A method, system and device for generating lattice structure for additive manufacturing

Abstract

The present specification relates to a method for generating a lattice structure for additive manufacturing, the method comprising: generating a cell model covering a model to be printed, the cell model being composed of a plurality of virtual cells, the plurality of virtual cells including at least one external virtual cell, at least a portion of each external virtual cell being located outside the outer contour of the model to be printed; filling a cellular structure in each virtual cell in the cell model to obtain a lattice model; and correcting a target portion of the lattice model corresponding to the at least one external virtual cell based on the outer contour of the model to be printed to obtain a corrected lattice model, the corrected lattice model being used for additive manufacturing of the model to be printed.

Description

Technical Field

[0001] This specification relates to the technical field of additive manufacturing (also known as 3D printing), and in particular to a method, system, and device for generating a lattice structure for additive manufacturing. Background Art

[0002] The lattice structure is a spatial grid-like structure composed of cellular structures. The lattice structure has many advantages such as light weight, high strength, heat insulation, energy absorption and shock absorption, and noise reduction. It is widely used in many fields such as additive manufacturing, aerospace, and shipbuilding. However, in the traditional lattice structure generation process, the cellular structure is mostly a single scale or a single configuration. For irregularly shaped printed object models, it is often necessary to compress the cellular structure to make the lattice structure fit the printed object model. This approach will cause the cellular structure in the edge area of the lattice structure to be distorted, resulting in the alienation of local performance of the printed part and affecting the performance of the printed part.

[0003] Therefore, a method for generating a dot matrix structure is needed to meet the performance of the printed part. Summary of the Invention

[0004] One of the embodiments of the present specification relates to a method for generating a lattice structure for additive manufacturing, the method comprising: generating a cell model covering a model to be printed, the cell model being composed of a plurality of virtual cells, the plurality of virtual cells including at least one external virtual cell, at least a portion of each external virtual cell being located outside the outer contour of the model to be printed; filling a cellular structure in each virtual cell in the cell model to obtain a lattice model; and correcting a target portion of the lattice model corresponding to the at least one external virtual cell based on the outer contour of the model to be printed to obtain a corrected lattice model, the corrected lattice model being used for additive manufacturing of the model to be printed.

[0005] One of the embodiments of the present specification also relates to a lattice structure generation system, the system comprising: a cell model generation module, for generating a cell model covering a model to be printed, the cell model being composed of a plurality of virtual cells, the plurality of virtual cells including at least one external virtual cell, at least a portion of each external virtual cell being located outside the outer contour of the model to be printed; a cell structure filling module, for filling a cell structure in each virtual cell in the cell model to obtain a lattice model; a lattice model correction module, for correcting a target portion in the lattice model corresponding to the at least one external virtual cell based on the outer contour of the model to be printed to obtain a corrected lattice model, the corrected lattice model being used for additive manufacturing of the model to be printed.

[0006] One of the embodiments of this specification also relates to a lattice structure generation device, including a processor, wherein the processor is used to execute the lattice structure generation method mentioned above. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] This specification will be further described in the form of exemplary embodiments, which will be described in detail with reference to the accompanying drawings. These embodiments are not limiting, and in these embodiments, like numbers represent like structures, wherein:

[0008] Figure 1 is a system block diagram of a lattice structure generation system according to some embodiments of this specification;

[0009] Figure 2 is an exemplary flow chart of a method for generating a lattice structure for additive manufacturing according to some embodiments of this specification;

[0010] Figure 3 is an exemplary flow chart of a target node offset method according to some embodiments of this specification;

[0011] Figures 4A-4D is an example diagram of a sole model printing process according to some embodiments of this specification;

[0012] Figures 5A-5C is an example diagram of the sole model printing process according to the traditional method; and

[0013] Figures 6A-6B This is an example diagram of performing target node offset according to some embodiments of this specification. DETAILED DESCRIPTION

[0014] To more clearly illustrate the technical solutions of the embodiments of this specification, the following briefly describes the drawings required for describing the embodiments. Obviously, the drawings described below are merely examples or embodiments of this specification. Those skilled in the art can apply this specification to other similar scenarios based on these drawings without inventive effort. Unless otherwise apparent from the context or otherwise noted, the same reference numerals in the figures represent the same structure or operation.

[0015] It should be understood that the terms "system," "device," "unit," and / or "module" used herein are a method for distinguishing different components, elements, parts, portions, or assemblies at different levels. However, if other terms can achieve the same purpose, the terms may be replaced by other expressions.

[0016] As used in this specification and claims, unless the context clearly indicates otherwise, the words "a," "an," "an," and / or "the" do not refer to the singular but also include the plural. Generally speaking, the terms "comprises" and "include" only indicate the inclusion of the steps and elements specifically identified, and these steps and elements do not constitute an exclusive list. A method or apparatus may also include other steps or elements.

[0017] Flowcharts are used throughout this specification to illustrate the operations performed by systems according to embodiments of this specification. It should be understood that preceding or following operations do not necessarily need to be performed in exact order. Instead, the steps may be processed in reverse order or simultaneously. Furthermore, other operations may be added to these processes, or one or more operations may be removed from these processes.

[0018] The lattice structure is a spatial grid-like ordered porous structure formed by an array of cellular structures. The cellular structure consists of multiple nodes and connecting rod units. Additive manufacturing technology can print the printing model based on the lattice structure to produce a variety of part entities. As the complexity of the model to be printed increases, how to achieve high-quality printing through lattice design becomes an important technical issue. However, when using the traditional lattice filling method to print models with irregular shapes to be printed, the size of the cell cannot change with the thickness of the part. In areas where the part is thinner, the cellular structure needs to be extruded and deformed to fill the lattice. At this time, the extrusion deformation of the cellular structure (also known as structural distortion) will cause the number of connecting rods in the deformed area to increase, causing the mechanical properties of this printed area to change, which does not meet the mechanical properties required in the model design; at the same time, blockage may occur during the printing process, increasing the chance of printing failure.

[0019] Figures 5A-5C This is a schematic diagram of printing a sole model according to the traditional method. Figure 5A The sole model shown. Figure 5B As shown in , the sole model will be divided into several hexahedrons of different sizes to fit the model outline of the sole model. Figure 5C As shown in the figure, each hexahedron will be filled with a cell structure (such as a fluorite structure) to form a lattice structure. Since the sizes of the hexahedrons in the traditional lattice structure are different, when filling the cell structure (especially when filling the cell structure in some relatively small hexahedrons), the cell structure often needs to be structurally distorted so that it can be completely filled into the hexahedron. For example, from Figure 5C It can be seen that in the area where the model thickness is thinner ( Figure 5CIn the B1 area in the middle, the cell structure undergoes structural distortion during filling. The size of the cell structure in the B1 area after structural distortion is smaller than that in the B2 part, and the density of the connecting rods in the B1 part is greater than the density of the connecting rods in the B2 part. Since the connecting rods are denser in the structurally distorted part (such as the B1 area), the parts printed in this part will have a higher hardness, and it may be impossible to obtain parts that meet the design requirements. On the other hand, when printing the structurally distorted area (such as the B1 area), since the size of the cell structure becomes smaller, the risk of printing blockage and printing failure during printing increases accordingly.

[0020] In order to solve the above problems, in one or more embodiments involved in this specification, a method for generating a lattice structure for additive manufacturing is proposed. The method includes generating a cell model covering the model to be printed, and then filling a cellular structure in each virtual cell to obtain a lattice model. The cell model is composed of a plurality of virtual cells, and the plurality of virtual cells include at least one external virtual cell, and at least a portion of each external virtual cell is located outside the outer contour of the model to be printed. In some embodiments, each virtual cell can have the same shape and size. At this time, a cellular structure of the same size can be selected for filling according to the size of the virtual cell to avoid structural distortion of the cellular structure in the thinner area of the model. In addition, the lattice structure generated by the above method can have the same density in different areas. This can avoid the problem of printing blockage due to overly dense lattices, improve printing efficiency, and save printing materials.

[0021] In some embodiments, the lattice structure generation method further includes modifying the target portion corresponding to the virtual cells in the lattice model based on the outer contour of the model to obtain a modified lattice model. For example, the target portion of the lattice model can be cut based on the outer contour of the to-be-printed model, removing the portion of the cell structure outside the outer contour, wherein each cut cell structure is separated from the outer contour by at least one cut point; the cut points can then be connected to obtain a modified lattice model. This method improves the conformity of the lattice model to the outer contour of the original to-be-printed model.

[0022] Figure 1 It is a system block diagram of a lattice structure generation system according to some embodiments of this specification.

[0023] like Figure 1 The lattice structure generation system 100 (referred to as the system 100 ) can be implemented on any computing system and can include a cell model generation module 110 , a cell structure filling module 120 , and a lattice model correction module 130 .

[0024] The cell model generation module 110 can be used to generate a cell model that covers the model to be printed. The cell model is composed of multiple virtual cells. The multiple virtual cells include at least one external virtual cell, wherein at least a portion of each external virtual cell is located outside the outer contour of the model to be printed.

[0025] The cell structure filling module 120 may be configured to fill each virtual cell in the unit cell model with a cell structure to obtain a lattice model.

[0026] The lattice model correction module 130 can be used to correct the target part corresponding to the at least one external virtual cell in the lattice model based on the outer contour of the model to be printed to obtain a corrected lattice model, and the corrected lattice model is used for additive manufacturing of the model to be printed.

[0027] In some embodiments, the lattice model correction module 130 is also used to: cut the target part of the lattice model based on the outer contour of the model to be printed, remove part of the cell structure outside the outer contour, wherein at least one cutting breakpoint is generated between each cut cell structure and the outer contour; and process the cutting breakpoint to obtain a corrected lattice model.

[0028] In some embodiments, the lattice model correction module 130 is further configured to: determine, for each of the cutting breakpoints, a target breakpoint to be connected to the cutting breakpoint; and connect the cutting breakpoint to the at least one target breakpoint.

[0029] In some embodiments, the cell structure includes a plurality of nodes. The lattice model correction module 130 is further used to: before cutting the target part of the lattice model based on the outer contour of the model to be printed, screen out at least one target node from the multiple nodes of the cell structure, and the distance between each target node and the outer contour meets a preset condition; offset the at least one target node onto the outer contour. In some embodiments, the lattice model correction module 130 is further used to: obtain an outer bias surface of the outer contour of the model to be printed, the outer bias surface being obtained by offsetting the outer contour outward by a first distance; obtain an inner bias surface of the outer contour of the model to be printed, the inner bias surface being obtained by offsetting the outer contour inward by a second distance; and determine the node between the inner bias surface and the outer bias surface as the at least one target node.

[0030] In some embodiments, the dot matrix model correction module 130 is further configured to smooth the line between the cutting breakpoint and each corresponding target breakpoint based on the outer contour of the to-be-printed model.

[0031] In some embodiments, the cell structure includes at least two cell structures. The cell structure filling module 120 is further configured to obtain an array relationship between the at least two cell structures and fill each virtual cell with a cell structure based on the array relationship to obtain a lattice model.

[0032] It should be understood that Figure 1 The system and its modules shown can be implemented in various ways. For example, in some embodiments, the device and its modules can be implemented by hardware, software, or a combination of software and hardware. Among them, the hardware part can be implemented using dedicated logic; the software part can be stored in a memory and executed by an appropriate instruction execution device, such as a microprocessor or dedicated hardware. Those skilled in the art will understand that the above-mentioned methods and devices can be implemented using computer-executable instructions and / or contained in processor control code, for example, such as a carrier medium such as a disk, CD or DVD-ROM, a programmable memory such as a read-only memory (firmware), or a data carrier such as an optical or electronic signal carrier. The device and its modules of this specification can not only be implemented by hardware circuits such as very large-scale integrated circuits or gate arrays, semiconductors such as logic chips, transistors, or programmable hardware devices such as field programmable gate arrays, programmable logic devices, etc., but can also be implemented by software executed by various types of processors, or by a combination of the above-mentioned hardware circuits and software (for example, firmware).

[0033] Figure 2 is an exemplary flow chart of a method for generating a lattice structure according to some embodiments of this specification.

[0034] In some embodiments, Figure 2 The process 200 shown can be performed by Figure 1 For ease of understanding, this application takes the sole model as an example, combined with Figures 4A-4D The method for generating a lattice structure is described. It should be noted that the sole model described below is for illustration only and does not constitute a limitation of this application. It is understood that in one or more embodiments of this specification, the model to be printed can be any other model besides the sole model, and this specification does not impose any limitation thereto.

[0035] Step 210 , generating a cell model covering the model to be printed. In some embodiments, step 210 may be performed by the cell model generation module 110 .

[0036] The cell model is composed of multiple virtual cells, which must cover the entire volume of the model to be printed. The multiple virtual cells include at least one external virtual cell, which is a cell at least partially located outside the outer contour of the model to be printed. In some embodiments, the cell model can be generated using a finite element analysis algorithm or a finite difference method.

[0037] In some embodiments, the shapes of different virtual cells may be the same or different. For example, the shape of the virtual cell may be a tetrahedron, a pentahedron, a hexahedron, or the like, or the like, or different shapes. Preferably, the shapes of different virtual cells may be the same. In some embodiments, the shape of the virtual cell may be similar to the shape of the cell structure to be subsequently filled. By setting this up, the amount of calculation required for subsequent cell structure filling can be reduced, and the occurrence of the phenomenon in which the cell structure cannot fill the entire virtual cell during filling can be reduced. For example, when the cell structure to be filled is a tetrahedron and the virtual cell is set to a cube, the cell structure cannot fill the entire virtual cell, resulting in some areas being unable to be filled. Therefore, in one or more embodiments of this specification, the shape of the virtual cell may be set according to the shape of the cell structure to be subsequently filled. For example, when the cell structure to be filled is a tetrahedron, the virtual cell may also be set to a tetrahedron. For another example, when the cell structure to be filled is a hexahedron, the virtual cell may also be set to a hexahedron shape.

[0038] In some embodiments, the sizes of different virtual cells may be the same or different. In some embodiments, the sizes of the virtual cells may not be exactly the same. For example, in Figure 4A In areas where the midsole model is thinner, the size of the virtual cells can be set to be smaller to fit the model to the greatest extent. In some embodiments, the size of the virtual cells can be set to be exactly the same.

[0039] Preferably, the virtual cell can be set to a hexahedron of exactly the same shape and size. When the virtual cell is set to a hexahedron, it can be convenient to fill in a cell structure with a hexahedral shape (such as a body-centered cubic, face-centered cubic, etc. cell structure). More preferably, the virtual cell can be set to a cube of exactly the same shape and size. The size of the cube can be set arbitrarily. For example, the side length of the cube can be set to 2 millimeters (mm), 3mm, 5mm, etc. When the virtual cell is set to a cube, any completely symmetrical cell structure can be added thereto to generate a lattice model, so that the mechanical properties of the solid model printed based on the lattice model are similar in all directions.

[0040] For example, Figure 4A Shown is a sole model 400A, Figure 4BThe cell model 400B corresponding to the sole model 400A is shown. Figure 4B As shown, the cell model 400B includes a plurality of virtual cells, which are cubes of identical shape and size. The plurality of virtual cells include a plurality of external virtual cells 410, each of which has at least a portion outside the outer contour of the sole model 400A.

[0041] Step 220 , filling a cell structure in each virtual cell in the cell model to obtain a lattice model. In some embodiments, step 220 may be performed by the cell structure filling module 120 .

[0042] A cell structure is the unit structure that constitutes a lattice model. The lattice model can be obtained by orderly arranging multiple cell structures. In some embodiments, the cell structure filling module 120 can fill each virtual cell with a cell structure and then remove the virtual cells to obtain a lattice model containing only the cell structure. In some embodiments, the dimensional parameters and / or internal structure of the cell structure can be pre-set. The dimensional parameters of the cell structure can include the shape and size of the cell structure's outer contour. For example, if the cell structure is a hexahedron, the cell dimensions can include the cell's length, width, and height. For another example, if the cell structure is a tetrahedron, the cell dimensions can include the lengths of the cell structure's six sides. In some embodiments, the dimensional parameters of the cell structure can be related to the dimensions of the virtual cell. For example, the dimensional parameters of the cell structure can be determined based on the dimensional parameters of the virtual cell so that a virtual cell can be fully filled with an integer number of cell structures. By way of example only, if the cell structure can be a 5mm×5mm×5mm cube and the virtual cell dimensions can be 5mm×10mm×15mm, then six complete cell structures can be filled in one virtual cell. For another example, the size of a virtual cell can be 50mm×10mm×100mm. In this case, 400 complete cell structures can be filled into one virtual cell. It can be understood that when the size of the cell structure is related to the size of the virtual cell, the side length of the virtual cell can be an integer multiple of the length of one side of the cell size. With this setting, when filling a virtual cell with a cell structure, an integer number of complete cell structures can be filled.

[0043] The internal structure of the cell structure may include one or more connecting rods and multiple nodes, where each connecting rod can be used to connect two nodes. For example, the internal structure of the cell can be any one of a fluorite structure, an anti-fluorite structure, a NaCl structure, a CsCl structure, an α-Al2O3 structure, a diamond structure, and the like.

[0044] In some embodiments, a cell structure can be used to fill virtual cells. In some embodiments, multiple cell structures can be used to fill virtual cells. Different types of cell structures can have different cell sizes and / or different cell internal structures. Exemplarily, the application scenario of filling with two cell structures A and B is described as an example. For example, the two cell structures A and B are both fluorite structures, but their sizes are different. For another example, the two cell structures A and B have the same size, but A is a fluorite structure and B is an anti-fluorite structure. For another example, the two cell structures A and B have different internal structures and different sizes.

[0045] In some embodiments, before using multiple cell structures to fill virtual cells, the cell structure filling module 120 can obtain the array relationship between the multiple cell structures and fill each virtual cell with cell structures based on the array relationship. The array relationship between the multiple cell structures can reflect the filling rules of different cell structures in the virtual cell. The filling rules may include the ratio of the multiple cell structures, the array repetition method, etc. For example, when the two cell structures A and B described above are used to fill the virtual cell together, the array relationship can stipulate that the number ratio of the two cell structures is 1:1, and they are arranged at various intervals in the virtual cell. At this time, in any direction in the virtual cell, the cell structure is arranged in the form of A, B, A, B...A, B. It should be noted that those skilled in the art can arbitrarily change the embodiments of this specification based on the knowledge of the embodiments of this specification. For example, the multiple cell structures can be any number, such as 2, 3, 5, etc. Similar changes are still within the scope of protection of this specification.

[0046] Step 230 : Based on the outer contour of the to-be-printed model, the target portion corresponding to the at least one external virtual cell in the lattice model is corrected to obtain a corrected lattice model. In some embodiments, step 230 may be performed by the lattice model correction module 130 .

[0047] Take the sole model as an example (the sole model is as follows Figure 4A As shown), the lattice model obtained in step 220 is as follows Figure 4C ( Figure 4C It is not difficult to see that the lattice model obtained in step 220 has some connecting rods in the cell structure exceeding the outer contour of the sole model. Figure 4C The obtained model is then used for additive manufacturing (3D printing), but the printed part does not conform to the designed outline. Figure 4CThe edges of the model have many independent connecting rods, each connected to a node at one end and unconnected to any other nodes at the other end (a cantilever structure). This type of connecting rod has poor strength and is prone to breakage or damage after printing. Therefore, the dot matrix model correction module 130 needs to correct the target portion corresponding to at least one external virtual cell based on the outer contour of the printed model to address the aforementioned technical issues.

[0048] As mentioned above, some of the external virtual cells of the cell model may be located outside the outer contour of the model to be printed (e.g. Figure 4B 410 is the external cell). If the model is printed directly based on the lattice model generated in step 220, the printed part may not match the outer contour of the model to be printed. Therefore, it is necessary to correct the target part of the lattice model corresponding to the external virtual cell. In some embodiments, the lattice model correction module 130 can cut the target part of the lattice model based on the outer contour of the model to be printed, and remove part of the cell structure outside the outer contour. Specifically, the cell structure contained in the target part of the lattice model may be cut and thus become incomplete. For example, at least one connecting rod in each cut cell structure will be cut by the outer contour of the model to be printed. In this specification, the point where the cell structure intersects with the outer contour of the model to be printed is called a cutting breakpoint. Furthermore, the lattice model correction module 130 can process the cutting breakpoints generated by the cutting to obtain a corrected lattice model.

[0049] In some embodiments, the lattice model correction module 130 may interconnect different cutting breakpoints to obtain a corrected lattice model. In some embodiments, the lattice model correction module 130 may determine at least one target breakpoint to be connected to the cutting breakpoint, and then connect the cutting breakpoint to each of the determined target breakpoints. In some embodiments, the lattice model correction module 130 may determine other breakpoints in the same cell structure as the cutting breakpoint as target breakpoints. In some embodiments, the lattice model correction module 130 may determine breakpoints in adjacent cell structures to the cutting breakpoint as target breakpoints. In some embodiments, the target breakpoint corresponding to a cutting breakpoint may be determined based on the distance between it and the other cutting breakpoints. For example, for cutting breakpoint X, the lattice model correction module 130 may determine the cutting breakpoint Y with the shortest distance from it as the target breakpoint for cutting breakpoint X. For another example, the lattice model correction module 130 may determine the cutting breakpoint Y with a distance from cutting breakpoint X less than a first distance threshold as the target breakpoint for cutting breakpoint X. Furthermore, the lattice model correction module 130 may connect the cutting breakpoint X and each cutting breakpoint Y.

[0050] In some embodiments, the line connecting a cutting breakpoint and its corresponding target breakpoint can be a straight line or a curved line. In some embodiments, the dot matrix model correction module 130 can also smooth the line connecting the cutting breakpoint and each corresponding target breakpoint based on the outer contour of the model to be printed. This smoothing process can make the line connecting the cutting breakpoint and the target breakpoint conform to the outer contour of the model to be printed. In this way, the fit between the corrected dot matrix model and the model to be printed can be further improved.

[0051] Below Figures 4A to 4D The specific process of the process 200 is described in detail by taking it as an example.

[0052] for Figure 4A The model to be printed 400A shown in FIG. 2 can be used to generate a cell model 400B covering the model to be printed. The cell model is as shown in FIG. Figure 4B Further, the cell structure can be filled in each virtual cell in the cell model 400B in step 220 to obtain Figure 4C The lattice model 400C shown in . Since the cell model 400B contains some external virtual cells 410 that exceed the model to be printed, after the cell structures are filled in these external virtual cells, these cell structures will also partially exceed the range of the model to be printed. In order to make the shape of the final lattice model match the original model to be printed 400A, the lattice model 400C can be corrected based on the outer contour of the model to be printed in the manner of step 230. For example, the cell structure in the external virtual cell can be cut based on the outer contour of the model to be printed 400A, and the cell structure outside the outer contour can be removed. Then, the cut breakpoints obtained by cutting can be connected to each other to obtain Figure 4D As shown in the figure, the modified dot matrix model 400D can fit the outline of the model 400A to be printed.

[0053] It should be understood that the above description of process 200 is merely exemplary and is not intended to limit the scope of protection of this specification. For those skilled in the art, multiple corrections and changes can be made under the guidance of this specification. However, these corrections and changes will not depart from the scope of protection of this specification. In some embodiments, process 200 may include one or more additional steps. In some embodiments, one or more steps of process 200 described above may be omitted or split into multiple sub-steps.

[0054] For example, before cutting the target part of the lattice model based on the outer contour of the model to be printed, the lattice model correction module 130 can also offset the target node in the cell structure to reduce the number of breakpoints. For more information on offsetting the target node, see Figure 3 The corresponding description will not be repeated here.

[0055] For another example, after step 230, a physical printing model corresponding to the model to be printed can be generated based on the corrected lattice model. In some embodiments, before the lattice model is printed, the parameters of the connecting rods in the lattice model can be set to generate a physical printing model that meets the requirements. The parameters of the connecting rods may include the length of the connecting rods, the thickness of the connecting rod diameter, etc. It can be understood that the parameters of different connecting rods in the cell structure will affect the performance of the physical printing model. For example, the thicker the diameter of the connecting rod, the higher the stiffness of the printed part entity, and the higher the modulus of resistance to deformation per unit volume. For another example, the longer the length of the connecting rod, the worse the stiffness of the printed part entity, and the worse the modulus of resistance to deformation per unit volume.

[0056] by Figure 4D Taking the modified dot matrix model 400D shown as an example, in some implementation scenarios, the upper and lower bottom surfaces of the sole components are subjected to pressure. In this case, the diameter of the connecting rods perpendicular (or nearly perpendicular) to the upper and lower bottom surfaces in the modified dot matrix model 400D can be adaptively increased to resist the pressure borne by the upper and lower bottom surfaces and increase the service life of the printed sole components. In some implementation scenarios, similar adjustments can also be made in the horizontal direction of the sole components. For example, the diameter of the connecting rods of the arch and forefoot components can be adaptively increased to provide stronger support.

[0057] In some implementation scenarios, the diameter of the connecting rod can also be gradually increased. Figure 4D Taking the modified lattice model 400D as an example, the diameter of the connecting rods near the instep can be adjusted to be smaller, while the diameter of the connecting rods farther from the instep can be adjusted to be larger. This arrangement makes the lattice units closer to the instep softer, increasing wearing comfort, while the units closer to the ground are harder, increasing the support capacity of the sole.

[0058] In some embodiments, setting of connecting rod parameters in the lattice model may also be performed in step 220 .

[0059] Figure 3 This is an exemplary flowchart of a target node offset method according to some embodiments of this specification.

[0060] In some embodiments, Figure 3 The process 300 shown can be performed by Figure 1Specifically, process 300 may be executed by the lattice structure generation system 100. Specifically, process 300 may be executed by the lattice model correction module 130. Process 300 may be executed before cutting the target portion of the lattice model based on the outer contour of the model to be printed (e.g., before step 230). Process 300 may specifically include the following steps.

[0061] Step 310 : Filter out at least one target node from the multiple nodes of the cell structure, where the distance between each target node and the outer contour meets a preset condition.

[0062] In some embodiments, the preset condition may be related to the distance between the node and the outer contour of the model to be printed. For example, the preset condition may be that the minimum distance between the node and the outer contour of the model to be printed is less than a second distance threshold.

[0063] In some embodiments, the preset condition may relate to whether the node is located within a preset spatial region near the outer contour of the model to be printed. For example, the lattice model correction module 130 may obtain the inner and outer offset surfaces of the outer contour and determine the space between the inner and outer offset surfaces as the preset spatial region. The lattice model correction module 130 may then determine all nodes within this preset spatial region as target nodes.

[0064] Specifically, the lattice model correction module 130 can obtain an outer offset surface and an inner offset surface of the outer contour of the to-be-printed model, wherein the outer offset surface is obtained by offsetting the outer contour outward by a first distance, and the inner offset surface is obtained by offsetting the outer contour inward by a second distance. The lattice model correction module 130 can further determine a node between the inner offset surface and the outer offset surface as a target node. The first distance and the second distance can be the same or different.

[0065] By determining the target nodes based on the preset spatial area, the dot matrix model correction module 130 does not need to calculate the distance between each node and the outer contour of the model to be printed. This can improve the efficiency of determining the target nodes and quickly identify all target nodes.

[0066] It should be noted that those skilled in the art can make various reasonable transformations to the technical solution of this specification on the basis of this specification. For example, the determination of the above-mentioned target node can be achieved in other feasible ways. As an example only, the lattice model correction module 130 can only obtain the outer bias surface, and determine the node between the outer bias surface and the outer contour as the target node. For another example, the lattice model correction module 130 can only obtain the inner bias surface, and determine the node between the inner bias surface and the outer contour as the target node. Similar transformations are still within the scope of protection of this specification.

[0067] Step 320: offset the at least one target node onto the outer contour.

[0068] The offset target node and other nodes of the lattice can form a preliminary revised lattice model. The lattice model revision module 130 can perform step 230 on the preliminary revised lattice model to generate a final revised lattice model.

[0069] In some embodiments, the lattice model correction module 130 may offset the target nodes along the direction of their minimum distance to the outer contour of the model to be printed. In some embodiments, the lattice model correction module 130 may also set a minimum adjacent distance, requiring the distance between the offset target nodes to be no less than the minimum adjacent distance. This setting can ensure a relatively even distribution of the target nodes along the outer contour of the model to be printed, thereby avoiding issues such as two target nodes being too close together and the connecting rods being too densely packed in the initially corrected lattice model.

[0070] It can be understood that by using the process 300 to offset the target node in the cell structure and then performing the correction process in step 230, some technical effects can be achieved. Figures 6A-6B Further explanation will be given. Figure 6A Schematic diagram of some nodes of the lattice model. Figure 6B To follow the process 300 pairs Figure 6A Schematic diagram after processing the nodes in . Figure 6A and 6B In the figure, curve S1 is the outer contour line of the model to be printed, and P1, P2, P3, P4, and P5 are the four nodes connected to P1.

[0071] On the one hand, the method shown in process 300 can reduce the number of breakpoints generated by cutting. Figure 6A As shown, node P1 is connected to the other four nodes P2, P3, P4, and P5. If the dot matrix model is cut directly using the outer contour S1 of the model to be printed, four corresponding cutting points C1, C2, C3, and C4 will be generated. If node P1 is located between the outer bias surface and the inner bias surface, after processing using the method of process 300, P1 will be offset to the outer contour surface. The node diagram after offset is as follows Figure 6B As shown in P11 in the figure. Obviously, at this point, the outer contour (S1) of the model to be printed is used for cutting, and the cutting point coincides with node P11 (only one cutting point is generated). Thus, process 300 can reduce the number of cutting points, thereby reducing the amount of computation required to connect the cutting points and smooth the connecting lines when executing step 230, thereby improving computational efficiency.

[0072] On the other hand, the process 300 can avoid the generation of some short connecting rods. Figure 6AAs shown, if the node P1 is very close to the outer contour surface (such as a distance of only 0.1 mm), if cutting is performed directly based on the outer contour surface S1, four cutting breakpoints C1, C2, C3, and C4 will be generated. These four cutting breakpoints are connected to the node P1 to produce four short connecting rods. Furthermore, these cutting breakpoints need to be interconnected in the manner shown in step 230. After the breakpoints are connected, the density of the connecting rods in this area is very high, which will cause the stiffness of this area to be too high after printing. If the node P1 is located between the outer bias surface and the inner bias surface, after the process 300 is used for biasing, this node is offset to the outer contour (such as moving to the position of P11 as shown in Figure 6). At this time, the four cutting breakpoints C1, C2, C3, and C4 and the short connecting rods will not be generated, thereby avoiding the problem of too dense distribution of the connecting rods, thereby improving the quality of the printed solid model.

[0073] The beneficial effects that may be brought about by the embodiments of this specification include but are not limited to: 1) In some embodiments of this specification, virtual cells of the same size are used to construct a cell model covering the model to be printed. When filling the cell structure, even in areas where the part thickness is thinner, there is no need to distort the cell structure, thereby improving the quality of the printed entity model; 2) The shape of the virtual cell is set similarly to the cell structure, which can reduce the amount of calculation when filling the cell structure and reduce the phenomenon that the cell structure cannot fill the entire virtual cell when filling the cell structure; 3) Based on the outer contour of the model, the target part corresponding to the virtual cell in the lattice model is corrected, which can improve the fit between the lattice model and the outer contour of the model to be printed, thereby improving the printing quality; 4) The lattice model is preliminarily corrected by offsetting the target node, which can reduce the number of cutting breakpoints generated when cutting using the outer contour, and further reduce the amount of calculation required for connecting and smoothing the cutting breakpoints, thereby improving the calculation efficiency. It should be noted that different embodiments may have different beneficial effects. In different embodiments, the beneficial effects that may be produced may be any one or a combination of the above, or any other possible beneficial effects.

[0074] While the basic concepts have been described above, it will be apparent to those skilled in the art that the detailed disclosure is merely illustrative and does not limit this specification. Although not explicitly stated herein, various modifications, improvements, and revisions to this specification may be made by those skilled in the art. Such modifications, improvements, and revisions are suggested in this specification and remain within the spirit and scope of the exemplary embodiments of this specification.

[0075] This specification also uses specific terms to describe the embodiments of this specification. For example, "one embodiment," "an embodiment," and / or "some embodiments" refer to a feature, structure, or characteristic associated with at least one embodiment of this specification. Therefore, it should be emphasized and noted that references to "one embodiment," "an embodiment," or "an alternative embodiment" two or more times in different locations in this specification do not necessarily refer to the same embodiment. Furthermore, certain features, structures, or characteristics of one or more embodiments of this specification may be appropriately combined.

[0076] In addition, unless expressly stated in the claims, the order of the processing elements and sequences, the use of alphanumeric characters, or the use of other names described in this specification are not intended to limit the order of the processes and methods of this specification. Although the above disclosure discusses some of the invention embodiments currently considered useful through various examples, it should be understood that such details are for illustrative purposes only, and the appended claims are not limited to the disclosed embodiments. On the contrary, the claims are intended to cover all modifications and equivalent combinations that are consistent with the spirit and scope of the embodiments of this specification. For example, although the system components described above can be implemented by hardware devices, they can also be implemented only by software solutions, such as installing the described system on an existing server or mobile device.

[0077] Similarly, it should be noted that, in order to simplify the presentation of this specification and thus facilitate understanding of one or more embodiments of the invention, the foregoing descriptions of the embodiments of this specification sometimes combine multiple features into a single embodiment, figure, or description thereof. However, this disclosure method does not imply that the subject matter of this specification requires more features than those recited in the claims. In fact, an embodiment may have fewer features than all of the features of a single disclosed embodiment.

[0078] In some embodiments, numbers are used to describe the quantity of components and attributes. It should be understood that such numbers used in the description of the embodiments are modified by the modifiers "about", "approximately" or "substantially" in some examples. Unless otherwise stated, "about", "approximately" or "substantially" indicate that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the description and claims are approximate values, which may change according to the required characteristics of individual embodiments. In some embodiments, the numerical parameters should take into account the specified significant digits and adopt the general method of retaining digits. Although the numerical domains and parameters used to confirm the breadth of their range in some embodiments of this specification are approximate values, in specific embodiments, the settings of such numerical values are as accurate as possible within the feasible range.

[0079] Each patent, patent application, patent application publication, and other materials, such as articles, books, specifications, publications, and documents, cited in this specification is hereby incorporated by reference in its entirety. This includes application history documents that are inconsistent with or conflict with the content of this specification, as well as documents (currently or subsequently attached to this specification) that limit the broadest scope of the claims of this specification. It should be noted that if the descriptions, definitions, and / or terminology used in the accompanying materials are inconsistent or conflicting with the content of this specification, the descriptions, definitions, and / or terminology used in this specification will control.

[0080] Finally, it should be understood that the embodiments described in this specification are intended only to illustrate the principles of the embodiments of this specification. Other variations may also fall within the scope of this specification. Therefore, by way of example and not limitation, alternative configurations of the embodiments of this specification may be considered consistent with the teachings of this specification. Accordingly, the embodiments of this specification are not limited to the embodiments explicitly described and illustrated in this specification.

Claims

1. A method for generating a lattice structure for additive manufacturing, characterized in that: The method comprises: Generate a cell model covering the model to be printed, wherein the cell model is composed of a plurality of virtual cells, the plurality of virtual cells including at least one external virtual cell, and at least a portion of each external virtual cell is located outside the outer contour of the model to be printed; Filling a cell structure in each virtual cell in the cell model to obtain a lattice model; Obtaining an outer offset surface of the outer contour of the to-be-printed model, wherein the outer offset surface is obtained by offsetting the outer contour outward by a first distance; Obtaining an inner offset surface of the outer contour of the to-be-printed model, wherein the inner offset surface is obtained by offsetting the outer contour inwardly by a second distance; determining a node between the inner bias surface and the outer bias surface as at least one target node; offsetting the at least one target node onto the outer contour, wherein the offset target node and other nodes in the lattice model form a preliminarily corrected lattice model; Cutting the target portion of the preliminarily corrected lattice model based on the outer contour of the to-be-printed model, removing a portion of the cell structure outside the outer contour, wherein at least one cutting breakpoint is generated between each cut cell structure and the outer contour; The cutting breakpoints are processed to obtain a modified lattice model, and the modified lattice model is used to perform additive manufacturing on the model to be printed.

2. The method according to claim 1, characterized in that The multiple virtual cells are hexahedrons with the same size.

3. The method according to claim 1, characterized in that The processing of the cutting breakpoints to obtain a modified lattice model includes: For each of the cutting points, determining at least one target breakpoint to be connected to the cutting breakpoint; and The cutting breakpoint is connected to the at least one target breakpoint.

4. The method according to claim 3, characterized in that The processing of the cutting breakpoints to obtain a modified lattice model further includes: Based on the outer contour of the to-be-printed model, a line between the cutting breakpoint and each corresponding target breakpoint is smoothed.

5. The method according to claim 1, wherein The cell structure includes at least two cell structures, and filling the cell structure in each virtual cell in the unit cell model to obtain a lattice model further includes: Acquiring an array relationship between the at least two cell structures; A cell structure is filled in each virtual unit cell based on the array relationship to obtain a lattice model.

6. A lattice structure generation system, characterized in that: The system comprises: a cell model generation module, configured to generate a cell model covering the model to be printed, wherein the cell model is composed of a plurality of virtual cells, wherein the plurality of virtual cells include at least one external virtual cell, and at least a portion of each external virtual cell is located outside the outer contour of the model to be printed; a cell structure filling module, configured to fill a cell structure in each virtual cell in the cell model to obtain a lattice model; Lattice model correction module for Obtaining an outer offset surface of the outer contour of the to-be-printed model, wherein the outer offset surface is obtained by offsetting the outer contour outward by a first distance; Obtaining an inner offset surface of the outer contour of the to-be-printed model, wherein the inner offset surface is obtained by offsetting the outer contour inwardly by a second distance; determining a node between the inner bias surface and the outer bias surface as at least one target node; offsetting the at least one target node onto the outer contour, wherein the offset target node and other nodes in the lattice model form a preliminarily corrected lattice model; Cutting the target portion of the preliminarily corrected lattice model based on the outer contour of the model to be printed, removing part of the cell structure outside the outer contour, wherein at least one cutting breakpoint is generated between each cut cell structure and the outer contour; The cutting breakpoints are processed to obtain a modified lattice model, and the modified lattice model is used to perform additive manufacturing on the model to be printed.

7. A lattice structure generating device, comprising a processor, wherein the processor is configured to execute the lattice structure generating method according to any one of claims 1 to 5.

Images