Simulating Microgravity Additive Manufacturing Using Neutral Buoyancy for Space-Based Structural Fabrication

Additive manufacturing (AM) in space offers critical advantages for on-demand fabrication and in-situ repairs; however, microgravity and low thermal convection present unique challenges for material deposition and part integrity. This study presents a ground-based method to simulate space-like conditions using neutral buoyancy with ASA filament submerged in silicone oil. Experiments explored the effects of print speed and oil temperature on warping, sagging, and mechanical properties. Results show that printing at lower speeds (5 mm/s) in oil improves interlayer adhesion, with up to 13% higher tensile strength. Thermal trials demonstrated increased warping at higher temperatures, highlighting the influence of convection on print stability. Using benchmark geometries and ASTM D638 tensile testing, this work validates the effectiveness of neutral buoyancy as a testbed for simulating microgravity-induced AM defects. These findings support the development of scalable terrestrial simulations for future space-based AM operations.