Characterization of Specimens 3D Printed by Fused Filament Fabrication Using Advanced Thermoplastic Composites Developed for Aerospace Applications

Additive Manufacturing (AM) and in particular Fused Filament Fabrication (FFF) is considered as a common method to manufacture parts for different applications. The variety of materials that FFF offers makes this technology very useful in different industrial fields, such as ground transportation and aerospace. High-Temperature Plastics (HTPs) like polyetheretherketone (PEEK) and polyetherimide (PEI) offer great mechanical and thermal properties that can be further improved with the addition of reinforcements such as carbon fibres (CF) to create High-Temperature Reinforced Plastics (HTRPs). Commercial materials for high-performance applications are currently available on the market, but the variety of these materials is limited and their price is considerably high. This project used an open-source FFF printing machine with heated chamber (AON-M2) to print newly developed HTRPs based on PEI (commercial name: ULTEM). PEI presents better mechanical properties than standard printing materials like polylactic acid (PLA) or the acrylonitrile butadiene styrene (ABS) but materials cost is reduced by half compared to PEEK. Developed materials by the Laboratory for Multiscale Mechanics (LM2) and the National Research Council (NRC) of Canada with different percentages of CF and Thermal Black (TB) reinforcements were printed. Composites containing up to 40 wt.% CF were printed. The mechanical properties of the samples 3D printed with commercial HTPs and HTRPs and with the developed advanced composites were evaluated using the tensile test standard ASTM D638 (Standard Test Method for Tensile Properties of Plastics). The maximum Young’s modulus and Ultimate Tensile Strength (UTS) obtained for the samples 3D printed with the reinforced developed filaments was 3.3 GPa and 47 MPa, respectively. In addition, the samples were analyzed by Scanning Electron Microscopy (SEM) and micro Computed Tomography (micro-CT). The images obtained with SEM and micro-CT allowed to understand the relationship between the mechanical properties and the porosities inside the samples, which in the case of the developed materials were ∼16 %.