Application Comparison of the Circular and Elliptic Working Coil Used in Sheet Metal Electromagnetic Forming

In the sheet metal electromagnetic forming, the shape and dimension of the working coil directly affect the force applying on the sheet metal and have a key function for the deforming result. Here, the distribution of the magnetic induction intensity of the elliptic working coil is achieved through the deduction of the magnetic induction intensity generated by elliptic line current, and further the distribution of the magnetic induction intensity of the circular working coil and the distribution of the electromagnetic force that applies on the sheet metal are also achieved. Two groups of experiments are performed. The first, the sheet metals are deformed by using the hole mould, and the circular and elliptic working coil are respectively used. The deforming depths of the two parts are compared. The second, the sheet metals are deformed by using the rectangular mould, and the circular and elliptic working coil are respectively used. The deforming of the center position and the deforming sufficiency along the length of the two parts are compared. By the analysis of the experiment results after considering the distribution law of the magnetic induction intensity, the authors can get the suitable condition about when the two kinds of working coil are used: for a long workpiece, the elliptic working coil is better than the circular working coil; for the piece which has much demand for deforming in the center position, the circular working coil is better.