Abstract
A curved-hole machining technique is proposed using a metal ball electrode suspended by a lead wire from the head of an electrical discharge machine. In this study, the electrode, which consisted of a 5.5-mm-diameter copper-tungsten-alloy electrode ball suspended with a silver chain or a cupper foil, a straight holes over 30 mm were machined into a Zn alloy workpiece at a constant rate. Under certain working conditions, the drilling speed using this suspended electrode with the chain was faster than that using a rod electrode. While using this method, servo voltage was a critical factor for stable machining. Attempts were made to machine a curved hole by varying the tilt angles of the workpiece; curved holes were created at tilt angles of 15°, 30° and 45°.
