Patent ID: 9421627
Filing Date: 2016-08-23
CPC Classification: B23H

Claim Text:
1. A wire electric discharge machining apparatus comprising: a lower arm and an upper arm, which support a wire therebetween and move to machining positions in parallel to a first direction, for the wire to machine a workpiece; a surface plate having a vacant inner area, for placing the workpiece thereon by supporting a part of the workpiece with an outer area which surrounds the vacant inner area, wherein the wire moves in the vacant inner area while machining the workpiece; a machining bath having a casing which holds a machining liquid, into which the surface plate is placed, and has a side surface through which the lower arm extends, wherein by moving a horizontal relative position between the lower and upper arms and the casing in the first direction, a horizontal relative position between the wire and the workpiece is changed; and a bellows which extends through the side surface of the casing and encloses a part of the lower arm, wherein the casing is supplied with the machining liquid so that a machining position at which the wire machines the workpiece, among the machining positions, is immersed in the machining liquid, a first end of the bellows, that is inside the machining bath, is attached to the lower arm so that the bellows does not move underneath the vacant inner area, regardless of the machining position to which the upper and lower arms move the wire within the vacant inner area, the upper and lower arms are attached to a column which extends perpendicular to the first direction and is configured to move together with the upper and lower arms, a distance between the first end of the bellows and the wire is greater than a distance between sides of the vacant inner area which oppose one another in the first direction, and the first direction is coincident with an axial direction of the lower arm, and is a direction to move the wire orthogonally away from the side surface of the casing.