| 摘要 |
PURPOSE:To meke it possible to distinguish between an abnormality due to a tol deficit and the expiration of the life of a tool due to abrasion, by providing below the tool a positional detector for measuring a gap between a work piece and the tool so that an alarm is issued when the difference between an original gap value at the begining of the cutting and a gap value during the cutting exceeds a predetermined value. CONSTITUTION:An original gap value ai between a positional detector 6 located below a tool 2 and a work piece 4 upon the begining of the cutting, is stored in a memory 12, and is subtracted from a gap value aii during the cutting. Then, the magnitude of the difference is compared in a comparator 14 with a set value K1, and therefore, an alarm signal is issued when the magnitude exceeds the set value K1. Further, differences each between a final value signal aie upon the completion of working and the original value ai are cumulated, and a signal indicating that the life of the tool is expired, is issued when the cumulated value exceeds a set value K2. With this arrangement, an abnormality due to a tool deficit and the expiration of the life of the tool due to abrasion may be separately detected by only one detector. |
