If we encounter the following problems, we should deal with this problem.
(1) when the cutting edge is worn, the tensile stress of the material increases, and the tendency of turning and twisting of the stamping parts increases. When the material is produced, the size of the punching hole will be smaller.
2. Material pressure will cause plastic deformation of materials, which will lead to larger punching size. When the strong pressure is reduced, the size of the punching hole will be smaller.
(3) the shape of the end of the punch. If the ends are sloped or curved, the punching force will not be easy to produce material and distortion due to the decrease of blanking force. When the end of the punch is planar (no slant or arc), the punching size will be smaller.