Simulation of sheared edge formation process in blanking of sheet metals

Abstract

Numerical simulation of the blanking process of sheet metals, i.e. the formation of rollover, burnish surface and burr, is done using a rigid–plastic finite element code developed by the authors. The Jeong expression is used as a ductile fracture criterion and is linked with the simulation. The rollover length increases as the clearance between the punch and die increases, and as the n-value of the material increases. On the other hand, the burnish length increases as the clearance decreases and the n-value decreases. The burr height increases linearly with respect to the radius of the tool edge. A conventional simulation method is proposed that predicts the formed burnish length from the clearance and n-value. To confirm the results of the finite element simulation, blanking experiments were also carried out using sheet metal of 3mm thickness under various clearances and for different materials. The experimental results show good agreement with the finite element simulation results.