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

Abstract

This application belongs to the field of advanced manufacturing technology and discloses an enhanced design and laser selective melting forming method for a porous metal plate. The method comprises constructing a first enveloping cuboid of the porous metal plate model; constructing a second enveloping cuboid within the first enveloping cuboid; constructing a cross-plate unit within the second enveloping cuboid, wherein the cross-plate unit comprises at least four plates parallel to the Z axis, the plates intersecting at the central axis of the second enveloping cuboid and extending radially outward to connect with the inner wall of the second enveloping cuboid; designing a hollow area in the center of the plate to obtain a reinforcing rib plate unit; within the first enveloping cuboid, the reinforcing rib plate unit is replicated along the Y-axis and Z-axis directions to form a reinforcing rib plate array area; performing a Boolean subtraction operation on the reinforcing rib plate array area and the porous metal plate model to obtain a porous metal area, thereby obtaining an enhanced porous metal plate model. Through this application, a porous metal plate with both high mechanical properties and high sweating and cooling performance can be obtained.

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 transpiration cooling technology using porous metals as carriers is considered a key technology for improving the load-bearing and thermal management performance of aerospace equipment and an ideal solution for aircraft to cope with extreme thermal loads. Active transpiration cooling is the active thermal protection technology with the highest theoretical cooling efficiency, and the fabrication of porous metal structures is key to this technology. Traditional porous metal manufacturing processes, such as powder sintering and wire mesh weaving, still have significant limitations. For example, pore parameters cannot be precisely controlled, mechanical properties are poor, and forming complex shapes is difficult, making them difficult to meet the manufacturing requirements of active transpiration cooling components for aerospace equipment. Selective laser melting (SLM), also known as laser selective melting, is an ideal solution for fabricating porous metal structures. The main methods used include digital modeling and parameter control. The parameter control method can form porous metal structures with micron-scale pore sizes suitable for active transpiration cooling. However, existing solutions generally suffer from insufficient mechanical properties and are prone to cracking during the SLM process due to the inability to resist residual stress, making them difficult to meet the requirements of aerospace equipment. Summary of the Invention

[0003] In view of the defects of the existing technology, the purpose of this application is to provide an enhanced design method and a laser selective melting forming method for porous metal plates, mainly to solve the problem that the existing porous metal plates cannot simultaneously have 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:

[0005] S1 constructs a first enveloping cuboid of the porous metal plate model; and constructs a second enveloping cuboid within the first enveloping cuboid;

[0006] S2: constructing a cross plate unit within the second enveloping cuboid, wherein the cross plate unit includes at least four plates parallel to the Z axis, the plates intersecting at the central axis of the second enveloping cuboid and extending radially outward to meet the inner wall of the second enveloping cuboid; a hollow area is designed in the center of the plates to obtain a reinforcing rib plate unit;

[0007] S3, within the first enveloping cuboid, replicating the reinforcing rib unit along the Y-axis direction and the Z-axis direction to form a reinforcing rib array area;

[0008] 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.

[0009] The enhanced design method provided in this application does not require complex 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.

[0010] Furthermore, the positional relationship between the first enveloping cuboid and the second enveloping cuboid satisfies:

[0011] 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];

[0012] 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];

[0013] Among them, X 1max 、Y 1max 、Z 1max are the maximum coordinate values ​​of the first envelope 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; X 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 、Z2min are the minimum coordinate values ​​of the second enveloping cuboid in the X, Y, and Z axis directions respectively.

[0014] 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.

[0015] Furthermore, in step S2, the plate thickness of the reinforcing rib plate unit is 0.2 mm to 1.0 mm.

[0016] Furthermore, in step S2, the hollow area is an axisymmetric shape.

[0017] Furthermore, in step S2, the hollow area is elliptical.

[0018] Furthermore, the distance between the hollow area and each side of the rectangular side surface of the plate body where it is located is the same.

[0019] Furthermore, in step S3, in the X, Y and Z directions, the spacing between the reinforcing rib array area and the first enveloping cuboid is the same.

[0020] According to another aspect of the present application, a method for laser selective melting forming of a porous metal plate is provided, wherein the forming method is performed using a porous metal plate reinforcement model obtained by any of the aforementioned reinforcement design methods, and the forming method comprises:

[0021] S1 sets printing process parameters by partition based on the porous metal plate reinforcement model data;

[0022] S2 performs laser selective melting according to the printing process parameters to obtain a reinforced porous metal flat plate.

[0023] Furthermore, in step S1, the step of setting the printing process parameters in different zones 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.

[0024] Furthermore, the laser scanning interval of the porous metal region is 1.5 to 4 times the width of the corresponding laser cladding line.

[0025] Furthermore, the laser scanning interval of the reinforcing rib array area is 0.5 to 1 times the width of the corresponding laser cladding line.

[0026] In general, the above technical solutions conceived by this application have the following beneficial effects compared with the existing technologies:

[0027] (1) The enhanced design method provided in this application only requires designing 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 for slicing the three-dimensional digital model, and improving printing efficiency.

[0028] (2) The enhanced design method of this application optimizes the key elements such as the geometric characteristics, shape and size, and positional relationship of the enhanced structure. By using the cross plate as the basic unit of the enhanced 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 enhanced structure at the three-dimensional center of the porous metal plate, the uniformity 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.

[0029] (3) In the laser selective melting forming method provided by this application, the continuous heating, melting, cooling and solidification of the metal powder material will generate large residual stresses inside the product. In addition, 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 as a whole. This can share the residual stress during the printing process, thereby significantly reducing the risk of cracking of the porous metal plate and improving printing stability.

[0030] (4) In the laser selective melting forming method provided in the present application, by specially designing the laser scanning spacing of the porous metal flat plate area and the corresponding laser cladding line width, and 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. In this way, an enhanced porous metal flat plate consistent with the design model can be obtained in the laser selective melting forming process, thereby further reducing the difficulty and computational complexity of the porous metal flat plate enhancement design stage. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a schematic flow chart of the enhanced design method for the porous metal plate provided in this application;

[0032] Figure 2 This is a schematic diagram of the first enveloping rectangular parallelepiped structure of the porous metal flat plate model provided in this application;

[0033] Figure 3 This is a schematic diagram of the second envelope cuboid structure provided by this application;

[0034] Figure 4 This is a schematic diagram of a cross-plate unit structure constructed in a second enveloping cuboid provided by the present application;

[0035] Figure 5 This is a schematic diagram of a cross-plate unit provided by the present application, in which an elliptical hollow area is designed on the plate body;

[0036] Figure 6 This is a schematic diagram of the structure of the reinforcement rib array area provided by this application;

[0037] Figure 7 This is a schematic diagram of the porous metal flat plate reinforcement model provided by this application;

[0038] Figure 8 This is a schematic diagram of the SLM process parameter settings provided by this application;

[0039] Figure 9 This is a schematic diagram of layer-by-layer scanning of the laser scanning path provided in this application.

[0040] In all the drawings, the same reference numerals are used to represent the same elements or structures. The structures corresponding to the numbered labels 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

[0041] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to 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.

[0042] This application provides an enhanced design method for porous metal plates, such as Figure 1 As shown, the design method includes the following steps:

[0043] S1 constructs a first enveloping cuboid 1 of a porous metal plate model; and constructs a second enveloping cuboid 2 within the first enveloping cuboid 1;

[0044] S2 constructs a cross plate unit 3 within 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 radially outward 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.

[0045] 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;

[0046] 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.

[0047] The enhanced design method provided in this application does not require complex 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.

[0048] In step S1, a porous metal plate model is first designed in CAD software. This is the original three-dimensional mathematical model of the porous metal plate (hereinafter referred to as the original three-dimensional digital model). This original three-dimensional digital model only requires a solid model containing the product's external shape information, without the need for additional pore structure design. The SLM printing coordinate system is selected as a Cartesian coordinate system. The length direction of the original three-dimensional digital model is set as the SLM printing build direction, which is parallel to the Z axis. The thickness direction of the original three-dimensional digital model is parallel to the X axis, and the width direction of the original three-dimensional digital model is parallel to the Y axis.

[0049] 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 .

[0050] (X 1min ,Y 1min ,Z 1min )、(X 1min ,Y 1min ,Z 1max ), (X 1min ,Y 1max ,Z 1min )、(X1min ,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 envelope cuboid 1 of the original three-dimensional digital model of the porous metal plate, as shown in 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 .

[0051] Then, a second enveloping cuboid 2 is set up inside the first enveloping cuboid 1, as shown in FIG. 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 .

[0052] More specifically, the positional relationship between the first enveloping cuboid 1 and the second enveloping cuboid 2 satisfies:

[0053] (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];

[0054] (2) In the Y-axis direction, Y 1min ≤Y 2min <Y 2max ≤Y 1max , and |Y 1min -Y 2min ∣∈[0,2.0mm];

[0055] (3) In the Z-axis direction, Z 1min ≤Z 2min <Z 2max ≤Z1max , and |Z 1min -Z 2min ∣∈[0,2.0mm].

[0056] In step S2, the specific steps of constructing the cross plate unit 3 in the second envelope cuboid 2 constructed above include: Figure 4 As shown, within 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. 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.

[0057] In other embodiments, the aforementioned cross-plate unit can also be designed as a cross-structure with a 45° angle to the two diagonals of the rectangular projection surface, or designed as an irregular cross-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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] 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 reinforcement rib array area 5 is a linear array. The width of the reinforcement 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.

[0062] In step S4, the relative positional 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 the porous metal plate reinforcement model, which is also used as the printing digital model used in the subsequent SLM process.

[0063] In another embodiment of the present application, a method for laser selective melting forming of a porous metal plate is 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 includes:

[0064] S1 sets the printing process parameters based on the porous metal plate reinforcement model data; that is, the porous metal plate reinforcement model printing data is input into the SLM equipment, and the subsequent printing process parameters are set in different zones;

[0065] S2 performs laser selective melting according to the printing process parameters to obtain a reinforced porous metal flat plate.

[0066] In step S1, the steps of setting the printing process parameters in different zones 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.

[0067] 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, and the laser scanning pitch of the reinforcing rib array region is 0.5 to 1 times the width of the corresponding laser cladding line.

[0068] 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 within 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 8 As 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.

[0069] 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 Figure 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 with a porous structure and a solid reinforcement structure formed in one piece is obtained.

[0070] The above-mentioned solution of this application is introduced below through several specific embodiments.

[0071] Example 1

[0072] 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:

[0073] 1) Design an original 3D digital model of the porous metal plate (hereinafter referred to as the original digital model) in CAD software. The dimensions of the original digital model are 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 build 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.

[0074] 2) Based on 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.

[0075] 3) Set up a second enveloping cuboid 2 inside the first enveloping cuboid 1. The length of the second enveloping cuboid 2 in the X direction is 4mm, the length in the Y direction is 4mm, and the length in the Z direction is 8mm. The positional relationship between the second enveloping cuboid 2 and the first enveloping cuboid 1 in the X-axis direction is |X1max -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.

[0076] 4) Construct a cross plate unit within the second enveloping cuboid 2. Specifically, within 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. 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.

[0077] 5) Design an elliptical hollow shape that runs through the four plates of the cross plate unit 3; the distance between the four vertices of the ellipse and the four edges of the rectangular surface on the plate where it is located is 0.5 mm. Perform a Boolean subtraction operation on the elliptical hollow shape and the cross plate unit 3 to obtain a reinforced rib plate unit that can balance mechanical properties and sweating cooling performance.

[0078] 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 and Z-axis directions to form a reinforcing rib array area. The spacing between the reinforcing rib array area and the adjacent side surfaces of the first enveloping cuboid 1 in the X-direction, Y-direction, and Z-direction is 1 mm.

[0079] 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 a 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.

[0080] 8) For SLM, the pre-laid powder bed thickness was set to 0.05mm. The laser scanning path for the porous metal flatbed digital model was set to parallel within the same powder layer and rotated 90° between adjacent powder layers. Based on basic process testing, the laser cladding line width was 0.12mm. Therefore, the laser scanning spacing was set to 0.3mm for the porous metal area and 0.1mm for the rib array area.

[0081] 9) SLM printing was initiated using GH4169 nickel-based high-temperature alloy. For each powder layer, a pre-set laser scanning path was used to form a dense solid in the reinforcement rib array area and a porous structure in the porous metal area. After layer-by-layer printing, a porous metal flat plate reinforced product with a porous-solid integrated structure was obtained.

[0082] Example 2

[0083] This embodiment provides a SLM forming method for a TA15 titanium alloy porous metal flat plate, which differs from Example 1 in that:

[0084] In step 1), an original digital model of the porous metal plate is designed in CAD software, and the size of the original digital model is 20 mm × 20 mm × 2 mm.

[0085] In step 2), the first envelope cuboid 1 constructed has an X-direction length of 2 mm, a Y-direction length of 20 mm, and a Z-direction length of 20 mm.

[0086] In step 3), the length of the second envelope cuboid 2 is 2mm in the X direction, 2mm in the Y direction, and 4mm in the Z direction. 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 position relationship of the first enveloping cuboid 1 in the Z-axis direction as |Z 1min -Z 2min ∣=0mm, that is, Z 1min The sides overlap.

[0087] In step 4), a cross plate unit 3 is constructed in the second enveloping cuboid 2. Specifically, two straight lines parallel to the diagonals of the rectangular projection surface are designed in the rectangular projection surface of the XY plane of the second enveloping cuboid 2, and the distance between the two straight lines is 0.2 mm. 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. The cross-shaped enclosed area is stretched by 4 mm in the Z direction to obtain the required cross plate unit 3.

[0088] 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, thereby obtaining a reinforced rib plate unit that can take into account both mechanical properties and sweating cooling performance.

[0089] In step 6), the reinforcing rib units in the second enveloping cuboid 2 are replicated along the Y-axis and Z-axis directions within the size range of the first enveloping cuboid 1 to form a linear array of reinforcing rib array areas, 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.

[0090] 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.

[0091] In step 8), the thickness of the powder bed pre-laid during SLM formation was set to 0.03mm. The laser scanning path for the porous metal flatbed digital model was set to parallel the laser scanning tracks within the same powder layer and rotate the laser scanning tracks by 60° between adjacent powder layers. Based on basic process experiments, the laser cladding line width is 0.1mm. Therefore, the laser scanning spacing is set to 0.3mm for the porous metal area and 0.1mm for the reinforcement rib array area.

[0092] 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.

[0093] Example 3

[0094] This embodiment provides a SLM forming method for an AlSi10Mg aluminum alloy porous metal flat plate, which differs from the previous two embodiments in that:

[0095] 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.

[0096] 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.

[0097] In step 3), the length of the second envelope 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 envelope cuboid 2 and the first envelope 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 -Z2min ∣=2mm.

[0098] 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 along the Z direction by a length of 12 mm to form a cross plate unit 3.

[0099] In step 5), an elliptical hollowing is designed on each plate body of the cross plate unit 3, and the distance between the vertex of the ellipse and the rectangular side edge of the plate body on which it is located is 0.6 mm. After a Boolean subtraction operation is performed on the elliptical hollowing 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.

[0100] In step 6), the reinforcing rib elements within the second enveloping cuboid 2 are replicated along the Y and Z axes within the dimensions of the first enveloping cuboid 1 to form a linear array of reinforcing ribs. Each reinforcing rib element has a length of 6 mm in the Y axis and a height of 12 mm in the Z axis. The spacing between the reinforcing structure and each adjacent side surface of the first enveloping cuboid 1 in the X, Y, and Z directions is 2 mm.

[0101] In step 7), the relative positional 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. A Boolean subtraction operation is performed on 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;

[0102] In step 8, the thickness of the powder bed pre-laid during SLM was set to 0.03mm. The laser scanning path for the porous metal flatbed digital model was set to parallel the laser scanning tracks within the same powder layer and rotate the laser scanning tracks 45° between adjacent powder layers. Based on basic process tests, the laser cladding line width was set to 0.1mm. For the porous metal area, the laser scanning spacing was set to 0.3mm; for the reinforced structure, the laser scanning spacing was set to 0.08mm.

[0103] 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 solid 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 a porous-solid integrated structure is obtained.

[0104] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A method for enhancing the design of a porous metal plate, characterized in that: The design method includes: S1 constructs a first enveloping cuboid (1) of a porous metal plate model; and constructs a second enveloping cuboid (2) within 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 in the center of the plate to obtain a reinforcing rib plate unit (4); S3: within the first enveloping cuboid (1), duplicating the reinforcing rib unit (4) 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, wherein: The positional relationship between the first envelope cuboid (1) and the second envelope 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 envelope 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 envelope 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 method for enhancing the design of a porous metal plate according to claim 1, wherein: In step S2, the plate cross direction of the reinforcing rib plate unit (4) coincides with the bottom diagonal direction of the second enveloping cuboid (2).

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

5. The method for enhancing the design of a porous metal plate according to claim 1, wherein: In step S2, the hollow area is in an axisymmetric shape.

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

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

8. The method for enhancing the design of a porous metal plate according to claim 1, wherein: In step S3, in the X, Y and Z directions, the spacing between the reinforcing rib array area (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 sets printing process parameters by partition based on the porous metal plate reinforcement model data; 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, wherein: In step S1, the steps of setting the printing process parameters by zone are 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.

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