Electromagnetic pulse-assisted incremental drawing of aluminum cylindrical cup

Based on the needs of low plasticity materials and large height diameter ratio parts forming, a new forming approach named electromagnetic pulse-assisted incremental drawing (EMPAID) has been proposed in this study. The radial magnetic force produced by circular auxiliary coils on and underneath a flange pushes sheet metal in the radial direction. The axial magnetic force generated by drawing coil in the bottom of the punch pushes the sheet metal into the die cavity. The magnetic force produced by the corner coil provides a through-thickness pressure on the sheet metal around the die corner, which prevents wrinkling. The forming process and principle of the new method are analyzed in this study. To investigate the effects of the auxiliary and corner coils, which are added to stamping tools to improve the wall-thickness distribution, the stress state, and the forming quality, two different cases are compared and analyzed in simulation and experimentally. The result indicates that the radial magnetic force generated by the auxiliary coil could reduce the radial tensile stress, which mitigates the crack of the workpiece. Using this new forming method, the limit drawing height can be increased to 2.16 times of that in the conventional drawing.