Analytical Modeling of Top Roller Position for Multiple Pass (3-Roller) Cylindrical Forming of Plates

As forming of the double or multiple curvature surfaces, includes roller forming at least once in the sequential process; its efficient performance is of great importance for controlling the final product dimensions. Most efficient and economical way to produce the cylinder is to roll the plate through the roller in single pass. Literature review revels that, most of the reported analytical models for the prediction of springback were developed with the assumption of zero initial strain. However, in practice multiple pass bending is recommended to work within the power limitation of the machine and to improve the accuracy of the final product. An attempt is made to develop the analytical model for estimation of top roller position as a function of desired radius of curvature, for multiple pass 3-roller forming of cylinders, considering real material behavior. Due to the change of Young's modulus of elasticity (E) under deformation, the springback is larger than the springback calculated with constant E. Developed analytical model was modified to include the effect of change of Young's modulus during the deformation. Developed multiple pass analytical models were compared with the single pass analytical model and experiments (on pyramid type 3-roller bending machine).Copyright © 2006 by ASME