Electromagnetic micro-forming using flat spiral coil

Compared with the traditional uniform pressure coils, flat spiral coils have simpler structure and longer service life, as well as appropriately uniform electromagnetic force on sheet. Therefore, in this study, a flat spiral coil is used for the micro-forming of thin sheet metal. The effects of discharge voltage (U), cushion block thickness (H), and number of discharge times (N) on sheet forming quality are analyzed experimentally and by numerical simulation. With the increase of discharge voltage, the moldability of the sheet metal is improved. Nevertheless, the moldability of the sheet metal increases first and then decreases with increasing cushion block thickness. Compared to one time discharge, two successive discharges can improve the moldability of the sheet. The value of the filling rate reached 0.89 when U = 6 kV, H = 1.0 mm, and N = 2. Thus, sheet metals can be micro-formed using a flat spiral coil.