Bending of stainless steel thin sheets by a raster scanned low power CO2 laser. http://dx.doi.org/10.1016/j.jmatprotec.2008.06.026

Abstract

Laser forming of thin metal sheet plates using a low output power CO2 laser has been successfully performed using a mirror based scanning system. Graphite coated AISI 302 stainless steel plates, 0.3 mm thick, have been bent using a 60W CO2 laser with a stepped scanning pattern, changing relevant variables such as scanning pattern width, scanning step and traverse velocity. Due to the small thickness of the metal plates, the resultant bending mechanism is basically buckling, but with two critically important differences. Unlike traditional buckling mechanism, it seems possible to predict the direction of the bending, which will always be towards the energy source, even in the case of strongly plastically pre-strained samples. Nonetheless, a thermal gradient mechanism component appears to operate perpendicular to the traversing direction due to the high scanning speed of the laser beam. Additionally, it has been found that using different scanning pattern widths, it is possible to change the turn radius of the bending corners, distributing the bending effect evenly across the scanning width, obtaining very smooth and round corners, more suitable from a mechanical resistance point of view, rather than traditional sharp corners.