Absorptivity measurement of solid and powder bed under IR laser beam

The effective absorptivity of IR laser light for different powder beds were studied. reflectivity aluminum, titanium, stainless steel and copper alloys was measured using an appropriate Ulbricht sphere. Laser irradiation reliably detected by a photodiode. Reflectivity carefully as function illuminated area bed density. Several size distributions thicknesses chosen to evaluate the impact on absorption. Two spot diameters tested variation reflectivity. significantly higher than uniform surface similar material due multiple scattering. In addition, substrate is responsible non-negligible in inhomogeneity strongly modified absorption small size. fluctuated during transition from state molten pool state.