Development and validation of a simple impulse-based method for inductor design in electromagnetically driven tools for high-speed material processing

Electromagnetically driven tools offer a promising way to accelerate conventional tools to high speeds in order to take advantage of the beneficial effects of high strain rates in material processing. However, the systematic design of inductors for such systems is still largely based on time-consuming coupled multiphysics simulations, which hinders industrial implementation. This paper presents and validates a two-step, pulse-based methodology for the simple design of inductors for electromagnetic drive systems for high-speed tools. The goal is to maximize the kinetic energy transferred to a striking tool (hammer) for a given capacitor charging energy. In the first step, a simplified computational model combines analytical expressions for the resonant circuit with fast, decoupled 2D finite element simulations (FEMM) to estimate the impulse transmitted to the hammer during the first half-wave of the discharge current. A systematic parameter study of the inductor’s inner and outer diameters, number of turns, and turn width reveals clear trends and identifies geometries that maximize efficiency in terms of the conversion of electrical to mechanical energy. In the second step, selected variants are evaluated using fully coupled 3D simulations in LS-DYNA to determine the resulting hammer velocity. For a representative high-speed blanking application, the proposed workflow results in a coil with an inner diameter of 40 mm, an outer diameter of 150 mm, and 8 turns , which achieves a modeled hammer impact velocity of 50.8 m/s. Acceleration tests with the electromagnetically driven hammer confirm the modeled current and velocity profiles and show that approximately 75% of the final hammer impact velocity is generated within the first half-wave of the current, providing direct experimental validation of the key assumption of the simplified model. The proposed methodology thus offers a practical and computationally efficient approach for the development of electromagnetic drive systems for high-speed material processing.