Application of Cold Punch Process and Edge Stretch Analysis to Eliminate Failure Conditions in Forming of Sheet Steels

The present paper identifies two situations where fracture in stampings during forming could be corrected by proper analysis of the conditions limiting the ductility. In one case, failures were identified to be related to heat generated during forming and the problem corrected by cooling the relevant areas of the punch. In the other case, splits were identified due to excessive work hardening of the sheared edge and insufficient ductility for the particular curvature used. This problem was solved by edge stretch analysis which suggested an increase in radius in the affected area.