Processing of multi-featured parts using sing point incremental hydro-forming

In single point incremental forming (SPIF), a technical challenge is to form multi feature parts, particularly those with unique structures. In response to this issue, a new process combining hydraulic bulging and SPIF is presented for the mouldless manufacture of multi-featured parts with sharp structures in a single clamping. In the first phase, hydraulic bulging is performed on the initial sheet to obtain a domed shell. In the second phase, local areas of the domed shell are subjected to SPIF with the assistance of hydraulic supports to achieve the concavo-convex features. In the third phase, the convex features are subjected to SPIF with the assistance of hydraulic bulging to achieve conical features. Simultaneously, the influence of hydraulic pressure on geometric accuracy, strain distribution, and forming mechanism is compared at different forming stages. The feasibility of the novel process can be verified through successful FEM and experiment of multi-feature parts.