Advanced Composites and FFF Process: How to Boost the Parts Performance for Aerospace and Ground Transportation Applications

Conference Abstract: Fused Filament Fabrication (FFF) is an effervescent technology with a high potential to transform the industry and the product development process. The global market for AM of plastics will reach, by 2025, USD 4.8 billion for 3D printers and USD 3.2 billion for printable plastics. Final parts performance is, for now, affected by the composition of available filaments combined to the quality of existing 3D printing process. The filaments are not yet fully adapted to print performant parts, such as for aerospace or ground transportation. These industries are asking for filaments made from high-melting temperature advanced composites. Many challenges are observed during the part building using the FFF process. Very rapid cooling of the molten filament, printing at lower temperatures than expected, lack of layers adhesion or unachieved full crystallinity are disadvantages leading to low performance parts. The existing FFF printers for high melting temperature composites still need optimizations to achieve performant parts.

This work presents how to improve the quality of open-source advanced composites for FFF and how to advance the open-source FFF process in order to print parts with boosted performance. Advanced composites were developed starting from two Poly-Ether-Ketone-Ketone (PEKK), a semi-crystalline and a pseudo-crystalline grade. Composites were compounded using carbonaceous recycled fibers and eco-fillers and, further, extruded in filaments having unique hybrid combinations. An existing open-source FFF process for high-temperature composites having a heated chamber, was highly improved by adding a device at the printer head. This helped to maintain the temperature of the in-printing surface much higher than the current heated closed chamber, i.e., beyond the critical Tc (up to 275 °C) of the advanced composites. This helped to increase layer-to-layer adhesion, decrease the voids presence, achieve full crystallinity, and boosted the performance of the parts up to 80% compared to a normal printing.