Study on Improvement of Surface Straightness in Wire-EDM

This paper describes the method for the improvement of surface straightness in finishing of wire electric discharge machinings (Wire-EDM). In general, two kinds of shapes are formed on surfaces of workpieces ; that is, concave forms and convex forms. The mechanism of forming these shapes is strongly related to the mechanical behavior of a wire electrode. The wire electrode is vibrated by discharge reaction forces, and the irregularity of these forces makes the concave form on the finished-surface. The supply of intermittent voltages prevents long ignition delay time, so that it inhibits the variance of forces on the wire electrode. The simulation indicated reduction effects of vibration of the wire electrode in the intermittent voltage condition. Straightness of surfaces was also improved by the experiment in finish-machining.