The purpose of this research was to investigate the suitability of the Fused Filament Fabrication (FFF) process for low pressure/vacuum environment. This included investigating the ability of an FFF printer to function in a vacuum and evaluation of the dimensional accuracy and mechanical properties of the manufactured components. For this purpose, a commercially available FFF printer using polycarbonate as raw material was placed in a vacuum environment of 10 mbar. Test components were then fabricated in vacuum with a control group fabricated in a normal atmosphere (1 bar). Test components were evaluated for dimensional and mass accuracy, quality and presence of defects. Flexural, tensile and compressive testing was carried out according to ASTM D790, D638 and D695 respectively. Dimensional analysis of components showed equivalent small deviation for both environments. Components fabricated in the vacuum environment had 5.4% higher tensile yield strength and 59% higher extension at break compared to components printed in a normal atmosphere indicating an increased strength and ductility. Components tested in compression had approximately 11.2% higher compressive strength when printed in a vacuum environment. No differences were observed during the flexural test. In space, due to the vacuum environment, polymers and organic material are susceptible to release molecules via an outgassing process. Assessment of the molecular organic contamination generate during the printing process in vacuum is low and seems to mostly originated from the components of the printer. The results provided demonstrated the possibility to use the FFF process in a vacuum environment to fabricate dimensionally accurate, high-quality polycarbonate components with a variety of geometries without loss of mechanical performance. This work provides a proof of concept that FFF can be used to develop out-of-earth manufacturing technologies (in orbit/in space/on planet) allowing part production for new maintenance and repair strategy or to potentially manufacture entire structure more efficiently overpassing launch constrain by using only raw material brought from earth.

The purpose of this research was to investigate the use of Fused Filament Fabrication (FFF) to fabricate structural components from polycarbonate in an on-orbit environment. This included investigating the ability of an FFF printer to function in a simulated on-orbit environment and evaluation of the dimensional accuracy and mechanical properties of components fabricated in a simulated on-orbit environment. A commercially available FFF printer was placed in a vacuum environment of 1000 Pa. Aspects of the on-orbit environment other than the pressure were ignored. Tests were performed in vacuum to determine functionality of the printer. Test components were then fabricated in vacuum with a control group fabricated in a normal atmosphere. Test components were evaluated for dimensional and mass accuracy, quality and presence of defects. Flexural, tensile and compressive testing was carried out according to ASTM D790, D638 and D695 respectively. The FFF process was successfully carried out in a vacuum environment. Dimensional analysis of components showed that there were often significantly different dimensions depending on the environment they were printed however they pose little practical issues. There was no consistent change in the mass or quality of components when fabricated vacuum. Components fabricated in the vacuum environment had 5.4% higher tensile yield strength and 59% higher extension at fracture than components printed in a normal atmosphere indicating increased strength and ductility. Components tested in compression had approximately 11.2% higher ultimate compressive strength when printed in a vacuum environment. No differences were observed during the flexural test. It was found to be possible to use the FFF process in a vacuum environment to fabricate dimensionally accurate, high quality polycarbonate components with a variety of geometries. This is a promising conclusion as it provides a proof of concept that FFF can be used in an on-orbit environment. In the future FFF could be used for maintenance and repair of satellites or to manufacture entire space systems more efficiently than current manufacture on-ground and launch methods.