Abstract: This article studied the deformation mode during superplastic bulging of conical cup from sheet metal. The forming process was divided into three stages. Based on the fundamental equations of superplastic mechanics and relevant physico-geometric assumptions, the analysis for such a forming process was conducted stage by stage. The equations of optimal loading curves in each stage, the methods for. calculating forming time under different loading conditions, and the theoretical formulae used for computing the minimal thickness and some other geometric parameters of the component to be bulged were derived. Finally, a brief discusson was given.

Key words: superplastic mechanics, conical cup, bulging, loading curae, forming time