Patent ID: 7371989

Claim:
A wire electric discharge machine having a taper machining function for machining a workpiece between a first plane and a second plane such that a machining shape on the first plane and a machining shape on the second plane are not congruent according to a machining program, comprising: first means for obtaining a first machining path on the first plane and a second machining path on the second plane based on each of command blocks of the machining program; second means for calculating lengths of the first machining path and the second machining path; third means for adjusting a reference wire-diameter correction amount based on the lengths of the first and second machining paths to obtain adjusted wire-diameter correction amounts for the first and second machining paths, respectively; fourth means for correcting the first machining path and the second machining path according to the adjusted wire-diameter correction amounts to obtain corrected first and second machining paths; and fifth means for performing a taper machining by driving upper and lower wire guides relative to the workpiece according to the corrected first and second machining paths.