Generally speaking, the stamping parts need to have a certain R. It is impossible to achieve a complete sharp angle, but the visually perceived "spike" itself is with a certain r:
1. Draw-up type, which can be used to draw a relatively large R when deep drawing, and a smaller R angle by adding shaping.
2, flanging (bending type), directly using a very small R angle: machine does not process the R angle, when using the cracking, use sandpaper to polish the small R, why can not reach
I am afraid that a certain R angle is also required for the blanking. The general blanking is to use the blanking die. Otherwise, the cutting edge and the wear are too fast, and a small amount of material is used for the plasma cutting machine or the numerical control laser cutting machine.