Optimization of the loading curve of variable blank holder force in deep drawing

In deep drawing, a new thought of applying dual layers of rings, which are parallel to each other, has been achieved to asynchronously vary Blank Holder Force (BHF) at different regions of sheet flange, by dint of replacing different little mandrils in length between dual layers of rings. On the other hand, in order to solve the problem that how to get the optimum loading curve of BHF and measure friction or evaluate lubricant in deep drawing, a probe sensor with structure of dual cantalevers, based on the theory of resistance strain slice, has been developed for measuring real-time friction coefficient of sheet flange's surface. This probe sensor can not only measure out real-time BHF, but also figure out real-time friction coefficient. By the way of analyzing whether the distribution of friction is good or bad, one optimized loading curve of BHF can be finally obtained during the whole deep drawing process.