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During the rolling of doubly-curved sheet metal surfaces, the ow of metal is very complicated and will affect by the dimension of rolling deformation zone. The dimension of rolling deformation zone is mainly affected by the rolling reduction and the central cross-section diameter of the rollers. In this paper, the in uence of central cross-section diameter of the rollers on the longitudinal bending deformation of formed spherical surfaces and the stability of the rolling process is studied combined with the rolling reduction. The current research results show that the larger the central cross-section diameter of the rollers, the more stable the rolling process, and the better the shape accuracy of the formed spherical surface. When the central cross-section diameter of the rollers is relatively small, the longitudinal bending deformation of the formed spherical surface increases with the increase of the central cross-section diameter of the rollers. However, an excessively large roller diameter will restrain the longitudinal bending deformation of the sheet. When the central cross-section diameter of the rollers is relatively large, the longitudinal bending deformation of the formed spherical surface will decrease with the increase of the central cross-section diameter of the rollers. The results in this study can be used as a reference for the design of roller to ensure that the formed doubly-curved surface can obtain greater longitudinal bending deformation and better shape accuracy under the same rolling reduction.

The research and development of flexible forming technology have a crucial role in the personalized production and manufacturing of three-dimensional (3D) surface sheet metal parts. Three-dimensional surface rolling with rigid arc-shaped rollers (TSRRAR), a new flexible forming technology, was investigated to effortlessly produce 3D surface parts. Numerical simulation and experimental analysis mainly include data at four values of the difference in axial radius of roller (-2, 2, 6 and 10 mm) to explore this technology's forming ability. It was demonstrated that various shapes could be obtained only based on one group of rollers. The maximum resultant force decreased from 3.07 to 2.21 KN, and the required maximum compression rate from 4.22 to 2.48 % with the same longitudinal curvature radius (179 mm) to be obtained. Therefore, the forming difficulty can be reduced by selecting the difference in axial radius of roller.