Cold rotary forming of thin-wall component from flat-disc blank

Flow forming, one of the rotary-forming processes, is used mainly to produce thin-walled high-precision tubular components. Due to its flexibility and low tool load requirement, the process has great potential to be extended to the forming of net-shape components for thin and intricate features from bulk raw materials, such as solid bar ingot, cast and forged performs. In the work reported in this paper, a flow-forming facility was established to investigate the feasibility of forming thin-walled cups from flat-disc blanks by investigating the effects of roller geometry, degree of material reduction and roller geometry on material flow. In addition, a 3D Finite Element (FE) model was developed to simulate the ‘bending’ process, based on the experimental conditions.The results showed that it is possible to adopt a two-step forming process, ‘bending’ and flow forming to enable material flow along the mandrel in order to form a thin-wall cup component using two different profiles and adopting an axial roller movement. Quality of the cups formed depends on the diameter reduction, starting disc thickness of the blank and the number of pass in the flow-forming stage. The results predicted by the FE simulation was compared with the experimental results and showed close agreement. This work illustrates the possibility of adopting flow-forming processes for the production of thin section, which would be difficult and expensive to produce by press forming. In addition, it also showed that although FEM is an effective tool to optimize process parameters, computational time remains as the main barrier for its prevalent usage especially for incremental processes such as flow forming and spinning processes.