A method of building a self-supporting honeycomb model

Abstract

The application relates to the printing technical field and discloses a self-supporting honeycomb model building method, which comprises the following steps: determining the bounding box of a target model; generating a first honeycomb model comprising a plurality of first prism structures according to the bounding box and the target model; generating a TPS curved surface; cutting and trimming the plurality of first prism structures by the TPS curved surface to form a second honeycomb model comprising a plurality of second prism structures; and generating a self-supporting honeycomb model according to the target model and the second prism structures. Through the above steps, the top of each first prism structure is accurately trimmed based on a self-supporting angle and local geometric characteristics by using a TPS curved surface, suspended islands and large-area horizontal regions generated by traditional honeycombization are eliminated, and the generated lightweight model can be successfully subjected to additive manufacturing without adding any external support.

Description

Technical Field

[0001] This invention relates to the field of printing technology, and more specifically to a method for constructing a self-supporting honeycomb model. Background Technology

[0002] In additive manufacturing, to reduce model weight, save printing materials, and shorten printing time, lightweight internal filling structures are often designed. Among these, honeycomb structures are widely used due to their excellent specific strength and material utilization. In existing technologies, the method for generating the honeycomb structure inside a model typically involves generating a regular honeycomb mesh within the model's internal space based on its shape, and then obtaining the hollow model through Boolean operations.

[0003] However, these conventional methods have significant limitations when dealing with industrial parts models with complex free-form surfaces, such as orthodontic models. Because the surfaces of these models are typically uneven, with complex features like grooves and holes, the top surface of the standardized honeycomb structure generated inside often cannot perfectly fit the complex curved surface of the model's outer wall. This results in locally suspended "islands" or large, nearly horizontal areas at the top of the honeycomb. In 3D printing based on the principle of layered manufacturing, these suspended structures lack sufficient solid material for support, making them highly susceptible to collapse, deformation, or printing failure during printing, severely impacting the yield rate of the finished product. Summary of the Invention

[0004] In view of this, the present invention provides a method for constructing a self-supporting honeycomb model to solve the problem that in the 3D printing process based on the principle of layered manufacturing, such suspended structures lack sufficient solid material for support, making them prone to collapse, deformation or printing failure during printing, which seriously affects the yield of finished products.

[0005] This invention provides a method for constructing a self-supporting honeycomb model, comprising the following steps: Determine the bounding box of the target model; generate a first honeycomb model including several first prism structures based on the bounding box and the target model; generate a TPS surface; cut and trim several first prism structures from the TPS surface to form a second honeycomb model including several second prism structures; generate a self-supporting honeycomb model based on the target model and the second prism structures.

[0006] In one optional implementation, determining the bounding box of the target model further includes the following steps: Set a first direction, and set the regular bottom surface of the target model as the marker surface; rotate the target model until the marker surface is perpendicular to the first direction; stretch the marker surface toward the first direction by a preset distance to generate a first model; shell the first model to obtain first data; generate the bounding box based on the first data.

[0007] In one optional implementation, after shelling the first model to obtain the first data, the method further includes the following step: reverting the first model back to the target model.

[0008] In one optional implementation, generating the bounding box based on the first data further includes the following steps: Calculate the first enclosing body of the first data; enlarge the first enclosing body by a preset factor to form a second enclosing body; and open a plurality of through holes along the first direction on the second enclosing body to form the enclosing box.

[0009] In one alternative implementation, the preset distance is set to be greater than the wall thickness of the target model.

[0010] In one optional implementation, generating a first honeycomb model comprising a plurality of first prism structures based on the bounding box and the target model specifically includes the following steps: Perform a Boolean subtraction operation between the bounding box and the first data to obtain a first honeycomb model containing a plurality of first prism structures, confined within the first data.

[0011] In one optional implementation, generating the TPS surface specifically includes the following steps: Based on the preset self-supporting angle value, and using the center of the bounding box and the four horizontal corners as control points, a TPS surface conforming to the self-supporting angle is generated below each of the first prism structures.

[0012] In one optional implementation, the TPS surface cutting and trimming of several first prism structures to form a second honeycomb model including several second prism structures further includes the following steps: Based on the set self-supporting angle value, the intersection position of the TPS surface and the corresponding first prism structure is calculated; the TPS surface is used to cut the corresponding first prism structure to form the second prism structure; the above steps are repeated until all the first prism structures are cut to form the second prism structure to combine and form the second honeycomb model.

[0013] In an optional implementation, calculating the intersection position of the TPS surface and the corresponding first prism structure based on the set self-supporting angle value further includes the following steps: Find all triangular facets and concave vertices in one of the first prism structures that meet the self-supporting angle; filter all the triangular facets and concave vertices to obtain an effective region; calculate the lowest point of all facet vertices and concave vertices in the effective region, and obtain the distance s from the lowest point to the TPS surface; move the corresponding TPS surface a distance s along the first direction to intersect with the first prism structure.

[0014] In one optional implementation, the step of generating a self-supporting honeycomb model based on the target model and the second prism structure further includes the following steps: Perform a Boolean subtraction operation between the target model and the second prism structure to obtain a self-supporting honeycomb model confined within the target model.

[0015] Beneficial effects: Through the above steps, by using the TPS surface to precisely trim the top of each first prism structure based on self-supporting angles and local geometric features, the suspended islands and large horizontal areas generated by traditional honeycombing are eliminated, so that the generated lightweight model can be successfully additively manufactured without adding any external support.

[0016] Furthermore, compared to related technologies that involve lifting the honeycomb as a whole or excessively cutting it to avoid suspension, this method preserves the honeycomb material to the greatest extent while ensuring self-support, thus achieving a better balance between structural lightweighting and mechanical strength.

[0017] The entire process can be executed automatically by a computer program, without the need for manual intervention in the support design of each complex honeycomb cell. It is particularly suitable for lightweight processing of industrial part models with complex free-form surfaces, grooves, and cavities, overcoming the limitations of existing technologies in processing such models. Attached Figure Description

[0018] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Figure 1 This is a flowchart illustrating the steps of a self-supporting honeycomb model construction method according to an embodiment of the present invention. Figure 2 This is a schematic diagram of the structure of the first model according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of the first data in an embodiment of the present invention; Figure 4This is a schematic diagram of the structure of the enclosure box according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the structure of the first honeycomb model according to an embodiment of the present invention; Figure 6 This is a schematic diagram of the structure of one of the first prism structures according to an embodiment of the present invention; Figure 7 This is a schematic diagram of the TPS surface structure according to an embodiment of the present invention; Figure 8 For the purposes of this embodiment of the invention Figure 6 A schematic diagram of the second prism structure obtained by TPS surface cutting of the first prism structure; Figure 9 This is a schematic diagram of the structure of the second honeycomb model according to an embodiment of the present invention; Figure 10 This is a schematic diagram of the structure of a self-supporting honeycomb model according to an embodiment of the present invention; Explanation of reference numerals in the attached figures: 1. Target Model; 11. First Model; 12. First Data; 2. Enclosure box; 3. First prism structure; 4. First honeycomb model; 5. TPS surface; 6. Second prism structure; 7. Second honeycomb model; 8. Self-supporting honeycomb model. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] In additive manufacturing, to reduce model weight, save printing materials, and shorten printing time, lightweight internal filling structures are often designed. Among these, honeycomb structures are widely used due to their excellent specific strength and material utilization. In existing technologies, the method for generating the honeycomb structure inside a model typically involves generating a regular honeycomb mesh within the model's internal space based on its shape, and then obtaining the hollow model through Boolean operations.

[0022] However, these conventional methods have significant limitations when dealing with industrial parts models with complex free-form surfaces, such as orthodontic models. Because the surfaces of these models are typically uneven, with complex features like grooves and holes, the top surface of the standardized honeycomb structure generated inside often cannot perfectly fit the complex curved surface of the model's outer wall. This results in locally suspended "islands" or large, nearly horizontal areas at the top of the honeycomb. In 3D printing based on the principle of layered manufacturing, these suspended structures lack sufficient solid material for support, making them highly susceptible to collapse, deformation, or printing failure during printing, severely impacting the yield rate of the finished product.

[0023] To solve the above technical problems, the following will be combined with... Figures 1 to 9 The following describes embodiments of the present invention.

[0024] According to an embodiment of the present invention, a method for constructing a self-supporting honeycomb model 8 is provided, such as... Figure 1 As shown, it includes the following steps: Step S1: Determine the bounding box 2 of the target model 1.

[0025] First, a first direction is set in the 3D modeling software. In this embodiment, the first direction is the negative Z-axis direction. The regular bottom surface of complex models such as the jawbone is identified and automatically or manually marked as a marked surface. Generally speaking, the regular bottom surface is a plane.

[0026] Rotate the target model 1 in the 3D modeling software, adjust the posture of the target model 1, and make the marked surface of the target model 1 perpendicular to the first direction through the rotation operation.

[0027] like Figure 2 As shown, the marked surface is stretched by a preset distance along the first direction to generate an extended solid, which together with the target model 1 forms the first model 11. The preset distance should be greater than the wall thickness of the target model 1, and the preset distance is preferably the wall thickness plus 2mm to ensure that the subsequent shelling operation can generate a complete inner surface.

[0028] like Figure 3 As shown, a shelling operation is performed on the first model 11 to obtain a shell with a specific thickness, which is denoted as the first data 12. After obtaining the first data 12, the first model 11 is reverted to the original target model 1 state.

[0029] Calculate the bounding box 2 of the first data 12, i.e. the first bounding volume, and enlarge the first bounding volume by a preset factor in each dimension to obtain the second bounding volume.

[0030] Within the three-dimensional space of the second enclosing body, several through holes are formed along the first direction. These through holes are arranged in a regular hexagonal honeycomb pattern, filling the entire second enclosing body, thus forming a solid with a hollow honeycomb interior and a cuboid exterior, such as... Figure 4 As shown, this entity is the bounding box 2. The bounding box 2 needs to ensure that the honeycomb area formed by its several through holes can completely cover the first data 12.

[0031] Step S2: Generate a first honeycomb model 4 including a plurality of first prism structures 3 based on the bounding box 2 and the target model 1.

[0032] Perform a Boolean subtraction operation between the bounding box 2 obtained in step S1 and the first data 12, as follows: Figure 5 As shown, the first data 12 is reduced by the bounding box 2 into several first prism structures 3, and the collection of several first prism structures 3 constitutes the first honeycomb model 4. Figure 6 As shown, each first prism structure 3 is a column with a complex top shape.

[0033] Step S3: Generate TPS surface 5.

[0034] For each of the first prism structures 3 in the first honeycomb model 4, such as Figure 7 As shown, a separate TPS surface 5 for trimming is generated. The specific steps are as follows: A self-supporting angle value is preset according to the process requirements. Using the center point of the axially enclosing box 2 of the first prism structure 3 to be processed and its four corner points on the horizontal direction of its bottom surface as control points, a smooth TPS surface 5 is generated below the corresponding first honeycomb model 4 using thin-plate spline interpolation algorithms. Specifically, the TPS surface 5 has a fixed boundary inclination angle equal to the self-supporting angle, gradually transitioning from the periphery to the center. That is, starting from the boundary with the self-supporting angle, the curvature of the surface gradually and smoothly decreases towards the center of the model. Finally, at the highest point in the center of the model, the surface tends to flatten, forming a smooth arch or dome-shaped structure, which is the TPS surface 5. The angle between the tangent at any point on the TPS surface 5 and the horizontal plane is greater than or equal to the self-supporting angle value, thus geometrically satisfying the self-supporting condition.

[0035] Step S4: The TPS surface 5 is cut and trimmed to form a second honeycomb model 7 that includes a number of second prism structures 6.

[0036] For each first prism structure 3, firstly, identify the triangular facets at the top of the first prism structure 3 whose normal angle with the first direction is less than the self-supporting angle, as well as all concave vertices located in local recessed areas. Then, filter all these triangular facets and concave vertices, removing invalid regions that are too small or too isolated, to obtain the effective region. Calculate the point P with the lowest coordinate value along the first direction among all facet vertices and concave vertices within this effective region. Calculate the perpendicular distance s from point P to the initial TPS surface 5 generated for the prism. Finally, translate the initial TPS surface 5 a distance s along the opposite direction of the first direction, so that the translated TPS surface 5 passes through or supports the lowest point P. This position is the intersection point of the calculated TPS surface 5 and the corresponding first prism structure 3.

[0037] like Figure 8 As shown, the TPS surface 5 is used to cut the corresponding first prism structure 3, removing the irregular portion above the TPS surface 5 and retaining the regular prism portion below. All points at the top of the retained portion are located below its corresponding TPS surface 5, thus ensuring that the inclination angle at any point on the top meets the self-support requirement. This generates a second prism structure 6.

[0038] Repeat steps S3 and S4 as described above until each first prism structure 3 in the first honeycomb model 4 has been processed, resulting in several second prism structures 6, such as... Figure 9 As shown, the set of all the second prism structures 6 constitutes the second honeycomb model 7.

[0039] Step S5: Generate the final self-supporting honeycomb model 8.

[0040] like Figure 10 As shown, a Boolean subtraction operation is performed between the original target model 1 and the second honeycomb model 7. After the operation, a self-supporting honeycomb model 8 is obtained, which is completely set within the target model 1 entity, and the target model 1 has a honeycomb-shaped open cavity at the bottom, and the top of the open cavity can realize a printable self-supporting lightweight structure.

[0041] Through the above steps, by using the TPS surface 5 to precisely trim the top of each first prism structure 3 based on the self-supporting angle and local geometric features, the suspended islands and large horizontal areas generated by traditional honeycombing are eliminated, so that the generated lightweight model can be successfully additively manufactured without adding any external support.

[0042] Furthermore, compared to related technologies that involve lifting the honeycomb as a whole or excessively cutting it to avoid suspension, this method preserves the honeycomb material to the greatest extent while ensuring self-support, thus achieving a better balance between structural lightweighting and mechanical strength.

[0043] The entire process can be executed automatically by a computer program, without the need for manual intervention in the support design of each complex honeycomb cell. It is particularly suitable for lightweight processing of industrial part models with complex free-form surfaces, grooves, and cavities, overcoming the limitations of existing technologies in processing such models.

[0044] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A method for constructing a self-supporting honeycomb model, characterized in that, Includes the following steps: Determine the bounding box (2) of the target model (1); generate a first honeycomb model (4) including a plurality of first prism structures (3) based on the bounding box (2) and the target model (1); generate a TPS surface (5); cut and trim a plurality of the first prism structures (3) using the TPS surface (5) to form a second honeycomb model (7) including a plurality of second prism structures (6); generate a self-supporting honeycomb model (8) based on the target model (1) and the second prism structures (6). The process of determining the bounding box (2) of the target model (1) further includes the following steps: Set a first direction, set the regular bottom surface of the target model (1) as the mark surface; rotate the target model (1) until the mark surface is perpendicular to the first direction; stretch the mark surface toward the first direction by a preset distance to generate a first model (11); shell the first model (11) to obtain first data (12); generate the bounding box (2) according to the first data (12). The process of generating the bounding box (2) based on the first data (12) further includes the following steps: Calculate the first enclosure of the first data (12); enlarge the first enclosure by a preset factor to form a second enclosure; and open a plurality of through holes along the first direction on the second enclosure to form the enclosure box (2). The step of generating a first honeycomb model (4) comprising several first prism structures (3) based on the bounding box (2) and the target model (1) specifically includes the following steps: Perform a Boolean subtraction operation between the bounding box (2) and the first data (12) to obtain a first honeycomb model (4) that includes a plurality of first prism structures (3) within the first data (12). The generation of the TPS surface (5) specifically includes the following steps: Based on the preset self-supporting angle value, with the center of the bounding box (2) and the four horizontal corners as control points, a TPS surface (5) conforming to the self-supporting angle is generated below each of the first prism structures (3). The process of cutting and trimming several first prism structures (3) from the TPS surface (5) to form a second honeycomb model (7) including several second prism structures (6) also includes the following steps: Based on the set self-supporting angle value, the intersection position of the TPS surface (5) and the corresponding first prism structure (3) is calculated; the TPS surface (5) is used to cut the corresponding first prism structure (3) to form the second prism structure (6); the above steps are repeated until all the first prism structures (3) are cut to form the second prism structure (6) to combine and form the second honeycomb model (7). The step of calculating the intersection position of the TPS surface (5) and the corresponding first prism structure (3) based on the set self-supporting angle value further includes the following steps: Find all triangular facets and concave vertices in one of the first prism structures (3) that meet the self-supporting angle; filter all the triangular facets and concave vertices to obtain an effective region; calculate the lowest point of all facet vertices and concave vertices in the effective region, and obtain the distance s from the lowest point to the TPS surface (5); move the corresponding TPS surface (5) a distance s along the first direction to intersect with the first prism structure (3).

2. The method for constructing a self-supporting honeycomb model according to claim 1, characterized in that, After shelling the first model (11) to obtain the first data (12), the method further includes the following steps: reverting the first model (11) back to the target model (1).

3. The method for constructing a self-supporting honeycomb model according to claim 2, characterized in that, The preset distance is set to be greater than the wall thickness of the target model (1).

4. The method for constructing a self-supporting honeycomb model according to claim 1, characterized in that, The process of generating a self-supporting honeycomb model (8) based on the target model (1) and the second prism structure (6) further includes the following steps: The target model (1) and the second prism structure (6) are subtracted by Boolean to obtain a self-supporting honeycomb model (8) confined within the target model (1).

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