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Mold Manufacturing/Stamping Die Common Fault Analysis and Solution

2023/07/03

Stamping die is a special process equipment for processing materials into parts (or semi-finished products) in cold stamping processing, called cold stamping die (commonly known as cold stamping die). Stamping is a pressure processing method that uses a mold installed on a press to apply pressure to the material at room temperature to cause separation or plastic deformation to obtain the required parts.

　　Stamping is one of the practical processes for mass production of parts. In the stamping production process, the mold has the most problems, and it is the most important factor in the entire stamping production factor. directly affect production efficiency and cost. Affect the delivery cycle of the product. Mold problems mainly focus on mold damage, product quality defects and mold sharpening, which have plagued industry production for a long time. Only by correctly handling these key points. Stamping production can proceed smoothly.

　　Die failure is the most likely problem in stamping production, which often causes production stoppage and affects the product production cycle. Therefore, the cause of mold failure must be found as soon as possible and repaired reasonably.

　　1. Mold damage Mold damage refers to mold cracking, breaking, expansion, etc. To deal with mold damage, it is necessary to find the cause from the aspects of mold design, manufacturing process and mold use. First of all, it is necessary to check whether the manufacturing material of the mold is suitable, and whether the corresponding hot spot embedding process is reasonable. Usually, the heat treatment process of the mold material has a great influence on it. If the quenching temperature of the mold is too high, the quenching method and time are unreasonable, and the tempering times, temperature, and elbow are improperly selected, the mold will be damaged after entering the stamping production. If the size or depth of the blanking hole is not designed enough, it is easy to block the slot and cause damage to the blanking plate. The design of the spring force is too small or the height of the sleeve is not equal, which will cause the spring to break and the blanking plate to tilt, resulting in overlapping punches and damage to the parts.

　　Improper fixing of the punch or insufficient screw strength will cause the punch to fall or break.

　　When the mold is used, the position and direction of the parts are installed incorrectly or the bolts are not fastened well. The working height is adjusted too low, and the guide post is not lubricated enough. Faults in the feeding equipment, abnormalities in the press, etc., will cause damage to the mold. If foreign matter enters the mold, overlapping parts, waste clogging, etc. are not dealt with in time, and the production continues, it is easy to damage the blanking plate, punch, lower template and guide pillar of the mold.

　　2. In the stamping process of mold jamming, once the mold clamping is inflexible or even stuck, production must be stopped immediately to find out the cause of mold jamming and troubleshoot. Otherwise, the failure will be enlarged and the mold will be damaged.

　　The main causes of mold jamming are: poor mold guidance and tilt. Or there are foreign objects between the templates, so that the templates cannot be flattened; the mold strength design is not enough or the force is uneven. Cause mold deformation, for example, the hardness and thickness design of the mold base and template are too small, and it is easy to be deformed by external force impact; the mold position is not installed correctly, and the positioning error of the upper and lower molds is out of tolerance. Or the precision of the press is too poor, which causes the mold to interfere; the strength of the punch is not enough, and the position of the big and small punches is too close, so that the lateral force of the mold is unbalanced. At this time, the strength of the punch should be improved, and the guidance and protection of the unloading plate should be enhanced.

　　3. Mold damage and maintenance The mold cost for stamping production is high. Usually the mold cost accounts for 1/5-1/4 of the total cost of the part. This is because, in addition to the difficulty and high cost of mold manufacturing. After putting into production, the mold repair and sharpening maintenance costs are also high, and the original cost of the mold only accounts for about 40% of the entire mold cost. Therefore, timely maintenance of the mold to prevent damage to the mold can greatly reduce the cost of the mold for stamping production.

　　Generally speaking, after the mold is damaged, there is still a choice between repair and scrap. Unnatural wear failures of stamping dies, such as destruction of non-critical parts. As well as failures such as broken small punches, shortened punch upsetting, cracking of the concave template, cracking of the punching edge, etc. Most of them can be completely restored to normal state through maintenance methods, and put into stamping production again. but. When the key parts of the mold are seriously damaged, sometimes the convex and concave molds are damaged at the same time. The one-time repair cost exceeds 70% of the original cost of the die, or the life of the die is approaching. Then the significance of maintenance is not great. At this time, scrap molds should be considered: except for large molds and continuous molds with complex structures. When the mold repair technology is too complicated, the cost of mold repair is too high, and the difficulty will inevitably make the maintenance cycle too long, which will seriously affect the normal production of stamping. It should be scrapped in advance and the mold should be remanufactured.

　　Stamping production efficiency and cost are very dependent on the mold. For the failure of the mold during the production process, specific problems should be analyzed in detail to formulate a correct maintenance plan. Solve problems such as mold damage, mold jamming, sharpening and product quality defects in a timely manner. Only by properly handling the relationship between mold maintenance and scrap can the time for mold repair and shutdown be reduced, the production cycle shortened, and the stamping production ensured.

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