| 摘要 |
PURPOSE:To prevent the erroneous detection due to noise by outputting an alarm signal on the basis of the detection signal for the breakage of a tool by a sound-wave sensor only when the number of revolutions of a main shaft becomes over a prescribed value, in an NC machine tool. CONSTITUTION:A controller 2 drives a machine tool 1 according to a set program, and when the revolution speed signal supplied from a revolution speed sensor 10 exceeds a certain value, said controller outputs a revolution speed signal (a). While, an AE signal (b) is outputted from an AE detector 5 according to the output supplied from a sound-wave sensor 4 according to the cutting condition, and if anomaly exists, a cutting anomaly signal (c) is outputted, and input into a tool breakage judging apparatus 6 with the signal (a). When the both signals (a) and (c) are H, an alarm signal (d) which passes through the AND circuit 15 in case of turning-ON of an unmanned operation switch 18 is sent into the NC controller 2, through an AND circuit 14, and an alarm signal (e) is sent into a power source apparatus 17, and the machine stops operation, and the necessary information is displayed onto an indicator 9. Therefore, the noise in transient period in the revolution of the main shaft can be removed. |
