Wire EDM taper cutting method using path data of two planes of a workpiece

Claim 1

A wire electrode discharge machining method for cutting a workpiece by moving a wire electrode relative to the workpiece and producing an electric discharge across the wire electrode and the workpiece, comprising the steps of: preparing and entering path data specifying contours on an upper and on a lower plane of the workpiece; separately preparing and entering auxiliary data including an amount of wire diameter compensation, workpiece mounting position and guide positions necessary for moving the wire electrode relative to the workpiece; continuously finding first relative travel quantities (Δx w1 , Δy w1 ; Δx w2 , Δy w2 ) of the wire electrode with respect to the upper and lower planes of the workpiece over a predetermined period of time; converting said first relative travel quantities into second relative travel quantities (Δx u , Δy u ; Δx d , Δy d ) of the upper and lower guides with respect to said workpiece by using said auxiliary data including workpiece mounting position and guide position data; moving the upper and lower guides relative to the workpiece in accordance with said second relative travel quantities; producing pulses of a number of equivalent to integral portions of said second relative travel quantities to move the uppr and lower guides relative to the workpiece; and correcting subsequent second relative travel quantities of the upper and lower guides with respect to the workpiece by decimal portions of the present second relative travel quantities.