ABSTRACT
A commonly used laser absorption model, proposed in, assumes diffusive radiation transport in the powder. This assumption, however, is not applicable for the thin, low-porosity metal powder layer used in the selective laser melting process, for which the thickness is a few powder particles. The effect is especially important for highly reflective metals, such as those used in the additive manufacturing of jewelry. An important component of modeling efforts is the description of the absorption of the metal powder and of the spatial distribution of the absorbed radiation. A realistic powder has a distribution of sizes and a nonuniform geometrical arrangement, generally with a porosity greater than that of an ideal array. The calculations show that the resulting powder absorptivity is significantly higher than the absorptivity of a flat surface or of a single, isolated sphere, thus confirming the important role of multiple scattering.
