Investigation of Tailored Pressure Distributions by Vaporizing Tailored Foils

Abstract

The rapid vaporization of thin metallic conductors can be used for innovative high speed forming processes. Metal wires or foils are vaporized when a high current is applied. The generated metal gas or plasma expands very rapidly with high pressure and impacts on an intermediate polyurethane plate near the wires or foils. A shock wave is induced into the polyurethane plate and provides the pressure pulse to the sheet metal, leading to a deformation of the sheet. This process requires no expensive tool coils and no electrical conductivity of the workpiece, which makes it attractive to multiple fields of application such as forming and impact welding. In this study, the basic process parameters that influence the shock pressure were experimentally identified including the charging energy of capacitor bank, foil geometry (thickness and width) and thickness of polyurethane plate. Based on the experiments of the parameter investigations, different new foil designs were investigated in order to acquire a tailored pressure distribution. The results show that the shock pressures can be located at different positions in a discontinuous way. Besides, the pressure amplitudes and areas at different positions can also be varied, which depends on the vaporized foil geometries at those positions.