| 摘要 |
PURPOSE:To detect damage of a multi-blade tool, by applying the rectified output of an AE sensor to second band-pass filters having a pass frequency determined by the product of the rotational speed of a spindle and the number of blades of the tool, and by adding the levels thereof together so that the obtained value is compared with the the output level of a first band-pass filter having the pass frequency determined by the product of the rotational speed of the spindle and the number of blades of the tool. CONSTITUTION:During cutting of a workpiece 2, an AE signal detected by an AE sensor 6 is amplified by an amplifier 8 and is delivered to a full-wave rectifying circuit 9 for delivering frequency signals in accordance with the rotational speed of a spindle and the number of a multi-blade tool 4. If any chipping or damage is there in a part of the multi-blade tool 4, the frequency component in accordance with the rotational speed of the spindle 5 and higher harmonic frequency components may be simultaneously produced in addition to the frequency corresponding to the product of the rotational speed of the spindle 5 and the number of blades of the multi-blade tool 4. Accordingly, by comparing the sum of odd- number mode harmonic frequency components corresponding to the rotational speed of the spindle 5, with the frequency corresponding to the product of the rotational speed of the spindle and the number of the blade of the tool, tool damage may be detected. Accordingly, it is possible to detect damage of a multi-blade tool with a high degree of accuracy on a real time base. |
