Punch Edge Control for Tool Life Extension and Finer Blanking

Fine blanking punch edge profile was designed to control the local metal flow around the edge by chamfering technique. Massive nitrogen supersaturation (MNS) was utilized as a surface treatment of chamfered edges, corners and punch surfaces. MNSed SKH51 square punch with the chamfered edges was used for finer blanking of AISI304 austenitic stainless-steel sheets. The edge profile distortion was significantly reduced from normal blanking with and without edge chamfers. The burr height of blanks was also reduced so that dimensional accuracy in fine blanking was improved together with punch-life extension by the present punch design.