| 摘要 |
PURPOSE:To enable to detect the generation of an abnormal condition of a tool easily and correctly, by a method wherein the current passing in a feed motor is detected when an abnormal condition occurs at a turning tool, and the condition is judged to be abnormal when the current value detected exceeds a preset value. CONSTITUTION:A main spindle motor 2 of a swivelling automatic machine 1 rotates a chuck 3 gripping a work. The feed motor 4 controls the feed of a tool rest 6 fitted with cutting tools 7, 8 or the like. A setter 12 is provided for setting a threshold current and it generates a set voltage signal corresponding to the threshold current. A comparator 13 compares a signal V generated by a current detector 10 with the set signal Vc, and it generates an abnormality detection signal when V> Vc. Thus, a threshold value is selected from a plurality of threshold values in accordance with NC information, and an abnormality detection signal is outputted when the current flowing in the feed motor exceeds the relevant threshold value. |
