Thermo-mechanical studies on bending mechanism, bend angle and edge effect during multi-scan laser bending of magnesium M1A alloy sheets

This paper presents numerical as well as experimental studies carried out to obtain large bend angle (of the order of 10) in difficult-to-form material, magnesium M1A alloy. Experimental studies were conducted to check the feasibility for bending of material using laser bending process. A finite element based three-dimensional non-linear thermo-mechanical numerical model was developed to simulate the multi-scan laser bending process. The computations provided by the numerical model were validated with experiments; and the validated model was used to investigate the bending mechanism and deformation behavior of the worksheet during multi-scan laser bending process. It was observed that the number of scans has a profound influence on the bending mechanism and deformation behavior. The results showed that the induced thermal stresses decrease and plastic strains increase with number of scans. Edge effect decreases with the increase in number of scans and laser power; whilst it increases with the increase in beam diameter and scan speed. The presented results provide a useful insight into the processing mechanism and will be useful in the selection of suitable process conditions for obtaining large bend angles with minimal edge effect. (C) 2016 The Society of Manufacturing Engineers. Published by Elsevier Ltd. All rights reserved.