Analysis of Wire Impedance in Wire-EDM Considering Electromagnetic Fields Generated around Wire Electrode

It is difficult to find the optimum machining conditions in wire electrical discharge machining (wire-EDM), because discharge current is influenced by the impedances of the wire and workpiece electrodes which may vary depending on the diameter of the wire, height of the workpiece and materials of wire and workpiece even if the pulse conditions are the same. Hence, this study aims to develop a simulator to analyze the distribution of the current density, and magnetic flux density in and around the wire t o obtain the impedances of the wire and workpiece electrodes using the electromagnetic field analysis by finite element method (FEM). With this method, the dependences of the impedances on the electromagnetic properties of the electrodes were investigated. The impedances measured using an LCR meter coincided with the analysis results. Thus it was confirmed that this analysis is useful to obtain the discharge current waveform which may change depending on the dimensions and material properties of the electrodes, serving a tool to optimize the machining conditions.