Experimental Studies on TGM and BM Dominated Curvilinear Laser Bending of Aluminum Alloy Sheets

During Laser bending process, the worksheet bends by means of thermal stresses induced by the laser beam irradiation. It can be achieved by various mechanisms viz. temperature gradient mechanism (TGM), buckling mechanism (BM) and upsetting mechanism (UM). The interactive effect of process parameters viz. laser power, scanning speed, beam diameter and absorption coefficient decide the occurrence of bending mechanism during a laser bending operation. Literature reports experimental as well numerical studies on the effect of process parameters viz. laser power, scan speed, beam diameter on the process mechanism and process performance. However, a very few attempts have been made on the study of shape of laser irradiation path on the quality and productivity of laser bending operation. Curvilinear laser bending is generally used to produce complex shapes using lasers. In this chapter an experimental study on the curvilinear laser bending of aluminum sheets for TGM and BM mechanisms has been presented. Initially the basic principle of the laser bending process and TGM and BM are discussed. Then the experimental procedure, plans are presented. The results are discussed in terms of the effect of laser power and scan speed on the bend angle and edge effect during parabolic irradiation. The experiments are carried out for both thick as well as thin worksheets. It was found that, in thin sheets, the scanning path curvature does not have significant effect on the bend angle however, in thick sheets the bend angle increases with decrease in scanning path curvature. The deformation behavior of curvilinear laser bending was found to be different from that of straight line laser bending process. The presented results may be used as guidelines to generate complex shapes in aluminum and its alloys using lasers.