Electromagnetic effects of electrode materials and sizes on discharge current and wire vibration in Wire-EDM

Abstract

This study aims to develop a simulation tool to analyze the influence of wire structure, workpiece material, and workpiece thickness on the discharge current and wire vibration caused by the electromagnetic force observed in wire electrical discharge machining (WEDM), taking into consideration the electromagnetic field around the electrodes. The distribution of current density and magnetic flux density, electromagnetic force acting on the wire, and wire vibration were analyzed by coupling the equation for the entire discharge circuit with the Poisson’s equation of the magnetic vector potential around the wire. Monolithic brass wire showed higher discharge current than coated steel wire, resulting in larger electromagnetic force acting on the wire. A copper workpiece exhibits smaller but reversed phase wire vibration compared with steel workpiece. Thicker workpieces cause larger wire vibration because the electromagnetic force acts on the wire electrode along a greater distance.