Design essentials of the hottest progressive die a

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Key points of progressive die design and troubleshooting in production (Part 2)

3.1 product burr increases

when the die is produced for a period of time, the burr of production parts will increase. At this time, the cutting edges of male and female dies should be checked. If the cutting edges are found or high-tech board cards need to be repaired, worn or broken, grinding should be carried out, and the male or female dies should be padded with gaskets of corresponding thickness after grinding. When the die has been grinded for many times, check whether the straight wall of the cutting edge has been grinded off If there is no knife edge and straight wall, replace the female die insert. If the edges of the male and female dies are not worn, and the burrs on the parts are uneven, it is because the blanking gap has offset. At this time, adjust the gap

3.2 waste floating

in stamping production, waste floating is a major problem, which will not only affect production, but also damage the mold. Generally speaking, the round or square shaped waste is easy to float, while the complex shaped waste is less likely to float

the causes and solutions of some waste floating are introduced below

(1) the blanking clearance is large. If the waste material often floats up in the mold test stage, it indicates that the blanking clearance is too large The die should be remade and the blanking clearance reduced. If the waste material floats only occasionally, the roughness can be increased by electric spark discharge in the cavity of the die. (2) The surface of the punch is too smooth, and the waste is attached to the punch under the action of atmospheric pressure, which can increase the pores on the punch. (3) The waste material floats up due to unilateral blanking, and sharp corners are added on the non blanking side to squeeze the waste material. (4) If the stamping speed is high, it should be considered to reduce the speed. If the speed cannot be reduced due to production needs, the ejector rod can be added on the punch to push the waste

in addition, there are some human factors, such as insufficient demagnetization after cutting Tang, excessive stamping oil used in Shenya production, etc., which should be avoided as far as possible

3.3 lamination phenomenon

after the last station in stamping production is cut off, the production parts are blown out of the mold in time, which is still left. In the economic operation of China's extruder industry, there have been several positive signals on the mold, which is very easy to produce lamination phenomenon. Laminations are very dangerous and can easily damage the mold. There are many factors that can judge the quality of the experimental machine, such as insufficient wind force, adhesion of stamping oil, and production parts hooked on the ejector rod. In view of these factors, a variety of measures can be taken to prevent the occurrence of overlapping parts. For example, in stamping production, it is necessary to ensure that the air blowing force is large enough. When designing the mold, the ejector rod should be added to the concave template and the discharge plate. The ejector rod on the concave template should be designed to be larger than the hole on the part at least, or simply adopt the shooting block structure to avoid the production parts hanging on the ejector rod. When designing the concave template, a wide slope should be designed at the end of the concave template on the premise of ensuring the blanking strength, so that the production parts can slide out of the mold smoothly. In addition, in the design, it should also be considered that the cattle parts to be cut should extend out of the concave template or at least half of the slope at the last station, and slide out of the mold by relying on the self weight of the production parts as much as possible

3.4 material leakage hole blockage

in stamping production, if there is material leakage hole blockage and it is not found in time, it is easy to damage the mold, resulting in punch fracture or female die expansion crack. The leakage hole shall be prevented from being blocked to ensure smooth leakage Be sure to press the size of the leakage hole. For some small protruding parts, the size of the leakage hole should be appropriately enlarged; For the blockage of the leakage hole caused by the waste rolling, the size of the leakage hole should be reduced. During mold design Enough attention should be paid to the leakage hole. The concave template should be used as a reference when designing the concave mold base plate to ensure that the leakage profile of the concave mold base plate is larger than that of the concave template. The concave mold base plate should be used as a reference when designing the lower mold base And so on, the stiffness of the host. Finally, make sure that the leakage hole of the mounting plate is smaller than that of the machine tool. Otherwise, a slope should be made on the lower mounting plate to ensure that the waste will eventually slide into the leakage hole of the machine tool

in addition, excessive grinding dam or stamping oil at the die edge will also cause blockage of the leakage hole. It is necessary to grind in time or reduce the replacement of stamping oil

3.5 poor feeding

poor feeding may affect production at least, or damage the mold at most. The reasons are as follows:

(1) there is a difference between the feeding progress distance and the designed step distance during production, so the feeding progress distance should be adjusted. (2) If the spacing of lifting nails is too large, the number of lifting nails should be increased. (3) The lifting height of the strip is not enough, and the strip is easy to hook on the lifting block or ejector rod. The lifting height of the strip should be increased. (4) The feeding gap of the lifting nail is too small, and the strip feeding is not smooth, so the gap should be appropriately enlarged. (5) If the strip is too wide and thin, it is easy to cause warping, and a lifting block should be added in the middle of the strip

4 conclusion

design is the source. Although design only accounts for about 10% of the mold cost, it determines 70% - 80% of the whole mold cost. Therefore, designers must consider the mold structure in detail, consider improving productivity and how to facilitate maintenance. However, it cannot completely rely on design. In actual production, it is also necessary to analyze specific problems and adjust the mold according to the actual situation. In the production of mold repair, maintenance is also very important. During mold maintenance We should pay more attention to the details, find out the root cause and guide the maintenance. When disassembling the mold, be careful to prevent damage to the mold. Regular maintenance

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