Feasibility of Mass Production Verified by Cut Surface Quality and Tool Load in Negative Clearance Blanking

Abstract

The fine blanking method is one of the methods that do not cause fracture on the cut surface by press blanking. However, if fine blanking is directly applied to microblanking, there remain problems in die manufacturing accuracy and tool alignment. The authors examined the effectiveness of negative clearance as a solution. Specifically, it was clarified that the use of negative clearance can suppress the fracture of the cut surface, but the load on the punch becomes high. Therefore, in this study, we attempted to reduce the load on the punch by a slightly chamfering the punch edge and die edges. First, the optimum chamfer size and clearance were obtained by FEM analysis, and press blanking was performed under the conditions obtained by the analysis. As a result, it was clarified that the punch can withstand 10,000 shots in blanking a SUS304 thin plate.