Laser absorptivity on wavy molten metal surfaces: Categorization of different metals and wavelengths

摘要: The absorptivity of a laser beam interacting at grazing incidence with the processing front during welding, cutting, or drilling depends on metal to be processed and wavelength. smooth is homogeneously governed by angle-dependent operating range corresponding Fresnel-curve. In contrast, wavy strongly modulates across surface. calculated modulation presented for five different metals four wavelengths. A discussion based respective optical constants Fresnel-curves leads categorization absorption behavior, mainly dividing into low high electrical conductivity as well short 10.6 μm long Six categories are distinguished. particular, highly conductive remain reflective wavelength, even front. Exceptions higher overall absorptance Cu 532 nm Al 808 532 nm.