Present state and some problems in the method of machining inside thread

The development of the traditional technology and latest development on inside thread machining were reviewed.Based on the discussion on the characteristics of extruding tapping,vibration tapping and vibration plastic process,the new methods of compound vibration extruding tapping for the internal thread processing were put forward,and the mechanism that decreased the friction and tapping torque was analyzed.Furthermore,the existing problems have also been pointed out.