WIRE ELECTRIC DISCHARGE MACHINING METHOD

摘要

A wire electric discharge machining method for improving a machining precision when machining a corner portion. A speed is gradually reduced starting at point A until the machining of a corner portion C-D is initiated, and machining is performed on the corner portion C-D at a constant feed speed. Then, the machining feed speed is gradually increased starting at point D where the machining of the corner portion has been completed until the original speed is restored at point F. In accordance with this change in feed speed, the off-time of a voltage applied between a wire and a work is increased starting at point B, reduced starting at point E after the machining of the corner portion is completed, and restored to the original level at point F. Furthermore, the flow rate of processing liquid is also reduced with the progress of machining of the corner portion. This process is controlled in accordance with the radius curvature of the corner portion by automatically changing a feed speed along the corner portion, off-time and flow rate of processing liquid. There is little deflection of the wire electrode at the start and during the machining of the corner portion, whereby the precision with which corner portion is machined is improved.