Energy release rate based approach for the wear of punches in precision blanking of high strength steel

Punch wear is a major issue in the blanking of high strength steel (HSS) sheets. To study wear physics, a blanking test with tight side clearances was implemented, and the results compared with numerical simulations with appropriately calibrated critical damage value. Based on observations of worn punches, wear angle was found to adequately represent changing geometry of the cutting edge. Using modified geometries, burr formation, stress-state at the punch and load–displacement curves are investigated. Punch wear and shear crack mechanics are found to strongly relate to the changes in the load–displacement curve, and the release rate of punching energy.