Mold manufacturing/stamping die common fault analysis and solution

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

Stamping is one of the practical processes for the production of high-volume parts forming. During the stamping production process, the most problems occur in the die, which is the most important factor in the whole stamping production element. It directly affects production efficiency and cost. It affects the delivery cycle of products. Die problems are mainly focused on die damage, product quality defects and die sharpening, which have long plagued the industry production. Only by correctly handling these key points. Stamping production can only be carried out smoothly.

Die failure is the most common problem in stamping production, often causing production stoppages and affecting the product production cycle. Therefore, it is necessary to find the cause of die failure as soon as possible and repair it reasonably.

1、Die damage Die damage refers to die cracking, fracture, rising open, etc. To deal with the problem of die damage, we must find the reason from the design of die, manufacturing process and die use. First of all, we should review whether the manufacturing material of the mold is suitable, and whether the corresponding heat treatment and burial process is reasonable. Usually, the heat treatment process of the mold material has a great influence on it. If the quenching temperature of the die is too high, the quenching method and time are unreasonable, as well as the number of tempering times and temperature and elbow room are not properly selected, all of them will lead to the damage of the die after entering the stamping production. The size or depth of the drop hole is not designed enough, which will easily block the slot hole and cause damage to the drop plate. The spring force design is too small or the contour sleeve is not equal in height, which will cause the spring to break and the drop plate to be tilted. Overlapping punching will cause damage to the parts.

Improper fixation of punch or insufficient strength of screw. It will cause the punch to fall off or break.

When the die is used, the parts are incorrectly installed in position and direction or the bolts are not fastened properly. The working height is adjusted too low, and the guide pillar is not lubricated enough. Faulty feeding equipment, abnormal press, etc., can cause damage to the die. If there are foreign objects into the mold, overlapping parts, scrap blockage, etc. are not dealt with in time, continue processing production, it is easy to damage the mold drop plate, punch, lower template and guide pillar.

2、Card die During the stamping process, once the die is not flexible or even stuck, it is necessary to stop the production immediately, find out the cause of the card die and troubleshoot. Otherwise, it will expand the fault and lead to mold damage.

The main reasons for mold jamming are: poor die guidance, tilt. Or there is a foreign body between the template, so that the template can not be flat; mold strength design is not enough or uneven force. Cause mold deformation, for example, the hardness and thickness of mold base and mold plate are designed too small, which are easily deformed by external impact; the mold position is not installed correctly, and the positioning error of upper and lower mold is super poor. Or the accuracy of the press is too poor, so that the die produces interference; the strength of the punch is not enough, the size of the punch is too close to the position, so that the lateral force of the die is not balanced. In this case, the punch strength should be improved and the unloading plate should be enhanced to guide the protection.

3、Die damage and maintenance The die cost of stamping production is high. Usually the die 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 the die manufacturing. The maintenance cost of repairing and sharpening the die after it is put into production is also high, while the original cost of the die only accounts for about 40% of the whole die cost. Therefore, timely repairing the die and preventing the damage of the die can greatly reduce the die cost of stamping production.

Generally speaking, after a die is damaged, there is also a problem of choosing between repair and scrap. Unnatural wear and tear effects of stamping dies, such as damage to non-critical parts As well as failures such as breakage of small convex dies, upsetting and shortening of convex dies, cracking of concave plates, chipping of blanking edges, etc.. Most of them can be fully restored to normal condition and put back into stamping production by repair methods. However. When the key parts of the die are seriously damaged, sometimes the convex and concave dies are damaged at the same time. The one-time repair cost is more than 70% of the original cost of the die, or the life of the die is near. Then the repair is not very meaningful, and the scrapping of the die should be considered at this time: except for large dies and continuous dies with complicated structure. When the die repair technology is too complicated, the die repair cost is too big and the difficulty is bound to make the repair cycle too long, which seriously affects the normal production of stamping, early failure scrapping should be chosen and the die should be remanufactured.

Stamping production efficiency and cost are very dependent on the die. For the malfunction of the die during the production process, specific analysis of the problem should be made and the correct maintenance plan should be formulated. Promptly solve the problems of mold damage, mold jamming, sharpening and product quality defects. The relationship between die repair and scrapping should be handled well in order to reduce the downtime of die repair, shorten the production cycle and ensure the normal operation of stamping production.