Driver roll speed influence in Ring Rolling process

Ring Rolling is an advanced local incremental forming technology to fabricate directly precise seamless ring-shape parts with various dimensions and materials. To produce a high-quality ring different speed laws should be defined: the speed laws of the Idle and Axial rolls must be set to control the ring cross section and the Driver roll angular velocity must be chosen to avoid too high localized deformation on the ring cross section. Usually, in industrial environment, a constant rotation is set for the Driver roll, but this approach does not guarantee a constant ring angular velocity because of its diameter expansion. In particular, the higher is the ring diameter the lower is its angular velocity. The main risk due to this constrain is the generation of a non-uniform ring geometry. An innovative approach is to design a Driver Roll speed law to obtain a constant ring angular velocity. In this paper a FEM approach was followed to investigate the Driver roll speed influence on the Ring Rolling process. Different Driver roll speed laws were tested starting from a model defined in an industrial plant. Results will be analyzed by a geometrical and physical point of view.