In-situ forming of lunar regolith simulant via selective laser melting

Selective laser melting (SLM) technique in combination with the in-situ resource utilization (ISRU) concept can be an off-world manufacturing solution to the significant engineering challenge on the large-scale construction for extra-terrestrial bases. The feasibility of SLM process applied to the additive manufacturing of lunar in-situ resource was investigated by utilizing lunar regolith simulant. A laser source was utilized to melt the powder locally in a layer-wise manner. In order to successfully fuse the powder into parts with low laser power, high efficiency and high geometrical accuracy, the SLM process parameters were investigated and evaluated by laser volume energy density. The results show that the simulant can be successfully fused into parts with high geometrical accuracy using SLM process with low laser power due to its high absorbance and low mass loss. The fabricated part quality depends on the laser volume energy density: increase of laser volume energy density input results in better mechanical properties of parts; however, excessive laser volume energy density input leads to high distortion of parts. Poor powder fluidity of the raw simulant is observed due to its complex particulate shape and a wide range of particle size distribution. The powder fluidity of the simulant is improved by optimizing its particle size range, resulting in a denser and more uniform powder bed, which can avoid defects within fabricated parts. © 2019, Editorial Board of JBUAA. All right reserved.