With high frequency vibration of small amplitude on the cutting tool, the interaction conditions between the contacting surfaces of the tool and the workpiece are different from those in the conventional cutting process. In ultrasonic vibration cutting, instead of static friction between the tool and the workpiece, dynamic friction will be generated and the friction between the tool and the work-material will be reduced. The additional reciprocating movement between the contacting surfaces of the tool and the workpiece results in the periodical change of the friction force on the rake and flank face of the tool. Thus, the resistance to chip flow is decreased and the chips can be generated under better conditions.