A novel continuous roll forming process of sheet metal based on bended rolls

Abstract

To effectively manufacture three-dimensional sheet metal parts with various curvatures produced in small-batch quantity, a continuous roll forming (CRF) process is proposed and investigated. The sheet metal is compressed between pairs of bended rolls and formed into a doubly curved surface. The shapes of forming rolls and the gap between the two rolls are piecewise controlled at a series of points. The two bended rolls and the nonuniformly distributed roll gap between them make the sheet metal bent in longitudinal and transverse directions simultaneously after the sheet metal passes through the roll gap, and a three-dimensional surface is formed continuously with the rotation of forming rolls. The relation between longitudinal elongation distribution and longitudinal bending deformation is discussed, and the lateral spreading in CRF process is analyzed; the method to compute the roll gap and the curved profiles of forming rolls are presented. Forming experiments for torus-shaped surface parts were carried out, and the experiment results demonstrate the feasibility and validity of CRF process and the presented methods.