, the width of the laser cladding line is 0.1mm; for the porous metal area, the laser scanning spacing is set to 0.3mm; for the reinforced structure, the laser scanning spacing is set to 0.08mm.

[0068] In step 9), AlSi10Mg aluminum alloy is used for SLM printing. For each powder layer, a pre-set laser scanning path is used to form a dense entity in the reinforced structure area, and a porous metal structure is formed in the porous metal area. After printing layer by layer, a porous metal flat plate reinforced product with porous-solid integrated formation is obtained.

[0069] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for enhancing the design of a porous metal plate, characterized in that: The design method comprises: S1 constructs a first enveloping cuboid (1) of a porous metal plate model; and constructs a second enveloping cuboid (2) in the first enveloping cuboid (1); S2 constructs a cross plate unit (3) in the second enveloping cuboid (2), wherein the cross plate unit (3) comprises at least four plates parallel to the Z axis, the plates intersecting at the central axis of the second enveloping cuboid (2) and extending radially outwards to connect with the inner wall of the second enveloping cuboid (2); a hollow area is designed at the center of the plate to obtain a reinforcing rib plate unit (4); S3: within the first enveloping cuboid (1), the reinforcing rib unit (4) is replicated along the Y-axis direction and the Z-axis direction to form a reinforcing rib array region (5); S4 performs a Boolean subtraction operation on the reinforcing rib array region (5) and the porous metal plate model to obtain a porous metal region; the reinforcing rib array region (5) and the porous metal region together constitute a porous metal plate reinforcement model.

2. The method for enhancing the design of a porous metal plate according to claim 1, characterized in that: The positional relationship between the first enveloping cuboid (1) and the second enveloping cuboid (2) satisfies: In the X-axis direction, X 1min ≤X 2min <X 2max ≤X 1max , and |X 1max -X 2max ∣=∣X 1min -X 2min ∣∈[0,2.0mm]; In the Y-axis direction, Y 1min ≤Y 2min <Y 2max ≤Y 1max , and |Y 1min -Y 2min |∈[0,2.0mm]; in the Z-axis direction, Z 1min ≤Z 2min <Z 2max ≤Z 1max , and |Z 1min -Z 2min ∣∈[0,2.0mm]; Among them, X 1max , Y 1max , Z 1max are the maximum coordinate values ​​of the first enveloping cuboid (1) in the X, Y, and Z axis directions, respectively. 1min , Y 1min , Z 1min are the minimum coordinate values ​​of the first enveloping cuboid (1) in the X, Y, and Z axis directions respectively; 2max , Y 2max , Z 2max are the maximum coordinate values ​​of the second enveloping cuboid (2) in the X, Y, and Z axis directions, respectively. 2min , Y 2min , Z 2min are the minimum coordinate values ​​of the second enveloping cuboid (2) in the X, Y and Z axis directions respectively.

3. The enhanced design method of the porous metal plate according to claim 1, characterized in that: In step S2, the plate body intersection direction of the reinforcing rib plate unit (4) coincides with the bottom surface diagonal direction of the second enveloping cuboid (2).

4. The method for enhancing the design of a porous metal plate according to claim 1, characterized in that: In step S2, the plate body thickness of the reinforcing rib plate unit (4) is 0.2 mm to 1.0 mm.

5. The enhanced design method of the porous metal plate according to claim 1, characterized in that: In step S2, the hollow area is an axisymmetric shape.

6. The method for enhancing the design of a porous metal plate according to claim 5, characterized in that: In step S2, the hollow area is elliptical.

7. The method for enhancing the design of a porous metal plate according to claim 5, characterized in that: The distance between the hollow area and each side of the rectangular side surface of the plate body where the hollow area is located is the same.

8. The method for enhancing the design of a porous metal plate according to claim 1, characterized in that: In step S3, in the X, Y and Z directions, the spacing between the reinforcing rib array (5) and the first enveloping cuboid (1) is the same.

9. A method for forming a porous metal plate by laser selective melting, characterized in that: The forming method is performed using a porous metal flat plate reinforcement model obtained by the reinforcement design method according to any one of claims 1 to 8, and the forming method comprises: S1, based on the porous metal plate reinforcement model data, setting printing process parameters by partition; S2 performs laser selective melting according to the printing process parameters to obtain a reinforced porous metal flat plate.

10. The forming method according to claim 9, characterized in that: In step S1, the step of setting the printing process parameters by partition is as follows: in the porous metal area, the distance between adjacent laser scanning tracks is set to be greater than the width of the laser cladding line; in the reinforcing rib array area, the distance between adjacent laser scanning tracks is set to be no greater than the width of the laser cladding line; and / or, the laser scanning spacing in the porous metal flat plate area is 1.5 to 4 times the width of the corresponding laser cladding line; and / or, the laser scanning spacing in the reinforcing rib array area is 0.5 to 1 times the width of the corresponding laser cladding line.

Images