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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).

In pyramid type three-roller bending process, it is difficult to deform the plate perfectly to the required circular shape and it mainly depends on the skill of the operator. Presented work shows the finite element (FE) simulations of three-roller plate bending process to study the influence of different parameters, such as roller position, rolling speed, plate material, plate length and friction (at roller plate interfaces) on the bending quality of the deformed plate. FE simulations were performed based on the elastic–plastic explicit dynamic finite element method under the Hyperform LS-DYNA environment. FE simulation results were verified with the experimental results. Parametric studies were carried out to investigate the effect of various parameters on the quality of the final shape. Reported work will be helpful to process engineers in predicting the final radius of curvature and deviation of plate prior to manufacturing. This will reduce the trail and error in achieving the final geometry.

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