| 摘要 |
A variation amount of current for driving a feed motor (M) for running and moving a wire electrode (11) is obtained as a value corresponding to a variation in the sliding resistance between the wire electrode and wire guides (7, 8) in association with a variation in the taper angle of the wire electrode (11). The above value so obtained is fed back to a brake device (20) for imparting a braking force to the wire electrode (11) so as to increase or decrease the braking force. As a result of this, the tension of the wire electrode (11) in an electric discharge machining area is maintained constant irrespective of variation in taper angle, whereby it is possible not only to prevent the breaking of a wire but also to obtain a uniform working precision. <IMAGE> |
