Investigation of blank bow defect after roller leveller by finite element analysis

Sheet metal often shows curvature, shape defects and internal (residual) stresses which are not complying with the increasing requirements for the quality needed for customers. Roller levelling is one of the ways to flatten a metal sheets. The setting up of such machines is extremely complex and mainly depends on the operator's experience. The main objective of this paper is investigation of adjustable parameters of roller leveller together with elastic-plastic material behaviour on the internal stresses formation. High and unbalanced values of residual stresses lead to blank bow defects in a final product. In this study, numerical finite element (FE) 2D-model of roller levelling process is proposed to use. Properties of the material were determined experimentally. The blank bow magnitude was simulated and compared with experimental results and have a good accuracy for FE prediction. (paper)