Patent ID: 6921876

Claim:
A method for adjusting a gap between a workpiece and an upper nozzle of a wire electric discharge machine, said wire electric discharge machine including a machining power supply for generating an electric discharge between a wire electrode and the workpiece, an upper nozzle for supplying working fluid between said wire electrode and said workpiece, an upper guide for holding said upper nozzle, a servo motor for driving said upper guide along an axis of said wire electrode and a control unit for controlling said servo motor, said method comprising the steps of: arranging a spacer member of a known thickness between said workpiece and said upper nozzle; moving said upper nozzle toward said workpiece thereby to bring said upper nozzle into contact with said spacer member; separating said upper nozzle from said workpiece by a predetermined distance after detecting the contact between said upper nozzle and said spacer member; removing said spacer member from between said workpiece and said upper nozzle; and approximating said upper nozzle into proximity with said workpiece so that said upper nozzle and said workpiece are spaced away from each other by a desired gap distance; wherein the gap between said upper nozzle and said workpiece is adjusted by moving said upper nozzle by a length equal to the distance determined on the basis of the thickness of said spacer member and the desired gap distance between said upper nozzle and said workpiece.