Method for generating lattice unit structure for 3D printing

Abstract

The present specification relates to a method for generating a lattice unit structure for 3D printing by which a lattice structure printed by the method can have a good damping effect and a good supporting capability, that is, when a user wears the sole to move, the lattice units of the sole can maintain the overall shape of the sole, and the entire shape of the sole can be maintained. Therefore, the structure is prevented from twisting and the sole is prevented from deforming.

Description

Technical Field

[0001] The present invention relates to the technical field of lattice unit structure, and in particular to a method for generating a lattice unit structure for 3D printing and a sole using the structure. Background Art

[0002] 3D printing is a manufacturing technology, also known as additive manufacturing technology or rapid prototyping technology. It is a technology that uses digital model files as the basis, and uses powdered metals, ceramics or plastics and other bondable materials to construct objects by printing layer by layer. The lattice structure is currently a powerful design tool in 3D printing. It can achieve a variety of possibilities for different appearances and performances of printed parts according to different uses. The lattice structure can vary greatly from microscopic to macroscopic structure. Different lattice structures and the use of different materials to prepare lattice structures will show completely different mechanical properties. Therefore, how to design 3D printed parts through the shape, size, hierarchical structure, and material composition of the lattice structure to maximize product performance is a very important technical issue.

[0003] Although the soles printed with the lattice structure have good air permeability, they are insufficient in shock absorption, structural stability, and support capacity. In addition, one-piece printing is not easy to achieve and it is difficult to meet the needs of use. The sole structure needs to have good shock absorption and support capacity at the same time. That is, when the user wears the sole for exercise, the lattice structure of the sole needs to maintain the overall shape of the lattice structure to prevent the structure from twisting and the sole from deforming. Summary of the invention

[0004] The purpose of the present invention is to improve the deficiencies of the prior art and to provide a method for generating a lattice unit structure for 3D printing. The lattice structure printed by this method can have a good shock-absorbing effect and a good supporting capacity. That is, when a user wears the sole for exercise, the lattice unit of the sole can maintain the overall shape of the sole, avoiding twisting of the structure and deformation of the sole.

[0005] To achieve the above object, the technical solution of the present invention is: a method for generating a lattice unit structure for 3D printing, comprising the following steps:

[0006] a) placing any plane of a regular dodecahedron on the XY plane, setting the plane as the bottom plane, and the line connecting one of the vertices of the top plane of the regular dodecahedron corresponding to the bottom plane and the midpoint of the side opposite to the vertex is parallel to the X-axis;

[0007] b) generating a bounding box of the dodecahedron, the bounding box being a minimum cuboid that encloses all vertex coordinates of the dodecahedron; c) generating a Thiessen polygon structure with the bounding box as the range and the center point of the dodecahedron and the center point of each face of the regular dodecahedron as reference points;

[0008] d) scaling the bounding box on a single axis to generate a cube;

[0009] e) The polygons enclosed in the cube are the unit cells of the lattice structure;

[0010] f) mirroring the unit cells in the x, y and z directions in an arbitrary order to generate eight consecutive unit cells to form the lattice unit structure.

[0011] Furthermore, the side length of the cube is 5-30 mm.

[0012] Furthermore, the lattice unit structure is integrally formed by 3D printing.

[0013] In addition, the present invention records a sole that uses a 3D printed lattice unit structure to generate a shoe sole, wherein the sole is filled with the lattice unit structure, and the upper and lower surfaces of the sole are respectively provided with a sole fitting portion and an upper fitting portion.

[0014] Furthermore, the sole is integrally formed by 3D printing. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present invention is further described in the form of exemplary embodiments, which will be described in detail by way of the accompanying drawings. These embodiments are non-limiting, in which:

[0016] Figure 1 This is a schematic diagram of the placement of the regular dodecahedron.

[0017] Figure 2 Schematic diagram of the structure of the bounding box of a regular dodecahedron.

[0018] Figure 3 A schematic diagram of generating Thiessen polygon structure.

[0019] Figure 4 This is a schematic diagram of scaling a rectangular block to a cube.

[0020] Figure 5 Schematic diagram of the lattice unit structure.

[0021] Figure 6 It is a test data diagram of the external impact resistance performance of the lattice unit structure in the present invention and the lattice structure disclosed in the patent (CN113491372A). DETAILED DESCRIPTION

[0022] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. On the contrary, the present invention covers any substitutions, modifications, equivalent methods and schemes made on the essence and scope of the present invention as defined by the claims. Further, in order to make the public have a better understanding of the present invention, some specific details are described in detail in the detailed description of the present invention below. For those skilled in the art, the present invention can be fully understood without the description of these details. On the contrary, the present invention covers any substitutions, modifications, equivalent methods and schemes made on the essence and scope of the present invention as defined by the claims. Further, in order to make the public have a better understanding of the present invention, some specific details are described in detail in the detailed description of the present invention below. For those skilled in the art, the present application can be fully understood without the description of these details.

[0023] The present invention discloses a method for generating a lattice unit structure for 3D printing, such as Figure 1 As described, a regular dodecahedron 10 is placed in a fixed position: any plane of the regular dodecahedron 10 is placed in the XY plane, and the plane is set as the bottom plane, and at the same time, the line connecting a vertex A in the top plane corresponding to the bottom plane and the midpoint B of the side opposite to the vertex A is parallel to the X axis. In this patent application, the example of the XY plane is only one of the embodiments of the technology described, and is not the only possible implementation method. As the regular icosahedron mentioned above, it is a completely symmetrical geometric structure, and the above placement position can also be other two planes, namely the XZ or YZ plane.

[0024] like Figure 2 As shown, a bounding box 20 is generated with the regular dodecahedron 10 in this placement position, and the bounding box 20 is the smallest cuboid that encloses all vertex coordinates of the regular dodecahedron 10; the bounding box 20 is an algorithm for calculating the optimal enclosing space of a series of vertices, for example, all vertex coordinates of an irregular geometric body are enclosed in a smallest cuboid box.

[0025] like Figure 3 As shown, the Thiessen polygon structure is generated with the bounding box 20 as the range and the center point of the regular dodecahedron 10 and the center point of each face of the regular dodecahedron as reference points.

[0026] In some embodiments, the side length of the regular dodecahedron is 3.568 mm. Figure 1 The above positions are placed to generate a bounding box 20, the long side a of the bounding box 20 is 9.82 mm, the wide side b is 9.34 mm, and the height c is 7.95 mm. Figure 4As shown, the bounding box 20 is enlarged to 10 mm in a single axis to generate a cube 40, and the lengths of the three sides e, d, and f of the cube 40 are all 10 mm. The polygonal structure enclosed in the cube 40 is the unit cell C of the lattice structure. According to different uses and different shoe size requirements, the side length of the cube 40 ranges from 5 to 30 mm.

[0027] In some embodiments, the unit cell C is first mirrored along the x-axis to generate two unit cells C-Cx, and then (C-Cx) is mirrored along the y-axis to generate four unit cells (C-Cx)-(C-Cx)y. Finally, the four unit cells (C-Cx)-(C-Cx)y are mirrored along the z-axis to generate eight unit cells {(C-Cx)-(C-Cx)y}-{(C-Cx)-(C-Cx)y}z. The eight consecutive unit cells constitute the lattice unit structure.

[0028] In some embodiments, the unit cell C is first mirrored along the y-axis to generate two unit cells C-Cy, and then (C-Cy) is mirrored along the z-axis to generate four unit cells (C-Cy)-(C-Cy)z. Finally, the four unit cells (C-Cy)-(C-Cy)z are mirrored along the x-axis to generate 8 unit cells {(C-Cy)-(C-Cy)z}-{(C-Cy)-(C-Cy)z}x. These eight consecutive unit cells constitute the lattice unit structure.

[0029] In some embodiments, the unit cell C is first mirrored along the z-axis to generate two unit cells C-Cz, and then (C-Cz) is mirrored along the x-axis to generate four unit cells (C-Cz)-(C-Cz)x. Finally, the four unit cells (C-Cz)-(C-Cz)x are mirrored along the y-axis to generate eight unit cells {(C-Cz)-(C-Cz)x}-{(C-Cz)-(C-Cz)x}y. The eight consecutive unit cells constitute the lattice unit structure.

[0030] Because the lattice unit structure is mirrored in any order along the x, y, and z axes, it can achieve hexagonal continuity in up, down, left, right, front, and back directions. That is to say, multiple unit cells C can be placed up and down, or placed front and back, or placed left and right, or placed in any direction or in any combination of multiple directions. This multi-form and multi-level placement arrangement can achieve the continuity of the overall line segment of the lattice unit structure (such as Figure 5 As shown in the figure, it has high strength and good support, that is, when the user wears the sole for exercise, the lattice structure of the sole can well maintain the overall shape of the sole, avoiding the twisting of the structure and deformation of the sole. At the same time, because of its hexagonal continuity, it is convenient to print and form in one piece.

[0031] like Figure 6 As shown in the figure, the lattice structure disclosed in the patent (CN113491372A) and the lattice structure of the present invention are subjected to external impact resistance test data. It can be seen that the horizontal axis is the deformation degree of the lattice structure after being impacted, in mm, and the vertical axis is the impact energy, in N; the upper right curve is the lattice structure data of the present invention. ， The lower right curve is the data of the lattice structure disclosed in the patent (CN113491372A). When the lattice structure disclosed in the patent (CN113491372A) and the lattice structure disclosed in the present invention are both compressed to 4mm, the lattice structure disclosed in the present invention requires 350N, while the lattice structure disclosed in the patent (CN113491372A) requires 50N; when the lattice structures are compressed to 8mm, the lattice structure disclosed in the present invention requires 500N, while the lattice structure disclosed in the patent (CN113491372A) requires 200N. As shown by the above test results, under the same deformation conditions, the lattice structure disclosed in the present invention can absorb more impact energy, has higher impact resistance, can better resist external forces and is not easy to produce permanent shape changes. In other words, the lattice structure disclosed in the present invention has higher strength and good support.

[0032] The lattice unit structure for 3D printing disclosed in the present invention undergoes elastic deformation after the top or bottom surface is subjected to pressure parallel to the normal direction of these two surfaces. However, due to the asymmetric design of the top and bottom surfaces, the elastic modulus of the lattice structure does not remain consistent during the entire elastic deformation process, so the stress-strain curve of its elastic deformation is not a straight line. If the lattice structure is used to prepare the sole, such an elastic deformation process can provide the wearer's foot with better shock-absorbing and cushioning comfort.

[0033] In some embodiments, the lattice unit structure and the sole using the lattice unit structure are integrally formed by 3D printing. Specifically, the 3D printing technology may be photo-curing 3D printing. The specific printing steps include:

[0034] Step 1: Create a three-dimensional model of the lattice unit structure and the sole in computer software. Those skilled in the art can create the three-dimensional model in software such as Rhino, Grasshopper, Solidworks, Catia or UG.

[0035] Step 2: Use a light-curing 3D printing technology device to use an elastic resin material to print the lattice unit structure and the sole of the present invention from the three-dimensional model made in the above steps.

[0036] (Optional) Step 3: Clean the printed lattice unit structure and the sole to remove the excess uncured resin on the surface;

[0037] (Optional) Step 4: If an elastic resin material with multiple curing mechanisms is used, the photocured print is further cured; the further curing conditions may be thermal curing (including heating curing, room temperature curing, oven curing, water bath curing and other applicable curing conditions) or further photocuring.

[0038] It should be further explained that the lattice unit structure disclosed in the present invention can be applied to products in other fields besides soles, and there is no limitation in the present embodiment. In particular, according to the different properties of the materials used in the lattice unit structure, combined with its structure, it can meet the mechanical property requirements of different products. Generally speaking, the materials used for photocuring 3D printing of the lattice unit structure include two major categories of photocurable resins, one is traditional photocurable resins, and the other is dual-curable resins. Among them, traditional photocurable resins mainly include photocurable resin monomers or oligomers, and photoinitiators. In addition to photocurable resin monomers or oligomers and photoinitiators, dual-curable resins also have components that are still uncured after the photocuring step. The uncured components can be further cured in the post-curing step after the photocuring step.

[0039] Specifically, the photocurable resin monomer and / or oligomer can be an acrylate material containing a carbon-carbon double bond, the specific monomer can be an acrylate, the oligomer can be a polyurethane methacrylate and / or a polyurethane acrylate, wherein the photoinitiator can be one of benzoin, diphenylacetophenone (diphenylacetophenone), benzophenone, aromatic acylphosphine oxide (such as 2,4,6-trimethylbenzoyl-diphenylphosphine oxide or TPO), thiopropoxythioxanthone, or a mixture of multiple ones.

[0040] In particular, the uncured component may be a mixture of one or more of cyanate, isocyanate, TPU (thermoplastic polyurethane elastomer rubber), epoxy resin, and silicone resin.

[0041] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but not to impose any restrictions thereon. Although the technical solutions of the present invention are described in detail with reference to the above embodiments, a person skilled in the art should understand that the technical solutions described in the above embodiments can still be modified, or some or all of the technical features can be replaced by equivalents, and these modifications and equivalent replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for generating a lattice unit structure for 3D printing, characterized in that: a) placing any plane of a regular dodecahedron on the XY plane, setting the plane as the bottom plane, and the line connecting one of the vertices of the top plane of the regular dodecahedron corresponding to the bottom plane and the midpoint of the side opposite to the vertex is parallel to the X-axis; b) generating a bounding box of the dodecahedron, the bounding box being a minimum cuboid enclosing all vertex coordinates of the dodecahedron; c) using the bounding box as the range, the center point of the dodecahedron and the center point of each face of the regular dodecahedron as reference points to generate a Thiessen polygon structure; d) scaling the bounding box on a single axis to generate a cube; e) The polygon enclosed in the cube is the unit cell of the lattice structure; f) mirroring the unit cells in the x, y and z directions in an arbitrary order to generate eight consecutive unit cells to form the lattice unit structure.

2. A method for generating a lattice unit structure for 3D printing according to claim 1, characterized in that: The side length of the cube is 5-30 mm.

3. A method for generating a lattice unit structure for 3D printing according to claim 1, characterized in that: The lattice unit structure is integrally formed by 3D printing.

4. A shoe sole using the lattice unit structure according to claims 1-3, wherein the shoe sole is filled with the lattice unit structure, and the upper and lower surfaces of the shoe sole are respectively provided with a sole fitting part and a shoe upper fitting part.

5. The sole according to claim 4, characterized in that The sole is integrally formed by 3D printing.

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