Tensile properties of carbon fiber reinforced nylon prepared with material extrusion additive manufacturing

Carbon fiber reinforced nylon (CFRN) composites are increasingly utilized in manufacturing, automotive, and industrial sectors due to their superior mechanical properties. In recent years, additive manufacturing or three-dimensional (3D) printing has emerged as a prominent method for fabricating CFRN materials. However, systematic investigations into the optimization of key 3D printing parameters, particularly extruder temperature, printing speed and infill pattern, remain limited. This gap hinders the ability to consistently achieve optimal mechanical performance. This study examined the influence of nozzle temperature, printing speed and infill pattern on the tensile strength of CFRN specimens. A Taguchi L9 (3³) orthogonal array was employed to design experiments across three levels of extruder temperature (260 °C, 280 °C, 300 °C), printing speed (40 mm/s, 70 mm/s, 100 mm/s) and infill pattern (triangle, grid, honeycomb). The bed temperature was held constant at 80 °C, with an infill density of 20. Each configuration was printed five times in accordance with ASTM D638-22 standards, and the resulting data were analyzed using ANOVA to identify statistically significant factors. The results showed that the highest tensile strength recorded was 20.7 MPa, achieved at an extruder temperature of 280 °C, a printing speed of 40 mm/s, and a grid infill pattern. Notably, lower extruder temperatures produced softer materials with weaker interfacial bonding to carbon fibers, while specimens printed at 280 °C demonstrated enhanced hardness and improved fiber-matrix adhesion, despite the presence of voids attributed to trapped air. These findings offer practical guidance for optimizing 3D printing parameters in CFRN fabrication, contributing to improved mechanical performance and material efficiency, and advancing the capabilities of additive manufacturing technologies. © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2025.