Abstract: Sheet hydroforming with its many advantages is gaining increasing popularity in industry. This study proposes a new method named hydromechanical deep drawing assisted by augmented radial pressure. By using aluminum alloy 2A12O, the effect of the pressures in both the die cavity and blank rim cavity on the wall thickness distribution is separately studied with the assistance of the finite element method (FEM). The optimal pressures in the die cavity and the blank rim cavity as well as the proper ratio between them are obtained. Cups with more uniform thickness distribution and better quality can be successfully formed when the pressure in the die cavity is about 15.0-20.0 MPa together with a radial pressure in proportion of 1.45 to the cavity pressure. By using the loading paths obtained from simulation, a cup with a drawing ratio of 2.65 is successfully formed and the processing window for the cavity pressure is provided.

Key words: aluminum alloys, hydromechanical deep drawing, passive pressure, radial pressure, sheet forming