Hydroforming of Y-shapes—product and process design using FEA simulation and experiments

Exhaust system components such as 3-way connectors (Y-shapes) are often manufactured by tube hydroforming. Compared to stamping, tube hydroforming offers higher part quality (tighter tolerances, increased rigidity) with lower manufacturing costs (reduced number of forming and assembly operations). In this study, the estimation of the process parameters for hydroforming Y-shapes, i.e. pressure levels, axial feeds, and initial tube length, are discussed. These estimated parameters are then “optimized” through conducting FEA simulations and verified with hydroforming experiments. A geometric parameter that is of importance is the tube length, which affects formability of the protrusion. Y-shape hydroforming experiments were conducted to investigate this effect. As expected, Y-shapes with shorter length formed a longer protrusion with the same axial feeds applied.