A method for manufacturing a mold for interchangeable material of automobile covering parts

Abstract

The present invention discloses a method for forming and manufacturing an interchangeable material mold for automobile covering parts, comprising the following steps: optimization of typical features of parts, CAE calculation of drawbead grouping, CAE analysis and blank control of large margin forming, live block formation of special features, manufacturing of smoothed surfaces by craftsmen, main drawing forming control, shaping fine-tuning, and finished products. The present invention, through a brand-new process mode, can perform forming operations on two or more materials with the same mold, greatly reducing the mold cost and product development cycle for automobile manufacturing of different materials, providing excellent technical solutions for automobile product performance upgrades and new energy transformation of traditional automobiles, and becoming a key technical support for rapid automobile upgrades. Blank control provides a new forming control mode for cold stamping of sheet metal, which can be used as a guiding mode in rapid cold stamping experiments of various new materials, greatly increasing the preferred range of forming solutions.

Description

Technical Field

[0001] The present invention relates to the technical field of automobile covering part mold manufacturing, in particular to a molding and manufacturing method of an automobile covering part interchangeable material mold. Background Art

[0002] With the rapid development of the automobile industry, the demand for high-quality automobiles and lightweight energy-saving demands are constantly advancing. Although traditional automobile manufacturing technology is mature and the cost of covering materials is low, the demand for energy conservation and environmental protection and people's demand for differentiated automobile performance have made the development of automobiles face diverse choices. Some people need economy and practicality, some need high-end comfort, and some need energy saving and endurance. Therefore, new materials have emerged in the application of automobile covering parts. Aluminum alloys, magnesium-aluminum alloys, high-strength plates and other materials are constantly expanding their application to meet people's needs for energy conservation, emission reduction and high-end experience.

[0003] However, automotive panels are limited by the sheet material and cold stamping process. The cold stamping forming state is complex, and the forming margin, stamping force, and rebound deformation properties and methods of different materials are different. The presentation of various cold stamping defects also varies greatly. As a result, the cold stamping molds for automotive panels are only developed for a single material. Different automotive panel molds need to be developed for automotive panels made of different materials to meet the needs of the material forming properties. In addition, the development cycle of automotive panel molds is 1-2 years, and the cost of each part is over one million. Due to the mold development cycle and cost constraints, the multi-material automotive panel becomes a high-cost, long-term technical problem. It is impossible to take into account both the high-quality requirements and the conventional economic requirements of the automobile, posing a huge challenge to the lightweight improvement and energy saving and consumption reduction of the automobile. Summary of the Invention

[0004] In view of the deficiencies in the above-mentioned background technology, the present invention proposes a method for manufacturing automobile cover parts by using interchangeable material molds, which solves the technical problem of various defects when molding automobile parts made of different materials in the same mold.

[0005] The technical solution of this application is:

[0006] A method for forming and manufacturing a mold for interchangeable material of an automobile cover, comprising the following steps:

[0007] Step 1: Optimize typical features of parts. Use the traditional single-material forming process analysis method, take the material with poor forming performance and severe springback deformation among the materials to be interchanged as the reference shape, perform forming analysis calculations, and optimize the feature areas of the parts where forming defects are concentrated.

[0008] Step 2: CAE calculation of drawbead groups. Using the material with the greater forming force among the interchangeable materials as the calculation master, the part shape with optimized typical features is supplemented with forming process and CAE analysis. During process supplementation, the drawbead controlled by forming is decomposed from one to two or more, and the drawbead is optimized from a follow-to-form mode to a mode parallel to the blank direction to form regular drawbead groups.

[0009] Step 3: CAE analysis of large-margin forming and blank control. After completing the CAE calculation of the drawbead grouping, the initial process supplementary model is obtained. Then, batch CAE analysis is performed and the process supplementary model is optimized based on the results until the CAE analysis shows that the overall product forming is normal and the blank holder force in the forming margin is within the range of plus or minus 20T. At this point, the CAE analysis of the high-forming force material is completed, and the obtained large-margin process supplementary model is the process model master.

[0010] The materials that need to be interchanged are then subjected to CAE analysis and calculation according to the process model master. The calculation is grouped and the material size is reduced in 5mm increments, either single-sided or multi-sided. The blank area is continuously reduced to cover the drawbead until each side is covered by a drawbead.

[0011] Compare the results of group calculations and select 1-3 CAE analysis results with the best forming effects as the alternative process types. Pay attention to the state where the blank size is reduced on different sides of the blank when selecting.

[0012] Step 4: Special features are made movable. If the result of the third step is state 3.1, then directly skip this step and go to step 5. If the result is state 3.2, then design movable inserts for the difficult-to-form parts, adjust the product shape at the insert parts or add supplementary product structures for analysis. At this time, the special feature parts will present different states during molding. CAE analysis is performed until the adjustment of the special feature parts meets the molding requirements. At this time, the best alternative process number is selected as the process number of the interchangeable material.

[0013] Step 5: The craftsman smoothes the surface.

[0014] Step 6: Main drawing forming control.

[0015] Step 7: Fine-tune the shape.

[0016] Step 8: Finished product: Through debugging and molding experiments with different materials, a stable mold and product state can be obtained, and an excellent interchangeable material mold can be obtained.

[0017] Preferably, in step 1, the optimization is based on the principle of not hindering the overlap of parts, and is adjusted with the goal of enhancing the force-bearing strength of the parts to meet the needs of part molding.

[0018] Preferably, in step 1, the feature area of ​​the part is optimized in the following ways:

[0019] (1) For the risk area of ​​forming cracking, the optimization method is to reduce the feature height. If the height cannot be reduced, the shape transition area is enlarged to reduce the feature fluctuation. The height is reduced or the transition area is enlarged to calculate the appropriate point close to the forming limit to avoid blind optimization that affects the performance of the part.

[0020] (2) For the insufficient strength area caused by insufficient forming and drawing, an absorption feature is added. The feature addition adopts a melon seed-shaped absorption protrusion along the main load-bearing direction of the part as the main mode, and deformation optimization is performed according to the forming requirements and part matching requirements;

[0021] (3) For the concentrated risk areas of distortion and rebound, add arc-shaped protrusions to block the counter-force along the main load-bearing direction of the parts.

[0022] Preferably, in step 2, the drawbead grouping is calculated as follows:

[0023] The number of drawbeads n = the traditional calculated drawbead height [h / 3], n = 1, 2, 3; when n>3, take n = 3;

[0024] The drawbead heights from inside to outside are: h / n+1, h / n, h / n-1;

[0025] Drawbead spacing D>15mm.

[0026] Preferably, in step 3, the following steps are also included:

[0027] Step 3.1: If the best molding effect meets the material molding requirements, the best candidate process number type can be directly selected as the process number type of the interchangeable material;

[0028] Step 3.2: If the optimal molding effect results in local molding difficulties and other parts are normal, the alternative process data will be put into the subsequent processing stage;

[0029] Step 3.3: If there are still many poorly formed areas even in the case of the best forming effect, perform the second step of drawbead grouping CAE calculation, adjust the drawbead position again to a position more parallel to the direction of the blank boundary, and appropriately expand or shorten the drawbead spacing, change the traditional drawbead form of square or round bars to a combination of square and round bars, and repeat the large margin forming CAE analysis and blank control operation in step 3 until the result shows the status of step 3.1 or step 3.2.

[0030] Preferably, if multiple materials need to be interchanged, steps 2, 3, and 4 need to be repeated until a common process type is selected.

[0031] Preferably, in step 5, the craftsman smoothing the surface comprises the following three steps:

[0032] Step 5.1: Optimize the consistency of the product process model according to the craftsman finishing mode. This mainly involves rounding and streamlining the high-concave and high-relief areas of the surface. The rounding is enlarged by R1-3mm based on the shape and matching requirements to make it more consistent with the smooth transition mode, thus obtaining the final process model.

[0033] Step 5.2: After the process data is determined, the mold is designed and manufactured according to the process data. During the machining stage of the manufacturing process, super finishing is required to ensure the smoothness of the mold surface. At the same time, the entire machining process requires changing the program design mode and performing milling on the concave fillets of the mold surface. The milling depth is a gradual transition from 0 to -3mm.

[0034] Step 5.3: After the processing is completed, the mold surface is streamlined and polished, that is, the mold surface is polished as a whole according to the direction of force, so that the polishing defects change in an overall convenient molding trend, and the polishing needs to be carried out in two steps of rough pushing and fine pushing.

[0035] Preferably, in step 6, when the mold enters the debugging stage, if product defects such as rebound, distortion, and deformation occur, the following steps should be taken:

[0036] Step 6.1, adjust the size of the product blank, enlarge or reduce the product blank size in units of 2mm according to the molding defect status, check the defect status, and select the state with the smallest defect;

[0037] Step 6.2 After adjusting the product blank size, perform pressure increase and decrease test in units of 5T and select the optimal blank holder force state as the optimal blank holder force;

[0038] Step 6.3: After completing 6.1 and 6.2, conduct a comprehensive analysis of the defective areas of the product, and then modify and debug the drawing process by re-adjusting the numerical model. Try to avoid correcting product defects through subsequent trimming or shaping molds to prevent cold work hardening and uncertainty secondary molding.

[0039] Preferably, in step 7, the main methods of shaping fine-tuning include: step 7.1, the shaping mold should be fully conformed, and the surface area should be processed and manufactured according to the requirements of the drawing mold, and large areas of gaps should be avoided as much as possible to avoid concentrated shaping force.

[0040] Preferably, in step 7, the main method of shaping and fine-tuning also includes: step 7.2, the shaping mold should be shaped in blocks according to the plane and elevation according to the shape of the product, and the shaping should be carried out in the form of overall plane shaping and side elevation shaping, and the shaping control range should be refined so that different shaping modes can be adopted in different areas to flexibly deal with product defects of different materials.

[0041] Compared with the prior art, the technical solution of the present invention includes the following technical effects:

[0042] 1. This invention uses a brand-new process mode to perform molding operations on two or more materials with the same mold, significantly reducing the mold cost and product development cycle for manufacturing automobiles made of different materials. It provides an excellent technical solution for upgrading automobile product performance and transforming traditional automobiles into new energy vehicles, becoming a key technical support for the rapid upgrading of automobiles.

[0043] 2. Blank control provides a new forming control mode for sheet metal cold stamping, which can be used as a guiding mode in the rapid cold stamping experiments of various new materials, greatly increasing the preferred range of forming solutions.

[0044] 3. Billet control uses billet size reduction as an experimental and debugging mode. Reducing billet size can directly reduce the production cost of automotive parts, providing an excellent solution for cost reduction in automobile manufacturing. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0046] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0047] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without creative work are within the scope of protection of the present invention.

[0048] In order to solve the technical problems existing in the background technology, the technical solution of the present invention has systematically analyzed the forming methods, forming control schemes and causes of cold stamping defects of various types of materials, and relied on the company's R&D institutions to carry out continuous research and batch experiments to develop a forming and manufacturing method of interchangeable material molds for automobile covering parts. This technology solves the problem of forming automobile parts with different materials in the same mold through the innovation of forming control mode, component shape optimization, drawbead grouping control, material size control analysis, CAE convergence analysis, process supplementary fine-tuning, fine transition surface forming, main drawing forming control and special feature activation. It realizes the forming and manufacturing of interchangeable material molds for automobile covering parts, provides strong impetus for the diversification of automobile materials and the development of new energy vehicles, and also provides strong technical support for the lightweight, green and low-carbon and sustainable upgrading of automobiles.

[0049] The main process of the present invention is as follows: The present invention is based on a systematic analysis of the forming methods, forming control schemes and causes of cold stamping defects of various types of materials, and on group batch experiments of cold stamped automobile parts of different shapes made of different materials; the traditional surface fillet forming control mode is changed, and the forming control mode is controlled by grouping the sheet size and draw ribs. The material replacement control mode is adjusted through CAE large margin forming calculation and forming force adjustment, and the system method of part shape optimization, craftsman smoothing surface manufacturing, main drawing forming control and special feature live block is used to solve the problem of different materials sharing the same set of molds to realize part forming. The present invention is suitable for interchangeable cold stamping forming of automobile parts between ordinary steel plates, aluminum plates, magnesium aluminum plates and high-strength steel plates. The thickness of the plate used in the experiment of the present invention is 0.5-2mm. The main process of the present invention is as follows:

[0050] A method for forming and manufacturing a mold for interchangeable material of automobile covering parts, such as Figure 1 As shown, the following steps are included:

[0051] Step 1: Optimize typical features of parts. Use the traditional single-material forming process analysis method, take the material with poor forming performance and severe springback deformation among the materials to be interchanged as the reference shape, perform forming analysis calculations, and optimize the feature areas of the parts where forming defects are concentrated.

[0052] Step 2: CAE calculation of drawbead groups. Using the material with the greater forming force among the interchangeable materials as the calculation master, the part shape with optimized typical features is supplemented with forming process and CAE analysis. During process supplementation, the drawbead controlled by forming is decomposed from one to two or more, and the drawbead is optimized from a follow-to-form mode to a mode parallel to the blank direction to form regular drawbead groups.

[0053] Step 3: CAE analysis of large-margin forming and blank control. After completing the CAE calculation of the drawbead grouping, the initial process supplementary model is obtained. Then, batch CAE analysis is performed and the process supplementary model is optimized based on the results until the CAE analysis shows that the overall product forming is normal and the blank holder force in the forming margin is within the range of plus or minus 20T. At this point, the CAE analysis of the high-forming force material is completed, and the obtained large-margin process supplementary model is the process model master.

[0054] The materials that need to be interchanged are then subjected to CAE analysis and calculation according to the process model master. The calculation is grouped and the material size is reduced in 5mm increments, either single-sided or multi-sided. The blank area is continuously reduced to cover the drawbead until each side is covered by a drawbead.

[0055] Compare the results of group calculations and select 1-3 CAE analysis results with the best forming effects as the alternative process types. Pay attention to the state where the blank size is reduced on different sides of the blank when selecting.

[0056] Step 4: Special features are made movable. If the result of the third step is state 3.1, then directly skip this step and go to step 5. If the result is state 3.2, then design movable inserts for the difficult-to-form parts, adjust the product shape at the insert parts or add supplementary product structures for analysis. At this time, the special feature parts will present different states during molding. CAE analysis is performed until the adjustment of the special feature parts meets the molding requirements. At this time, the best alternative process number is selected as the process number of the interchangeable material.

[0057] Step 5: The craftsman smoothes the surface.

[0058] Step 6: Main drawing forming control.

[0059] Step 7: Fine-tune the shape.

[0060] Step 8: Finished product: Through debugging and molding experiments with different materials, a stable mold and product state can be obtained, and an excellent interchangeable material mold can be obtained.

[0061] On the basis of the above embodiment, as a preferred embodiment, in step 1, the optimization is based on the principle of not hindering the overlap of parts, and is adjusted with the orientation of enhancing the force-bearing strength of the parts to meet the needs of part molding.

[0062] Based on the above embodiment, as a preferred embodiment, in step 1, the feature area of ​​the part is optimized in the following ways:

[0063] (1) For the risk area of ​​forming cracking, the optimization method is to reduce the feature height. If the height cannot be reduced, the shape transition area is enlarged to reduce the feature fluctuation. The height is reduced or the transition area is enlarged to calculate the appropriate point close to the forming limit to avoid blind optimization that affects the performance of the part.

[0064] (2) For the insufficient strength area caused by insufficient forming and drawing, an absorption feature is added. The feature addition adopts a melon seed-shaped absorption protrusion along the main load-bearing direction of the part as the main mode, and deformation optimization is performed according to the forming requirements and part matching requirements;

[0065] (3) For the concentrated risk areas of distortion and rebound, add arc-shaped protrusions to block the counter-force along the main load-bearing direction of the parts.

[0066] Preferably, in step 2, the drawbead grouping is calculated as follows:

[0067] The number of drawbeads n = the traditional calculated drawbead height [h / 3], n = 1, 2, 3; when n>3, take n = 3;

[0068] The drawbead heights from inside to outside are: h / n+1, h / n, h / n-1;

[0069] Drawbead spacing D>15mm.

[0070] Based on the above embodiment, as a preferred embodiment, in step 3, the following steps are further included:

[0071] Step 3.1: If the best molding effect meets the material molding requirements, the best candidate process number type can be directly selected as the process number type of the interchangeable material;

[0072] Step 3.2: If the optimal molding effect results in local molding difficulties and other parts are normal, the alternative process data will be put into the subsequent processing stage;

[0073] Step 3.3: If there are still many poorly formed areas even in the case of the best forming effect, perform the second step of drawbead grouping CAE calculation, adjust the drawbead position again to a position more parallel to the direction of the blank boundary, and appropriately expand or shorten the drawbead spacing, change the traditional drawbead form of square or round bars to a combination of square and round bars, and repeat the large margin forming CAE analysis and blank control operation in step 3 until the result shows the status of step 3.1 or step 3.2.

[0074] Based on the above implementation, as a preferred implementation, if multiple materials need to be interchanged, steps 2, 3 and 4 need to be repeated until a common process type is selected.

[0075] Based on the above embodiment, as a preferred embodiment, in step 5, the craftsman smoothing the surface manufacturing includes the following three steps:

[0076] Step 5.1: Optimize the consistency of the product process model according to the craftsman finishing mode. This mainly involves rounding and streamlining the high-concave and high-relief areas of the surface. The rounding is enlarged by R1-3mm based on the shape and matching requirements to make it more consistent with the smooth transition mode, thus obtaining the final process model.

[0077] Step 5.2: After the process data is determined, the mold is designed and manufactured according to the process data. During the machining stage of the manufacturing process, super finishing is required to ensure the smoothness of the mold surface. At the same time, the entire machining process requires changing the program design mode and performing milling on the concave fillets of the mold surface. The milling depth is a gradual transition from 0 to -3mm.

[0078] Step 5.3: After the processing is completed, the mold surface is streamlined and polished, that is, the mold surface is polished as a whole according to the direction of force, so that the polishing defects change in an overall convenient molding trend, and the polishing needs to be carried out in two steps of rough pushing and fine pushing.

[0079] Based on the above embodiment, as a preferred embodiment, in step 6, when the mold enters the debugging stage, if product defects such as rebound, distortion, and deformation occur, the following steps should be taken:

[0080] Step 6.1, adjust the size of the product blank, enlarge or reduce the product blank size in units of 2mm according to the molding defect status, check the defect status, and select the state with the smallest defect;

[0081] Step 6.2 After adjusting the product blank size, perform pressure increase and decrease test in units of 5T and select the optimal blank holder force state as the optimal blank holder force;

[0082] Step 6.3: After completing 6.1 and 6.2, conduct a comprehensive analysis of the defective areas of the product, and then modify and debug the drawing process by re-adjusting the numerical model. Try to avoid correcting product defects through subsequent trimming or shaping molds to prevent cold work hardening and uncertainty secondary molding.

[0083] On the basis of the above-mentioned embodiment, as a preferred embodiment, in step 7, the main methods of the shaping fine-tuning include: step 7.1, the shaping mold should be fully conformed to the shape, and the surface area should be processed and manufactured according to the requirements of the drawing mold, and large-area gaps should be avoided as much as possible to avoid the concentration of shaping force.

[0084] On the basis of the above-mentioned embodiment, as a preferred embodiment, in said step 7, the main method of the shaping and fine-tuning also includes: step 7.2, the shaping mold shall be shaped in blocks according to the plane and elevation according to the shape of the product, and the shaping shall be carried out in the form of overall plane shaping and side elevation shaping, and the shaping control range shall be refined so that different shaping modes can be adopted in different areas to flexibly deal with product defects of different materials.

[0085] Any details not provided in the present invention are conventional technical means known to those skilled in the art.

[0086] The above content shows and describes the basic principles, main features and beneficial effects of the present invention. The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of protection of the present invention.

Claims

1. A method for forming and manufacturing a mold for an automobile cover with interchangeable materials, characterized in that The following steps are involved: Step 1: Optimize typical features of parts. Use the traditional single-material forming process analysis method to take the material with poor forming performance and severe springback deformation among the interchangeable materials as the reference shape, perform forming analysis calculations, and optimize the feature areas of the parts where forming defects are concentrated. Step 2: CAE calculation of drawbead groups. Using the material with the greater forming force among the interchangeable materials as the calculation master, the part shape with optimized typical features is supplemented with forming process and CAE analysis. During the process supplement, the drawbead controlled by forming is decomposed from one to two or more, and the drawbead is optimized from a conformal mode to a mode parallel to the blank direction to form regular drawbead groups. Step 3: CAE analysis of large-margin forming and blank control. After completing the CAE calculation of the drawbead grouping, the initial process supplementary model is obtained. Then, batch CAE analysis is performed and the process supplementary model is optimized based on the results until the CAE analysis shows that the overall product forming is normal and the blank holder force in the forming margin is within the range of plus or minus 20T. At this point, the CAE analysis of the high-forming force material is completed, and the obtained large-margin process supplementary model is the process model master. The materials that need to be interchanged are then subjected to CAE analysis and calculation according to the process model master. The calculation is grouped and the material size is reduced in 5mm increments, either single-sided or multi-sided. The blank area is continuously reduced to cover the drawbead until each side is covered by a drawbead. Compare the results of group calculations and select 1-3 CAE analysis results with the best forming effects as candidate process types. When selecting, try to choose the state where the blank size is reduced on different sides of the blank. In step 3, the following steps are also included: Step 3.1: If the best molding effect meets the material molding requirements, directly select the best candidate process type as the process type of the interchangeable material; Step 3.2: If the optimal molding effect results in local molding difficulties and other parts are normal, the alternative process data will be put into the subsequent processing stage; Step 3.3: If the optimal forming effect still results in a large number of poorly formed areas, perform the second step of CAE calculation for drawbead grouping. Adjust the drawbead position to a position more parallel to the blank boundary. Also, appropriately increase or decrease the drawbead spacing. Change the traditional square or round drawbead form to a combination of square and round drawbeads. Repeat the large margin forming CAE analysis and blank control operations in step 3 until the results match those of step 3.1 or step 3.

2. Step 4: Special feature movable blocks. If the result of step 3 is state 3.1, skip this step and proceed directly to step 5. If the result is state 3.2, design movable inserts for difficult-to-form areas, adjust the product shape at the inserts, or add supplementary product structures and conduct analysis. At this time, the special feature areas will present different states during molding. CAE analysis is performed until the adjustments to the special feature areas meet the molding requirements. At this time, the optimal alternative process number is selected as the process number of the interchangeable material. Step 5: Craftsmen smooth the surface; Step 6: Main drawing forming control; Step 7: Shaping and fine-tuning; Step 8: Finished product: Through debugging and molding experiments with different materials, a stable mold and product state can be obtained, and an excellent interchangeable material mold can be obtained.

2. The method for forming and manufacturing an automobile panel interchangeable material mold according to claim 1, characterized in that: In step 1, the optimization is based on the principle of not hindering the overlap of parts, and is adjusted with the goal of enhancing the stress-bearing strength of the parts to meet the needs of part molding.

3. The method for forming and manufacturing an automobile panel interchangeable material mold according to claim 1 or 2, characterized in that: In step 1, there are several ways to optimize the feature area of ​​the part: (1) For the risk area of ​​forming cracking, the optimization method is to reduce the feature height. If the height cannot be reduced, the shape transition area is enlarged to reduce the feature fluctuation. The height is reduced or the transition area is enlarged to calculate the appropriate point close to the forming limit to avoid blind optimization that affects the performance of the part. (2) For the insufficient strength area caused by insufficient forming and drawing, an absorption feature is added. The feature addition adopts a melon seed-shaped absorption protrusion along the main load-bearing direction of the part as the main mode, and deformation optimization is performed according to the forming requirements and part matching requirements; (3) For the concentrated risk areas of distortion and rebound, add arc-shaped protrusions to block the counter-force along the main load-bearing direction of the parts.

4. The method for forming and manufacturing an automobile panel interchangeable material mold according to claim 3, characterized in that: In step 2, the drawbead grouping is calculated as follows: The number of drawbeads n = the traditional calculated drawbead height [h / 3], n = 1, 2, 3; when n>3, take n = 3; The drawbead heights from inside to outside are: h / n+1, h / n, h / n-1; Drawbead spacing D>15mm.

5. The method for forming and manufacturing an automobile panel interchangeable material mold according to any one of claims 1, 2, and 4, characterized in that: If multiple materials need to be interchanged, repeat steps 2, 3, and 4 until a common process type is selected.

6. The method for forming and manufacturing an automobile panel interchangeable material mold according to claim 5, characterized in that: In step 5, the craftsman's smoothing surface manufacturing includes the following three steps: Step 5.1: Optimize the consistency of the product process model according to the craftsman finishing mode. This mainly involves rounding and streamlining the high-concave and high-relief areas of the surface. The rounding is enlarged by R1-3mm based on the shape and matching requirements to make it more consistent with the smooth transition mode, thus obtaining the final process model. Step 5.2: After the process data is determined, the mold is designed and manufactured according to the process data. During the machining stage of the manufacturing process, super finishing is required to ensure the smoothness of the mold surface. At the same time, the entire machining process requires changing the program design mode and performing milling on the concave fillets of the mold surface. The milling depth is a gradual transition from 0 to -3mm. Step 5.3: After the processing is completed, the mold surface is streamlined and polished, that is, the mold surface is polished as a whole according to the direction of force, so that the polishing defects change in an overall convenient molding trend, and the polishing needs to be carried out in two steps of rough pushing and fine pushing.

7. The method for forming and manufacturing an automobile panel interchangeable material mold according to claim 6, characterized in that: In step 6, when the mold enters the debugging stage, if product defects such as rebound, distortion, and deformation occur, the following steps should be taken: Step 6.1, adjust the size of the product blank, enlarge or reduce the product blank size in units of 2mm according to the molding defect status, check the defect status, and select the state with the smallest defect; Step 6.2 After adjusting the product blank size, perform pressure increase and decrease test in units of 5T and select the optimal blank holder force state as the optimal blank holder force; Step 6.3: After completing 6.1 and 6.2, conduct a comprehensive analysis of the defective areas of the product, and then modify and debug the drawing process by re-adjusting the numerical model. Try to avoid correcting product defects through subsequent trimming or shaping molds to prevent cold work hardening and uncertainty secondary molding.

8. The method for forming and manufacturing an automobile panel interchangeable material mold according to any one of claims 1, 2, 4, 6, and 7, characterized in that: In step 7, the main methods of shaping and fine-tuning include: step 7.1, the shaping mold should be fully conformed to the shape, and the surface area should be processed and manufactured according to the requirements of the drawing mold, and large areas of gaps should be avoided as much as possible to avoid concentrated shaping force.

9. The method for forming and manufacturing an automobile panel interchangeable material mold according to claim 8, characterized in that: In step 7, the main method of shaping and fine-tuning also includes: step 7.2, the shaping mold should be shaped in blocks according to the plane and elevation according to the shape of the product, and the shaping should be carried out by overall plane shaping and side elevation shaping. The shaping control range should be refined so that different shaping modes can be used in different areas to flexibly deal with product defects of different materials.

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