Additive manufacturing supporting structure of complex curved surface part

Abstract

The additive manufacturing supporting structure comprises a base, a side supporting apron, a spiral column, a side extending branch, a middle supporting branch, a contact layer and a supporting circular truncated cone, the side supporting apron is located at the outer edge of the bottom of the base, the supporting circular truncated cone is located at the lower end of the base and located on the inner side of the side supporting apron, and the spiral column is located at the upper end of the base. Through the arrangement of the supporting circular truncated cone, the contact area between the supporting circular truncated cone and the printing bottom plate can be reduced, the supporting strength of the base can be guaranteed while the contact surface is further reduced through the arrangement of the circular truncated cone, and the stability of the base is guaranteed through the cooperation of the side supporting apron, so that collapse is avoided, and the printing precision is guaranteed; through the cooperative arrangement of the side supporting apron and the supporting circular truncated cones, when disassembly is difficult, the side supporting apron can be extruded and damaged through a tool, so that the supporting circular truncated cones are exposed, and the base can be prized and removed through the gap between the supporting circular truncated cones and a lever, so that disassembly and use are facilitated.

Description

Technical Field

[0001] The present invention relates to the technical field of additive manufacturing, and specifically to a support structure for additive manufacturing of complex curved surface parts. Background Art

[0002] 3D printing, also known as additive manufacturing technology, is a technology for manufacturing solid parts by the method of gradually accumulating materials layer by layer according to three-dimensional CAD data. Additive manufacturing is a technology for manufacturing solid parts by the method of gradually accumulating materials. Compared with the traditional material removal - cutting processing technology, it is a "bottom-up" manufacturing method.

[0003] In the prior art, the bottom of the support structure used in additive manufacturing mostly directly contacts the bottom plate. And to ensure the support stability, the contact area is relatively large. When it is necessary to remove the solid after printing, it is easy to make the disassembly difficult due to the large contact area and high connection tightness. When using a mesh support, it is easy for the upper layer of material to collapse, resulting in deviation of the support position and affecting the printing accuracy. Summary of the Invention

[0004] The purpose of the present invention is to provide a support structure for additive manufacturing of complex curved surface parts, so as to solve the problems in the above background art that the bottom of the support structure used in additive manufacturing mostly directly contacts the bottom plate. And to ensure the support stability, the contact area is relatively large. When it is necessary to remove the solid after printing, it is easy to make the disassembly difficult due to the large contact area and high connection tightness. When using a mesh support, it is easy for the upper layer of material to collapse, resulting in deviation of the support position and affecting the printing accuracy.

[0005] To achieve the above purpose, the present invention provides the following technical solution: A support structure for additive manufacturing of complex curved surface parts, including a base, a side support apron, a spiral column, side extension branches, middle support branches, a contact layer and a support round table. The side support apron is located at the outer edge of the bottom of the base. The support round table is located at the lower end of the base and inside the side support apron. The spiral column is located at the upper end of the base. The side extension branches are located on the outer surface of the spiral column. The middle support branches are located at the upper end of the spiral column. The contact layer contacts the surface of the curved surface part.

[0006] Preferably, it further includes an inner support sleeve, a horizontal plate and a vertical plate. The inner support sleeve is located inside the spiral column. The lower ends of the spiral column and the vertical plate both contact the lower end inside the base. The upper ends of the spiral column and the vertical plate both contact the upper end inside the spiral column. The horizontal plate and the vertical plate are both located between the spiral column and the inner support sleeve.

[0007] Preferably, the contact layer is fixedly connected to the ends of the side extension branches and the middle support branches. The base, the side support apron, the spiral column, the side extension branches, the middle support branches, the contact layer, the inner support sleeve, the horizontal plate, the vertical plate and the support round table are all integrally provided.

[0008] Preferably, it also includes a supporting production method, the specific steps of which are:

[0009] S1. Surface feature analysis and data preprocessing: Obtain the geometric features of complex surfaces and locate overhanging areas;

[0010] S2. Support area division: matching differentiated support structures and optimizing material distribution;

[0011] S3, base and platform connection structure generation: enhance platform adhesion;

[0012] S4. Parametric design of main support columns: enhance support stiffness and reduce parts adhesion;

[0013] S5. Internal lightweight structure generation: reduce material consumption and ensure support strength;

[0014] S6. Material and process parameter optimization and layered output: Adapt to material properties to ensure printing accuracy.

[0015] Preferably, in step S1, the specific steps are:

[0016] S11. Calculation of triangular face normals: For the triangular face slices of the input complex surface part model, a weighted average algorithm is used to calculate the vertex normals. The formula is:

[0017]

[0018] Among them, F v is the set of adjacent faces of vertex v, n f is the face normal, A f is the patch area, normal calculation error, n v is the vertex normal;

[0019] S12. Curvature radius classification: Calculate the vertex curvature radius R using the principal curvature estimation algorithm and classify the surface types into: sharp surface, transition surface, and gentle surface;

[0020] S13, Determine the overhang angle and calculate the angle θ between the normal line of the dough and the vertical direction. When , it is marked as the hanging area, and the threshold of high shrinkage material drops to 40°.

[0021] Preferably, in step S2, the model is divided into a sharp surface undercut area, a transition surface overhang area and a gentle surface support area according to the surface type and the overhang angle, and the support structure type is matched.

[0022] Preferably, in step S3, the support frustum layout algorithm is as follows: Based on the model center and the weight of the suspended area, automatically identify 3 - 5 main support points, produce support frustums with a distance of 5 - 8 mm and a height of 2 - 3 mm between them, a spacing of ≥15 mm, and a density of 100%;

[0023] The generation procedure of the side support apron is: Produce a side support apron with a thickness half of the base thickness and a height equal to that of the support frustum at the outer edge of the base.

[0024] Preferably, in step S4, it includes the geometric optimization of the spiral column and the generation logic optimization of the side - extending branches. When optimizing the geometry of the spiral column, use Euler's formula to calculate the critical load of the curved surface. The formula is:

[0025]

[0026] where P cr is the critical buckling load, E is the elastic modulus of the material, I is the moment of inertia of the cross - section, L is the height of the support column, μ is the length coefficient, to ensure the anti - lateral deformation ability of the spiral column during printing;

[0027] The generation logic of the side - extending branches is: Extend from the outer surface of the spiral column at an angle of 45° - 60°, with a length of 5 - 10 mm, a diameter of 1 - 1.5 mm, and the spacing is denser as the radius of curvature decreases, to enhance the support at the edge of the curved surface.

[0028] Preferably, in step S5, the lightweight structure includes a hollow grid support. Specifically: Build a double - layer orthogonal grid inside the spiral column: The vertical plates are radially supported by the inner support sleeves, and the horizontal plates are circularly reinforced. The grid size is adaptively adjusted according to the diameter of the spiral column.

[0029] Preferably, in step S6, the specific steps are:

[0030] S61. The material - adaptive parameter card dynamically adjusts the support parameters according to the characteristics of the thermoplastic material;

[0031] S62. Print process matching: The nozzle path preferentially prints the support frustums and the side support aprons. The spiral column uses a helical scan, and the branch structure is extruded at single points;

[0032] S63. Layered sectioning: Through the G - code parser, fuse the support structure and the part model to generate layer - by - layer printing data to ensure the matching of the layering accuracy between the support and the part.

[0033] Compared with the prior art, the beneficial effects of the present invention are:

[0034] 1. In the present invention, through the setting of the supporting frustum, the contact area with the printing base plate can be reduced. By using the frustum setting method, the contact surface can be further reduced while ensuring the supporting strength of the base. Cooperating with the side support apron, the stability of the base can be ensured, thus avoiding collapse and ensuring printing accuracy. Through the combined setting of the side support apron and the supporting frustum, when disassembly is difficult, tools can be used to squeeze and damage the side support apron, so that the supporting frustum is exposed. Using the gap between the supporting frustums, a lever can be used to pry and remove the base for easy disassembly and use.

[0035] 2. In the present invention, through the setting of the contact layer, the supporting accuracy is ensured. Since the surface density of the contact layer is high, the surface will be relatively flat, so that the surface of the curved surface part in contact can be relatively flat, reducing the time required for subsequent processing and improving the part accuracy. Through the tapers at the ends of the middle support branches and the side extension branches, the contact area with the part surface can be reduced, avoiding slow heat dissipation caused by large-area contact and reducing the flatness of the contact surface. And this design is convenient for disassembly from the part. Through the setting of the inner support sleeve, the horizontal plate and the vertical plate, the inside of the screw column is hollow, reducing the material usage while ensuring the strength of the screw column.

[0036] 3. In the present invention, through the intelligent analysis of the surface normal, curvature radius and overhang angle, different support structures such as bionic branches, screw column + grid, and honeycomb grid can be respectively matched for sharp curved surfaces, transition curved surfaces and gentle curved surfaces, avoiding the problems of "over-support" or "under-support" in uniform support. The anti-collapse ability is increased by 40%, and the part size accuracy is greatly improved. Through algorithms such as curvature tracking, Euler formula anti-buckling calculation, and automatic material parameter matching, the full process automation of the support structure from analysis to generation is realized. The single design time is shortened from 0.5 - 1 hour to within 10 minutes. At the same time, through the software integration of the support structure strength simulation and real-time visualization function, the risk areas are automatically marked to avoid the risk of printing failure in advance. Through geometric-mechanical coupling design, material-process collaborative optimization, and disassembly-strength balance innovation, the technical bottleneck of the traditional support structure is broken through, and the core goals of "high precision, high efficiency, and low cost" are achieved in the additive manufacturing of complex curved surface parts, which has significant engineering application value and industry promotion significance. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is a three-dimensional structural schematic diagram of the additive manufacturing support structure for a complex curved surface part of the present invention Figure 1 ;

[0038] Figure 2 is a three-dimensional structural schematic diagram of the additive manufacturing support structure for a complex curved surface part of the present invention Figure 2 ;

[0039] Figure 3Schematic diagram of the internal structure of the additive manufacturing support structure for a complex curved surface part of the present invention;

[0040] Figure 4 Top view section of the additive manufacturing support structure for a complex curved surface part of the present invention;

[0041] Figure 5 Flowchart for generating the additive manufacturing support structure for a complex curved surface part of the present invention.

[0042] In the figure:

[0043] 1. Base; 2. Side support apron; 3. Spiral column; 4. Side extension branch; 5. Middle support branch; 6. Contact layer; 7. Inner support sleeve; 8. Horizontal plate; 9. Vertical plate; 10. Support frustum. Detailed implementation manner

[0044] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0045] Embodiment 1: Refer to Figures 1 - 4 As shown: An additive manufacturing support structure for a complex curved surface part includes a base 1, a side support apron 2, a spiral column 3, a side extension branch 4, a middle support branch 5, a contact layer 6, and a support frustum 10. The side support apron 2 is located at the outer edge of the bottom of the base 1. The support frustum 10 is located at the lower end of the base 1 and inside the side support apron 2. The spiral column 3 is located at the upper end of the base 1. The side extension branch 4 is located on the outer surface of the spiral column 3. The middle support branch 5 is located at the upper end of the spiral column 3. The contact layer 6 is in contact with the surface of the curved surface part. It also includes an inner support sleeve 7, a horizontal plate 8, and a vertical plate 9. The inner support sleeve 7 is located inside the spiral column 3. The lower ends of the spiral column 3 and the vertical plate 9 are both in contact with the lower end inside the base 1. The upper ends of the spiral column 3 and the vertical plate 9 are both in contact with the upper end inside the spiral column 3. The horizontal plate 8 and the vertical plate 9 are both located between the spiral column 3 and the inner support sleeve 7. The contact layer 6 is fixedly connected to the ends of the side extension branch 4 and the middle support branch 5. The base 1, the side support apron 2, the spiral column 3, the side extension branch 4, the middle support branch 5, the contact layer 6, the inner support sleeve 7, the horizontal plate 8, the vertical plate 9, and the support frustum 10 are all integrally provided. The printing density of the support frustum 10 and the contact layer 6 is greater than that of the base 1 and the spiral column 3 to ensure the support strength. The thickness of the side support apron 2 is half of the thickness of the base 1. The inside of the middle support branch 5 and the side extension branch 4 uses grid support to ensure the strength of the side extension branch 4 and the middle support branch 5.

[0046] In the present invention, by providing the support frustum 10, the contact area with the printing base plate can be reduced. By using the frustum shape, the contact surface can be further reduced while ensuring the support strength for the base 1. In cooperation with the side support apron 2, the stability of the base 1 is ensured, thus avoiding collapse and ensuring printing accuracy. Through the combined setting of the side support apron 2 and the support frustum 10, when disassembly is difficult, tools can be used to crush the side support apron 2, so that the support frustum 10 is exposed. By using the gap between the support frustums 10, a lever can be used to pry and remove the base 1 for easy disassembly and use. By providing the contact layer 6, the support accuracy is ensured. Since the surface density of the contact layer 6 is high, the surface will be relatively flat, so that the surface of the curved surface part in contact can be relatively flat, reducing the time required for subsequent processing and improving the part accuracy. Through the tapers at the ends of the middle support branches 5 and the side extension branches 4, the contact area with the part surface can be reduced, avoiding slow heat dissipation caused by large-area contact and reducing the flatness of the contact surface. Moreover, this design facilitates disassembly from the part. By providing the inner support sleeve 7, the horizontal plate 8, and the vertical plate 9, the inside of the screw column 3 is made hollow, reducing material usage while ensuring the strength of the screw column 3.

[0047] Embodiment 2: Refer to Figure 5 As shown, it further includes a support production method, and the specific steps are as follows:

[0048] Step 1, Curved surface feature analysis and data preprocessing: Obtain the geometric features of the complex curved surface and locate the suspended area;

[0049] The specific steps are as follows:

[0050] 1. Triangular patch normal calculation: Slice the triangular faces of the input complex curved surface part model, and use the weighted average algorithm to calculate the vertex normal. The formula is:

[0051]

[0052] Among them, F v is the set of adjacent patches of vertex v, n f is the patch normal, A f is the patch area, the normal calculation error, and n v is the vertex normal;

[0053] 2. Curvature radius classification: Calculate the vertex curvature radius R through the principal curvature estimation algorithm, and classify the curved surface types into: sharp curved surface, transitional curved surface, and flat curved surface;

[0054] 3. Overhang angle determination: Calculate the angle θ between the skin normal and the vertical direction. When , it is marked as the suspended area, and the high shrinkage material threshold is reduced to 40°.

[0055] Step 2. Support area division: Match the differential support structure, optimize the material distribution, and divide the model into a sharp curved surface undercut area, a transition curved surface overhanging area, and a gentle curved surface support area according to the curved surface type and the overhang angle, and match the support structure type.

[0056] Step 3. Generation of the connection structure between the base and the platform: Enhance the adhesion of the platform. The layout algorithm of the support frustum 10 is as follows: Based on the model center and the weight of the overhanging area, automatically identify 3 - 5 main support points, and generate support frustums 10 with a distance of 5 - 8 mm between them, a height of 2 - 3 mm, a spacing of ≥15 mm, and a density of 100%;

[0057] The generation procedure of the side support apron 2 is: Generate a side support apron 2 with a thickness half of the thickness of the base 1 and a height equal to that of the support frustum 10 at the outer edge of the base 1.

[0058] Step 4. Parametric design of the main support columns: Enhance the support stiffness and reduce part adhesion, including geometric optimization of the spiral column 3 and generation logic optimization of the side extension branches 4. When performing geometric optimization of the spiral column 3, use Euler's formula to calculate the critical load of the curved surface. The formula is:

[0059]

[0060] where, P cr is the critical buckling load, E is the elastic modulus of the material, I is the moment of inertia of the cross-section, L is the height of the support column, μ is the length coefficient, to ensure the anti-lateral deformation ability of the spiral column 3 during the printing process;

[0061] The generation logic of the side extension branches 4 is: Extend from the outer surface of the spiral column 3 at an angle of 45° - 60°, with a length of 5 - 10 mm, a diameter of 1 - 1.5 mm, and the spacing is densified as the radius of curvature decreases to enhance the support at the edge of the curved surface.

[0062] Step 5. Generation of the internal lightweight structure: Reduce material consumption and ensure support strength. The lightweight structure includes a hollow grid support. Specifically: Build a double-layer orthogonal grid inside the spiral column 3: The vertical plate 9 provides radial support with the inner support sleeve 7, and the horizontal plate 8 provides annular reinforcement. The grid size is adaptively adjusted according to the diameter of the spiral column 3.

[0063] Step 6. Optimization of material and process parameters and layer-by-layer output: Adapt to the material characteristics and ensure printing accuracy. The specific steps are:

[0064] 1. The material adaptive parameter card dynamically adjusts the support parameters according to the characteristics of the thermoplastic material;

[0065] 2. Printing process matching: The nozzle path preferentially prints the support frustum 10 and the side support apron 2. The spiral column 3 uses a spiral scan, and the branch structure is extruded at a single point;

[0066] 3. Layered section: Through the G-code parser, the support structure and the part model are integrated to generate layer-by-layer printing data, ensuring the matching of the layer accuracy between the support and the part.

[0067] In the present invention, through the intelligent analysis of the surface normal, curvature radius and overhang angle, differential support structures such as bionic branches, spiral columns 3 + meshes, and honeycomb meshes can be respectively matched for sharp curved surfaces, transitional curved surfaces and flat curved surfaces, avoiding the problems of "over-support" or "under-support" of uniform support, improving the anti-collapse ability by 40%, and greatly improving the part size accuracy. Through algorithms such as curvature tracking, Euler formula anti-buckling calculation, and automatic material parameter matching, the full process automation of the support structure from analysis to generation is realized, and the single design time is shortened from 0.5 - 1 hour to within 10 minutes. At the same time, through the software integration of the support structure strength simulation and real-time visualization function, the risk areas are automatically marked to avoid the risk of printing failure in advance. Through the geometric-mechanical coupling design, material-process collaborative optimization, and disassembly-strength balance innovation, the technical bottleneck of the traditional support structure is broken through, and the core goals of "high precision, high efficiency, and low cost" are achieved in the additive manufacturing of complex curved surface parts, with significant engineering application value and industry promotion significance.

[0068] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An additive manufacturing support structure for complex curved surface parts, characterized in that: It includes a base (1), a side support apron (2), a spiral column (3), side extension branches (4), middle support branches (5), a contact layer (6) and a support frustum (10). The side support apron (2) is located at the outer edge of the bottom of the base (1). The support frustum (10) is located at the lower end of the base (1) and inside the side support apron (2). The spiral column (3) is located at the upper end of the base (1). The side extension branches (4) are located on the outer surface of the spiral column (3). The middle support branches (5) are located at the upper end of the spiral column (3). The contact layer (6) contacts the surface of the curved surface part.

2. The additive manufacturing support structure for complex surface parts according to claim 1, characterized in that: It also includes an inner support sleeve (7), a horizontal plate (8), and a vertical plate (9). The inner support sleeve (7) is located inside the spiral column (3). The lower ends of both the spiral column (3) and the vertical plate (9) contact the inner lower end of the base (1). The upper ends of both the spiral column (3) and the vertical plate (9) contact the upper end inside the spiral column (3). The horizontal plate (8) and the vertical plate (9) are both located between the spiral column (3) and the inner support sleeve (7).

3. The additive manufacturing support structure for complex surface parts according to claim 1, characterized in that: The contact layer (6) is fixedly connected to the ends of the side extension branches (4) and the middle support branches (5). The base (1), the side support apron (2), the spiral column (3), the side extension branches (4), the middle support branches (5), the contact layer (6), the inner support sleeve (7), the horizontal plate (8), the vertical plate (9) and the support frustum (10) are all integrally provided.

4. The additive manufacturing support structure for complex curved surface parts according to claim 2, characterized in that: It also includes a support production method, and the specific steps are as follows: S1. Curved surface feature analysis and data preprocessing: Obtain the geometric features of the complex curved surface and locate the suspended area. S2. Support area division: Match the differential support structure and optimize the material distribution. S3. Generation of the connection structure between the base and the platform: Enhance the adhesion of the platform. S4. Parametric design of the main support column: Enhance the support stiffness and reduce part adhesion. S5. Generation of the internal lightweight structure: Reduce material consumption and ensure the support strength. S6. Optimization of material and process parameters and layer-by-layer output: Adapt to the material characteristics and ensure the printing accuracy.

5. The additive manufacturing support structure for complex surface parts according to claim 4, characterized in that: In step S1, the specific steps are as follows: S11. Triangular patch normal calculation: Slice the triangular faces of the input complex curved surface part model, and use the weighted average algorithm to calculate the vertex normal. The formula is: Among them, F v is the set of adjacent faces of vertex v, n f is the face normal, A f is the face area, the normal calculation error, n v is the vertex normal; S12. Curvature radius classification: Calculate the vertex curvature radius R through the principal curvature estimation algorithm, and classify the curved surface types as: sharp curved surface, transitional curved surface, and flat curved surface. S13. Determine and calculate the angle θ between the normal of the dough sheet and the vertical direction. When , mark it as the suspended area, and the threshold of the high-shrinkage material is reduced to 40°.

6. The additive manufacturing support structure for complex surface parts according to claim 4, characterized in that: In step S2, according to the curved surface type and the overhang angle, the model is divided into a sharp curved surface concave area, a transitional curved surface suspended area, and a flat curved surface support area, and the support structure type is matched.

7. The additive manufacturing support structure for complex surface parts according to claim 4, wherein: In step S3, the layout algorithm of the support frustum (10) is: Based on the model center and the weight of the suspended area, automatically identify 3 - 5 main support points, produce support frustums (10) with a distance of 5 - 8 mm between them and a height of 2 - 3 mm, a spacing ≥ 15 mm, and a density of 100%. The generation procedure of the side support apron (2) is: Produce a side support apron (2) with a thickness half of the thickness of the base (1) at the outer edge of the base (1), and a height equal to that of the support frustum (10).

8. The additive manufacturing support structure for complex surface parts according to claim 4, wherein: In step S4, it includes the geometric optimization of the spiral column (3) and the generation logic optimization of the side extension branches (4). When optimizing the geometry of the spiral column (3), the Euler formula is used to calculate the critical load of the curved surface, and the formula is: Among them, P cr is the anti-buckling critical load, E is the elastic modulus of the material, I is the moment of inertia of the cross-section, L is the height of the support column, and μ is the length coefficient, ensuring the anti-lateral deformation ability of the spiral column (3) during the printing process; The generation logic of the side extension branches (4) is as follows: extend from the outer surface of the spiral column (3) at an angle of 45° - 60°, with a length of 5 - 10 mm, a diameter of 1 - 1.5 mm, and the spacing is densified as the curvature radius decreases to enhance the support at the edge of the curved surface.

9. The additive manufacturing support structure for complex surface parts according to claim 4, characterized in that: In step S5, the lightweight structure includes a hollow grid support. Specifically, a double-layer orthogonal grid is built inside the spiral column (3): the vertical plate (9) provides radial support with the inner support sleeve (7), and the horizontal plate (8) provides annular reinforcement. The grid size is adaptively adjusted according to the diameter of the spiral column (3).

10. The additive manufacturing support structure for complex surface parts according to claim 4, characterized in that: In step S6, the specific steps are as follows: S61. The material adaptive parameter card dynamically adjusts the support parameters according to the characteristics of the thermoplastic material; S62. Printing process matching: The nozzle path preferentially prints the support frustum (10) and the side support apron (2). The spiral column (3) uses a spiral scan, and the branch structure is extruded at a single point; S63. Layered sectioning: Through the G-code parser, the support structure and the part model are fused to generate layer-by-layer printing data to ensure the matching of the support and part layer accuracy.

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