Lattice structure, part and preparation method thereof

Abstract

The invention provides a lattice structure, a part and a preparation method thereof. Wherein the lattice structure comprises a plurality of unit cells which are arranged periodically; the unit cell is provided with a plurality of connecting ends extending in different directions, and the peripheral appearance of each connecting end is in a curved surface shape; wherein the peripheral morphology of each connecting end is determined by a preset curved surface equation, so that at least the connecting ends of the adjacent unit cells are continuously connected. On the basis, the connecting end with the curved-surface-shaped peripheral appearance is beneficial for improving the problem of concentrated stress, and the overhanging risk can be reduced. Besides, the curved surface equation can further adjust the peripheral morphology of the connecting ends on the basis of a basic curved surface, so that the connecting ends of the adjacent unit cells are continuously connected, the situation that the structure is segmented or separated in the process of generating the low-density lattice structure is avoided, the continuity and uniformity of the lattice structure are enhanced, and the performance of the crystal lattice structure is improved. And the preparation cost can be reduced under the same supporting performance.

Description

Technical Field

[0001] The present invention relates to the technical field of mechanical manufacturing, and in particular to a lattice structure, parts and components and a preparation method thereof. Background Art

[0002] Additive manufacturing technology refers to a scientific and technological system that directly manufactures parts based on the discrete-stacking principle and driven by the three-dimensional data of parts. Based on different classification principles and understanding methods, additive manufacturing technology also has many names such as rapid prototyping, rapid prototyping, rapid manufacturing, 3D printing, etc. It combines the advantages of computer graphics processing, digital information and control, laser technology, electromechanical technology and material technology, and solves the problem of forming various complex structural parts in industry.

[0003] However, existing parts based on additive manufacturing technology are generally lattice structures based on truss support structures, which are characterized by generating unit structure modules based on the vertices and edges of polygonal structures. The final parts are repeated in three-dimensional space to generate periodic unit structure modules. This support lattice based on polyhedrons and square cross-sections has the defects of local stress concentration and weakened mechanical properties, and is prone to overhang deformation. In this regard, those skilled in the art have proposed to improve this problem by using surface design or solutions based on three-periodic minimal surface design. However, when the constant term in the currently used minimal surface implicit function equation reaches a certain threshold, the designed continuous area begins to segment or separate, and it is impossible to generate a low-density and continuously connected lattice structure.

[0004] Therefore, a new design method is urgently needed to solve the above problems. Summary of the invention

[0005] The object of the present invention is to provide a lattice structure, components and their preparation method, so as to solve at least one of the following problems: how to prepare low-density and lightweight components; how to improve the continuity of the lattice structure under the premise of low density and lightweight; how to improve the support of the lattice structure; how to adjust the support of the lattice structure; how to alleviate overhang deformation; how to prepare components suitable for vacuum environment; and how to reduce preparation cost.

[0006] In order to solve the above technical problems, the present invention provides a lattice structure, comprising: a plurality of periodically arranged unit cells;

[0007] The unit cell has a plurality of connection ends extending in different directions, and the peripheral morphology of each of the connection ends is a curved surface; wherein the peripheral morphology of each of the connection ends is determined by a preset curved surface equation so as to at least allow the connection ends of adjacent unit cells to be continuously connected.

[0008] Optionally, in the lattice structure, the surface equation includes basic surface terms and compensation terms; wherein the basic surface terms are used to determine the surface model of the unit cell, and the compensation terms are used to adjust the peripheral morphology of each of the connecting ends.

[0009] Optionally, in the lattice structure, the surface basic term includes a three-periodic minimal surface implicit function equation:

[0010] Cos(x)+Cos(y)+Cos(z)≥K1; or, Sin(x)+Sin(y)+Sin(z)≥K1;

[0011] Among them, (x, y, z) are the coordinates of any point in the three-dimensional space coordinate system, K1 is a constant term, and K1∈[0,π].

[0012] Optionally, in the lattice structure, the compensation term includes:

[0013] K2cos(x)cos(y)cos(z); or, K2sin(x)sin(y)sin(z);

[0014] Among them, (x, y, z) are the coordinates of any point in the three-dimensional space coordinate system, K2 is a constant coefficient, and K2∈[0,2].

[0015] Optionally, in the lattice structure, the compensation term includes:

[0016] K2[cos(x)cos(y)+cos(y)cos(z)+cos(z)cosx(x)]), or (K2[sin(x)sin(y)+siny(y)sin(z)+sin(z)sin(x)];

[0017] Among them, (x, y, z) are the coordinates of any point in the three-dimensional space coordinate system, K2 is a constant coefficient, and K2∈[0,1].

[0018] Optionally, in the lattice structure, the surface equation also includes a direction parameter P, the direction parameter P is a coefficient of a basic term of the surface, and P∈[0, 2].

[0019] Optionally, in the lattice structure, the lattice structure further includes a protective film, the protective film covers the outer surface of each of the unit cells, and / or the protective film covers the outer surface of the lattice structure.

[0020] Optionally, in the lattice structure, the material of the protective film includes a polymer material.

[0021] Based on the same inventive concept, the present invention also provides a component, including the lattice structure.

[0022] Based on the same inventive concept, the present invention also provides a method for manufacturing parts, which adopts an additive manufacturing process or a subtractive manufacturing process to manufacture the lattice structure, and / or to manufacture the parts.

[0023] In summary, the present invention provides a lattice structure, parts and methods for preparing the same. Wherein, the lattice structure includes a plurality of periodically arranged unit cells; the unit cells have a plurality of connecting ends extending in different directions, and the peripheral morphology of each of the connecting ends is in the shape of a curved surface; wherein the peripheral morphology of each of the connecting ends is determined by a preset surface equation, so as to at least make the connecting ends of adjacent unit cells continuously connected. Based on this, the connecting ends with a curved peripheral morphology are conducive to improving the problem of concentrated stress and can reduce the risk of overhang. In addition, the surface equation can further adjust the peripheral morphology of the connecting ends on the basis of the basic curved surface, so that the connecting ends of adjacent unit cells are continuously connected, avoiding the occurrence of structural segmentation or separation in the process of generating a low-density lattice structure, enhancing the continuity and uniformity of the lattice structure, and helping to reduce the preparation cost under the same support performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Those skilled in the art will appreciate that the accompanying drawings are provided for a better understanding of the present invention and do not constitute any limitation on the scope of the present invention.

[0025] Figure 1 It is a unit cell model designed by the surface equation in the prior art.

[0026] Figure 2 is a schematic diagram of a lattice structure in an embodiment of the present invention.

[0027] Figure 3 It is a flow chart of a method for designing a lattice structure model in an embodiment of the present invention.

[0028] Figure 4 It is a schematic diagram of a model corresponding to a surface equation in an embodiment of the present invention.

[0029] Figure 5 It is a schematic diagram of a model corresponding to a surface equation in an embodiment of the present invention.

[0030] Figure 6 It is a schematic diagram of the relationship between K1 and density ratio in a surface equation in an embodiment of the present invention.

[0031] Figure 7 It is a schematic diagram of the relationship between K1 and density ratio in a surface equation in an embodiment of the present invention.

[0032] Figure 8Schematic diagram of a unit cell model in an embodiment of the present invention.

[0033] Fig. 9 Schematic diagram of a unit cell model in an embodiment of the present invention.

[0034] Fig.10 It is a schematic diagram of a unit cell model and a lattice structure model in an embodiment of the present invention.

[0035] Fig.11 It is a schematic slice diagram of the lattice structure model in the embodiment of the present invention.

[0036] Fig.12 It is a schematic slice diagram of the lattice structure model in the embodiment of the present invention.

[0037] Fig.13 It is a slice diagram of the lattice structure model in the embodiment of the present invention.

[0038] Fig.14 It is a schematic diagram of a simulation test of a lattice structure model in an embodiment of the present invention.

[0039] Fig.15 It is a schematic diagram of simulation test of a rectangular lattice structure model in the prior art.

[0040] Fig.16 It is a schematic diagram of simulation test of a cylindrical lattice structure model in the prior art.

[0041] Fig.17 It is a schematic diagram of a simulation test of a lattice structure model in an embodiment of the present invention.

[0042] Fig.18 Schematic diagram of the structure of the composite unit cell in an embodiment of the present invention.

[0043] Fig.19 Schematic diagram of the structure of the composite lattice in the embodiment of the present invention.

[0044] Fig. 20 It is a schematic diagram of the structure of the component model in the embodiment of the present invention.

[0045] In the attached figure:

[0046] 100-unit cell; 100a-connection end;

[0047] 200-first curved surface model; 201-first compensation model; 202-first unit cell model;

[0048] 300 - second curved surface model; 301 - second compensation model; 302 - second unit cell model;

[0049] 400-third unit cell model;

[0050] 500-fourth unit cell model;

[0051] 600-lattice structure model; 600a-slice layer;

[0052] 700-inner unit cell; 701-outer unit cell; 702-composite unit cell;

[0053] 800-inner lattice; 801-outer lattice; 802-composite lattice;

[0054] 900-shell model;

[0055] C-cell; M-rectangular lattice structure model; N-cylindrical lattice structure model. DETAILED DESCRIPTION

[0056] In order to make the purpose, advantages and features of the present invention clearer, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the drawings are all in a very simplified form and are not drawn to scale, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention. In addition, the structure shown in the drawings is often a part of the actual structure. In particular, the emphasis of each drawing is different, and sometimes different proportions are used. It should also be understood that, unless otherwise specified or indicated, the terms "first", "second", "third", etc. in the specification are only used to distinguish between the various components, elements, steps, etc. in the specification, and are not used to represent the logical relationship or sequential relationship between the various components, elements, steps, etc.

[0057] It should be noted that in order to alleviate the defects of local concentrated stress and weakened mechanical properties of the lattice structure, the prior art uses the classic minimal surface implicit function equation Schwarz P: Cos(x)+Cos(y)+Cos(z)≥k to design the lattice structure. However, when the constant term k in the classic Schwarz P equation reaches a certain domain value, the continuous regions in the lattice structure will be separated or segmented, and it is impossible to generate a low-density and continuously connected lattice structure. Figure 1 As shown in the figure, the continuity of the basic unit structure (hereinafter referred to as cell C) in the lattice structure gradually decreases with the increase of k value. When the k value is equal to 1, the six connection ends of the cell C basically shrink to 0, and the cells C in the entire lattice structure are independent of each other and cannot be continuously connected. Therefore, the equation Schwarz P cannot be applied to the design of low-density lattice structures.

[0058] In this regard, this embodiment provides a lattice structure. Figure 2The unit cell structure includes a plurality of unit cells 100 arranged periodically; the unit cell 100 has a plurality of connection ends 100a extending in different directions, and the peripheral morphology of each of the connection ends 100a is a curved surface; wherein the peripheral morphology of each of the connection ends 100a is determined by a preset surface equation so as to at least ensure that the connection ends 100a of adjacent unit cells 100 are continuously connected.

[0059] It can be seen that the connection end 100a with a curved peripheral morphology is conducive to improving the problem of concentrated stress and reducing the risk of overhang. In addition, the surface equation can further adjust the peripheral morphology of the connection end 100a on the basis of the basic surface, so that the connection ends 100a of adjacent unit cells 100 are continuously connected, avoiding the occurrence of structural segmentation or separation in the process of generating a low-density lattice structure, enhancing the continuity and uniformity of the lattice structure, and helping to reduce the preparation cost under the same support performance.

[0060] The following is a combination of the design method of the lattice structure and the attached Figures 2 to 20 The lattice structure provided in this embodiment is described in detail.

[0061] It can be understood that the unit cell 100 in the lattice structure is designed by the surface equation, so this embodiment specifically describes the surface direction and the lattice structure through the design method of the lattice structure model.

[0062] See also Figure 3 , the design method of the lattice structure model includes:

[0063] Step 1 S10: constructing a surface equation; wherein the surface equation includes basic surface terms and compensation terms.

[0064] Because the lattice structure is a three-dimensional component composed of a plurality of identical unit cells 100 arranged and combined, and is used as a component in a mechanical device, the basic shape of the lattice structure needs to be taken as a starting point when designing the lattice structure, and factors such as the material, application scenario, and functional details of the lattice structure also need to be considered. Based on this, before executing step 1 S10, it is necessary to first determine the material properties and key geometric quantities of the lattice structure to construct a first peripheral model. The first peripheral model is the basic physical shape outline of the lattice structure. Optionally, the first peripheral model is generated by drawing software such as Wolfram Mathematica.

[0065] Furthermore, according to factors such as temperature and humidity, pH, electromagnetic environment, and lighting conditions of the application scenario, metal materials, non-metallic materials, or semiconductor materials that meet mechanical properties, optical properties, electromagnetic properties, electronic properties, physical and chemical properties, etc. are selected as the material of the lattice structure. It should be noted that the material of the lattice structure can be a single material or a composite material composed of multiple materials. After determining the material of the lattice structure, the key geometric quantities of the first peripheral model are defined according to the external shape of the required parts. That is, polygons, spline surfaces, etc. are generated using points, lines, and surfaces to form solid three-dimensional geometric shapes to determine the physical structure of the first peripheral model. Exemplarily, the first peripheral model can be a cuboid, a cube, a sphere, a cylinder, an ellipsoid, a cone, other polyhedrons, or more complex combined shapes.

[0066] After obtaining the first peripheral model, the first peripheral model is partially designed for functions according to the functional requirements of the required parts to construct the second peripheral model. Exemplarily, the local functions are designed for inlet and outlet joints, mounting holes, threaded holes, local reinforcement or thinning, chamfering, rounding or processing holes, etc., which can be partially refined according to the designer's experience and functions.

[0067] After obtaining the second peripheral model, the internal shape of the lattice structure can be designed, that is, the surface equation can be constructed according to the requirements of the lattice structure. The requirements of the lattice structure generally include differences in functions and performances, such as bearing capacity, structural natural frequency, structural mode, weight and mass distribution, etc. In addition, the bearing capacity of isotropic lattice structures in three dimensions is the same, and the bearing capacity of anisotropic lattice structures in three directions is different; therefore, the bearing capacity requirements in different directions also need to be considered when constructing the surface equation.

[0068] Further, the surface equation is a basic function equation for forming the unit cell 100 and the lattice structure. Preferably, the surface equation includes basic terms and compensation terms. The basic terms of the surface are used to generate a gradual surface structure to improve the problem of concentrated stress and reduce the risk of overhang. The compensation term is used to avoid structural segmentation or separation in the process of generating a low-density lattice structure, and can ensure that the lattice structure has better continuity and uniformity under the premise of low density and light weight, which is conducive to reducing the preparation cost under the same support performance. Exemplarily, the basic terms of the surface include a three-periodic minimal surface implicit function equation, namely Schwarz P: Cos(x)+Cos(y)+Cos(z)=0; or, Sin(x)+Sin(y)+Sin(z)=0; wherein (x, y, z) are the coordinates of any point in the three-dimensional space coordinate system.

[0069] Furthermore, in order to adjust the relative density ratio of the unit cell model, the surface equation may be:

[0070] Cos(x)+Cos(y)+Cos(z)≥K1; or, Sin(x)+Sin(y)+Sin(z)≥K1;

[0071] Among them, K1 is a constant term, and K1∈[0,π]. Based on this, the relative density ratio of the unit cell model can be changed by adjusting the constant term K1. It should be noted that the relative density ratio is the duty cycle, or porosity. From the above, it can be seen that the change in the value of the constant term K1 in the implicit function equation makes the original three-period minimal surface equation evolve into a three-period surface equation with constant mean curvature, and the surface equation with constant mean curvature maintains the characteristics of the minimal surface. Under the premise of determining the boundary and the enclosed volume, the area of ​​the surface is minimized, which is an ideal surface structure.

[0072] In order to solve the continuity problem of the low-density and lightweight lattice structure, the surface equation provided in this embodiment also includes a compensation term. In one embodiment, the compensation term includes:

[0073] K2cos(x)cos(y)cos(z); or, K2sin(x)sin(y)sin(z);

[0074] Wherein, K2 is a constant coefficient, and K2∈[0,2].

[0075] Exemplarily, the surface equation is:

[0076] Cos(x)+Cos(y)+Cos(z)-K2cos(x)cos(y)cos(z)≥K1;

[0077] Alternatively, the surface equation is:

[0078] Sin(x)+Sin(y)+Sin(z)-K2sin(x)sin(y)sin(z)≥K1;

[0079] like Figure 4 As shown, the first surface model 200 corresponding to the basic surface item is a spherical shape in a three-dimensional space, and the first compensation model 201 corresponding to the compensation item is a plurality of block structures distributed in the three-dimensional space. The first unit cell model 202 corresponding to the final item can be obtained through Boolean operation.

[0080] In another embodiment, the compensation term includes:

[0081] K2[cos(x)cos(y)+cos(y)cos(z)+cos(z)cosx(x)]; or,

[0082] K2[sin(x)sin(y)+siny(y)sin(z)+sin(z)sin(x)];

[0083] Wherein, K2 is a constant coefficient, and K2∈[0,1].

[0084] Exemplarily, the surface equation is:

[0085] Cos(x)+Cos(y)+Cos(z)-K2[cos(x)cos(y)+cos(y)cos(z)+cos(z)cosx(x)]≥K1;

[0086] Alternatively, the surface equation is:

[0087] Sin(x)+Sin(y)+Sin(z)-K2[sin(x)sin(y)+siny(y)sin(z)+sin(z)sin(x)]≥K1;

[0088] like Figure 5 As shown, the second surface model 300 corresponding to the basic surface term is a spherical shape in a three-dimensional space, and the second compensation model 301 corresponding to the compensation term is a plurality of block structures distributed in the three-dimensional space. The second unit cell model 302 corresponding to the final term can be obtained through Boolean operation.

[0089] according to Figure 4 and Figure 5 It can be clearly seen from the first unit cell model 202 and the second unit cell model 302 that the joints of the six connection ends of the unit cell are curved structures, and the diameters of the six connection ends also decrease in the direction away from the joints. Compared with the truss structure constructed in regular rectangular, cylindrical, etc. shapes, the connection of the unit cells provided in this embodiment has better support and is conducive to forming a low-density lightweight structure, thereby reducing costs.

[0090] Step 2 S20: adjusting the parameter values ​​in the surface equation to generate a unit cell model;

[0091] The parameter value includes the constant term K1 and the constant coefficient K2. In the process of adjusting the parameter value in the surface equation, the constant term K1 is adjusted to adjust the relative density ratio of the unit cell model; the constant coefficient K2 is adjusted to adjust the continuity and uniformity of the unit cell model.

[0092] Exemplarily, in one embodiment, the surface equation is:

[0093] Cos(x)+Cos(y)+Cos(z)-K2cos(x)cos(y)cos(z)≥K1; among them, K1∈[0, π]; K2∈[0, 2].

[0094] For example: Cos(x)+Cos(y)+Cos(z)-1.1cos(x)cos(y)cos(z)≥1.88;

[0095] That is, K1 = 1.88, K2 = 1.1; then the relative density ratio of the unit cell structure corresponding to the single-period three-dimensional space of [-π, π] is about 5%. Further, Figure 6 As shown, the relative density of the unit cell can be continuously changed in the range of 5%-35%, and can be fitted into a polynomial formula for later application. The larger K1 is, the smaller the density ratio R of the unit cell is.

[0096] Exemplarily, in another embodiment, the surface equation is:

[0097] Cos(x)+Cos(y)+Cos(z)-K2[cos(x)cos(y)+cos(y)cos(z)+cos(z)cosx(x)]≥K1;

[0098] Among them, K1∈[0,π]; K2∈[0,1].

[0099] For example:

[0100] Cos(x)+Cos(y)+Cos(z)-0.553[cos(x)cos(y)+cos(y)cos(z)+cos(z)cosx(x)]≥1.34;

[0101] That is, K1 = 1.34, K2 = 0.553; then the relative density ratio of the unit cell structure corresponding to the single-period three-dimensional space of [-π, π] is about 10%. Further, Figure 7 As shown, the relative density of the unit cell can be continuously changed in the range of 5% to 40%, and can be fitted into a polynomial formula for later application. The larger K1 is, the smaller the density ratio R of the unit cell is.

[0102] Furthermore, according to the surface equations of the above examples, the obtained unit cells are all isotropic structures. That is, the structures of the unit cells are symmetrical in the three directions of the three-dimensional space, and the supporting forces in all directions are the same. However, the actual working conditions may require larger supporting forces in some directions and weaker supporting forces in some directions. Therefore, in this embodiment, the parameter value also includes a directional parameter P, which is a coefficient of the basic term of the surface, and P∈[0,2]; then the directional parameter P is adjusted to adjust the support of the unit cell model in the three-dimensional direction respectively. Based on this, this embodiment also provides a surface equation for adjusting the support performance of the unit cell in each direction.

[0103] Exemplarily, the surface equation is:

[0104] P x Cos(x)+P y Cos(y)+P z Cos(z)-K2cos(x)cos(y)cos(z)≥K1;

[0105] Alternatively, the surface equation is:

[0106] P x Sin(x)+P y Sin(y)+P z Sin(z)-K2sin(x)sin(y)sin(z)≥K1;

[0107] Alternatively, the surface equation is:

[0108] P x Cos(x)+P y Cos(y)+P z Cos(z)-K2[cos(x)cos(y)+cos(y)cos(z)+cos(z)cosx(x)]≥K1;

[0109] Alternatively, the surface equation is:

[0110] P x Sin(x)+P y Sin(y)+P z Sin(z)-K2[sin(x)sin(y)+siny(y)sin(z)+sin(z)sin(x)]≥K1;

[0111] Among them, P x , P y and P z are the parameters of three mutually perpendicular directions in three-dimensional space, and P x ∈[0,2]; P x∈[0,2]; P z ∈[0,2].

[0112] For example, the surface equation is:

[0113] Cos(x)+Cos(y)+0.935Cos(z)-1.05cos(x)cos(y)cos(z)≥1.88;

[0114] Among them, P x =1,P y =1,P z =0.935, K1=1.88; K2=1.05. Figure 8 As shown, the connection ends of the third unit cell model 400 extending along the X-axis direction and the Y-axis direction have the same structure and the same diameter. The diameter of the connection end extending along the Z-axis direction is significantly increased, and the corresponding support force of the connection end extending along the Z-axis direction is greater than the support force of the connection end extending along the X-axis direction and the Y-axis direction. The connection end extending along the X-axis direction and the Y-axis direction only serves to connect or connect. The application conditions of this design are for certain specific or single load conditions, and it is hoped to achieve a lower relative density.

[0115] For another example, the surface equation is:

[0116] Cos(x)+Cos(y)+1.08Cos(z)-1.05[cos(x)cos(y)+cos(y)cos(z)+cos(z)cosx(x)]≥1.88;

[0117] Among them, P x =1,P y =1,P z =1.08, K1=1.88; K2=1.05. Fig. 9 As shown, the connection ends of the fourth unit cell model 500 extending along the X-axis direction and the Y-axis direction have the same structure and the same diameter. The diameter of the connection end extending along the Z-axis direction is significantly reduced, and the corresponding support force of the connection end extending along the Z-axis direction is less than the support force of the connection end extending along the X-axis direction and the Y-axis direction. The connection end extending along the Z-axis direction can only play the role of connection. The support performance of the fourth unit cell model 500 of this design is completely opposite to that of the third unit cell model 400. Based on this, the support performance of the unit cell model in different directions in three-dimensional space can be achieved by adjusting the direction parameter P, that is, when the density ratio is the same, by increasing or decreasing the size of the unit cell in a certain direction, the support force of the unit cell in this direction is correspondingly enhanced or weakened, thereby meeting the personalized needs of the unit cell and the lattice structure.

[0118] Step three S30: generating the lattice structure model 600 at least according to the unit cell model.

[0119] Further, a series of Boolean operations are performed based on the second peripheral model obtained above and the unit cell model obtained in step 2 S20, so that the lattice structure model 600 can be obtained. It should be noted that a plurality of the unit cell structure models are arranged according to the set requirements to form the lattice structure model 600. Fig.10 As shown, in a three-dimensional space with a period number of 2×2×2, two different unit cell models are respectively filled and combined to form two lattice structure models 600 with different densities, and each of the unit cell models is interconnected in the three-dimensional space and is orthogonal to one point. In addition, in the range of low density of 5% to 10%, each unit cell model in the lattice structure model 600 also remains connected, and there is no segmented separation, maintaining good continuity.

[0120] See also Figures 11 to 13 , Fig.11 and Fig.12 Schematic diagram of the slice of the lattice structure model 600 along the Z axis. Preferably, after the lattice structure model 600 is designed, the slice software platform is used to further refine the growth direction and support conditions of each layer. Fig.13 The figure shows a schematic diagram of 8-layer slices of the lattice structure model 600 along the Z axis. When the Z value changes, the curve of the area enclosed by the cross section changes continuously. When the Z value is low, that is, Z < 0.5, the area enclosed in the slice diagram 600a forms a window frame shape; when the Z value is in the middle section, that is, 0.5 < Z < 1.5, the area enclosed in the slice diagram 600a is a column area, and the shape of the area is a curve area close to a rhombus; when the Z value is high, 1.5 < Z < 3.14, the area enclosed in the slice diagram 600a is a column area, and the shape of the area is a curve area close to a circle. It can be seen that the slice schematic diagram can better reflect the internal structure of the lattice structure model 600.

[0121] Furthermore, after obtaining the lattice structure model 600, it is necessary to simulate and test the lattice structure model 600, and use the test results as feedback to adjust the parameter values ​​until the lattice structure model 600 meets the set requirements. Preferably, a finite element or physical field numerical simulation is performed. For example, the finite volume method, finite element method, and finite difference method are used to perform fluid mechanics calculations and verifications on the NS partial differential equations, using physical conditions that are as close as possible to the actual working conditions to simulate and measure whether the design meets the required functions and performance, and further determine whether the design results are optimized to meet expectations. For example, Fig.14As shown, the finite element simulation is used to verify the lattice structure model 600. A load of 1000N is applied vertically downward along the Z-axis direction on the top of the lattice structure model 600, and the material of the lattice structure model 600 is set to be an aluminum alloy material parameter with a Young's modulus of 140MP and a Poisson's ratio of 0.3. Through the finite element simulation, the maximum overall deformation is 0.7mm and the maximum vonMises stress is 15MPa.

[0122] Further, such as Figure 15 to Figure 17 As shown, Fig.15 The deformation test is carried out by using a rectangular lattice structure model M formed by a rectangular three-orthogonal unit cell model in the prior art; Fig.16 The deformation test is carried out using a cylindrical lattice structure model N formed by a cylindrical triorthogonal unit cell model; Fig.17 The deformation test is carried out on the lattice structure model 600 formed by the unit cell model provided in this embodiment. The density ratio of the three lattice structure models is the same, which is 10%; the number of periods is 2X2X2; the material is aluminum alloy, and the Young's modulus in the material parameters is 140MP, and the Poisson's ratio is 0.3; and at the same time, a load of -1000N is applied vertically downward along the Z axis on the top of the three lattice structure models. Through finite element simulation, the maximum von Mises stress of the three is 100MP, 80MP and 15MPa respectively. It can be seen that the lattice structure model provided in this embodiment has the same density ratio of 10%, the period number is 2X2X2, the material is aluminum alloy, and the Young's modulus in the material parameters is 140MP, and the Poisson's ratio is 0.3; and at the same time, the three lattice structure models are applied vertically downward along the Z axis. The maximum von Mises stress of the three is 100MP, 80MP and 15MPa respectively. Fig.17 The lattice structure model 600 has the best load-bearing capacity.

[0123] In summary, the design method of the lattice structure model provided in the present embodiment uses the three-period minimal surface implicit function equation as the basic equation to generate a gradual surface structure to improve the concentrated stress problem and reduce the risk of overhang. At the same time, a compensation term is added to the three-period minimal surface implicit function equation to avoid structural segmentation or separation in the process of generating a low-density lattice structure, and it can ensure that the lattice structure has better continuity and uniformity under the premise of low density and light weight, which is conducive to reducing the preparation cost under the same support performance. In addition, the design method of the lattice structure model provided in the present embodiment also sets a directional parameter, so as to adjust the directional parameters corresponding to the three-dimensional direction to achieve the adjustment of the support force in each direction, thereby meeting the requirements of the anisotropy of the lattice structure.

[0124] Based on this, according to the design method of the lattice structure model, the lattice structure model 600 can be designed, and then the lattice structure provided in this embodiment can be prepared according to the lattice structure model. Preferably, the lattice structure is prepared by an additive manufacturing process or a subtractive manufacturing process according to the lattice structure model 600. Specifically, the lattice structure model 600, the material of the lattice, the placement posture, the design of auxiliary support, the three-dimensional model slice and other related parameters are input into the relevant equipment to automatically generate the lattice structure. Exemplarily, the lattice structure is prepared by an additive manufacturing process. In general, the additive manufacturing process includes: additive manufacturing molding, wire cutting, sandblasting, ultrasonic cleaning, electrochemical corrosion of the outer surface, and coating or metal plating. Preferably, the lattice structure is manufactured by a 3D printing process. The lattice structure provided in this embodiment is supported by a continuous curved surface, and no additional auxiliary support manufacturing conditions are required during the 3D printing process. Under the premise of improving the performance of the device, the cost can be further reduced and the procurement cycle can be shortened.

[0125] This embodiment does not limit the specific process equipment used in the additive manufacturing process or the subtractive manufacturing process, nor does it limit the specific size and material of the lattice structure. Preferably, the thickness range of the curved surface of the lattice structure is: 0.1mm to 10mm. And, the lattice structure can be a single material or a composite material composed of multiple materials. Exemplarily, the material of the lattice structure is: stainless steel, aluminum alloy, titanium alloy, invar, plastic or nylon resin, etc.

[0126] Furthermore, the lattice structure provided in this embodiment also includes a protective film. The protective film covers the outer surface of each of the unit cells 100, and / or the protective film covers the outer surface of the lattice structure. Preferably, the material of the protective film includes but is not limited to a polymer material. Exemplarily, the lattice structure is prepared by an additive manufacturing process or a subtractive manufacturing process using a metal material, and then the lattice structure is immersed in a polymer material in a molten state so that the polymer material covers the surface of the lattice structure. Optionally, the polymer material completely seals the lattice structure, and the interior of the lattice structure covered with the polymer material does not have pores, that is, the surface of each unit cell 100 is attached with the polymer material. Alternatively, the polymer material is only attached to the outer surface of the lattice structure, and the interior of the lattice structure covered with the polymer material also has pores. Preferably, the lattice structure is made of metal, such as aluminum alloy or stainless steel, etc. Since the melting point of most polymer materials is lower than that of metal materials, the morphology of the lattice structure will not be affected during the process of covering the surface of the lattice structure with polymer materials. Furthermore, the lattice structure can also be coated with polymer materials by coating or casting.

[0127] It can be understood that the lattice structure covered with the polymer material is equivalent to a composite lattice structure having an inner and outer two-layer structure. Fig.18 and Fig.19 As shown, the inner layer unit cell 700 is a metal or non-metal material, and the outer layer unit cell 701 is the protective film, which can be a polymer material. When the outer layer unit cell 701 is sleeved on the inner layer unit cell 700, a composite unit cell 702 is formed. The outer layer unit cell 701 can better wrap and seal the inner layer unit cell 700, so that the composite lattice structure has the advantages of light weight and high rigidity, and low outgassing in a vacuum environment. It is particularly suitable as a material for the structural components of a lightweight sports platform in a vacuum environment. Similarly, the inner layer unit cell 700 constitutes the inner layer lattice 800, and the outer layer unit cell 701 constitutes the outer layer lattice 701. The inner layer lattice 800 and the outer layer lattice 801 are combined to form a composite lattice 802.

[0128] It should be noted that in actual working conditions, the lattice structure can be used alone as an open component, but in order to cooperate with the connection of other components in the equipment, in many cases the lattice structure is only used as the internal structure of the component, and a shell needs to be designed on the outer surface of the lattice structure to form a closed component. Based on this, this embodiment also provides a component, which includes the lattice structure. Because the structure of the component is of various types and has different morphologies, it is necessary to design the component model before preparing the component.

[0129] See also Fig. 20 , this embodiment also provides a component design method. According to the specific design requirements of the component, the component design method can adopt the above-mentioned lattice structure model design method to obtain the lattice structure model 600 as the component model. Alternatively, the above-mentioned lattice structure model design method is adopted to obtain the lattice structure model 600; and then the shell model 900 is designed according to the second peripheral model and the lattice structure model 600. The lattice structure model 600 is placed in the shell model 900, and the two are combined to form the component model. Among them, the second peripheral model needs to reserve a certain thickness when designing to prepare the shell model 900. Exemplary, such as Fig. 20 In the component model shown, the shell model 900 covers and defines the edge of the lattice structure model 600, and the lattice structure model 600 fills the shell model 900. Preferably, after the component model is designed, it is also necessary to perform simulation tests on the component model, and use the test results as feedback to adjust the component model until the component model is optimized to meet the set requirements.

[0130] Based on this, the present embodiment also provides a method for manufacturing a component, including: using an additive manufacturing process or a subtractive manufacturing process to manufacture the lattice structure, and / or, manufacturing the component. Specifically, when the lattice structure is an open independent component, the lattice structure model 600 can be obtained according to the above-mentioned design method, and then the lattice structure is automatically printed out according to the lattice structure model 600. Finally, the protective film is coated on the surface of the lattice structure as a component. When the component is composed of a plurality of lattice structures, the component model can be obtained according to the above-mentioned component design method, and then the component is automatically printed out according to the component model. Preferably, in the process of preparing the component, a polymer material is coated on the surface of the lattice structure in the component so that the polymer material covers the lattice structure, and the formed lattice structure is a composite lattice structure, which has the advantages of light weight, high rigidity and low outgassing in a vacuum environment.

[0131] Furthermore, after the parts are prepared, they need to be physically tested, such as physical experiments, mechanical strength, stiffness tests, vibration tests, thermal tests, fluid tests, etc. The test results and data are recorded in the test report to determine whether the physical parts have met the required indicators.

[0132] In summary, the lattice structure, parts and their preparation method provided in this embodiment. Among them, the lattice structure adopts the surface equation as the basic equation in the design process to generate a gradual surface structure to improve the concentrated stress problem and reduce the risk of overhang. Also, a compensation term is used to avoid the occurrence of structural segmentation or separation in the process of generating a low-density lattice structure, and it can ensure that the lattice structure has better continuity and uniformity under the premise of low density and light weight, and realizes the continuous connectivity of the lattice structure within the periodic boundary range such as the region between [-π,π], and has better support capacity, which is conducive to achieving a smaller deformation amount under the support performance of the same material, and can also reduce the preparation cost. Also, the surface of the lattice structure provided in this embodiment is also coated with a protective film, that is, the lattice structure is composed of a composite material, so that the lattice structure has the advantages of light weight, high rigidity and low outgassing in a vacuum environment, and is particularly suitable as a material for structural components of a lightweight sports platform in a vacuum environment.

[0133] The above description is only a description of the preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any changes or modifications made by a person skilled in the art in the field of the present invention based on the above disclosure shall fall within the scope of protection of the technical solution of the present invention.

Claims

1. A lattice structure, characterized in that: include: Multiple unit cells arranged periodically; The unit cell has a plurality of connection ends extending in different directions, and the peripheral morphology of each of the connection ends is a curved surface; wherein the peripheral morphology of each of the connection ends is determined by a preset curved surface equation so as to at least allow the connection ends of adjacent unit cells to be continuously connected.

2. The lattice structure according to claim 1, characterized in that The surface equation includes basic surface terms and compensation terms; wherein the basic surface terms are used to determine the surface model of the unit cell, and the compensation terms are used to adjust the peripheral morphology of each of the connection ends.

3. The lattice structure according to claim 2, characterized in that The basic terms of the surface include the three-periodic minimal surface implicit function equation: Cos(x)+Cos(y)+Cos(z)≥K1; or, Sin(x)+Sin(y)+Sin(z)≥K1; Among them, (x, y, z) are the coordinates of any point in the three-dimensional space coordinate system, K1 is a constant term, and K1∈[0,π].

4. The lattice structure according to claim 2, characterized in that The compensation term includes: K2cos(x)cos(y)cos(z); or, K2sin(x)sin(y)sin(z); Among them, (x, y, z) are the coordinates of any point in the three-dimensional space coordinate system, K2 is a constant coefficient, and K2∈[0,2].

5. The lattice structure according to claim 2, characterized in that The compensation term includes: K2[cos(x)cos(y)+cos(y)cos(z)+cos(z)cosx(x)]), or (K2[sin(x)sin(y)+siny(y)sin(z)+sin(z)sin(x)]; Among them, (x, y, z) are the coordinates of any point in the three-dimensional space coordinate system, K2 is a constant coefficient, and K2∈[0,1].

6. The lattice structure according to claim 2, characterized in that The surface equation also includes a direction parameter P, which is a coefficient of the basic term of the surface, and P∈[0, 2].

7. The lattice structure according to claim 1, characterized in that The lattice structure further includes a protective film, wherein the protective film covers the outer surface of each unit cell, and / or the protective film covers the outer surface of the lattice structure.

8. The lattice structure according to claim 7, characterized in that The material of the protective film includes polymer material.

9. A component, characterized in that: Comprising the lattice structure as claimed in any one of claims 1 to 8.

10. A method for manufacturing a component, characterized in that: The lattice structure according to any one of claims 1 to 8 is manufactured by using an additive manufacturing process or a subtractive manufacturing process, and / or the component according to claim 9 is manufactured.

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