Surface scratches (strain):

Surface scratches are usually caused by the following reasons:

(1) The rounded corners of the die are not smooth enough, so the material will be scratched during the drawing process, and the material may adhere to the die, causing scratches.

(2) Because dirt falls into the die or the drawing oil is not clean, the surface of the part will also be scratched.

(3) If the pressing surface is composed of inserts, scratches will also be caused due to poor combination of the inserts; because the process supplementary part is too small, the scratches passing through the die opening are not cut off.