傾斜面への微小径穴加工における超音波振動の効果

Abstract

This paper describes the effects of ultrasonic vibration on the characteristics of microdrilling into inclined surface. In the experiment, duralumin with an inclined surface of 15-60 degrees is drilled with ultrasonic vibration by carbide drill of diameter lmm. The frequency of ultrasonic vibration is 40kHz and its amplitude is 3.5μm. As a result of the experiment, it is found that ultrasonic vibration improves dimensional accuracy and form accuracy. By observing the drilling process at the beginning of penetration using a quick-stop device and by analyzing radial forces, it is cleared that applying ultrasonic vibration improves the engage performance of drill at the hole entrance. The reason for this may be that effects of ultrasonic vibration such as hammering motion, reduction of cumulative displacement of drill due to intermittent cutting and reduction in friction reduce the skidding and the wandering of a drill at, the hole entrance. Because the microdrilling with ultrasonic vibration into a workpiece which has large inclination angle such as 60 degrees could be done well and has better accuracy than microdrilling without vibration, it is found that application of ultrasonic vibration is useful to drill into an inclined surface.