Dual-Channel Uniform Pressure Tooling Coil—An Electromagnetically Optimized Uniform Pressure Actuator for Pulsed Electromagnetic Metal Forming

Pulsed power is at the core of electromagnetic (EM) forming, which is a specialized and emerging manufacturing technique that deforms the workpiece using Lorentz forces produced by the discharge of a pulsed current through an EM actuator or tooling coil. The uniform pressure actuator (UPA) is the most widely used tooling coil for pulsed sheet metal manufacturing applications that offers broad forming prospects. The main focus of this article is to examine the design of EM actuators with an emphasis on pulsed power, taking an EM perspective rather than a manufacturing one. The emphasis of the article is on the EM principles and components involved in the design of pulsed power EM actuators for manufacturing applications, to understand their working principle and how they can be optimized. The present design of the UPA is inefficient and does not utilize the stored energy in the pulsed magnetic field to the full extent. The novel contribution of the present work is on the optimization of the uniform pressure EM actuator by maximizing the induced eddy currents in the workpiece by efficiently designing the geometrical configuration of the actuator. The optimized uniform pressure EM actuator has led to the design of a novel dual-channel uniform pressure EM tooling coil. The recently developed tooling coil has been compared to the conventional UPA in various aspects such as the effect of designed geometry on the pulse power efficiency, EM pressure applied, stress on the coil, and so on. The results indicate a significant enhancement in all these aspects of the novel tooling coil. In addition, a fast analytical method to solve EM fields and force computations developed by the authors previously based on current-carrying filaments has been used for solving the EM fields. The article also studies the important design parameters to be considered while designing the novel tooling coil. Finally, to validate the design, it compares the performance of the developed tooling coil with a conventional UPA (or UPTC) for a flat sheet metal free-forming process and the results are experimentally verified.