| 摘要 |
PURPOSE:To make it possible to surely detect abnormality of multi-edged tools, by comparing cepstrum of the period of the next tool reaching the position of an arbitrary tool of multi-edged tools and the period of one rotation of the tool. CONSTITUTION:The output voltage of a stress sensor 5 corresponding to cutting force is delivered to a cepstrum processor 10 through an amplifier 6, a low-pass filter 7 and a capacitor 8. Further, a computing circuit 11 receives the rotational speed S of a milling cutter 1 and the number of tools (n), and computes the amplitude C1 of cepstrum of the period of the next tool reaching the position of an arbitrary tool of the cutter and the amplitude Cn of cepstrum of the period of one rotation of the cutter 1. The computing circuit 11 further receives a threshold value L corresponding to the ratio of the amplitudes C1a, Cn, and if Cn/C1> L, delivers a feed stop signal to an NC controller 12 for controlling the milling cutter. With this arrangement the NC controller 12 stops the feed of the cutter 1, and abnormality of the tool may be surely informed to the worker. |
