December 11, 2023
Surface bruises:
Main causes of surface pressure injuries:
(1) Improper material selection for the working part of the mold.
(2) Low heat treatment hardness.
(3) Die fillet wear.
(4) Poor smoothness.
(5) The surface quality of the curved blank is poor (rust, scarring, etc)
(6) Material thickness is out of tolerance.
(7) Unreasonable selection of process plan.
(8) Lack of lubrication, etc.