Deep rolling of fine blanking punch edges

Fine blanking is an economical process to manufacture components with a high sheared edge quality. Fine blanking of high-strength steels leads to an increase of the wear of fine blanking punches and deteriorates the economical efficiency of this process. In preliminary work lateral surfaces of cylindrical punches made of different hardened steels industrially used for tool manufacturing were deep rolled. Under proper process parameters a reduction of surface roughness, a hardness increase as well as an induction of compressive residual stresses in the surface layer were achieved. Therefore, deep rolling has a potential to improve the wear resistance of fine blanking punches. In order to improve the quality of the sheared edge of a workpiece, fine blanking punches must have a round fillet on the cutting edge. Filleting through plastic deformation can improve the wear resistance of this most loaded region of the fine blanking punch. In order to perform the filleting of the cutting edge through plastic deformation and to induce strain hardening and compressive residual stresses into the edge region a novel profiled deep rolling tool is developed in this work. Furthermore, the technical feasibility of the edge deep rolling with regard to the processing of fine blanking punches is assessed for the first time. The approach is based on a numerical modeling and experimental investigation of edge deep rolling.