Abstract: The system response was determined by the joint way between servo motor and variable pump. In order to achieve a compromise among high speed, high precision, and low noise, a new joint way of the motor and variable pump was proposed. Dual-mass and three-mass systems were analyzed by theory of torsion vibration system. The torsion vibration characteristic was simulated and the experiment was carried out. It was found that the dual mass system has better response.

Key words: injection molding machine, servo motor, variables pump, response