Investigation of the manufacturability of a copper coil for use in space components by means of the fused filament fabrication process

Metal-filled polymers can serve as the starting material to produce complex metal structures using the cost-effective additive manufacturing process Fused Filament Fabrication (FFF). In this process, the filaments consisting of polymer binders (e.g., polylactic acid (PLA)) and micropowder of highly conductive metals (e.g., copper) are extruded through a nozzle to build up the desired geometry layer by layer. The manufacturability of a complex copper coil for use in satellite actuators with two commercially available filaments (Electrifi and Filamet Copper) using FFF was investigated and the electrical conductivity of the printed material was determined. A design of experiment with variation of extruder temperature and printing speed was used to evaluate different parameter sets. The selected parameter set was then used to produce cuboids to determine the electrical conductivity and an exemplary coil geometry. While the coil could be printed in two sizes (original and enlarged by a factor of two) with one of the investigated filaments, this was not possible with the other filament because the printed material was not dimensionally stable with the selected process parameter set. For the Electrifi filament, that is electrically conductive without post processing, the material achieved a maximum electrical conductivity of 5.59 . 10(-3) % IACS (0.033 Omega cm). This was in alignment with other published results for this filament. The other filament Filamet Copper is not conductive in the as-built state. After debinding and sintering, the material achieved a maximum electrical conductivity of 45.84% IACS (3.77 . 10(-6)Omega cm).