Patent ID: 6984800
Filing Date: 2006-01-10
Classification: B23H

Abstract:
1. A wire electric discharge machine for performing electric discharge machining on a workpiece, having a wire guide, a nozzle attached to said wire guide for supplying machining fluid, wire guide driving means for moving the wire guide, a table for mounting the workpiece, table driving means for moving the table and a controller for controlling the electric discharge machining accordance to a machining program, said machine comprising: wire supply means for supplying a wire electrode through the wire guide toward the workpiece; wire supply-amount measuring means for measuring a supply amount of the wire electrode; wire front-end detecting means for detecting a front end of the wire electrode being supplied by said wire supply means at a wire front-end detecting position; and wire contact detecting means for detecting contact of the front end of the wire electrode with an upper surface of the workpiece, wherein a position of the upper surface of the workpiece is determined based on the wire front-end detecting position and a supply amount of the wire electrode measured by said supply amount measuring means from when the front end of the wire electrode is detected by said wire front-end detecting means till the contact of the front end of the wire electrode with the upper surface of the workpiece is detected by said wire contact detecting means.