30 Experiences in Stamping Die Design and Process

1. Before designing the material belt, be sure to understand the tolerance requirements of the parts, material properties, punch tonnage, punch table, SPM (strokes per minute), feeding direction, feeding height, mold thickness requirements, material utilization, mold life .

2. When designing the material belt, CAE analysis should be carried out at the same time, mainly considering the material thinning rate, which should generally be less than 25%. Special deep-drawn stainless steel materials can be annealed after pre-stretching. With a high-frequency annealing machine, the thinning rate can be accepted to 40%. When designing the strip, you must communicate with the customer more, and it is best to ask the customer to provide it before For reference, the empty step is also very important. When the length of the mold allows, leaving an empty step appropriately is very helpful for mold modification after the test.

3. The material belt design is an analysis of the molding process of the product, which basically determines the success of the mold.

4. In the continuous mold design, the material lifting design is very important. If the material lifting rod cannot lift the entire material belt, automatic continuous production cannot be carried out.

5. In the mold design, mold material selection, heat treatment and surface treatment (such as TD, TICN, TD takes 3-4 days), especially for stretched parts, if there is no TD, the mold surface will be easily burned and fluffed .

6. In the mold design, for the surface with small hole position or tolerance requirements, adjust the inserts as much as possible, which is convenient for adjustment during mold trial and production, so that it is easy to achieve. The size requirements of the parts must be made at the same time as the upper and lower molds. Adjustable inserts. For the word mark, it is required to be disassembled on the punching machine, and there is no need to disassemble the lower mold, which is a waste of time.

7. When designing a hydrogen spring, design it according to the pressure analyzed by CAE. Don’t design an oversized hydrogen spring to prevent the product from breaking. The usual situation is: the pressure is small, the product wrinkles, the pressure is high, the product ruptures. To solve product wrinkles, you can use the method of locally increasing drawbeads, first fix the position of the sheet with the drawbeads, and then stretch to reduce the wrinkles.

8. When you try the mold for the first time, you must slowly close the upper mold. When there is a stretching process, you must use a fuse to test the thickness of the material level. After the material level gap reaches the material thickness, try the mold again. The knife edge must be first. That’s right. Please use movable inserts to adjust the height of the drawbead.

9. When testing the mold, the reference hole and reference surface must be equipped with the mold before placing the product on the gage for measurement, or sending it to the CMM for 3D report, otherwise it is meaningless.

10. The red sheet must be properly matched, and the fit rate is above 80%, before the cut can be opened and the CMM report can be made. It is very important to match the red lead, otherwise the product will be unstable and the later model modification cannot be judged, and the part size will not meet the customer’s requirements. To

11. Customer sample requirements: generally first laser office→cutting office→100% OK. At the laser office stage, red pill must be prepared, feeding and adjusting, to solve the problems of cracks, wrinkles, and dimensional tolerances, before opening the cutting. Basically correct the main problems during the operation, followed by fine-tuning (partial improvement of the mold). To

12. In the case that the customer must cut the mouth but the process conditions are not mature, consider cutting the soft material (that is, directly use 45 steel to cut the knife, directly solder when changing the cut, and then open the formal hard material after the size is OK. blade). To

13. For 3D complex products, you can use the 3D laser method to remove the laser. Before the 3D laser, you must make the 3D graphics, use the CNC to set the reference point and then send the 3D laser. The 3D laser needs to be positioned sand. To

14. For high-strength steel plates, the blade material should be made of cemented carbide materials such as A88 or V4.

15. When trying the mold, to test the stretching effect, you can put sandpaper on different positions on the material to test the effect. After confirming the effect, place the movable drawbead or the movable hemp lattice at the corresponding position (that is, put a piece of plated part). Grinding into pits), used for friction to hinder material feeding.

16. For parts with a lot of bending, the bending should be adjusted step by step according to the process when adjusting the mold. To

17. When adjusting the forming angle, you can reduce the R angle during bending or move the folding line reference to achieve the purpose of forming angle.

18. When adjusting the mold, most of the gaskets are used to adjust the height of the forming male, or the forming male parts can be moved left and right. The gaskets generally use stainless steel hard plates. (If the customer is not allowed to use gaskets, wait for the mold to be adjusted before making a new workpiece for the customer)

19. Molded parts made of stainless steel cannot use TD, but (TICN) or PVD.

20. It is necessary to determine when the customer’s formal materials will arrive, and save the use of materials when trying out the mold to avoid the phenomenon of insufficient materials. To

21. There are two types of continuous mode sensors, one is the step sensor, and the other is the blanking sensor. To

22. The inclination of the waste hopper is not less than 30 degrees. For the low-angle Scope box, it can be solved by installing a pneumatic vibrator (Pneumatic Vibration). To

23. For the trimming lines that are affected by forming, choose to cut after forming, and special positions can be realized by cross-cutting.
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24. For multiple reference hole positions, it is best to use one-time punching forming method to avoid affecting the accuracy after the step-by-step punching.

25. For the analysis of the test mode, the strip after the test must be analyzed step by step, and the red lead strip should be attached. To

26. For product rupture, it can be carried out in various ways such as adding packaging, extruding materials, increasing the forming area of the sheet rod, and opening holes during the pre-stretching. CAE analysis should be carried out before mold modification. To
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27. The product material is divided into two types: coil and sheet. Some coils need to be slit to the width of the strip again after they arrive at the factory. Usually, the size of the slitting is negative tolerance (minus 0.5mm), and the inner diameter of the coil To fit the size of the feeding rack, avoid being too large or too small and too heavy.

28. During mold processing, the thread-cut pin hole is usually used as the benchmark for the number of hits. After CNC programming, the operator needs to give the programmer the coordinates of the two holes. After the programmer finds the angle, the program is placed in one Processing after the angle. Usually when the template is processed for the first time, there is no need to find the angle for edge processing.

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

30. In the case that the size of the hardware sample does not meet the requirements, it can be realized by shaping, including plum blossom pile, flattening again, simple punching and so on. …

The above is a summary of some experience in the actual stamping work, I hope it will be helpful to those who read this article, improve the on-time pass rate of the mold, and reduce the number of mold trials.