Analysis of Electromagnetic Force in Rough Cutting of Wire-EDM

Abstract

This paper describes changes in the electromagnetic force applied to the wire electrode with increasing depth of cut in wire electrical discharge machining (WEDM). In this study, the electromagnetic force was analyzed by finite element method (FEM). Vibration of the wire when the electromagnetic force was applied to the wire independently was also analyzed. The wire movement was then measured when the current in the wire was changed in the same way as the discharge current with the gap voltage between the wire and workpiece kept at zero. It was found that the electromagnetic force is repulsive when the workpiece material is copper and attractive when the workpiece is steel. In both cases, the force is maximum when the depth of cut is about equal to or smaller than the wire diameter. Compared with the impulse of the electrostatic force, the impulse of the electromagnetic force is even larger in rough cutting.