In the field of automotive manufacturing, the design of automotive sheet metal parts molds is an extremely important task that directly affects the quality and production efficiency of automobiles. The following is the specific process of automotive sheet metal parts mold design.
I. Product Analysis and Demand Confirmation
- Thoroughly study the 3D model or drawings of automotive sheet metal parts to understand their shape, size, precision requirements, surface quality requirements, etc. According to statistics, about 80% of mold design problems can be discovered and resolved at this stage. For example, for sheet metal parts with dimensional accuracy requirements within ±0.05mm, more accurate mold design and processing are required.
- Analyze the material characteristics of sheet metal parts, including material strength, hardness, ductility, etc., to determine the appropriate processing technology. Generally speaking, the usage proportion of high-strength steel has gradually increased in recent years, accounting for about 40% of the materials for automotive sheet metal parts.
- Communicate with customers or automotive manufacturers to clarify design requirements, such as production batch, production cycle, cost limitations, etc. For example, for large-scale production projects, the durability and production efficiency of molds are key considerations; while for small-batch production, cost control is more important.
II. Process Planning
- Determine the forming process of sheet metal parts, commonly including stamping, drawing, bending, etc. Select the most suitable process according to the shape and requirements of the parts. According to industry statistics, the stamping process accounts for about 70% in the manufacturing of automotive sheet metal parts.
- Plan the basic structure of the mold, including mold types (single-operation molds, compound molds, progressive molds, etc.) and the number of stations of the mold. For example, for sheet metal parts with complex shapes, multi-station progressive molds may be required to improve production efficiency.
The following is a comparison of the characteristics of different forming processes:
| Forming Process | Advantages | Disadvantages | Applicable Range |
|---|---|---|---|
| Stamping | High production efficiency, high dimensional accuracy | High mold cost | Simple-shaped sheet metal parts for large-scale production |
| Drawing | Can manufacture parts with complex shapes | Difficult process | Sheet metal parts with certain depth and shape requirements |
| Bending | Low cost, simple process | Relatively low precision | Relatively simple-shaped sheet metal parts |
III. Mold Structure Design
- Design of parting surface: Select an appropriate parting surface to ensure that the parts can be demolded smoothly, while considering the feasibility and cost of mold processing. Generally speaking, the selection of the parting surface should try to avoid complex curved surfaces and sharp corners.
- Design of cavity and core: Design the cavity and core according to the shape of the sheet metal part to ensure dimensional accuracy and surface quality. The surface roughness of the cavity and core is usually required to be below Ra0.8.
- Mold base design: Select an appropriate mold base structure to ensure the strength and stiffness of the mold. The material of the mold base is generally high-strength alloy steel, and its bearing capacity should be calculated according to the size and working pressure of the mold.
- Design of demolding mechanism: Design a reasonable demolding mechanism, such as ejector pins, push plates, sliders, etc., to ensure that the parts can be demolded smoothly. The motion accuracy of the demolding mechanism is required to be within ±0.02mm.
- Design of guiding mechanism: Set up a guiding mechanism to ensure the motion accuracy and stability of the mold. The fit clearance of the guiding mechanism is usually required to be between 0.02mm and 0.05mm.
IV. Process Parameter Calculation
- Calculate stamping process parameters, such as punching force, stamping speed, mold clearance, etc. For example, for a steel plate with a thickness of 1mm, the punching force is usually between several tens of tons and hundreds of tons, and the stamping speed is generally between several tens and hundreds of times per minute.
- Determine the parameters of the heating and cooling system of the mold to ensure temperature control during the working process of the mold. The temperature of the mold should generally be controlled within a certain range to ensure the forming quality of the parts and the service life of the mold.
V. Mold Part Design
- Design each mold part, such as punch, die, backing plate, fixing plate, etc. The dimensional tolerance of the parts should be strictly controlled according to the design requirements, generally between ±0.01mm and ±0.05mm.
- Mark the dimensions, tolerances, surface roughness and other technical requirements of the parts. The surface roughness requirements are determined according to the function and usage environment of the parts, generally between Ra0.4 and Ra3.2.
VI. Mold Assembly Design
- Formulate the assembly plan of the mold and determine the assembly sequence and method of each part. During the assembly process, the cleanliness and fit accuracy of the parts should be ensured.
- Check for interference after mold assembly to ensure that the mold can work normally. Interference checking can be performed through 3D simulation software to discover problems in advance and make adjustments.
VII. Simulation Analysis and Optimization
- Use finite element analysis software to perform simulation analysis on the mold, such as stamping process simulation, stress analysis, temperature field analysis, etc. According to statistics, simulation analysis can reduce about 30% of mold debugging time.
- Optimize the mold design according to the analysis results, such as adjusting the mold structure and optimizing process parameters. For example, by optimizing the mold clearance, the dimensional accuracy and surface quality of the parts can be improved.
VIII. Drawing and Review
- Draw the general assembly drawing and each part drawing of the mold to ensure the accuracy and completeness of the drawings. The drawings should comply with national standards and industry specifications, with clear and accurate markings.
- Review the drawings to check whether the dimension markings, technical requirements, assembly relationships, etc. are correct. The review process should be strictly controlled to ensure the quality of the drawings.
IX. Mold Manufacturing and Debugging
- Manufacture the mold according to the design drawings, select appropriate processing technologies and equipment to ensure the precision and quality of the mold. The precision requirements of mold manufacturing are usually between ±0.01mm and ±0.05mm.
- Conduct mold debugging and check the forming quality of the parts and the working performance of the mold through trial molding. The number of trial moldings is generally about 3 to 5 times to ensure that the mold reaches the best state.
- Analyze and solve the problems that occur during the debugging process, and optimize and improve the mold. For example, for the problem of part deformation, it can be solved by adjusting process parameters or mold structure.
X. Delivery and Acceptance
- Deliver the debugged mold to customers or automotive manufacturers. When delivering, complete technical documents and operation manuals should be provided.
- Customers or automotive manufacturers conduct acceptance of the mold to confirm that the mold meets the design requirements and production needs. The acceptance criteria should be clear and specific to ensure the quality and performance of the mold.
In conclusion, the design of automotive sheet metal parts molds is a complex and elaborate process that requires comprehensive consideration of multiple factors and strict adherence to the process for design and manufacturing to ensure that the quality and performance of the mold meet the needs of automotive manufacturing.
