A novel 3D printing scheme for lunar construction with extremely low binder utilization

Lunar construction has become a multidisciplinary, cutting-edge, and strategic topic worldwide with additive manufacturing as a key technology to build required structures. Targeting the low strength or excessive terrestrial materials utilization in current lunar 3D printing, a novel printing scheme is proposed herein to balance the processability and strength using minimal binders. A printing system was designed based on powder extrusion and passive roll-pressing. Therein, a screw-blade module with 73 % of full blade length can efficiently extrude dry and damp powders. An adjustable roller-spring module is applied to reveal the significance of harder lunar regolith, larger roller and stiffer spring on the powder printing. Using the roller with 50 mm of diameter and 78 N of pressure, a dense print layer can be obtained with > 2 mm of layer thickness and 2–5 MPa of flexural strength. Through experimental results and mechanical analysis a quantitative powder-roller interaction is established. Also, this printing system supports both premix printing and dry printing. The former can use fewer binders as low as 4 wt%, while the latter enables 2.6 times and 3.8 times higher flexural and bonding strength respectively. This low-binder powder 3D printing scheme will bring more prospects and advancements for future lunar constructions.