Closed-Loop Control of Sheet Metal Forming Using an Active Drawbead

Abstract

The intent of this work was to develop the drawbead as an active element in the closed-loop control of sheet metal forming operations. An instrumented, computer controlled drawing press was built on which blank holddown force and drawbead penetration can be varied during drawing. Closed-loop strip drawing process control was demonstrated by in-process measurement of punch force and adjustment of drawbead penetration so as to follow a specified punch force trajectory. In addition, sensors and transducers were developed to measure local forces for process monitoring.