An annular drive plate applied in the Lorentz force-driven sheet metal stamping

Lorentz force-driven sheet metal stamping is a new forming technology that combines the characteristics of quasi-static stamping and electromagnetic forming to produce forming rates that are much greater than those of conventional stamping and forming, effectively increasing the forming limits of the workpiece. The process uses a drive coil to generate an instantaneous, high Lorentz force on a highly conductive drive plate, which drives the punching motion of the punch. As the main force device, the drive plate is usually designed as a circular drive plate, which increases the weight of the drive plate and adversely affects the punching motion. In this paper, an annular drive plate is designed based on the distribution of Lorentz force in the electromagnetic forming process, and the electromagnetic parameters on the drive plate at different sizes as well as the effects on the punch speed and the final forming effect are analyzed by finite element model. The results show that: the electromagnetic parameters on the drive plate tend to increase with the decrease of the annular radius; when the profile of the annular drive plate is consistent with the profile of the drive coil, the punching speed is the largest, 23.8 m/s, which is improved by 27.2% compared with the circular drive plate, and the punching time is shortened by 27.8%; the final forming height of the workpiece is improved from 34.10 mm to 35.04 mm, and the maximum equivalent plasticity The maximum equivalent plastic strain decreased from 0.907 to 0.793, and the strain distribution was more uniform.