The effects of central cross-section diameters of rollers on doubly curved surface rolling

Abstract

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.

Influence of the rotational speed ratio of rollers on the three-dimensional surface rolling process

“…However, further increases in the rotational speed ratio lead to a resurgence in fluctuations of the equivalent plastic strain, reducing the stability of the forming process. According to the research by Chang et al [20], the shape accuracy of the formed spherical surface can be described by the deviation in longitudinal curvature. where E Li is the deviation in longitudinal curvature for the spherical surface, ρ Li is the local longitudinal curvature of the formed three-dimensional surface, and ρ L is the overall longitudinal curvature of the formed three-dimensional surface.…”