S. G. Luckey, P. A. Friedman, Ford Motor Company, Dearborn, MI; K. J. Weinmann, University of California - Berkely, Berkeley, CA
The conventional superplastic forming (SPF) of complex and deep geometries can result in excessive thinning and necking. To address these issues, a two stage SPF process has been developed and demonstrated in forming trials using a superplastic aluminum sheet alloy. This process preforms the blank with gas pressure to create length of line, while preserving metal thickness in certain regions to improve the thickness profile of the final part. In this paper, a preform has been designed to improve the forming of a complex component by providing a superior thickness profile and enabling a faster forming cycle as compared to a conventional single stage forming cycle. Finite element analysis was essential to the development of the preform since the preforming surface was not intuitive and could cause wrinkling in the final part.
Summary: A two stage superplastic forming process has been designed and experimentally demonstrated to improve the final thickness profile and enable a faster forming cycle as compared to conventional single stage superplastic forming.
