Patent ID: 8258420
Filing Date: 2012-09-04
Classification: B23H

Abstract:
1. A wire electrical discharge machining apparatus, when comprising a high impedance path and a low impedance path as feeding paths for supplying a main discharge current from a machining power supply to an inter-electrode gap between a wire electrode and a workpiece, the wire electrical discharge machining apparatus comprising: a path open/close unit capable of separately opening and closing each of the high impedance path and the low impedance path; an open/close pattern setting unit that sets an open/close pattern in which a combination of closing one of the feeding paths and opening another one of the feeding paths is designated for switching power feeding between the high impedance path and the low impedance path; a feeding-pulse-energy changing unit that generates a new open/close pattern in which a pulse energy per feeding pulse is changed in a present feeding path indicated by the open/close pattern by the open/close pattern setting unit such that a difference between discharge pulse energy applied to the inter-electrode from the machining power supply when feeding power from the high impedance path, and a discharge pulse energy when feeding power from the low impedance path is reduced; and a drive unit that controls opening and closing of the path open/close unit in accordance with the new open/close pattern generated by the feeding-pulse-energy changing unit.