Modelling and calibration of bending strains for iterative laser forming

We describe a simplified model for laser forming that identifies key features in bending behaviour and use approximations resulting from the model to characterize bending by the thermal gradient mechanism (TGM). The model predicts local curvature change in terms of area energy, interaction time and material thickness and from this derives the bending angle in terms of laser power, spot diameter and feed rate. It provides reasonable agreement between theory and measurement without the need for finite element (FE) analysis and identifies the areas where FE is needed to improve accuracy. In particular, it gives accurate predictions for threshold and saturation area energies, and so can be used in conjunction with the calibration tests to identify the optimum operating conditions for TGM laser forming. © 2005 IOP Publishing Ltd.