Abstract: To realize rapidly forming of three-dimensional surface parts, a new process for continuously forming surface parts based on the rolling using bended rolls is proposed. By controlling the gap distribution between the upper and lower forming rolls in the rolling process, the sheet metal is nonuniformly thinned in thickness direction while it is bent in the direction perpendicular to that of rolling, which leads to bending deformation in rolling direction. With the rotations of the forming rolls, the sheet metal is continuously deformed and a three-dimensional surface part is formed finally. The formation mechanism of curved surface is set forth, the theory on roll-forming of surface and controlling method for forming process are presented. The relationship between the deformation in thickness direction and that in rolling direction are analyzed and the formulation to evaluate the curvature in rolling direction is given, the methods to compute the gap between two rolls and the profiles of two rolls are provided. A small experimental device is developed and the continuous roll-forming tests for typical surface parts are carried out. The forming results of convex surface and saddle shaped surface parts are measured and analyzed, the analyzed results show that the shape errors of the formed parts are less than 1.2 mm. It is demonstrated that the proposed process is a feasible and effective way of forming three-dimensional surface parts.

Key words: Bended roll, Flexible forming, Rolling, Sheet metal, Three-dimensional surface, Coupling vibration analysis, Dynamic mesh force, Flexible structure, Planetary gear system