Parametric Design and Optimization of Eight-bar Mechanism Based on RecurDyn

This paper takes the closed eight-bar mechanism in large tonnage punching press as the study object. The geometric dimensions of the mechanism were optimized and designed on the basis of three design requirements of slider total stroke, maximum stretching depth and maximum stretching speed in effective tension process. The parametric model of the mechanism was built in the RecurDyn environment, and the displacement curve and velocity curve were obtained through the kinematic simulation. Based on the displacement curve, the slider total stroke was calculated. Based on the velocity curve and the maximum stretching speed requirement in the process of effective tension, the available maximum stretching depth was calculated and the dimension parameters of the mechanism were gained at last. The optimization results show that the available maximum stretching depth increased by 39% while the total length of eight bars remains unchanged.