Patent ID: 6781080
Filing Date: 2004-08-24
Classification: B23H

Abstract:
A wire electric discharge machine for conducting electric discharge machining on a workpiece by electric discharge generated in a working gap formed by a wire electrode and the workpiece by supplying electric discharge from a machining electric power source while a dielectric fluid is being supplied in the working gap formed by the wire electrode and the workpiece from flushing nozzles of dielectric fluid, comprising:normal electric discharge pulse detection means for detecting a normal electric discharge pulse in the working gap; normal electric discharge pulse calculation means for calculating normal electric discharge pulse energy from the detected normal electric discharge pulses; storage means for storing threshold value data in which a predetermined margin is ensured from an operation point when wire breakage occurs, found from a relation between the normal electric discharge pulse energy and the electric discharge machining energy setting value corresponding to various electric discharge machining conditions; and control means for controlling the electric discharge machining energy setting value so that the threshold value data can approach the operation point.