| 摘要 |
PURPOSE:To detect the presence of tool defect without fail by extracting the components of high frequency and the components of broad band from an AE signal and by comparing the difference between the broad band components and the values of the high frequency component times as amplification factor with a reference target value. CONSTITUTION:An AE signal is detected with a sensor 7 installed on a main shaft head 9. The AE signal is destributed to the high frequency components and the broad band components with a first by-pass filter 11 specified as about 250- 400kHz and a second by-pass filter 13 specified as about 1-30kHz, thereby transmitting the output signals A and B from detectors 15 and 19. The output signal A is introduced to an amplifier 17 having an amplification factor K and is multiplied by K. Subtraction is carried out between the signals KA and B with a subtracting calculator 21. The calculation result (kA-B) is input to a decision circuit 23 and is compared with a comparison target value C. When the calculation result (kA-B) exceeds the value C, the tool is determined as defective. With this construction, the presence of tool defect can be determined with one comparison target value irrespective of the kinds of tools or workpieces. |
