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This paper presents the numerical and experimental results of a study investigating helical rolling of ball studs. First, methods for producing balls studs widely used in the automotive industry are discussed. Then, in light of the discussed manufacturing techniques, a helical rolling process for producing this type of parts is proposed. The idea of rolling stepped parts in skew rolling mills is presented and the design concept for helical tools is described. Next, numerical results of a helical rolling process for ball studs are presented. Theoretical considerations are based on the results of simulations performed by the finite element method using the FORGE NxT simulation software. The simulations involved examining metal flow, thermal parameters and force parameters in the process, as well as predicting material cohesion loss based on the distribution of the Cockcroft-Latham ductile fracture criterion. The numerical results were verified experimentally. In the experiments, the process was investigated with respect to potential failure modes. The correctness of the designed numerical models of helical rolling was assessed based on the shape of produced forgings and the distributions of force parameters. Obtained results demonstrate that helical rolling is an effective technique for producing ball studs, and the design concept for helical tools can be based on the solutions developed for wedge tools used in cross wedge rolling.
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