Optimal design for the fluid cavity shape in hydromechanical fine blanking

Hydromechanical fine blanking with fluid cavities of various shapes is investigated in this work. In this paper, seven shapes (V, angled, U, and four elliptical shapes) are studied. It is shown that the U-shape produces the greatest burnished length among the seven flow cavity shapes. Furthermore, the hybrid experimental optimization technique is used to optimize the parameters of the U-shaped cavity. It is found that the burnished surface obtained from this approach can nearly reach the full thickness of the blank in one operation, which means that the fracture zone can be almost entirely eliminated. In addition, the surface roughness of the burnished surface ranges between 0.5 and 0.098 mu m, and the tolerance band for the diameter is between IT5 and IT7. These results represent an improvement over the values obtained with conventional fine blanking.