Feasibility of electromagnetic pulse-assisted incremental drawing with a radial magnetic force for AA-5052 aluminum alloy sheet

In the conventional drawing process, the predominant failure modes of a sheet metal are wrinkling and fracture. Wrinkling during the forming process can often be treated as a recoverable defect as it can be eliminated though the appropriate control of the blank holding force. Fracture, however, is a fatal flaw. When the fracture occurs, the drawing process cannot continue. We propose a new forming method that can handle large height/diameter ratios. The new method uses electromagnetic pulse-assisted incremental drawing (EMPAID) together with radial magnetic force and a suitable auxiliary coil structure and size. Both the calculated and experimental results indicate that the magnetic force generated by the auxiliary coils can increase the flange material flow and significantly improve the ability of the sheet metal to resist fracture. When only the auxiliary coil is used in the experiment, the drawing depth increases by 21.8 % (with respect to conventional drawing) if the auxiliary coils discharge once. The drawing depth can be increased by as much as 36.7 % when multiple discharges are applied. When the auxiliary coil is used in combination with other electromagnetic forming coils in the experiment, the maximum drawing height of the cylinder cup increases by 141.6 %, after multiple discharges.