A method for driving a die machining data surface deformation by using finite element comprehensive analysis results

Abstract

The application relates to a method for driving die machining data surface deformation by using finite element comprehensive analysis results, and relates to the die machining technical field, in particular to the stamping die machining technical field of automobile inner plate covering parts. The application provides a method for driving die machining data surface deformation by using finite element comprehensive analysis results, and the method is as follows: S1, obtaining the real stress distribution condition and the forming force load of a lower die of a die by using finite element CAE analysis of Autoform software, and performing CAE analysis on the structure of the lower die of the die; S2, outputting the CAE analysis result of the structure of the lower die of the die; and S3, driving die upper die machining data surface deformation by using the CAE analysis result of the structure of the lower die of the die. The method solves the problem that the elastic deformation of a stamping die is caused by stress when the stamping die works on a press, the elastic deformation has a great influence on the gap result between the upper die and the lower die, the die research and debugging period is long, and the cost is increased. The application is suitable for all stamping die machining of automobile inner plate covering parts.

Description

Technical Field

[0001] This invention relates to the field of mold processing technology, and particularly to the field of stamping mold processing technology for automotive interior panel coverings. Background Technology

[0002] When stamping dies operate on a press, they undergo elastic deformation under stress, which significantly affects the clearance between the upper and lower dies. While machining data to compensate for deformation, the compensation results often fail to match the actual elastic deformation area and amount of the die. This results in uneven clearance after die closing, failing to achieve the desired effect and leading to prolonged die repair and adjustment cycles and increased costs.

[0003] The existing mold structure only assumes that the lower mold is uniformly stressed. Then, the upper mold surface can only be divided into several areas, and the processing data of each area is used to make trend-based mold surface deformation. This results in the evaluation results not being completely consistent with the actual stress and deformation of the mold structure. Moreover, the evaluation is difficult and relies entirely on the experience of the staff, resulting in a relatively large evaluation error.

[0004] Existing technologies, such as patent document CN202110532624.8 published on August 13, 2021, describe a method for verifying the stiffness of a narrow wedge-shaped forming insert structure. The method mainly performs rigidity analysis on narrow mold components. However, the analysis assumes that the lower mold is uniformly stressed, while the actual stress state of the lower mold is uneven and non-uniform. Therefore, the rigidity analysis results can only provide a reference for optimizing the strength of the mold structure.

[0005] Existing technologies, such as patent document CN201210070151.5 published on July 25, 2012, describe a method for compensating the surface of a large stamping die for deflection deformation of a press. This method obtains the deflection variation area by applying different pressures to the press worktable, which is a qualitative analysis. However, it equals the deformation of the center of the press worktable with the deformation of the lower die center, and then takes the difference with reference to the change in the punch contour. Based on this difference, a distribution map and a planar deformation tool are made. A point-driven method is used to drive the surrounding area to compensate for the deformation of the die surface. This compensation method is essentially empirical and lacks scientific basis.

[0006] Existing technologies, such as patent document CN201611122873.5 published on March 29, 2017, describe a method for analyzing the structure of a drawing die based on an explicit dynamic finite element method. This method mainly involves establishing a drawing die model through UG and then converting it to STP format for strength and fatigue damage analysis using Hypermesh finite element software. This method is inflexible, does not perform stiffness analysis on the die structure, and involves multiple software platforms, making the analysis process cumbersome.

[0007] Existing technologies, such as patent document CN201610782774.3 published on February 1, 2017, describe a deformation-driven 3D model topology mapping method. This method mainly searches for mapping states through heuristic algorithms. The search process is driven by mapping energy. Finally, the corresponding source model and target model are visualized with the optimal mapping state, and the results are output. However, the model can only be visualized by driving the mapping energy.

[0008] Current technology utilizes Autoform software for CAE sheet metal formability analysis and Catia software for mold structure CAE analysis. However, the analysis results from the two software programs cannot be used together, presenting a technical challenge. This is because Autoform uses triangular mesh elements for CAE sheet metal formability analysis, while Catia uses tetrahedral mesh elements, making the data from Autoform unsuitable as input for Catia. Simply modifying the mold based on the analysis results from these two software programs also leads to prolonged mold repair and debugging cycles and increased costs. Summary of the Invention

[0009] This invention provides a method for driving the deformation of mold processing data surface using finite element comprehensive analysis results, which solves the problem that the elastic deformation of stamping molds under stress when working on the press has a great impact on the mold closing clearance between the upper and lower molds, resulting in long mold repair and debugging cycles and increased costs.

[0010] To achieve the above objectives, the present invention provides the following solution:

[0011] A method for driving surface deformation of mold machining data using finite element synthesis analysis results, the specific steps of which are as follows:

[0012] S1. Using Autoform software, finite element CAE analysis is used to obtain the actual force distribution and forming force load of the lower mold, and CAE analysis of the lower mold structure is performed.

[0013] S2. Output the CAE analysis results of the lower mold structure;

[0014] S3. Use the CAE analysis results of the lower mold structure to drive the surface deformation of the upper mold machining data.

[0015] Furthermore, in a preferred embodiment, the specific steps of step S1 described above are as follows:

[0016] S11. Use Autoform software to perform finite element CAE analysis to obtain the stress data of the lower mold node unit. The stress data are CSV format mesh node coordinate data file and CSV format mesh unit force load data file.

[0017] S12. Integrate the grid node coordinate data file and the grid unit force load data file to obtain a TXT format center of gravity-pressure combination four-dimensional vector data file;

[0018] S13. In the part design module environment of Catia software, the lower mold and the press worktable are assembled into a solid structure of the lower mold by Boolean operation of Catia software.

[0019] S14. In the structural CAE analysis module environment of Catia software, a CAE analysis template framework for the lower mold solid structure is generated. Within this framework, the lower mold solid structure is meshed. Then, the functional areas of the mold product surface are subdivided into mesh units. Fixed boundary conditions are applied to the static base surface of the lower mold solid structure, and sliding boundary conditions are applied to the guide surface of the lower mold solid structure. The motion constraints of the lower mold solid structure unit mesh are controlled. Using the pressure load command, a TXT format centroid-pressure combination four-dimensional vector data file is imported to generate the stress load on the lower mold structure surface. Based on the stress load on the lower mold structure surface, the deformation of the lower mold is analyzed and calculated to obtain the stress distribution state of the lower mold. Based on the stress distribution state, the deformation area and deformation data of the lower mold solid structure are obtained.

[0020] Furthermore, in a preferred embodiment, the specific steps of step S12 described above are as follows:

[0021] First, the stress data is filtered out. Based on the stress analysis target of the lower mold, the grid cells with stress values ​​≤ 0 are filtered out. Then, based on the extreme values ​​of the extreme regions of the measurement target, the coordinates outside the target coordinate region are selected. The coordinates outside the target coordinate region are XCoord, YCoord, and ZCoord. Based on the range of the coordinates outside the target coordinate region, the grid cells outside the target coordinate region that do not affect the stress state of the lower mold structure are filtered out, and the effective stress cells of the lower mold structure are retained.

[0022] Next, the coordinates of the centroid P1 of the grid cell are calculated. Each grid cell output by the Autoform software contains 3 nodes and a corresponding grid cell index number Element Idx. The three nodes are N1, N2 and N3. Each node contains three-dimensional coordinates and a corresponding node index number Node Idx. The three-dimensional coordinates are XCoord, YCoord and ZCoord. The three-dimensional coordinates of the corresponding node are found through the corresponding node index number Node Idx. The coordinates of the centroid P1 of each grid cell are obtained by using the weighted average formula (N1+N2+N3) / 3.

[0023] Next, the coordinates of each calculated centroid P1 and the grid cell index number are processed accordingly. The pressure value of the corresponding centroid P1 is found through the grid cell index number and integrated into a centroid-pressure combination four-dimensional vector, which consists of x, y, z and p.

[0024] Finally, output a TXT format four-dimensional vector file of the center of gravity-pressure combination. The four-dimensional vectors of the center of gravity-pressure combination of the grid cells are arranged horizontally into four columns and vertically in sequence to obtain a TXT format four-dimensional vector file.

[0025] Furthermore, in a preferred embodiment, the specific steps of step S2 described above are as follows:

[0026] S21. Extract the deformation data of the lower mold structure;

[0027] S22. Set the output format of the CAE deformation data of the lower mold structure to TXT format;

[0028] S23. Output the CAE deformation data of the lower mold structure in Catia.

[0029] Furthermore, in a preferred embodiment, the specific steps of step S21 described above are as follows:

[0030] First, in the structural CAE analysis module environment of the Catia software, check the distribution of mesh deformation, stress and strain, mesh node displacement and temperature field in the CAE analysis of the lower mold structure.

[0031] Then, the displacement of the mesh nodes in the CAE analysis data of the lower mold structure is used to obtain the deformation data of the lower mold structure.

[0032] Finally, the data on the press worktable, lower base plate, and connecting area in the deformation data of the lower mold structure are filtered to obtain the deformation data of the lower mold structure driven by the processing data.

[0033] Furthermore, in a preferred embodiment, the CAE deformation data of the lower mold structure in step S23 above includes the x, y, and z coordinates of the nodes and the deformation vectors of dx, dy, and dz for each node.

[0034] Furthermore, in a preferred embodiment, the specific steps of step S3 described above are as follows:

[0035] S31. Use displacement optimization tools to optimize the CAE deformation data of the lower mold structure and obtain the deformation point data of the lower mold structure.

[0036] S32. Set the deformation ratio coefficient and deformation tolerance;

[0037] S33. Based on the deformation point data of the lower mold structure, the deformation area and deformation amount of the lower mold are compensated in reverse on the upper mold to obtain the mold surface after compensation deformation.

[0038] Furthermore, in a preferred embodiment, the specific steps of step S32 described above are as follows:

[0039] In the Catia software's convex and concave design module environment, using the RSO digital deformation tool, the deformation point data of the lower mold structure are used to set the deformation ratio coefficient to 1 and the deformation tolerance to 0.02mm.

[0040] A system that utilizes finite element analysis results to drive surface deformation in mold processing data, the system specifically comprising:

[0041] Module 1 is used to obtain the actual stress distribution and forming force load of the lower mold using Autoform software finite element CAE analysis, and to perform CAE analysis on the structure of the lower mold.

[0042] Module 2 is used to output the CAE analysis results of the lower mold structure.

[0043] Module 3 is used to drive the surface deformation of the upper mold machining data using the CAE analysis results of the lower mold structure.

[0044] The beneficial effects are as follows: This invention provides a method for driving the surface deformation of mold processing data using finite element comprehensive analysis results, solving the problem that the elastic deformation of stamping dies under stress during operation on the press greatly affects the mold closing clearance, resulting in long mold repair and debugging cycles and increased costs. It also solves the problem that analysis data from Autoform software cannot be used as the input basis for Catia software.

[0045] Compared with the prior art, the present invention has the following advantages:

[0046] 1. Existing mold structures, which only assume uniform stress on the lower mold, suffer from drawbacks. The upper mold's overall surface is then divided into several zones, and trend-based deformation is applied to the machining data for each zone. This results in assessments that don't perfectly match the actual stress and deformation of the mold structure, making the assessment difficult and reliant on operator experience, leading to significant errors. This invention fully utilizes the digital results of two finite element analyses to accurately reproduce the stress on the lower mold structure. It quantitatively analyzes the distribution of digital points corresponding to the deformation areas and values ​​of the lower mold structure. During machining data design, the CAE analysis results of the lower mold structure are used as the driving element for the deformation of the upper mold machining data surface. This quantitative digital deformation ensures the upper mold machining data surface is completely consistent with the CAE analysis results of the lower mold structure, guaranteeing more scientific and accurate results. It effectively solves the problem of elastic deformation occurring when the pressing mold operates on the press, significantly affecting the mold closing clearance and causing long mold repair and debugging cycles and increased costs.

[0047] 2. Existing technology utilizes Autoform software for CAE sheet metal formability analysis and Catia software for mold structure CAE analysis. However, the analysis results from the two software programs cannot be combined, posing a technical challenge. This is because Autoform uses triangular mesh elements for CAE sheet metal formability analysis, while Catia uses tetrahedral mesh elements, making the data from Autoform unsuitable as input for Catia. Simply modifying the mold based on the analysis results from both software programs leads to prolonged mold repair and debugging cycles and increased costs. This invention provides a method for correcting mold processing data using finite element analysis results. This method solves the problem of the incompatibility between the finite element analysis software Autoform and Catia, resolving a long-standing unresolved issue.

[0048] 3. Existing Technology: A method for verifying the stiffness of a narrow, elongated wedge-shaped forming insert structure. This method primarily performs rigidity analysis on narrow, elongated mold components. However, it assumes uniform stress on the lower mold, while the actual stress on the lower mold is uneven and non-uniform. Therefore, the rigidity analysis results can only provide a reference for optimizing the mold structure strength. This invention provides a method for driving the deformation of mold processing data surfaces using finite element analysis results. Through CAE sheet metal forming analysis, the actual stress state of the lower mold is obtained and introduced into the structural rigidity analysis. This allows for the calculation of the actual deformation of the lower mold structure with very high accuracy.

[0049] 4. Existing technology: A method for compensating the surface of a large stamping die for deflection deformation of a press. The method obtains the deflection change area by applying different pressures to the press worktable, which is a qualitative analysis. However, it equals the deformation of the center of the press worktable with the deformation of the lower die center, and calculates the difference with reference to the change of the punch contour. Based on this difference, a distribution map and a planar deformation tool are made. A point-driven method is used to drive the surrounding area to compensate for the deformation of the die surface. This compensation method is essentially empirical and lacks scientific basis.

[0050] This invention provides a method for driving the deformation of mold processing data surface using finite element comprehensive analysis results. It adopts the rigid deformation analysis results of the lower mold structure and obtains the mold deformation compensation surface using a fully digital surface deformation method. Each deformation point is obtained entirely based on calculation and has scientific basis.

[0051] 5. Existing Technology: A method for analyzing the structure of a drawing die based on explicit dynamic finite element method. This method mainly involves creating a drawing die model using UG and then converting it to STP format for strength and fatigue damage analysis in Hypermesh finite element software. This method lacks flexibility, does not perform stiffness analysis on the die structure, and involves multiple software platforms, making the analysis process cumbersome. This invention provides a method that uses the results of comprehensive finite element analysis to drive the deformation of the die machining data surface, performing rigidity analysis on the die structure. Simultaneously, die design and rigidity analysis are performed on a single platform, resulting in simple operation, no data conversion, and high accuracy.

[0052] This invention is applicable to the stamping die processing of all automotive interior panel covering parts. Attached Figure Description

[0053] Figure 1 This is a flowchart illustrating a method for driving surface deformation of mold processing data using finite element comprehensive analysis results, as described in Embodiment 1.

[0054] Figure 2 This is a schematic diagram of the grid node coordinate data and grid element force load data of the lower mold in the method for driving the deformation of mold processing data surface using finite element comprehensive analysis results as described in Embodiment 2.

[0055] Figure 3 This is a schematic diagram of the combined solid structure of the lower mold after Boolean operation in the method for driving the deformation of mold processing data surface using finite element comprehensive analysis results as described in Embodiment 2.

[0056] Figure 4 This is a schematic diagram of the CAE analysis model of the lower mold structure in the method for driving the deformation of mold processing data surface using finite element comprehensive analysis results as described in Embodiment 2.

[0057] Figure 5 This is a schematic diagram illustrating the integration process of the mesh node coordinate data file and the mesh element force load data file in the method for driving mold processing data surface deformation using finite element comprehensive analysis results as described in Embodiment 3.

[0058] Figure 6 This is a schematic diagram of the CAE analysis mesh element type in the method for driving the deformation of mold processing data surface using finite element comprehensive analysis results as described in Embodiment 3.

[0059] Figure 7 This is a schematic diagram of the four-dimensional vector data file of the center of gravity-pressure combination in the method of driving the deformation of mold processing data surface using the results of finite element comprehensive analysis as described in Embodiment 3.

[0060] Figure 8 This is a schematic diagram of the CAE analysis results of the lower mold structure in the method for driving the deformation of mold processing data surface using finite element comprehensive analysis results as described in Embodiment 5.

[0061] Figure 9 This is a schematic diagram of the deformation data of the lower mold structure in a method for driving the deformation of mold processing data surface using finite element comprehensive analysis results as described in Embodiment Six.

[0062] Figure 10 (a) is a schematic diagram of the data point distribution of the lower mold structure before optimization in the CAE analysis results of the mold structure in the method of driving the deformation of mold processing data surface using finite element comprehensive analysis results described in Embodiment 7.

[0063] Figure 10 (b) is a schematic diagram of the distribution of optimized lower mold deformation data points in the CAE analysis results of the mold structure in the method of driving mold processing data surface deformation using finite element comprehensive analysis results as described in Embodiment 7.

[0064] Figure 11 This is a schematic diagram of the result after driving the deformation of the upper mold processing data surface in the method of driving the deformation of mold processing data surface using the results of finite element comprehensive analysis described in Embodiment 7.

[0065] Where: 1 is the lower mold, 2 is the lower base plate, 3 is the worktable, and Translational displacement magnitudes are the magnitudes of translational displacement. Detailed Implementation

[0066] Implementation Method 1. See Figure 1 This embodiment describes a method for driving surface deformation of mold processing data using finite element comprehensive analysis results. The method steps are as follows:

[0067] S1. Using Autoform software, finite element CAE analysis is used to obtain the actual force distribution and forming force load of the lower mold, and CAE analysis of the lower mold structure is performed.

[0068] S2. Output the CAE analysis results of the lower mold structure;

[0069] S3. Use the CAE analysis results of the lower mold structure to drive the surface deformation of the upper mold machining data.

[0070] This embodiment describes a method for driving surface deformation of mold machining data using finite element analysis results. It utilizes Autoform software for finite element CAE analysis to obtain the actual stress distribution and forming force load of the lower mold. The method performs CAE analysis on the lower mold structure, outputs the CAE analysis results, and finally uses these results to drive surface deformation of the upper mold machining data. This addresses the problem that elastic deformation occurs when stamping dies are subjected to stress on a press, significantly affecting the mold closing clearance and leading to long mold repair and debugging cycles and increased costs.

[0071] Existing mold structures, which only assume uniform stress on the lower mold, suffer from drawbacks. This necessitates dividing the upper mold's overall surface into several zones and then applying trend-based deformation analysis to the machining data for each zone. Consequently, the evaluation results cannot perfectly match the actual stress and deformation of the mold structure, and the evaluation is difficult, relying entirely on the experience of the operators, leading to significant errors. This embodiment provides a method that uses finite element analysis results to drive surface deformation in mold machining data. By utilizing finite element software to drive surface deformation in mold machining data, this method effectively solves the problem of elastic deformation occurring in pressing molds during operation on a press. This deformation significantly affects the gap between the upper and lower molds, resulting in long mold repair and debugging cycles and increased costs.

[0072] Implementation Method 2. See also Figure 2 , Figure 3 and Figure 4 This embodiment describes step S1 of the method for driving mold processing data surface deformation using finite element comprehensive analysis results as described in Embodiment 1. The specific steps of step S1 are as follows:

[0073] S11. Use Autoform software to perform finite element CAE analysis to obtain the stress data of the lower mold node unit. The stress data are CSV format mesh node coordinate data file and CSV format mesh unit force load data file.

[0074] S12. Integrate the grid node coordinate data file and the grid unit force load data file to obtain a TXT format center of gravity-pressure combination four-dimensional vector data file;

[0075] S13. In the part design module environment of Catia software, the lower mold and the press worktable are assembled into a solid structure of the lower mold by Boolean operation of Catia software.

[0076] S14. In the structural CAE analysis module environment of Catia software, a CAE analysis template framework for the lower mold solid structure is generated. Within this framework, the lower mold solid structure is meshed. Then, the functional areas of the mold product surface are subdivided into mesh units. Fixed boundary conditions are applied to the static base surface of the lower mold solid structure, and sliding boundary conditions are applied to the guide surface of the lower mold solid structure. The motion constraints of the lower mold solid structure unit mesh are controlled. Using the pressure load command, a TXT format centroid-pressure combination four-dimensional vector data file is imported to generate the stress load on the lower mold structure surface. Based on the stress load on the lower mold structure surface, the deformation of the lower mold is analyzed and calculated to obtain the stress distribution state of the lower mold. Based on the stress distribution state, the deformation area and deformation data of the lower mold solid structure are obtained.

[0077] In practical application, this embodiment uses an upper and lower mold, which are respectively clamped on the press slide and the worktable. After the robot places the sheet metal into the lower mold, the press slide drives the upper mold downwards to close with the lower mold, forming the sheet metal. The mold completes the stamping process. During sheet metal forming, the lower mold is the main stress-bearing component. Sheet metal forming is a non-linear process with uneven stress distribution; areas with small curvature (such as radius angles) experience greater stress, while areas with gentler curvature experience less stress. Previously, to simplify the analysis process, it was often assumed that the lower mold would be uniformly stressed. This approach leads to inaccurate analysis and prolonged mold maintenance and debugging cycles. This embodiment uses Autoform software for finite element CAE analysis, outputting the stress data of the lower mold node elements, forming two CSV files: one containing mesh node coordinate data, and the other containing mesh element stress load data. Figure 2 As shown; secondly, the mesh node coordinate data file and the mesh element force load data file are integrated to obtain a TXT format center of gravity-pressure combination four-dimensional vector data file; thirdly, in the part design module environment of Catia software, before the CAE deformation analysis and calculation of the lower mold, the lower mold and the press table are assembled into a solid structure by Boolean operation in Catia software, as shown. Figure 3As shown, some mold structures have separate lower mold and base plate components. These components need to be assembled into a single solid structure using Boolean operations, allowing for flexible selection based on on-site requirements. This approach maintains the accuracy of the calculation and analysis while reducing the number of solid units in the lower mold and shortening the model calculation time. Finally, the structural CAE analysis module environment of the Catia software is entered to generate a CAE analysis template framework for the lower mold solid structure. Within this framework, the lower mold solid structure is meshed. After meshing, the functional areas of the mold product surface are further subdivided into mesh units. The mesh size and chord height are subdivided to the extent that the geometric fillet features of the surface can be clearly distinguished. Fixed boundary conditions are applied to the static base surface of the lower mold solid structure, and sliding boundary conditions are applied to the guide surface of the lower mold solid structure to control the motion constraints of the lower mold solid structure unit mesh. Using the pressure load command, a TXT format centroid-pressure combination four-dimensional vector data file is imported to generate the force load on the surface of the lower mold structure, as shown below. Figure 4 As shown.

[0078] Implementation Method 3. See also Figure 5 , Figure 6 and Figure 7 This embodiment illustrates step S12 of the method for driving mold processing data surface deformation using finite element comprehensive analysis results described in Embodiment 2. The specific steps of step S12 are as follows:

[0079] First, the stress data is filtered out. Based on the stress analysis target of the lower mold, the grid cells with stress values ​​≤ 0 are filtered out. Then, based on the extreme values ​​of the extreme regions of the measurement target, the coordinates outside the target coordinate region are selected. The coordinates outside the target coordinate region are XCoord, YCoord, and ZCoord. Based on the range of the coordinates outside the target coordinate region, the grid cells outside the target coordinate region that do not affect the stress state of the lower mold structure are filtered out, and the effective stress cells of the lower mold structure are retained.

[0080] Next, the coordinates of the centroid P1 of the grid cell are calculated. Each grid cell output by the Autoform software contains 3 nodes and a corresponding grid cell index number Element Idx. The three nodes are N1, N2 and N3. Each node contains three-dimensional coordinates and a corresponding node index number Node Idx. The three-dimensional coordinates are XCoord, YCoord and ZCoord. The three-dimensional coordinates of the corresponding node are found through the corresponding node index number Node Idx. The coordinates of the centroid P1 of each grid cell are obtained by using the weighted average formula (N1+N2+N3) / 3.

[0081] Next, the coordinates of each calculated centroid P1 and the grid cell index number are processed accordingly. The pressure value of the corresponding centroid P1 is found through the grid cell index number and integrated into a centroid-pressure combination four-dimensional vector, which consists of x, y, z and p.

[0082] Finally, output a TXT format four-dimensional vector file of the center of gravity-pressure combination. The four-dimensional vectors of the center of gravity-pressure combination of the grid cells are arranged horizontally into four columns and vertically in sequence to obtain a TXT format four-dimensional vector file.

[0083] In practical applications, this implementation method first requires filtering and cleaning up invalid mesh node data due to the large amount of element data output by Autoform. Based on the target stress analysis of the lower mold, mesh elements with pressure values ​​≤0 are filtered out. Then, based on the extreme values ​​of the specific measurement target's limit region, coordinates outside the target coordinate region are selected. By limiting the range of coordinates outside the target coordinate region, mesh elements outside the target coordinate region that do not affect the stress state of the lower mold's physical structure are filtered out, retaining only the effective stress elements of the lower mold's physical structure. This reduces the amount of data required for subsequent calculations and accelerates analysis efficiency.

[0084] Secondly, because the stress load file output by the sheet metal forming analysis lacks the centroid coordinate information of the mesh elements, it cannot be used in Catia software for deformation analysis of the lower mold structure. Therefore, it is necessary to recalculate the centroid coordinate values ​​of the mesh elements. Autoform software uses triangular mesh elements for CAE analysis, while Catia software uses tetrahedral mesh elements. Therefore, the analysis elements used in Catia software for CAE analysis need to be matched using the centroid P1 coordinates of the triangular mesh and the tetrahedral mesh beforehand. Only after successful matching can the pressure of the triangular mesh be applied to the centroid P1 of the tetrahedral mesh in the Catia software's CAE analysis module. Each mesh cell output by the Autoform software consists of three nodes N1, N2, and N3 and a corresponding mesh cell index number Element Idx. Each node is composed of three-dimensional coordinates (XCoord, YCoord, and ZCoord) and a corresponding node index number Node Idx. The three-dimensional coordinates of the corresponding node can be found through the node index number. Then, the coordinates of the centroid P1 of each mesh cell are calculated using the weighted average formula (N1+N2+N3) / 3. Figure 6 As shown.

[0085] Next, the centroid coordinates and pressure data of each grid cell are integrated. Each grid centroid coordinate has a corresponding grid cell index number. First, the calculated coordinates of each grid centroid P1 and the grid cell index number are matched. Then, the pressure value of the corresponding grid centroid P1 is found through the grid cell index number. These are integrated into a centroid-pressure combined four-dimensional vector, which consists of x, y, z, and p, making it conform to the format requirements used by Catia software for stress analysis of the lower mold structure.

[0086] Finally, output a four-dimensional vector file. Since the Catia software requires the external force load on the lower mold as input when performing CAE analysis in TXT file format, the four-dimensional vector of the centroid-pressure combination is first laid out in an Excel spreadsheet. The x, y, z, and p values ​​of the centroid-pressure combination four-dimensional vectors of all mesh elements are arranged horizontally in four columns and vertically in sequence. The four-dimensional vector data is then directly output as a TXT file. Figure 7 As shown.

[0087] Existing technologies utilize Autoform software for CAE sheet metal formability analysis and Catia software for mold structure CAE analysis. However, the analysis results from the two software programs cannot be combined, posing a technical challenge. This is because Autoform uses triangular mesh elements for CAE sheet metal formability analysis, while Catia uses tetrahedral mesh elements, making the data from Autoform unsuitable as input for Catia. Simply modifying the mold based on the analysis results from both software programs leads to lengthy mold repair and debugging cycles and increased costs. This embodiment provides a method for driving mold machining data surface deformation using finite element analysis results. This method solves the problem of the incompatibility between the finite element analysis software Autoform and Catia, addressing a long-standing but unresolved issue.

[0088] Implementation Method 4. This implementation method illustrates step S2 in the method described in Implementation Method 1, which uses finite element analysis results to drive surface deformation of mold processing data. Step S2...

[0089] The specific steps are as follows:

[0090] S21. Extract the deformation data of the lower mold structure;

[0091] S22. Set the output format of the CAE deformation data of the lower mold structure to TXT format;

[0092] S23. Output the CAE deformation data of the lower mold structure in Catia.

[0093] In practical application of this embodiment, first, the deformation amount data of the lower die structure of the mold is extracted; then, the output format of the CAE deformation amount data of the lower die structure of the mold is set to the TXT format; finally, the CAE deformation amount data of the lower die structure of the mold is output in Catia, and the CAE deformation amount data of the lower die structure of the mold can be used to drive the deformation of the machining data surface of the upper die of the mold.

[0094] Embodiment Five. Refer to Figure 8 To illustrate this embodiment, this embodiment gives an example of step S21 in a method for driving the deformation of the machining data surface of a mold by using the comprehensive finite element analysis result described in Embodiment Four. The specific steps of the said step S21 are as follows:

[0095] First, in the environment of the structural CAE analysis module of Catia software, check the distribution of grid deformation, stress and strain, grid node displacement and temperature field in the CAE analysis of the lower die structure of the mold;

[0096] Then, obtain the deformation amount data of the lower die structure of the mold from the grid node displacement in the CAE analysis data of the lower die structure of the mold;

[0097] Finally, filter the data of the press workbench, lower bottom plate and connection area in the deformation amount data of the lower die structure of the mold to obtain the deformation amount data of the lower die structure of the mold for driving the machining data.

[0098] In practical application of this embodiment, in the environment of the structural CAE analysis module of Catia software, check the distribution of grid deformation, stress and strain, grid node displacement and temperature field in the CAE analysis of the lower die structure of the mold. If there is no abnormal prompt in Catia software, it is determined that the parameter setting and calculation process are qualified. Obtain the deformation amount data of the lower die structure of the mold from the grid node displacement in the CAE analysis data of the lower die structure of the mold; the deformation amount data of the lower die structure of the mold includes the calculation results of the press workbench, lower bottom plate, lower die and connection area. When performing the CAE analysis of the mold structure, in order to reduce the data volume and realize the rapid deformation drive of the machining data, filter out the press workbench, lower bottom plate and connection area, as Figure 8 shown.

[0099] Embodiment Six. Refer to Figure 9 To illustrate this embodiment, this embodiment gives an example of step S23 in a method for driving the deformation of the machining data surface of a mold by using the comprehensive finite element analysis result described in Embodiment Four. The CAE deformation amount data of the lower die structure of the mold in the said step S23 includes the x, y and z coordinates of the nodes and the deformation amount vectors of dx, dy and dz for each node.

[0100] In practical applications, this implementation method outputs the CAE deformation data of the lower mold structure generated after the mold CAE analysis in Catia. This data includes the x, y, and z coordinates of the nodes and the deformation vectors of dx, dy, and dz for each node. Figure 9 As shown, the grid node coordinates represent each point on the mold surface to be deformed, and the deformation vector of each node represents the change in the x, y, and z directions of each point on the mold surface to be deformed. This will give us the displacement changes of all points on the mold surface, providing data support for digital compensation of the mold surface and making the compensation results of the mold surface more refined, accurate and scientific.

[0101] Implementation Method Seven. See also Figure 10 and Figure 11 This embodiment describes step S3 of the method for driving surface deformation of mold processing data using finite element comprehensive analysis results as described in Embodiment 1. The specific steps of step S3 are as follows:

[0102] S31. Use displacement optimization tools to optimize the CAE deformation data of the lower mold structure and obtain the deformation point data of the lower mold structure.

[0103] S32. Set the deformation ratio coefficient and deformation tolerance;

[0104] S33. Based on the deformation point data of the lower mold structure, the deformation area and deformation amount of the lower mold are compensated in reverse on the upper mold to obtain the mold surface after compensation deformation.

[0105] In practical applications, this implementation method addresses the issue that the number of data nodes for mold deformation calculations using Catia in CAE is extremely large, making it difficult to guarantee the quality of surface deformation. Therefore, a displacement optimization tool is used to optimize the deformation data output from the mold structure CAE analysis results. This reduces unnecessary data points for the lower mold base plate and worktable, retaining only the lower mold deformation data points. Figure 10 As shown. This improves the output quality of CAE analysis results for mold structures and reduces the calculation time in Catia software. Although the analysis calculates the deformation of the lower mold structure, according to the forming principle, the lower mold is the reference. Therefore, the deformation area and amount of the lower mold are compensated in reverse on the upper mold, so that the allowance of the upper mold after deformation fills the area of ​​deformation of the lower mold, thus achieving the purpose of compensating for the deformation of the lower mold. In the convex and concave design module environment of Catia software, the deformation ratio coefficient and deformation tolerance are set through the RSO digital deformation tool. Based on the deformation point data of the lower mold structure, the deformation area and amount of the lower mold are compensated in reverse on the upper mold to obtain the mold surface after compensation deformation, as shown. Figure 11 As shown.

[0106] Implementation Method Eight. This implementation method illustrates step S32 of the method for driving mold processing data surface deformation using finite element comprehensive analysis results as described in Implementation Method Six. The specific steps of step S32 are as follows:

[0107] In the Catia software's convex and concave design module environment, using the RSO digital deformation tool, the deformation point data of the lower mold structure are used to set the deformation ratio coefficient to 1 and the deformation tolerance to 0.02mm.

[0108] In practical application, this implementation method uses the RSO digital deformation tool within the Catia software's convex / concave design module environment. It utilizes the processed lower mold deformation data, sets the deformation ratio coefficient to 1, and sets the deformation tolerance to 0.02mm. If the surface profile of the deformed upper mold meets the 0.02mm surface tolerance requirement, it is considered to be of acceptable quality.

[0109] Implementation Method Nine. A system for driving the deformation of mold machining data surfaces using finite element synthesis analysis results, the system specifically comprising:

[0110] Module 1 is used to obtain the actual stress distribution and forming force load of the lower mold using Autoform software finite element CAE analysis, and to perform CAE analysis on the structure of the lower mold.

[0111] Module 2 is used to output the CAE analysis results of the lower mold structure.

[0112] Module 3 is used to drive the surface deformation of the upper mold machining data using the CAE analysis results of the lower mold structure.

[0113] The above description is merely an embodiment of the present invention and is not intended to limit the invention. For those skilled in the art, the present invention can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of the claims of the present invention.

Claims

1. A method for driving surface deformation of mold machining data using finite element synthesis analysis results, characterized in that, The specific steps are as follows: S1. Using Autoform software, finite element CAE analysis is used to obtain the actual force distribution and forming force load of the lower mold, and CAE analysis of the lower mold structure is performed. The specific steps of step S1 are as follows: S11. Use Autoform software to perform finite element CAE analysis to obtain the stress data of the lower mold node unit. The stress data are CSV format mesh node coordinate data file and CSV format mesh unit force load data file. S12. Integrate the grid node coordinate data file and the grid unit force load data file to obtain a TXT format center of gravity-pressure combination four-dimensional vector data file; The specific steps of step S12 are as follows: First, the stress data is filtered out. Based on the stress analysis target of the lower mold, the grid cells with stress values ​​≤ 0 are filtered out. Then, based on the extreme values ​​of the extreme regions of the measurement target, the coordinates outside the target coordinate region are selected. The coordinates outside the target coordinate region are XCoord, YCoord, and ZCoord. Based on the range of the coordinates outside the target coordinate region, the grid cells outside the target coordinate region that do not affect the stress state of the lower mold structure are filtered out, and the effective stress cells of the lower mold structure are retained. Next, the coordinates of the centroid P1 of the grid cell are calculated. Each grid cell output by the Autoform software contains 3 nodes and a corresponding grid cell index number Element Idx. The 3 nodes are N1, N2 and N3. Each node contains three-dimensional coordinates and a corresponding node index number Node Idx. The three-dimensional coordinates are XCoord, YCoord and ZCoord. The three-dimensional coordinates of the corresponding node are found through the corresponding node index number Node Idx. The coordinates of the centroid P1 of each grid cell are obtained by using the weighted average formula (N1+N2+N3) / 3. Next, the coordinates of each calculated centroid P1 and the grid cell index number are processed accordingly. The pressure value of the corresponding centroid P1 is found through the grid cell index number and integrated into a centroid-pressure combination four-dimensional vector, which consists of x, y, z and p. Finally, output a TXT format four-dimensional vector file of the centroid-pressure combination. The four-dimensional vectors of the centroid-pressure combination of the grid cells are arranged horizontally into four columns and vertically in sequence to obtain a TXT format four-dimensional vector file. S13. In the part design module environment of Catia software, the lower mold and the press worktable are assembled into a solid structure of the lower mold by Boolean operation of Catia software. S14. In the structural CAE analysis module environment of Catia software, a CAE analysis template framework for the lower mold solid structure is generated. In the CAE analysis template framework, the lower mold solid structure is meshed, and then the functional area of ​​the mold product surface is subdivided into mesh units. Fixed boundary conditions are applied to the static base surface of the lower mold solid structure, and sliding boundary conditions are applied to the guide surface of the lower mold solid structure to control the motion constraints of the lower mold solid structure unit mesh. Through the pressure load command, a TXT format center of gravity-pressure combination four-dimensional vector data file is imported to generate the force load on the surface of the lower mold structure. Based on the force load on the surface of the lower mold structure, the deformation of the lower mold is analyzed and calculated to obtain the stress distribution state of the lower mold. Based on the stress distribution state of the lower mold, the deformation area and deformation data of the lower mold solid structure are obtained. S2. Output the CAE analysis results of the lower mold structure; S3. Use the CAE analysis results of the lower mold structure to drive the surface deformation of the upper mold machining data.

2. The method for driving mold machining data surface deformation using finite element comprehensive analysis results according to claim 1, characterized in that, The specific steps of step S2 are as follows: S21. Extract the deformation data of the lower mold structure; S22. Set the output format of the CAE deformation data of the lower mold structure to TXT format; S23. Output the CAE deformation data of the lower mold structure in Catia.

3. The method for driving mold machining data surface deformation using finite element comprehensive analysis results according to claim 2, characterized in that, The specific steps of step S21 are as follows: First, in the structural CAE analysis module environment of the Catia software, check the distribution of mesh deformation, stress and strain, mesh node displacement and temperature field in the CAE analysis of the lower mold structure. Then, the displacement of the mesh nodes in the CAE analysis data of the lower mold structure is used to obtain the deformation data of the lower mold structure. Finally, the data on the press worktable, lower base plate, and connecting area in the deformation data of the lower mold structure are filtered to obtain the deformation data of the lower mold structure driven by the processing data.

4. The method for driving mold machining data surface deformation using finite element comprehensive analysis results according to claim 2, characterized in that, The CAE deformation data of the lower mold structure in step S23 includes the x, y, and z coordinates of the nodes and the deformation vectors of dx, dy, and dz for each node.

5. The method for driving mold machining data surface deformation using finite element comprehensive analysis results according to claim 1, characterized in that, The specific steps of step S3 are as follows: S31. Use displacement optimization tools to optimize the CAE deformation data of the lower mold structure and obtain the deformation point data of the lower mold structure. S32. Set the deformation ratio coefficient and deformation tolerance; S33. Based on the deformation point data of the lower mold structure, the deformation area and deformation amount of the lower mold are compensated in reverse on the upper mold to obtain the mold surface after compensation deformation.

6. The method for driving mold machining data surface deformation using finite element comprehensive analysis results according to claim 5, characterized in that, The specific steps of step S32 are as follows: In the Catia software's convex and concave design module environment, using the RSO digital deformation tool, the deformation point data of the lower mold structure are used to set the deformation ratio coefficient to 1 and the deformation tolerance to 0.02mm.

7. A system for driving the deformation of mold machining data surfaces using finite element synthesis analysis results, characterized in that, The system is specifically as follows: Module 1 is used to obtain the actual stress distribution and forming force load of the lower mold using Autoform software finite element CAE analysis, and to perform CAE analysis on the structure of the lower mold. Specifically, the steps include the following: S11. Use Autoform software to perform finite element CAE analysis to obtain the stress data of the lower mold node unit. The stress data are CSV format mesh node coordinate data file and CSV format mesh unit force load data file. S12. Integrate the grid node coordinate data file and the grid unit force load data file to obtain a TXT format center of gravity-pressure combination four-dimensional vector data file; The specific steps of step S12 are as follows: First, the stress data is filtered out. Based on the stress analysis target of the lower mold, the grid cells with stress values ​​≤ 0 are filtered out. Then, based on the extreme values ​​of the extreme regions of the measurement target, the coordinates outside the target coordinate region are selected. The coordinates outside the target coordinate region are XCoord, YCoord, and ZCoord. Based on the range of the coordinates outside the target coordinate region, the grid cells outside the target coordinate region that do not affect the stress state of the lower mold structure are filtered out, and the effective stress cells of the lower mold structure are retained. Next, the coordinates of the centroid P1 of the grid cell are calculated. Each grid cell output by the Autoform software contains 3 nodes and a corresponding grid cell index number Element Idx. The 3 nodes are N1, N2 and N3. Each node contains three-dimensional coordinates and a corresponding node index number Node Idx. The three-dimensional coordinates are XCoord, YCoord and ZCoord. The three-dimensional coordinates of the corresponding node are found through the corresponding node index number Node Idx. The coordinates of the centroid P1 of each grid cell are obtained by using the weighted average formula (N1+N2+N3) / 3. Next, the coordinates of each calculated centroid P1 and the grid cell index number are processed accordingly. The pressure value of the corresponding centroid P1 is found through the grid cell index number and integrated into a centroid-pressure combination four-dimensional vector, which consists of x, y, z and p. Finally, output a TXT format four-dimensional vector file of the centroid-pressure combination. The four-dimensional vectors of the centroid-pressure combination of the grid cells are arranged horizontally into four columns and vertically in sequence to obtain a TXT format four-dimensional vector file. S13. In the part design module environment of Catia software, the lower mold and the press worktable are assembled into a solid structure of the lower mold by Boolean operation of Catia software. S14. In the structural CAE analysis module environment of Catia software, a CAE analysis template framework for the lower mold solid structure is generated. In the CAE analysis template framework, the lower mold solid structure is meshed, and then the functional area of ​​the mold product surface is subdivided into mesh units. Fixed boundary conditions are applied to the static base surface of the lower mold solid structure, and sliding boundary conditions are applied to the guide surface of the lower mold solid structure to control the motion constraints of the lower mold solid structure unit mesh. Through the pressure load command, a TXT format center of gravity-pressure combination four-dimensional vector data file is imported to generate the force load on the surface of the lower mold structure. Based on the force load on the surface of the lower mold structure, the deformation of the lower mold is analyzed and calculated to obtain the stress distribution state of the lower mold. Based on the stress distribution state of the lower mold, the deformation area and deformation data of the lower mold solid structure are obtained. Module 2 is used to output the CAE analysis results of the lower mold structure. Module 3 is used to drive the surface deformation of the upper mold machining data using the CAE analysis results of the lower mold structure.

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