A comparative study of cut front profiles and absorptivity behavior for disk and CO2 laser beam inert gas fusion cutting

Results of experimental investigations on disk and CO2 laser beam fusion cutting cold-work tool steel 90MnCrV8 are presented. The study was performed with the aim to detect features of the cut front geometry and differences in the corresponding absorptivity behavior as a function of the laser wavelength. Longitudinal sections of the cut front were prepared for different sheet thicknesses, focal plane positions, and cutting speeds. The digitalization of the geometrical cut front data enabled the determination of local inclination angles and the calculation of corresponding Fresnel absorptivity values. The analysis revealed that particular areas of the cut front geometry are preferably inclined to values close to the Brewster angle which offer the theoretical maximum absorptivity for both laser types.