Patent ID: 8188401

Claim:
A wire electric discharge machining apparatus comprising: a plurality of guide rollers that are arranged at intervals; a single electrode wire that is serially wrapped around said plurality of guide rollers to form a plurality of individual cutting wire portions that are spaced from one another between adjacent pairs of said guide rollers; a processing power supply including a power feed element that feeds electrical power to said cutting wire portions, individually; a plurality of wound coils of said electrode wire, a respective one of said coils being located between each respective adjacent pair of said individual cutting wire portions, respectively; and a plurality of cores of magnetic material, each core closing a respective magnetic circuit of each of said individual coils, each respective coil and core being magnetically insulated from the other coils and cores, whereby said individual cutting wire portions are electrically insulated from one another at high frequencies, wherein each of said cores has a disc-shaped configuration having an outer peripheral portion along an edge surface of the disc-shaped core and a shroud covering only part of said outer peripheral portion and defining a tunnel along said part of said outer peripheral portion, and each of said coils includes a portion of said electrode wire wound around said outer peripheral portion of a respective core having a disc-shaped configuration and passing through the tunnel of said core having the disc-shaped configuration.