Patent ID: 8881716
Filing Date: 2014-11-11
Classification: B23D,B24B,B26B,B28D

Abstract:
1. A wire saw adapted to cut a workpiece using a cutting wire, the wire saw comprising: a wire feeder that feeds the cutting wire; a first workpiece cutting unit including a plurality of first guide rollers and a first drive unit that rotationally drives the first guide rollers, the cutting wire fed from the wire feeder being wound around each of the first guide rollers to form a workpiece-cutting wire group; a second workpiece cutting unit including a plurality of second guide rollers and a second drive unit that rotationally drives the second guide rollers, the cutting wire led out from the first workpiece cutting unit being wound around each of the second guide rollers to form a workpiece-cutting wire group; a wire winder that winds the cutting wire led out from the second workpiece cutting unit; a tension detector that detects tension in the cutting wire between the first workpiece cutting unit and the second workpiece cutting unit; and a control device that causes the first drive unit and the second drive unit to rotationally drive the first guide rollers and the second guide rollers, respectively, at a predetermined rotational speed, wherein the control device: performs a feedback control of the rotational speed of the guide rollers based on a deviation between a tension detected value by the tension detector and an acceptable value set in advance; changes only the rotational speed of one of the first guide rollers and the second guide rollers so as to keep tension detected by the tension detector within a predetermined range when the deviation is smaller than a certain value; and changes the rotational speeds of both the first guide rollers and the second guide rollers so as to keep the tension detected by the tension detector within the predetermined range when the deviation is equal to or greater than the certain value.