Flexible roll forming process design for variable cross-section profile

Roll forming is a continuous bending operation in which a long strip of sheet metal is passed through sets of rolls mounted on consecutive stands, each set performing only an incremental part of the bend, until the desired cross-section profile is obtained. Roll forming technology has been widely used in the automotive industry due to its various advantages, such as high production speed, reduced tooling cost and improved quality. Recently, flexible roll forming process which allows variable cross sections of profiles by adaptive roll stands was developed. In this study, profile design for the hat-channel has been analytically performed on the basis of established longitudinal strain during the flexible roll forming. The effect of geometrical parameters such as base section width, side wall height and flange width on the longitudinal strain was analyzed. The analytical analysis was experimentally verified by lab-scale flexible roll forming machine. The results show that the profile design method preformed in this study is feasible and the parts with variable cross sections can be successfully fabricated with flexible roll forming process.