Dual-Mode Universal Tooling Coil—A Versatile Uniform Pressure Actuator for Attractive and Repulsive Pulsed Electromagnetic Forming

Pulsed power is fundamental to electromagnetic forming (EMF), a technique for shaping workpieces using Lorentz forces from pulsed current discharge through specialized electromagnetic (EM) actuators or coils. The tooling coil is a very critical component, generating magnetic pressure for workpiece deformation. Conventionally, the direction of the applied force on the workpiece is repulsive, however, several applications and assembly constraints require the force to be attractive. The generation of an attractive force on a nonferrous workpiece renders the designing process of the pulsed power circuit and tooling coil very complex, requiring a separate assembly and a different pulsed power circuit for the desired operation. The emphasis of this manuscript is on the EM principles governing the design of a novel tooling coil that integrates repulsive and attractive forming techniques into a single assembly, without altering the pulsed power system design. The authors propose a dual-mode universal uniform pressure tooling coil for sheet metal forming called the dual-mode universal uniform pressure tooling coil (DM-UUPTC). The manuscript also describes an analytical model for EM analysis of the designed tooling coils for both attractive and repulsive modes of operation. The tooling coil assembly has been fabricated, and free bulging experiments have been conducted on AA-6061-T6 aluminum sheets. The results are experimentally verified and compared with the simulated results.