Positrusion Filament Recycling System

TUI proposes a novel process to produce 3d printer feedstock filament out of scrap ABS on the ISS. Currently the plastic filament materials that most 3d printers use are produced with screw-based extruders that are fundamentally designed for high volume terrestrial production from uniformly pelletized resin feedstock. These require relatively large continuous batch sizes with significant operator inputs and have generally poor control over the produced filament geometry. Existing extrusion machines also tend to rely on separate facilities for fully drying the material beforehand, and do not inherently provide tight flow-rate control. The proposed effort will develop a filament extruding machine that uses a process called Positrusion that is designed from the ground up for optimally producing small batches of positively controlled round filament directly out of arbitrarily shaped scraps of ABS plastic, while meeting requirements for operation on the ISS. The machine will accept miscellaneous ABS parts, it will dry and degas the input material before melting and extruding it through a die, and the cross-sectional dimensions and feed-rate of the cooling extrudate will be tightly controlled in a continuous analog of closed-die molding.