Abstract
This paper reports the stress field inside of the workpiece under ultrasonically assisted orthogonal cutting (UAC) condition. UAC improves processing accuracy by reducing average cutting force. However general dynamometers have an insufficient frequency band to measure processing phenomena in ultrasonic band. Stress field inside of the workpiece during UAC was observed by combining method consists of the pulse emitting source synchronized with ultrasonically vibrating cutting edge and the photoelastic method. Instantaneous stress field also was observed during UAC. It was found that UAC reduced the stress field in comparison with conventional cutting.