Abstract
The aim of this study is to investigate the cutting phenomenon under Ultrasonically Assisted Cutting (UAC) condition. The vibrating cutting edge is considered to be cause of dynamic change of cutting force at ultrasonic frequency. However many researchers have explained the effect of UAC by evaluating the time-averaged cutting force, because it is difficult to measure the dynamic cutting force by using dynamometers. In this study, the instantaneous stress distribution on workpiece was visualized by photoelastic method in combination of pulse light emission synchronized with vibration of cutting edge. Applying a uniaxial compression test, the fringe map relative to phase-difference defined by Brewster's law was calibrated with stress distribution. Orthogonal cutting test was carried out at low cutting speed relative to vibration speed of insert. The cutting force calculated from stress distribution was considerably agreed with measured force by dynamometer. It was experimentally confirmed that the stress distribution under UAC condition showed the periodical change synchronized with insert vibration. The instantaneous maximum cutting force under UAC condition was smaller than that of conventional cutting condition. The geometrical analysis of cutting force explained the greater shear angle by decrease of friction angle under UVC condition.
