30 experience of stamping die design and process

1. Before designing the material belt, it is necessary to understand the tolerance requirements of parts, material performance, punch tonnage, punch table, SPM (punching per minute), feeding direction, feeding height, die thickness requirements, material utilization rate and die service life.

2. In the design of material belt, CAE analysis should be carried out at the same time, mainly considering the thinning rate of materials, generally less than 25%. Special deep drawing stainless steel material can be annealed after pre drawing. With high frequency annealing machine, the thinning rate can be accepted to 40%. When designing the material belt, we must communicate with the customer more. It is better to ask the customer to provide the previous mold photos or structure drawings for reference. The blank step is also very important. If the mold length allows, the blank step should be properly reserved for the mold change after the mold test Help is great.

3. Strip design is the analysis of product forming process, which basically determines whether the mold is successful.

4. In the design of continuous die, the design of material lifting is very important. If the whole material belt cannot be raised by the material lifting rod, the automatic continuous production cannot be carried out.

5. In die design, die material selection and heat treatment as well as surface treatment (such as TD, TiCN, TD time needs 3-4 days), especially for drawing parts, if there is no TD, the die surface will be easily pulled and burnt.

6. In the mold design, for the surface with small hole position or tolerance requirements, adjustable inserts shall be made as much as possible, so as to facilitate the adjustment during the mold test and production, so as to easily meet the dimensional requirements of the parts, and adjustable inserts shall be made when the upper and lower mold are in the same time. For the mark, it is required to be detachable on the punch. It does not need to lower the die and disassemble again, which wastes time.

7. When designing the hydrogen spring, design according to the pressure of CAE analysis. Do not design too large hydrogen spring to prevent the product from cracking. Usually, the pressure is small, the product is wrinkled, the pressure is large, and the product is broken. To solve the problem of product wrinkling, we can use the method of local increase of drawbead, first fix the sheet with drawbead, and then stretch to reduce wrinkling.

8. During the first die test, the upper die must be closed slowly. When there is drawing process, the fuse must be used to test the material level thickness. When the material level gap reaches the material thickness, try the die again. The blade must be aligned first. Please use movable inserts for drawbead to adjust the height of drawbead.

9. During the mold test, the reference hole and the reference plane must be assembled before the product is put on the inspection tool for measurement, or sent to CMM for 3D report, otherwise it is meaningless.

10. The red sheet must be well matched, and the fitting rate can only be cut when it reaches 80% or above, and the CMM report can be made, or the datum plane of the datum hole has been matched, the product has been very stable and the fitting rate can be reduced appropriately. It is very important to match red lead, otherwise the product is not stable, and it is impossible to judge the later mold modification, and the part size will not meet the customer's requirements.  

11. Requirements of customer sample office: laser office → cutting office → 100% OK Office. In laser office stage, red lead should be matched, materials should be sent and adjusted to solve the problems of cracking, wrinkling and dimensional tolerance. In cutting office, the main problems should be basically improved, followed by fine adjustment (mold partial improvement).  

12. Under the condition that the guest must cut but the process conditions are not mature, the soft cutting edge can be considered (i.e. the cutting edge is made of 45 steel directly, and the cutting edge is directly welded when the cutting is changed, and the formal hard cutting edge can be opened after the size is OK).  

13. For 3D complex products, the method of 3D laser can be used to remove laser. Before 3D laser, 3D graphics must be done well. After the benchmark position is set with CNC, 3D laser will be sent. 3D laser also needs positioning sand mold.  

14. For high-strength steel plate, the cutting edge material shall be made of A88 or V4 cemented carbide.

15. During die test, in order to test the tensile effect, sand paper can be placed on different positions of the material to test the effect. After the effect is determined, the movable drawbead or the movable pitting array (that is, grinding a plated piece into pitting) can be placed at the corresponding position to prevent the material from moving.

16. For the parts with more bends, adjust the bending step by step according to the process.  

17. When adjusting the forming angle, the R angle of bending can be reduced or the polyline datum can be moved to achieve the purpose of forming angle.

18. During mold adjustment, most of the gaskets are used to adjust the height of the molding male, or move the molding male left and right back and forth, and the gasket is generally made of stainless steel hard disk. (if the customer is not allowed to use gasket, wait for the mold to be adjusted before making new workpiece for the customer)

19. For stainless steel mold parts, TD cannot be used, and TiCN or PVD shall be used.

20. It is necessary to determine when the official materials of the guests will arrive, and save the use of materials during the mold test to avoid the phenomenon of insufficient materials.  

21. There are two kinds of sensors for continuous mode, one is step distance sensor and the other is blanking sensor.  

22. The slope of waste funnel shall not be less than 30 degrees. For the low angle waste box, pneumatic vibration can be installed to solve the problem.  

23. For the trimming line affected by the molding, it is necessary to select to cut after the molding, and the special position can be realized by cross cutting.

24. For multiple reference hole positions, it is better to adopt the method of one-time punching forming to avoid affecting the accuracy after step-by-step punching.

25. For mold test analysis, it is necessary to analyze the material belt after mold test step by step, and attach red lead material belt.  

26. For the product fracture, it can be carried out by adding package, extruding materials, increasing the forming area of sheet and rod, opening and other ways in the early stage of drawing, and CAE analysis shall be carried out before mold change.  

27. The product materials are divided into coil and sheet sheet sheet. Some coils need to be striped again to the strip width after arriving at the factory. Generally, the dimension is negative tolerance (negative 0.5mm) when striping, and the inner diameter of coil shall conform to the dimension of feeding rack to avoid too large, too small and too heavy.

28. During die processing, the pin hole cut by line is usually used as the collision number benchmark. After CNC programming, the operator needs to give the coordinates of the two holes to the programmer. After the programmer finds the angle, the program is placed at an angle before processing. Generally, when processing the formwork for the first time, it is not necessary to find the angle for edge touching processing.

29. The concept of fine blanking is to leave no blanking clearance (or only 0.5%). Generally, the blanking gap is 10% of the material thickness. The thicker the material is, the larger the gap proportion is.

30. When the size of the hardware template fails to meet the requirements, it can be achieved by shaping, including plum blossom pile, flattening again, simple punching and so on.