Impact of Fiber Orientation and Volume Fraction on the Mechanical Properties of 3D‐Printed Continuous Carbon Fiber‐Reinforced Polyamide Composites Using Towpreg Coextrusion Technology

Additive manufacturing of continuous fiber‐reinforced composites offers design flexibility and potential for high‐performance applications. Earlier fused filament fabrication process is limited to low‐strength thermoplastic polymers, new developments allow to incorporate continuous fibers. In this study, combined effect of fiber volume fraction (FVF) and fiber orientation on mechanical properties of composites printed using towpreg coextrusion is examined. Specimens with FVFs, 0%, 10%, and 20%, with fiber orientations, Type‐I (0°), Type‐II (±45°), and Type‐III (0°/90°), are tested under uniaxial tensile and flexural loadings. Tensile tests show that the specimens with 20% fiber with Type‐I orientation have tensile modulus of 20.71 GPa, and strength of 191.50 MPa, outperforming Type‐II (2.88 GPa, 75.7 MPa) and Type‐III (11.30 GPa, 187.43 MPa). Similarly, specimens with 20% fiber volume and Type‐I configuration result in the flexural modulus and strength of 16.81 GPa and 156.50 MPa, respectively. Furthermore, the Type‐II specimens show the lowest flexural modulus and strength of 2.32 GPa and 60.03 MPa, respectively, while Type‐III (8.83 GPa, 83.13 MPa) maintains an intermediate position. Scanning electron microscopy is used to analyze the microstructure of failed specimens. These findings emphasize the importance of FVF and fiber orientation in enhancing mechanical properties, providing direction for optimizing 3D printing parameters in composite manufacturing.