Abstract: A new hydraulic-pressure augmented deep drawing with fluid assisted blank holder is proposed in order to overcome the fracture tendency of the rubber diaphragm in deep drawing process with fluid assisted blank-holder and give full play to the effect of added radial pressure on the improvement of limiting drawing ratio. The radial pressure augmented by two pressure pistons is loaded onto the blank rim and the top surface of the blank flange, so the process of hydraulic-pressure augmented deep drawing with fluid assisted blank holder is realized. In order to reduce the frictional resistance on the interface between the blank flange and the draw die, the augmented liquid is also filled in the holes made on the certain part of the draw die surface. After a preliminary experimental validation for the proposed method, FEM is used to analyze the forming process and optimal parameters are obtained. Finally, the defined augmenting ratio zone for pressure is provided by experiments. It is found that there are two key points where the wall thickness is quite small and these two key points are caused by two peak values of the punch force respectively. A cup with a drawing ratio of 2.86 is successfully formed by using 2A12O aluminum alloy when the cavity pressure is 18 MPa and a booster piston of a ratio 2.4 is used.

Key words: Deep drawing, Fluid blank holder, Radial pressure