FORMING A STEP IN A SHEET METAL WORKPIECE THEREBY REDUCING SPRINGBACK

摘要

A high strength sheet metal blank (10) is formed in a press comprising a die (30), a punch (32) and a blank holder (34). A stepped portion (S) appears at both an outer side of the punch (32) and a pressing portion of the die (30). The stepped portion corresponds to a predetermined bent portion of the sheet. The blank is placed between the die and punch and kept with a blank holder (34). A step is formed near an edge of the blank by progressively pressing of the step portion, thereby reducing springback of the sheet after the forming process. A shoulder part of the stepped portion of the die may be adjustable thereby allowing the die to be optimized for different sheet thickness, bending angle or mechanical properties of the sheet.