ABSTRACT
Sheet metals are the thin-wall formed parts with same thickness and certain geometric dimensioning, which are widely used in automobiles, ships, machinery, chemicals, aerospace and other fields. Many relatively complicated and small sheet metal parts are produced by progressive die, which can complete all processing of the stamping part in a punching stroke. It is a kind of precise, efficient, high-speed, high quality and long life stamping die (Y.S. Chen 2012).
