A multi-constraint spinning process of ellipsoidal heads

In recent years, it has become increasingly popular to manufacture ellipsoidal heads using spinning technology due to increased usage of ellipsoidal head parts. Notably, wrinkling is one of the major defects in thin-walled part forming, which can become more severe in large diameter-to-thickness ratios. Therefore, it becomes urgently necessary to develop a new spinning process to avoid this defect. In this paper, a multi-constraint spinning process is proposed for manufacturing large ellipsoidal heads, which is included in a two-step spinning process. A finite element (FE) simulation and experimental evaluation have been carried out to investigate the feasibility of this novel spinning process for forming ellipsoidal heads. In particular, the law of material flow deformation and the influence of process parameters on the thickness uniformity are extensively analyzed. It can be concluded that ellipsoidal heads can be formed by this novel spinning process, which can obtain large diameter-to-thickness ratios without wrinkling. Moreover, the three-pass multi-constraint spinning can achieve better performance than single-pass spinning. The material flow can be stable; the deformation can be uniform after conventional spinning, and the wall thickness deviation can be stable within ± 10% without wrinkling, cracking, and other defects.