Development of a combination punch speed and blank-holder fuzzy control system for the deep-drawing process

To improve the productivity and formability of sheet metal having strain rate sensitivity, a new control system using a combination punch speed and blank-holder fuzzy control for the deep-drawing process is proposed. The control algorithm is based on an alternate switch mode system of both blank-holding force (BHF) and punch speed (SPD) control. A newly developed deep-drawing apparatus with the novel control system achieved on-line simultaneous fuzzy control on both BHF and SPD during the process. The experimental results for a steel sheet show that higher speed deep drawing can be successful at the SPD over 150 mm/min, at which fracture occurred under constant SPD condition. In addition, it was confirmed that the new combination of SPD and BHF fuzzy control system increased high performance productivity with 25% forming time reduction. Cup wall thickness distribution was also improved and deep drawability, beyond that for a constant SPD.