During the stamping process, what is the cause of the punch falling off?

In the process of stamping, we sometimes encounter the situation that the punch of the mold suddenly falls off, so what are the reasons that cause the punch to fall off? In fact, the main reason for the analysis of the falling off of the punch is that the punch is not firmly fixed. What are the reasons for the weak fixation of the punch? There are mainly the following five reasons: 1) For the fixed structure of the punch that adopts interference fit and press-in, because the required amount of interference cannot be reached during the manufacturing, the method of'twisting and squeezing' is used to remedy it, resulting in convex The mold is easy to loosen and fall off. 2) If the punch is not fixed by steps or fasteners, when the thicker, harder or more viscous material is punched and the gap between the discharge plate hole and the punch is too small, it will cause the unloading The increase of material force causes the punch to pull out. 3) The punch or die base has poor rigidity and elastic deformation occurs during the punching process, causing the punch to collide with the discharge plate or jam with the die, which increases the discharge force and makes the punch easy to pull out. 4) The gap between the convex and concave molds is too small, and the working surface is rough or the gap is on one side, and the discharge force can be increased during punching, causing the punch to pull out. 5) When using a low melting point alloy to fix the punch, there are no grooves on the assembly side of the punch and the assembly hole wall of the punch fixing plate, so that the punch is easy to pull out. The above are the five most common reasons why the punch falls off during our stamping process. When the punch falls off, you can first find the reasons in these five aspects. Previous post: How to calculate the unfolded length of sheet metal stamping and bending parts?