Chothe H.R., Huber T., Addiego F., Kukla C., Gonzalez-Gutierrez J.
Progress in Additive Manufacturing, vol. 10, n° 10, pp. 8197-8208, 2025
Additive manufacturing, particularly fused filament fabrication (FFF), is gaining attention in aviation due to its ability to produce lightweight, complex structures using high-performance thermoplastics such as polyetherimide (PEI) as metal substitutes. While weight reduction improves fuel efficiency and lowers operating costs, poor thermal conductivity remains a challenge, often leading to system failures caused by heat entrapment. This study investigates the thermal and microstructural properties of PEI and PEI–carbon fiber (CF) composite filaments and samples prepared via FFF. The incorporation of carbon fibers enhanced thermal conductivity in the printing direction, increasing it from 0.1532 W/m·K (PEI, at 90% extrusion multiplier and 370 °C printing temperature) to 0.2674 W/m·K (PEI–CF, at 85% extrusion multiplier and 350 °C printing temperature), and accelerated the cooling rate during printing from 22.7 to 41.46 °C/s. However, the addition of CF also increased porosity, emphasizing the need for optimization of printing parameters. These findings demonstrate that even though thermal conductivity increases due to the presence of carbon fiber addition in PEI, this increase is limited due to the porosity obtained in 3D printed specimens, thus necessitating a change in the processing conditions compared to unfilled PEI.
