| 摘要 |
PROBLEM TO BE SOLVED: To provide a NC device having an ultrasonic vibration tool capable of equal pitch working and moreover detecting wear of a stylus. SOLUTION: An ultrasonic wave signal S of a frequency equal to a resonant frequency of the ultrasonic vibration tool 6 is outputted with a phase locked loop(PLL) circuit 36, and also the frequency of the output signal S is followed and varied when the resonant frequency is varied owing to wear of the stylus 17. Therefore, the frequency of the signal S becomes a value corresponding to the quantity of wear of the stylus 17. The frequency of the signal S is detected with a frequency detecting circuit 40, and data showing the frequency are outputted to a CPU 21. In the case of executing equal pitch working, a synchronizing/switching circuit 35 is switched with the CPU 21, and the output signal S of the PLL circuit 36 is fed to an interporating arithmetic circuit 23. Thus, a transfer speed of motors 1, 2 and a vibration speed of the stylus 17 in the ultrasonic vibration tool 6 are synchronized, whereby dot working of the equal pitch is allowed. |
