超音波振動小径穴加工における切削機構

概要

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This paper describes two mechanisms ih ultrasonic-vibration assisted microdrilling. In the first experiment, the mechanism of the beginning of penetration was examined using a quick-stop device. In the second experiment, the chip formation mechanism in deep hole drilling (L/D=7) was examined. The drills with a diameter of I mm are clamped in a spindle ultrasonically vibrated with 40 kHZ in axial direction. When applying ultrasonic vibration the wandering of a drill at the hole entrance is inhibited because of the hammering motion ofthe chisel edge and reduction ofcumulative displacement of drill due to intermittent cutting. In addition to these effects, reduction of friction and increase in rake angle of the chisel edge improve the performance of drilling at the hole entrance. Ultrasonic vibration makes chip flow angle larger and chip side curl curvature smaller. One reason for this phenomenon may be that chip flow velocities at the inner and outer corner do not differ much, because the velocity component of ultrasonic vibration occupies the major part in the cutting velocity. Another reason may be the improved cutting condition at the chisel edge.
公益社団法人精密工学会の論文
1998-11-05