High Voltage, High Hopes: A Cautionary Tale of Through-Thickness Electroplastic for Springback Reduction

This work explores the feasibility of inducing springback reduction in AA5754 aluminium alloy sheets using a novel approach: Post-Forming Through-Thickness Electroplastic Effect (PF-TT-EPE). The concept aims to deliver high-energy electrical pulses directly through the sheet thickness via embedded tooling electrodes, enabling stress relaxation without external fixtures or process interruption. While theoretically promising, the experimental campaign encountered critical implementation challenges. Despite establishing a repeatable baseline springback of 11.8 ± 0.5°, all attempts to apply pulse trains above ~ 600 A·ms/mm² resulted in uncontrolled spark discharge, severe sample damage, and tooling degradation, linked to air gap formation and dielectric breakdown at the interface. At lower energies, the process proved electrically safe but ineffective in reducing springback. These findings highlight the fragility of die-integrated electrical delivery systems and expose the hidden complexity of ensuring stable, conductive contact under forming conditions. Rather than demonstrating success, this study contributes a clear boundary to the applicability of electroplastic forming techniques and outlines the key technical gaps that must be closed for PF-TT-EPE to move beyond concept.