Fundamental Study of Accuracy of Wire EDM (6th Report)

Study of EDM Conditions and Servo Feed Function of Finish Cut

Abstract

Unsuitable EDM conditions for the finish cut on wire EDM result in a concave or a convex wall straightness of the workpiece. It takes a long time to determine the proper EDM conditions for the finish cut because many test cuts of the workpiece are required. In this study, we investigate and discuss the EDM conditions and servo feed functions of the finish cut, by examining relationships between the wire behaviors and the wall straightness of the workpiece. A method of determining EDM conditions for the finish cut is described, based on a balance model of electrostatic force and discharge force acting on the wire. A servo feed function responding to the variation of skimmed depth is investigated. Control methods for responding to the height variation of the workpiece at the finish cut are discussed.