Research on die-less spinning by spherical roller of different radius

Die-less spinning is developed because of its advantages of low cost and high flexibility. The spherical roller has not been commonly used in the die-less spinning process. In previous studies, the sizes of the spherical rollers are varied, and the distributions of the wall thickness of the formed parts are inconsistent. To explore the effects of spherical roller dimensions on the formed parts, four spherical rollers of different radii are adopted to form the truncated cone-shaped parts. Meanwhile, the finite element models are established to analyze the stress states during the spinning process. The wall thickness distribution and the outer contour accuracy of the experimental parts are measured. Combined with the finite element simulation results, it is found that the curvature of the roller and the contact area between the roller and the sheet has an important influence on the wall thickness distribution and outer contour accuracy of the parts. In addition, the too-small radius of the roller makes the shear stress on the sheet material greatly increase. It results in the wall consistent with the sin law of die-less shear spinning.