Temperature Field Simulation of Wire Electrode in High-speed and Medium-speed WEDM under Moving Heat Source

Abstract

The high-speed and medium-speed wire electrical discharge machines which are originally developed in China are playing an important role in mold making. However, the wire electrode wear is a universal problem in the machining process because the wire electrode is used repeatedly. Considering the relative motion between the wire electrode and the workpiece, the heat transfer model of wire electrode under moving heat source was established, and the temperature field of wire electrode was simulated in single pulse discharge by FEM. The results indicated that the size of the melted zone along the wire electrode axial direction increased remarkably while the depth size, the width size and the volume of the melted zone reduced apparently when the wire running speed increased. It can be concluded that the high relative speed between the wire electrode and the workpiece is beneficial to reduce the wire electrode wear in radial direction. Furthermore, when the wire running speed is higher than a certain value, the discharge column will slide over the wire electrode surface before the wire material reaches its melting point, thus the melting and ablation of the wire electrode material does not happen, which can almost realize no wire electrode wear.