Patent ID: 8991381
Filing Date: 2015-03-31
Classification: B23D,B24B,B28D

Abstract:
1. A method of cutting a workpiece by using a wire saw in which a cutting wire fed from a wire feeder is wound around a plurality of guide rollers and then wound by a wire winder and by simultaneously performing cutting-feeding of relatively moving the workpiece with respect to a plurality of wires aligned between the guide rollers, while driving the wires in an axial direction thereof, the method comprising: a forward-driven cutting step of cutting the workpiece while feeding the wire from the wire feeder and winding the wire with the wire winder, adjusting tension in a wire fed from the wire feeder so as to approximate the tension in the wire fed from the wire feeder to a first target tension by pressing a feeding-side tension-application member against the wire fed from the wire feeder, and adjusting tension in a wire wound by the wire winder so as to approximate the tension in the wire wound by the wire winder to a second target tension lower than the first target tension by pressing a winding-side tension-application member against the wire wound by the wire winder; a backward-driven cutting step of cutting the workpiece while reversely feeding the wire wound by the wire winder from the wire winder and winding the wire with the wire feeder, adjusting tension in a wire fed from the wire winder so as to approximate the tension in the wire fed from the wire winder to a third target tension higher than the second target tension by pressing the winding-side tension-application member against the wire fed from the wire winder, and adjusting tension in a wire wound by the wire feeder so as to approximate the tension in the wire wound by the wire feeder to a fourth target tension lower than either of the first target tension and the third target tension by pressing the feeding-side tension-application member against the wire wound by the wire feeder; a first switching step of decelerating a driving speed of the wire after the forward-driven cutting step, reversing the driving direction of the wire and thereafter accelerating the driving speed of the wire to shift to the backward-driven cutting step; and a second switching step of decelerating a driving speed of the wire after the backward-driven cutting step, reversing the driving direction of the wire and thereafter accelerating the driving speed of the wire to shift to the forward-driven cutting step, wherein the forward-driven cutting step, the first switching step, the backward-driven cutting step, and the second switching step being repetitively performed in this order, wherein, in the first switching step, an adjustment of tension in the wire at a side of the wire winder is performed with the winding-side tension-application member, during the deceleration of the wire driving speed, so as to increase a target tension as to the wire at the side of the wire winder from the second target tension to the third target tension, and an adjustment of tension in the wire at a side of the wire feeder is performed with the feeding-side tension-application member, after completion of the deceleration of the wire driving speed, so as to reduce a target tension as to the wire at the side of the wire feeder from the first target tension to the fourth target tension.