Electromagnetically assisted sheet metal stamping with non-disposable foil coils

Abstract

Coil in electromagnetic forming (EMF) process commonly requires high strength and long longevity to be robust enough to accommodate great input energy that makes the coil difficult and costly to be manufactured. However, foil coils, in most cases, utilized for part calibration, vaporized for shearing, welding and embossing are less consuming in both time and outlay, easier to be fabricated and replaced, but are mostly disposable. Therefore, the purpose of this paper is to study feasibility of utilizing non-disposable foil coils in EMF process via forming the part (150mm×150mm) with hyperbolic curve like cross-section feature with 1mm thickness AA 2524-T3 aluminum alloy sheet. Copper foil of 0.5mm, 1mm thickness, wrapped in polyimide insulation foil are used as coils in two steps of a quasi-static two-mould-closing pre-forming and EMF process. Besides, practical orthogonal tests are deployed to explore these coils’ forming performance and find the factors’ influential sequence to obtain appropriate process parameters. Results of loose coupling simulation with selected parameters, using ANSYS APDL macro and ABAQUS keywords will be presented and compared with formed components corresponding to simulation load steps. Eventually, formability of sheet component under conditions of diverse charging voltage, foil thickness, foil layers and number of loading repetition and longevity of these coils were experimentally investigated. And the study demonstrates that this technique can be used to improve sheet metal stamping process.