| 摘要 |
PURPOSE:To achieve a higher accuracy in the detection of a tool breakage by arranging an acoustic emission AE level abnormality detector section and a frequency ratio rising abnormality detector section to outputs a tool abnormality signal when signals are generated simultaneously from both of the detector sections. CONSTITUTION:A level abnormality detector section 1 is made up of a full-wave rectification circuit 3, an equalization circuit 4 and a comparator 9 processes a signal from a preamplifier 2 with the full-wave rectification circuit 3 and the equalization circuit 4 to extract the average level of an AE signal. A frequency ratio rising abnormality detector section 11 are divided into two systems, numerator and matrix systems of a divider 8, which is an analog divider and outputs a value of Y/X. The frequency ratio Y/X is inputted into a first rising detector section 14 as differentiation circuit to detect a sharp change in the frequency ratio Y/X, namely rising, as distinguished as a friction phenomenon between the work and a worn cutting tool due to a shift from the normal cutting to an abnormal cutting. The variation rate of the Y/X, namely, rising of the output is inputted into a comparator 10 and when the variation rate of Y/X exceeds the set threshold, the comparator 10 outputs a rising abnormal signal in the variation rate of the frequency ratio Y/X. |
