Electric discharge machining method and apparatus for machining a

Abstract

An electric discharge machining system of machining a microshaft by electric discharge made between the microshaft and a conductive wire used as a working tool. The microshaft is vertically supported by a bearing to be rotatable about its own axis and movable up and down in directions of the axis by a microshaft driving device and the wire is arranged to travel in a direction of its own axis and to be movable in directions close to and away from the microshaft by a wire driving device, whereby the wire is relatively movable with respect to the microshaft in horizontal and vertical directions. On the electric discharge machine, a control unit controls the microshaft driving device and wire driving device so that the wire is moved up to a predetermined position horizontally away by a first predetermined distance from a first reference point in the horizontal directions that the axis of the wire intersects the axis of the microshaft and the microshaft is moved vertically by a predetermined distance with respect to the wire with the wire travelling in the direction of its own axis and the microshaft being rotated about its own axis. As a result, the microshaft is machined to have a diameter equal to twice the first predetermined distance and the machined portion of the microshaft has a length corresponding to the second predetermined distance.