Design of Roll-Forming Process for U-Profile Rail

Abstract Roll forming is a manufacturing process that involves plastic forming via bending using a rolling motion. During roll forming, a coil or blank is formed incrementally in a stepless and continuous process with the aid of rolls to fabricate profile rails. The shape of the rolls predicted the incremental deformation in the cross-sections of the U-profile rails. However, the final shape after the roll-forming process is entirely different from the modeled parts because of the springback caused by the mechanical properties of the materials. The design of roll-forming processes has been investigated to address typical plastic defects, such as springback and residual stress. Roll flower diagrams were developed in the initial stage of the design of the roll-forming processes. These diagrams show the cross-sectional shapes of the product at various stages of the process, superimposed on each other. The diagrams contain information for the process design, including the incremental deformation, number of passes, and setup angle of the rolls. There is no standard method for designing roll–flower diagrams. These were developed based on the designer’s experience with the material properties and multiple shapes. In this study, roll flower diagrams were designed using the developed formula, considering constant radius-of-curvature or length-of-curvature zones in the cross-sections of U-profile rails. Roll-forming processes were simulated using the commercial FEM code Abaqus to measure the loads of the rolls, springback of the blank, and residual-stress history. Simulation and experimental results regarding the shapes of the U-profile rails were compared to validate the process design method.