| 摘要 |
PURPOSE:To detect thermal cracks and injuries of a tool share point distinguishing from a difference of a time constant and a difference of a frequency component of an acoustic emission made by a cutting work. CONSTITUTION:After signals detected by an acoustic emission sensor 1 having been amplified by an amplifier 2, for the signal on one side, an output signal X4 is obtained through a high pass filter 14 and an envelope detector 15 and for the other, an output signal X15 is obtained through a low pass filter 14 and the envelope detector 15. Then, if the output signals X4, X15 are larger than a set point of threshold setter 8, both the output signals X9, X14 of amplitude discriminators 9, 16 are set so as to be at high levels and a damage discriminator 17 judges that the injuries arise when the output signals X9, X16 are both at the high level, that the thermal cracks are produced when the output signal S9 is at the high and the output X16 is at the low level and an alarm signal generator 13 ends a warning when the output signal of the damage discriminator 17 exceeds the predetermined frequencies. |
