Composite-Based Additive Manufacturing (CBAM): Mechanical characterization of high-throughput thermoplastic composites and demonstration for urban air mobility application

This study introduces Composite-Based Additive Manufacturing (CBAM), a novel laminate-based technique for fiber-reinforced thermoplastics, offering a promising alternative to conventional extrusion-based methods such as fused deposition modeling (FDM). CBAM consolidates thermoplastic micro-powders precisely patterned on fiber laminates with an automated system, enabling effective matrix impregnation and higher fiber volume fractions. Micro-X-ray computed tomography revealed that CBAM composites contain smaller, more uniformly distributed micropores, whereas FDM parts exhibit inter-filament macro-voids. The distinct microstructures from both processes along with printing directions lead to different mechanical performance. In tension, CBAM composites achieved Young's modulus of 10.0–11.4 GPa and strength of 119.4–121.1 MPa, significantly higher than FDM (4.2–8.1 GPa, 54.7–81.5 MPa), with reduced sensitivity to print orientation due to improved interlayer bonding. Flexural tests showed CBAM's modulus (8.1 GPa) and strength (103–106 MPa) remained consistent across orientations, again surpassing FDM, particularly for 45° flat specimens. In compression, CBAM exhibited lower strength (63.3 MPa at 0°, 54.4 MPa at 90°) than FDM (85.4–91.7 MPa), attributed to matrix-dominant properties. These results demonstrate that CBAM's improved tensile and flexural performance arises from the coupled effects of fiber orientation, volume fraction, and void morphology. To demonstrate application potential, a two-blade propeller was fabricated using CBAM with non-woven glass fiber and PA-12. Ten blades were produced within 3 h, meeting dimensional tolerances <1 mm—substantially faster than the 35–50 h typical of FDM. These establish CBAM as a rapid, precise, and structurally advantageous composite manufacturing technology for aerospace and advanced mobility applications.