3D-Printing of lunar soil simulant by direct-extrusion method

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MTech (Res); 2023; Mechanical engineering

The extrusion-based additive manufacturing (EAM) technique is recently being widely employed for the 3D printing of complex-shaped components made of ceramic powder (containing irregular-shaped particles) when it is cast in the form of a slurry/ink. In this work, we utilize a direct extrusion method for printing structures from extra-terrestrial soil simulants using a piston-based extruder. Printing is demonstrated using a slurry composed of lunar soil simulant (LSS) variant ISAC-1 (avg. particle size ~ 90µm) mixed with biopolymer guar gum as a sustainable binding agent and DI water as a solvent. Parts were printed using a 2 mm diameter nozzle by optimizing print speed, nozzle height, inter-layer drying time, and build temperature, to ensure shape retention post-printing. The final green parts were dried in a hot air oven (50°C) for 48hrs, followed by sandpaper polishing. The strengths of the printed specimens were evaluated using compression and flexure tests and were found to be comparable to that of bio-consolidated structures. Unlike solid geometries, the well-known shell-infill type area-filling strategy generated several travels and re-tracings in the toolpath for cellular geometries.