Deformation characteristics and process optimization in neck-spinning of variable-diameter tube

Neck-spinning has the advantages of short manufacturing cycle, high process flexibility, good forming ability and low production cost. It has been widely used to produce variable-diameter tubes in automotive and aerospace fields, such as gas cylinders and corrugated tube. However, the neck-spinning is a complex local loading and incremental forming process, which leads to severe local inhomogeneous deformation and the deformation state dynamically changes with loading region. These complex forming characteristics make it very difficult to predict the forming results and optimize the processing parameters in the neck-spinning. This paper reviews some typical advances on the investigations of neck-spinning, including the various deformation state, profile deflection, uneven wall thickness distribution, prediction model for wall thickness variation and process optimization method. Besides, some existing key challenges for the precision neck-spinning were outlined, such as the accurate prediction model for the wall thickness variation, the determination of maximum diameter reduction, the dynamic optimization of roller trace and processing parameters.