Study of magnetic force distribution for electromagnetic V-shape bending forming of small size flat sheet

Electromagnetic V-shape bending of small size sheet blank is investigated numerically and experimentally. Three-dimensional electromagnetic field models are established to calculate the magnetic force distribution on the sheet by software ANSYS/EMAG. Series of electromagnetic V-shape bending forming experiments are presented, in which small size uniform pressure coil and big size round flat spiral coil are used. The results show that small size uniform pressure coil is not suitable for electromagnetic forming of small size flat sheet, and the coil is susceptible to failure such as bulging, ablation and cracking. When the plane dimension of round flat spiral coil is bigger than sheet blank sizes, the induced current crowding effect will be resulted which seriously influence the magnetic force distribution on the sheet. In this case, magnetic force distribution can be adjusted through the change of the relative position between coil and sheet, the desired deformation can be obtained finally. Therefore, big size round flat spiral coil can be well applied to electromagnetic V-shape bending forming of small size flat sheet.