Reduction of springback in V-shaped parts using electromagnetic impulse calibration

Abstract

Abstract Many studies reported that a pulsed magnetic force acting on the bending area can significantly reduce and even eliminate the springback. However, a detailed mechanistic understanding of springback correction has not been reported. In this study, a finite-element model of electromagnetic impulse calibration was established to understand the mechanistic of springback correction. It was found that the springback angle after the coil discharging sharply decreased in comparison with quasi-static stamping. This shows that the simulation and experimental results are consistent. By analyzing the changes in displacement, plastic strain, and principal with time, we found that the sheet corner moves far away from punch by magnetic force firstly, and then the sheet corner immediately moves closer to the punch due to the sheet impact with die. Thus, the reverse bending appears at the sheet corner, generating additional tangential stress and then changing the tangential stress at sheet corner.