| 摘要 |
PURPOSE:To detect the breakage of a tool by converting the maximum peak value of an AE (acoustic emission) signal which is held by the circuit of a detecting device, into a digital signal by means of an analog/digital converter and, then, comparing the value with a reference value for judging breakage. CONSTITUTION:An AE wave which is generated while machining, is detected by an AE sensor 1 and converted into a voltage signal. The voltage signal is, then, sent to an amplifying detector 2 to be subjected to envelope detection. The maximum peak value Pmax of the AE signal is held for its peak over the effective duration Teff of detecting breakage by a peak hold circuit 3, sent into an analog/digital converter 4 while being gradually renewed, and converted into a digital signal Dmax. After that, the signal Dmax is compared with a threshold value of a supplementary function of a numerically controlling device 7 connected to a detector, a reference value L is compared with the signal Dmax, and judgement is made that the breakage of tool has occurred when the signal Dmax is above the reference value L, and a machine is stopped. |
