Abstract: By using servo driving combined with six-bar mechanism and controllability of servo motor and the six-bar linkage’s speed characteristics, control of variable blank holder force during deep drawing process is obtained. Based on consideration of both of elastic displacement and rigid displacement, mathematic model of relationship between input and output speeds of the mechanism is established. Therefore, as the parameters of the mechanism are given, the input speed of the actuator for blank-holder force (BHF) can be determined according to the relationship between BHF force versus stroke and consideration of the actuator’s deformation. On the basis of considering the maximum blank holder stroke and good transmission results, taking the minimum error between the output speed and that of press slider (during blank-holder’s stroke) and the minimum linkage sizes as objective functions, the dimensions of double-slider mechanism with six bars are optimized. Using the simulation software and with input simulation speed determined by the mathematic model given above，the results show that it is feasible to realize control for VBHF by using double-slider mechanisms with six bars combined with servo driver.

Key words: blank-holder force control, composite and servo-driven, six-bar linkages with double sliders, sheet metal forming