Influence of flow aid additives on optical properties of polyamide for Laser-Based Powder Bed Fusion
Maximilian K. Marschall, Christopher Heintges, Michael Schmidt
Abstract
Aim of this paper is to investigate the influence of flow aid additives on beam matter interaction of polyamide for laser-based powder bed fusion of polymers (PBF-LB/P). The optical energy input determines the laser beam powder interaction, quantified by absorption within the optical properties of a material. Additives like fumed silica for increasing powder flowability are important for using PBF-LB/P materials. The aid of those additives and restrictions in mechanical properties of built components using high portions of additives are already investigated, but not the change in relevant optical properties. Dry blends of polyamide powder with different weight percentage of additives, such as fumed silica, alumina and titania are investigated. A measurement system with a double-integrating-sphere setup and CO2 laser is used to characterize the beam matter interaction as the absorptance of optical energy in the powder layer. Based on this, the change in absorptance due to the influence of flow aid additives is investigated in order to be able to estimate possible effects on the processability.