Wire-cut electric discharge machining method

A wire-cut electric discharge machining method for cutting a workpiece along a predetermined path using a wire-cut electric discharge machine controlled by a numerical control device, said method comprising the steps of:

• dividing said predetermined path into a plurality of predetermined segments;
• rough-cutting a first segment of said predetermined path by moving the wire of said electric discharge machine with respect to the workpiece while producing a high-current short-pulse discharge between the wire and workpiece;
• finish-cutting the first segment of said predetermined path by moving the wire of said electric discharge machine with respect to the workpiece while producing a low-current pulse discharge between the wire and workpiece;
• and
• repeating the steps of rough-cutting and finish-cutting for the next segment.

A wire-cut electric discharge machining method for machining along a machining path having a plurality of predetermined sections, in an apparatus having a wire-cut electric discharge machine proved with a high-current short-pulse discharge circuit for producing a high-current, short-pulse discharge for a first cut between a wire and a workpiece, a low-current pulse discharge circuit for producing a low-current pulse discharge for a second cut between the wire and the workpiece, and a control means for switching a selected one of the discharge circuits into operation and for controlling the relative movement of the wire and the workpiece, said method comprising the steps of:

• including in an NC program an instruction commanding the execution of the second cut, feed rates f.sub.1 and f.sub.2, cutting conditions s.sub.1 and s.sub.2 and amounts of offset d.sub.1 and d.sub.2 for the first and second cuts and wire contouring data for each block;
• obtaining, in response to the second cut instruction, a path offset from a command path of a first block by the amount of offset d.sub.1 ;
• moving the wire relative to the workpiece along the commanded path at the feed rate f.sub.1 and under the cutting condition s.sub.1 to perform the first cut using the high-current short-pulse discharge circuit;
• obtaining, after the first cut, a point offset from the start point of the command path of the first block offset by the amount of offset d.sub.2 ;
• moving the wire back to the point with the electric discharge stopped;
• obtaining, after moving the wire back to the point, a path offset from the commanded path of the first block by the amount of offset d.sub.2 ;
• moving the wire relative to the workpiece along the path at the feed rate f.sub.2 and under the cutting condition s.sub.2 to perform the second cut using the low-current pulse discharge circuit;
• positioning the wire at the first cut end point after the second cut;
• and
• performing the foregoing steps for each of the predetermined sections.

A wire-cut electric discharge machining method for maching along a machining path having a plurality of predetermined sections, in an apparatus having a wire-cut electric discharge machine provided with a high-current short-pulse discharge circuit for producing a high-current, short-pulse discharge for a first cut between a wire and a workpiece, a low current pulse discharge circuit for producing a low-current pulse discharge for a second cut between the wire and the workpiece, and a control means for switching a selected one the discharge circuits into operation and for controlling the relative movement of the wire and the workpiece, said method comprising the steps of:

• including in an NC program an instruction commanding the execution of the second cut, feed rates f.sub.1 and f.sub.2, cutting conditions s.sub.1 and s.sub.2 and amounts of offset d.sub.1 and d.sub.2 for the first and second cuts and wire contouring data for each block;
• obtaining, in response to the second cut instruction, a path offset from a command path of a first block by the amount of offset d.sub.1 ;
• moving the wire relative to the workpiece along the commanded path at the feed rate f.sub.1 and under the cutting condition s.sub.1 to perform the first cut using the high-current short-pulse discharge circuit;
• obtaining, after the first cut, an offset point offset from the end point of the commanded path of the first block offset by the amount of offset d.sub.2 and moving the wire to the offset point at the feed rate f.sub.2 and under the cutting condition s.sub.2 ;
• obtaining an offset point offset from the start point of the commanded path of the first block by the amount of offset d.sub.1 and moving the wire relative to the workpiece to the offset point at the feed rate f.sub.2 and under the cutting condition s.sub.2 to perform the second cut using low-current pulse discharge circuit;
• moving the wire forward to the first cut end point, after the second cut, with the electric discharge stopped;
• and
• performing the foregoing steps for each of the predetermined sections.