SHEET METAL FORMING PROCESS CONTROL USING AN ACTIVE DRAWBEAD

摘要

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 press was built on which blank holddown force and drawbead penetration can be varied during drawing. Closed-loop process control was demonstrated in strip drawing by in-process adjustment of drawbead penetration so as to follow a specified punch force trajectory. In addition, the effects of drawbead penetration and die-binder gap on blank wrinkling inside and outside of the drawbead in cup drawing were described. When a die-binder gap was set to allow wrinkling outside the drawbead, the wrinkles did not propagate across the drawbead into the blank region inside the drawbead.