Laser additive manufacturing method for thin-wall three-period minimal curved surface lattice structure

Abstract

The invention discloses a thin-wall three-period minimal curved surface lattice structure laser additive manufacturing method, which relates to the field of additive manufacturing, and comprises the following steps: (1) according to a three-period minimal curved surface implicit function and additive manufacturing layer thickness, obtaining a single-channel contour path of each layer through direct slicing; (2) generating parallel filling lines in each layer, and intersecting the parallel filling lines with the combination of the contour paths of the layer and the higher layer; (3) combining every two intersection points to form a line segment, and taking the line segment as a filling path if sampling points of the line segment meet the conditions of a functional expression, an inclination angle and a length; (4) taking the filling path of the layer as a supporting layer, and moving the filling path upwards by one layer to form a filling layer; and (5) all the paths are input into additive manufacturing equipment, and different machining parameters are set for manufacturing. The laser path of the thin-wall three-period minimal curved surface lattice structure can be efficiently generated, only one melting channel is contained in the thickness direction of the structure, the wall thickness is smaller than 200 micrometers, and the cavity defect generated in the slicing process can be overcome.

Description

Technical Field

[0001] The present invention relates to the field of additive manufacturing, and in particular to a laser additive manufacturing method for a thin-wall three-periodic minimal surface lattice structure. Background Art

[0002] Additive manufacturing is one of the important fields of advanced manufacturing. Its "layered manufacturing, layer-by-layer stacking" molding method liberates the freedom of part manufacturing. It has unique advantages in the molding of complex geometric models and can realize many structures that are difficult to form with traditional manufacturing processes. In the process of implementing additive manufacturing technology, slicing the model to form the tool head path is one of the important steps in the pre-processing of additive manufacturing data.

[0003] The three-periodic minimal surface is continuous, smooth and has a large specific surface area. It is often used as a lattice structure to fill the inside of parts, so that the parts have excellent properties of light weight, high strength and good heat dissipation. In the industrial field, the large specific surface area makes it increasingly widely used in parts such as heat exchangers. At the same time, the development of additive manufacturing has also made it possible to form this complex structural model.

[0004] Currently, the common method of generating slicing paths for additive manufacturing is to export the three-dimensional model of the part into STL format, and then use special slicing software to convert it into a printing task file containing information such as paths and parameters. However, this solution has certain limitations: additive manufacturing demonstrates its advantages in the manufacture of complex parts. For complex lattice structures such as three-periodic minimal surfaces, they often have the common characteristics of complex internal structure and large specific surface area. The number of triangular facets in the STL file is positively correlated with the surface area of ​​the part, resulting in a large number of triangular facets that need to be stored in the STL file of complex parts. The part geometry design and path generation process require extremely high processing time and memory usage. In addition, STL model slicing often results in a closed contour surrounding the part, making it difficult to form a single-channel scanning path for an open surface, which limits the minimum wall thickness of additively manufactured micro-scale thin-walled parts.

[0005] After investigation, existing research mainly uses direct slicing technology to avoid the accuracy, efficiency and memory bottlenecks brought by STL models in the process of slicing complex parts, including explicit modeling direct slicing such as CAD direct slicing, point cloud direct slicing and other technologies, as well as discrete volume data direct slicing, implicit function direct slicing and other technologies. Three-periodic minimal surfaces can be directly represented by implicit function analytical expressions, and implicit function direct slicing can effectively improve slicing efficiency. Existing research has conducted extensive research on implicit function direct slicing of three-periodic minimal surfaces, but there are still the following limitations: 1. Existing research generally uses variant F 2 =C 2(where F is the implicit function of the three-periodic minimal surface, and C is a constant that controls the wall thickness of the model) is used to generate a three-periodic minimal surface model with a certain wall thickness, and the solid area is scanned. However, the wall thickness of the structure processed by this method exceeds the width of the double-pass molten pool and fails to reach the processing limit of the single-pass molten pool width; 2. For the existing single-pass scanning research on three-periodic minimal surfaces, hole defects will appear when the unit cell size exceeds 5mm, which will seriously affect the quality and performance of the parts.

[0006] Therefore, technicians in this field are committed to developing a laser additive manufacturing method for a thin-walled three-periodic minimal surface lattice structure. Summary of the invention

[0007] In view of the above-mentioned defects of the prior art, the technical problem to be solved by the present invention is that the three-periodic minimal surface lattice structure model currently used for additive manufacturing fails to reach the processing limit of the single-channel molten pool width, the slicing method has high memory occupancy and time consumption, low processing efficiency, and hole defects occur when the model unit cell size exceeds 5mm.

[0008] To achieve the above object, the present invention provides a laser additive manufacturing method for a thin-walled three-periodic minimal surface lattice structure, the method comprising the following steps:

[0009] Step 1: According to the implicit function model expression F(x, y, z)=0 of the three-periodic minimal surface and the layer thickness adapted to the laser selective melting additive manufacturing equipment, the single-channel contour path of each layer is obtained by direct slicing;

[0010] Step 2: traverse each layer of plane, generate a series of parallel fill lines according to the set fill line spacing value, and intersect the combination of the parallel fill lines, the contour path of this layer, and the contour path of a higher layer;

[0011] Step 3: The obtained intersection points are combined in pairs to form line segments. Sampling points are taken in each line segment. If the functional expression and the inclination angle requirements are met at the same time and the line segment length is greater than the set threshold, the line segment is retained as the filling path.

[0012] Step 4: The filling path of the layer is used as a support layer, and it is moved up one layer to form a filling layer, and different process parameters are set for the support layer and the filling layer to optimize the filling effect;

[0013] Step 5: Generate a path file recognizable by the additive manufacturing device based on the contour path and the filling path, input it into the additive manufacturing device, set processing parameters, and perform manufacturing.

[0014] Furthermore, the specific process of step 1 is: traverse the planes perpendicular to the z-axis at each height of the model according to the layer thickness information, and obtain the contour lines of the implicit function model F(x, y, z) = 0 in each plane as a single-channel contour scanning path. This process is called direct slicing.

[0015] The three-periodic minimal surface in step 1 is a Gyroid surface, a Primitive surface or a Diamond surface. The implicit function expression of the Gyroid surface is F(x, y, z) = sin(2πx / L)·cos(2πy / L)+sin(2πy / L)·cos(2πz / L)+sin(2πz / L)·cos(2πx / L)=0. The implicit function expression is F(x,y,z)=cos(2πx / L)+cos(2πy / L)+cos(2πz / L)=0; the implicit function expression of the Diamond surface is F(x,y,z)=sin(2πx / L)·sin(2πy / L)·sin(2πz / L)+sin(2πx / L)·cos(2πy / L)·cos(2πz / L)+cos(2πx / L)·sin(2πy / L)·cos(2πz / L)+cos(2πx / L)·cos(2πy / L)·sin(2πz / L)=0, where L is the unit cell size.

[0016] Furthermore, the unit cell size L is set to 5-30 mm, the thickness of the slice layer is set to 0.03-0.05 mm, and the parallel filling line spacing value is set to 0.03-0.2 mm.

[0017] Furthermore, the step 3 specifically comprises combining the obtained intersection points in pairs to form line segments. If the sampling point (x0, y0) taken in each line segment satisfies the function relationship F(x0, y0, z n )·F(x0,y0,z n+1 )<0, and the model inclination angle θ0 at this point satisfies cosθ0>c, and the length of the line segment is greater than the set value, then the line segment is retained as the filling path; where z n 、z n+1 It represents the z height of the nth and n+1th layers, and c is the set tilt angle cosine threshold.

[0018] Furthermore, the set value of the line segment length is set to 0.03-0.1 mm, and the set inclination angle cosine threshold c is set to 0.75-0.9.

[0019] Furthermore, the step 4 specifically comprises forming a support layer in the same area with the same path and different processing parameters before filling the void.

[0020] Furthermore, the step 5 specifically writes the contour path and the fill path into a path file recognizable by the laser selective melting device according to the standard format of the file, the format of the path file is CLI or SLC format, and the contour path and the fill path are written into different files respectively to distinguish the parameters such as processing power and scanning speed.

[0021] Furthermore, the thin-walled structure manufactured by the method contains only one melt path in the thickness direction, and the wall thickness is less than 200 microns.

[0022] Furthermore, the format of the path file is CLI format, the powder material used is 17-4PH stainless steel, the contour path laser power is 135W, and the scanning speed is 400mm / s; the filling layer path laser power is 135W, and the scanning speed is 300mm / s; the support layer laser power is 60W, and the scanning speed is 1520mm / s.

[0023] Furthermore, the format of the path file is SLC format, the powder material used is Ti6Al4V titanium alloy, the contour path laser power is 280W, and the scanning speed is 1200mm / s; the filling layer path laser power is 200W, and the scanning speed is 1000mm / s; the support layer laser power is 100W, and the scanning speed is 2000mm / s.

[0024] Furthermore, the format of the path file is CLI format, the powder material used is AlSi10Mg aluminum alloy, the contour path laser power is 350W, and the scanning speed is 1150mm / s; the filling layer path laser power is 350W, and the scanning speed is 1000mm / s; the support layer laser power is 200W, and the scanning speed is 2000mm / s.

[0025] The three-periodic minimal surface lattice structure has the advantages of light weight, high specific stiffness, high specific strength, high surface area, and multifunctionality. It has great application potential in the fields of aerospace, medical treatment, etc. At present, such complex structures are mainly manufactured by additive manufacturing technology. The present invention can efficiently form a laser selective melting processing path for a thin-walled three-periodic minimal surface lattice structure. The manufactured structure contains only one melt path in the thickness direction and can fill the void area generated during the slicing process, thereby realizing efficient and high-quality additive manufacturing of large lightweight lattice structures.

[0026] Compared with the prior art, the present invention has the following beneficial technical effects:

[0027] 1. The present invention proposes a path generation and additive manufacturing method based on single-channel scanning and direct slicing. According to the implicit function model expression F(x, y, z) = 0 of the three-periodic minimal surface and the layer thickness adapted to the additive manufacturing equipment, a direct slicing algorithm is developed to directly generate the single-channel contour path file of each layer, input the laser selective melting additive manufacturing equipment, and set the processing parameters for manufacturing. On the one hand, the wall thickness direction of the three-periodic minimal surface lattice structure manufactured by the formed path is only the width of the single-channel molten pool, which can achieve a thinner wall thickness, thereby increasing the specific surface area and reducing the weight; on the other hand, compared with STL model slicing, it can greatly reduce the time and memory usage of the slicing process, and can efficiently process large-scale lattice structure models. Compared with existing methods, the method used to manufacture three-periodic minimal surface lattice structures can greatly reduce path generation time and memory usage, and the computational efficiency is improved by more than an order of magnitude compared with STL slicing; the manufactured lattice structure has a thinner wall thickness of less than 200 microns, which is close to the processing limit of laser selective melting equipment; the manufactured three-periodic minimal surface lattice structure has broad application prospects in the field of lightweight multifunctional structures.

[0028] 2. The present invention proposes a thin-walled three-period minimal surface void filling method based on parallel filling, which determines the void area according to the surface inclination angle and the scanning path of the adjacent two layers, and generates a filling path in the void area according to the surface function, the inclination angle and the filling line segment length criterion, which can achieve the filling of the void area generated during the slicing process of the thin-walled three-period minimal surface lattice structure, and greatly reduce the void defects in the additive manufacturing process. In addition, the additive manufacturing of large-size unit cell thin-walled three-period minimal surface lattice structure can be realized, which solves the problem that when the model unit cell size exceeds 5mm in the existing three-period minimal surface single-pass scanning research, the void defect will appear, affecting the quality and performance of the product.

[0029] The concept, specific structure and technical effects of the present invention will be further described below in conjunction with the accompanying drawings to fully understand the purpose, characteristics and effects of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a flow chart of the laser selective melting additive manufacturing method of the thin-wall three-period minimal surface lattice structure of the present invention;

[0031] Figure 2 is a schematic diagram of a gyroid lattice structure model (left) for slicing and its slicing contour path (right) in Example 1 of the present invention;

[0032] Figure 3 Schematic diagram of the reason why a hollow area is generated in a slice in Embodiment 1 of the present invention;

[0033] Figure 4It is a schematic diagram of the intersection of a filling line and a combination of two adjacent layers of contour paths in Example 1 of the present invention;

[0034] Figure 5 is a schematic diagram of the nth layer contour path and the support layer path in Example 1 of the present invention;

[0035] Figure 6 is a schematic diagram of the n+1th layer contour path and the filling layer path in Example 1 of the present invention;

[0036] Figure 7 Schematic diagram of a part manufactured according to a path file in Example 1 of the present invention (unit cell size is 5 mm), (left) a thin-walled three-periodic minimal surface formed by additive manufacturing without adding a filling path, (right) a thin-walled three-periodic minimal surface formed by additive manufacturing with adding a filling path;

[0037] Figure 8 Schematic diagram of a part manufactured according to a path file in Example 1 of the present invention (unit cell size is 10 mm), (left) a thin-walled three-periodic minimal surface formed by additive manufacturing without adding a filling path, (right) a thin-walled three-periodic minimal surface formed by additive manufacturing with adding a filling path;

[0038] Fig. 9 is a schematic diagram of a primitive lattice structure model for slicing in Example 2 of the present invention;

[0039] Fig.10 This is a schematic diagram of the contour path obtained by slicing the primitive lattice structure model in Example 2 of the present invention;

[0040] Fig.11 is a schematic diagram of the nth layer contour path and the support layer path in Example 2 of the present invention;

[0041] Fig.12 is a schematic diagram of the n+1th layer contour path and the filling layer path in Embodiment 2 of the present invention;

[0042] Fig.13 is a schematic diagram of a diamond lattice structure model for slicing in Example 3 of the present invention;

[0043] Fig.14 This is a schematic diagram of the contour path obtained by slicing the diamond lattice structure model in Example 3 of the present invention;

[0044] Fig.15 is a schematic diagram of the nth layer contour path and the support layer path in Example 3 of the present invention;

[0045] Fig.16 It is a schematic diagram of the n+1th layer contour path and the filling layer path in Example 3 of the present invention. DETAILED DESCRIPTION

[0046] The following describes several preferred embodiments of the present invention with reference to the drawings in the specification, so that the technical content is clearer and easier to understand. The present invention can be embodied in many different forms of embodiments, and the protection scope of the present invention is not limited to the embodiments mentioned in the text.

[0047] In the drawings, components with the same structure are indicated by the same numerical reference numerals, and components with similar structures or functions are indicated by similar numerical reference numerals. The size and thickness of each component shown in the drawings are arbitrarily shown, and the present invention does not limit the size and thickness of each component. In order to make the illustration clearer, the thickness of the components is appropriately exaggerated in some places in the drawings.

[0048] like Figure 1 As shown, a flow chart of a method for laser selective melting additive manufacturing of a thin-walled three-periodic minimal surface lattice structure is provided. The method comprises the following steps:

[0049] Step 1: According to the implicit function model expression F(x, y, z)=0 of the three-periodic minimal surface and the layer thickness adapted to the additive manufacturing equipment, the single-channel contour path of each layer is obtained by direct slicing;

[0050] Step 2: traverse each layer of plane, generate a series of parallel fill lines according to the set fill line spacing value, and intersect the combination of the parallel fill lines, the contour path of this layer, and the contour path of a higher layer;

[0051] Step 3: The obtained intersection points are combined in pairs to form line segments. Sampling points are taken in each line segment. If the functional expression and the inclination angle requirements are met at the same time and the line segment length is greater than the set threshold, the line segment is retained as the filling path.

[0052] Step 4: The filling path of the layer is used as a support layer, and it is moved up one layer to form a filling layer, and different process parameters are set for the support layer and the filling layer to optimize the filling effect;

[0053] Step 5: Generate a path file recognizable by the additive manufacturing device based on the contour path and the filling path, input it into the additive manufacturing device, set processing parameters, and perform manufacturing.

[0054] The following is a description with reference to specific embodiments.

[0055] Example 1

[0056] Step 1. Taking the Gyroid surface in the three-periodic minimal surface as an example, its implicit function expression is F(x, y, z) = sin(2πx / L)·cos(2πy / L)+sin(2πy / L)·cos(2πz / L)+sin(2πz / L)·cos(2πx / L)=0. In this embodiment, the unit cell size L=30mm and the slice thickness are set to 0.03mm. According to the layer thickness information, the planes perpendicular to the z-axis at each height of the model are traversed to obtain the contour lines of the implicit function model F(x, y, z)=0 in each plane as the single-channel contour scanning path. This process is called direct slicing. The model and its slice contour path are shown as follows. Figure 2 shown.

[0057] like Figure 3 As shown in the figure, in the process of forming a single path by slicing a three-period minimal surface without thickness, if the surface inclination angle is too small, the model features will be missing, forming a void area, and then generating a hole defect in the additive manufacturing process, affecting the performance of the part. The subsequent steps 2-4 are used to generate a filling path for the void area.

[0058] Step 2: Set the filling line spacing h = 0.03 mm, and obtain a series of parallel filling lines according to the given slope. Figure 4 The figure shows the intersection of one of the fill lines with the combination of two adjacent contour paths, and (1)-(14) are the obtained intersection points.

[0059] Step 3: Combine the obtained intersection points in pairs to form line segments. If the sampling point (x0, y0) taken in each line segment satisfies the function relationship F(x0, y0, z n )·F(x0,y0,z n+1 )<0, and the model inclination angle θ0 at this point satisfies cosθ0>c, and the length of the line segment is greater than the set value (set to 0.05mm in the embodiment), then the line segment is retained as the filling path. n 、z n+1 represents the z height of the nth and n+1th layers, and c is the set tilt angle cosine threshold (set to 0.75 in the embodiment).

[0060] Step 4: Before filling the void, a support layer is formed in the same area using the same path and different processing parameters. Figure 5 , 6 Schematic diagrams of the nth layer contour path and support layer path, and the n+1th layer contour path and filling layer path are shown respectively.

[0061] Step 5. Write the contour path and fill path into a path file (such as CLI, SLC format) recognizable by the laser selective melting equipment according to the standard file format. The contour path and fill path are written into different files to set different parameters such as processing power and scanning speed. The path format used in this embodiment is CLI format, and the powder material used is 17-4PH stainless steel. The laser power of the contour path is 135W, and the scanning speed is 400mm / s; the laser power of the filling layer path is 135W, and the scanning speed is 300mm / s; the laser power of the support layer is 60W, and the scanning speed is 1520mm / s. The manufactured parts are as follows: Figure 7 , 8 shown.

[0062] Example 2

[0063] Step 1: Take the primitive surface in the three-periodic minimal surface as an example, and its implicit modeling function expression is F(x, y, z) = cos(2πx / L) + cos(2πy / L) + cos(2πz / L) = 0. In the embodiment, the unit cell size L is set to 5 mm, and the slice thickness is 0.03 mm. The model and its slice contour path are respectively as follows: Fig. 9 , 10 shown.

[0064] Step 2: Set the filling line spacing h=0.2 mm, obtain a series of parallel filling lines according to the given slope, and intersect the combination of the parallel filling lines, the contour path of this layer, and the contour path of a higher layer.

[0065] Step 3: Combine the obtained intersection points in pairs to form line segments. If the sampling point (x0, y0) taken in each line segment satisfies the function relationship F(x0, y0, z n )·F(x0,y0,z n+1 )<0, and the model inclination angle θ0 at this point satisfies cosθ0>c, and the length of the line segment is greater than the set value (set to 0.03 mm in the embodiment), then the line segment is retained as the filling path. n 、z n+1 represents the z height of the nth and n+1th layers, and c is the set tilt angle cosine threshold (set to 0.9 in this embodiment).

[0066] Step 4: Before filling the void, a support layer is formed in the same area using the same path and different processing parameters. Fig.11 The nth layer contour path and support layer path are shown. Fig.12 A schematic diagram showing the n+1th layer contour path and the filling layer path.

[0067] Step 5: Write the contour path and the filling path into a path file recognizable by the laser selective melting device according to the standard file format. The path format used in this embodiment is the SLC format, the powder material used is Ti6Al4V titanium alloy, the contour path laser power is 280W, the scanning speed is 1200mm / s; the filling layer path laser power is 200W, the scanning speed is 1000mm / s; the support layer laser power is 100W, and the scanning speed is 2000mm / s.

[0068] Example 3

[0069] Step 1. Taking the Diamond surface in the three-periodic minimal surface as an example, its implicit function expression is F(x, y, z) = sin(2πx / L)·sin(2πy / L)·sin(2πz / L)+sin(2πx / L)·cos(2πy / L)·cos(2πz / L)+cos(2πx / L)·sin(2πy / L)·cos(2πz / L)+cos(2πx / L)·cos(2πy / L)·sin(2πz / L) = 0. In the embodiment, the unit cell size L is set to 20 mm, and the slice thickness is 0.05 mm. The model and its slice contour path are respectively as follows: Fig.13 , 14 shown.

[0070] Step 2: Set the filling line spacing h=0.05 mm, obtain a series of parallel filling lines according to the given slope, and intersect the combination of the parallel filling lines, the contour path of this layer, and the contour path of a higher layer.

[0071] Step 3: Combine the obtained intersection points in pairs to form line segments. If the sampling point (x0, y0) taken in each line segment satisfies the function relationship F(x0, y0, z n )·F(x0,y0,z n+1 )<0, and the model inclination angle θ0 at this point satisfies cosθ0>c, and the length of the line segment is greater than the set value (set to 0.1 mm in the embodiment), then the line segment is retained as the filling path. n 、z n+1 represents the z height of the nth and n+1th layers, and c is the set tilt angle cosine threshold (set to 0.9 in the embodiment).

[0072] Step 4: Before filling the voids, a support layer is formed in the same area using the same path and different processing parameters to improve the collapse of the filling layer. Fig.15 The nth layer contour path and support layer path are shown. Fig.16 A schematic diagram showing the n+1th layer contour path and the filling layer path.

[0073] Step 5: Write the contour path and the filling path into a path file recognizable by the additive manufacturing equipment according to the standard format of the file. This embodiment adopts the laser selective melting process, the path output is in CLI format, the powder material used is AlSi10Mg aluminum alloy, the contour path laser power is 350W, the scanning speed is 1150mm / s; the filling layer path laser power is 350W, the scanning speed is 1000mm / s; the support layer laser power is 200W, and the scanning speed is 2000mm / s.

[0074] The preferred specific embodiments of the present invention are described in detail above. It should be understood that ordinary technicians in the field can make many modifications and changes based on the concept of the present invention without creative work. Therefore, all technical solutions that can be obtained by technicians in the technical field based on the concept of the present invention through logical analysis, reasoning or limited experiments on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A laser additive manufacturing method for a thin-walled three-periodic minimal surface lattice structure, characterized in that: The method comprises the following steps: Step 1: According to the implicit function model expression F(x, y, z)=0 of the three-periodic minimal surface and the layer thickness adapted to the laser selective melting additive manufacturing equipment, the single-channel contour path of each layer is obtained by direct slicing; Step 2: traverse each layer of plane, generate a series of parallel fill lines according to the set fill line spacing value, and intersect the combination of the parallel fill lines, the contour path of this layer, and the contour path of a higher layer; Step 3: The obtained intersection points are combined in pairs to form line segments. Sampling points are taken in each line segment. If the functional expression and the inclination angle requirements are met at the same time and the line segment length is greater than the set threshold, the line segment is retained as the filling path. Step 4: The filling path of the layer is used as a support layer, and it is moved up one layer to form a filling layer, and different process parameters are set for the support layer and the filling layer to optimize the filling effect; Step 5: Generate a path file recognizable by the additive manufacturing device based on the contour path and the filling path, input it into the additive manufacturing device, set processing parameters, and perform manufacturing.

2. The single-pass scanning laser additive manufacturing method for a thin-walled three-periodic minimal surface lattice structure according to claim 1, characterized in that: The specific process of step 1 is: traverse the planes perpendicular to the z-axis at each height of the model according to the layer thickness information, and obtain the contour lines of the implicit function model F(x, y, z) = 0 in each plane as a single-channel contour scanning path. This process is called direct slicing.

3. The laser additive manufacturing method for a thin-walled three-periodic minimal surface lattice structure according to claim 1, characterized in that: The step 3 specifically comprises combining the obtained intersection points in pairs to form line segments. If the sampling points (x0, y0) taken in each line segment satisfy the functional relationship F(x0, y0, z n )·F(x0,y0,z n+1 )<0, and the model inclination angle θ0 at this point satisfies cosθ0>c, and the length of the line segment is greater than the set value, then the line segment is retained as the filling path; where z n 、z n+1 It represents the z height of the nth and n+1th layers, and c is the set tilt angle cosine threshold.

4. The laser additive manufacturing method for a thin-walled three-periodic minimal surface lattice structure according to claim 1, characterized in that: The set value of the line segment length is set to 0.03-0.1 mm, and the set inclination angle cosine threshold c is set to 0.75-0.

9.

5. The laser additive manufacturing method for a thin-walled three-periodic minimal surface lattice structure according to claim 1, characterized in that: The step 4 specifically comprises forming a support layer in the same area using the same path and different processing parameters before filling the void.

6. The laser additive manufacturing method for a thin-walled three-periodic minimal surface lattice structure according to claim 1, characterized in that: The step 5 specifically includes writing the contour path and the filling path into a path file recognizable by the laser selective melting device according to the standard format of the file. The format of the path file is CLI or SLC format. The contour path and the filling path are written into different files respectively to distinguish the parameters such as processing power and scanning speed.

7. The laser additive manufacturing method for a thin-walled three-periodic minimal surface lattice structure according to claim 1, characterized in that: The thin-walled structure manufactured by the method contains only one melting path in the thickness direction, and the wall thickness is less than 200 microns.

8. The laser additive manufacturing method for a thin-walled three-periodic minimal surface lattice structure according to claim 1, characterized in that: The format of the path file is CLI format, the powder material used is 17-4PH stainless steel, the contour path laser power is 135W, and the scanning speed is 400mm / s; the filling layer path laser power is 135W, and the scanning speed is 300mm / s; the support layer laser power is 60W, and the scanning speed is 1520mm / s.

9. The laser additive manufacturing method for a thin-walled three-periodic minimal surface lattice structure according to claim 1, characterized in that: The format of the path file is SLC format, the powder material used is Ti6Al4V titanium alloy, the contour path laser power is 280W, and the scanning speed is 1200mm / s; the filling layer path laser power is 200W, and the scanning speed is 1000mm / s; the support layer laser power is 100W, and the scanning speed is 2000mm / s.

10. The laser additive manufacturing method for a thin-walled three-periodic minimal surface lattice structure according to claim 1, characterized in that: The format of the path file is CLI format, the powder material used is AlSi10Mg aluminum alloy, the contour path laser power is 350W, and the scanning speed is 1150mm / s; the filling layer path laser power is 350W, and the scanning speed is 1000mm / s; the support layer laser power is 200W, and the scanning speed is 2000mm / s.

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