Electromagnetic impulse calibration in V-shaped parts

In this study, a 2D finite-element model of electromagnetic impulse calibration was established to understand the mechanistic of springback correction. According to the results both in experiment and simulation, the springback angle after the coil discharging sharply decreases in comparison with quasi-static stamping, and the springback angle decreases gradually with the increasement in discharging energy. Finally, negative springback under the 6-KJ condition both occur in experimental and simulation results. It was found the sheet corner moves far away from punch by magnetic force and the inertial effect caused by magnetic force firstly. When the sheet peak reaches the maximum position, the sheet corner immediately reverse bending and moves closer to the punch. The phenomenon of reverse bending generates additional tangential stress in opposite direction, which decreases the original tangential stress on sheet corner and even makes the sheet corner undergo plastic deformation in high discharge energy. The discoveries showed in this paper will provide theoretical basis for controlling the springback of complex parts in the future.