Theoretical prediction of flange wrinkling in the first-pass conventional spinning of dual-metal sheets

Abstract Flange wrinkling will occur when the dual-metal sheet is formed to a certain degree in conventional spinning, leading to forming failure, so it is necessary to study the flange wrinkling defects. In order to predict and avoid the flange wrinkling, a theoretical model for calculating the forming limit was proposed according to the energy method. Additionally, experiments and numerical simulations were conducted to study the wrinkling and verify the established model. Based on the above analytical model, forming limit diagrams of flange wrinkling in the first-pass conventional spinning were given, and the effects of roller feed rate (f), blank thickness (t), the thickness ratio (λ) of each layer on the flange wrinkling of dual-metal sheets were further analyzed. It is concluded that increasing the roller feed rate and reducing the thickness of the dual-metal sheet will cause the flange to be more prone to instability and wrinkles. And analytical results are consistent with numerical and experimental results. Considering that the finite element (FE) model is difficult to set up, the theoretical method provides guidance for the selection of process parameters to avoid wrinkling defects.