Wire electric discharge machining method

A wire electric discharge machining method for cutting a plurality of male forms off a workpiece using a wire electric discharge machine having an annealing/fusing device for annealing a wire into a straight shape upstream of an upper wire guide in a wire path and fusing the wire near the upper wire guide, and an automatic wire connecting device for automatically connecting the wire by restricting the wire by a machining fluid flow from a nozzle of the upper guide, said method comprising the steps of:

• (a) inputting a machining program defining a plurality of machining paths corresponding to the respective male forms and setting a reserve amount for a first electric discharge machining and a backward amount for a second discharge machining;
• (b) performing the first discharge machining by (b1) automatically connecting the wire through a machining-start hole in the first machining path by said automatic wire connecting device, to perform an electric discharge machining for shaping along the first machining path based on said machining program, (b2) stopping the electric discharge machining at a stop position with said reserve amount left along the first machining path, to anneal and fuse the wire by said annealing/fusing device, and (b3) performing and stopping the electric discharge machining along successive machining paths in the same manner as said steps (b1) and (b2);
• and
• (c) performing the second discharge machining by (c1) automatically connecting the wire at a wire connecting position turned back by said backward amount from said stop position in said step (b2) along a machined groove formed in the electric discharge machining of said step (b1), (c2) cutting off a first male form by performing the electric discharge machining from said wire connecting position along the first machining path based on said machining program, (c3) annealing and fusing the wire by said the annealing/fusing device, and (c4) cutting off said plurality of male forms successively in the same manner as said steps (c1), (c2) and (c3).