Effect of reverse pre-bulging on magnetic medium deep drawing formability of aluminum spherical bottom cylindrical parts

The fairing represented by the structural characteristics, nowadays, of spherical bottom cylindrical parts is mostly utilized to protect the shell of space launch vehicle. However, such components have a pre-bulging behavior in the flexible medium-assisted deep drawing. If not properly controlled, excessive thinning of wall thickness will result in cracking defects. In this paper, the effect of reverse pre-bulging on magnetic medium-assisted deep drawing of aluminum spherical bottom cylindrical parts is studied and contrasted. The results show that the pre-bulging can improve the formability and quality of the components of the magnetic media–assisted deep drawing. When the pre-bulging height increases from 0 to 6 mm, the maximum thinning rate of the wall thickness of deep drawing parts decreases by about 28%, and the coordinated deformation and uniformity of the wall thickness of each part are significantly improved. At the same time, the ultimate forming height of spherical bottom cylindrical parts is increased by about 10%, the springback is obviously reduced, and the accuracy of the shape and size is improved. It provides scientific guidance for a precise forming process and quality control of typical thin-walled deep cavity components with geometric characteristics such as spherical bottom or cone.