Laser-Assisted Fused Filament Fabrication for Mechanical Strength Improvement of Carbon Fiber–Reinforced Polyether Ether Ketone

In contrast to traditional polymer fabrication, additive manufacturing eliminates the need for tooling and reduces production lead times, making it ideal for batch production. Specifically, fused filament fabrication (FFF) is notable for its liquid and powder-free process, which is suitable for vacuum and low-gravity conditions. However, the anisotropic strength of FFF parts limits their use. This research presents a methodical approach to improve the mechanical strength of 3D-printed carbon fiber (CF)-reinforced polyether ether ketone (PEEK) components, aiming for improved mechanical strength by applying in-process laser heating. CF PEEK is selected for its exceptional strength, durability, and heat resistance. The core of this laser technique is to increase the interface temperature, slowing down the cooling phase, which promotes polymer chain movement and entanglement, leading to enhanced mechanical properties. This method significantly boosts the mechanical strength of 3D-printed PEEK in the build direction from 9.3 MPa to 60.5 MPa, with the strain increasing by 150%. Additionally, there are notable differences in fracture behavior: the control sample fractures at the interlayer interface, while the laser-treated sample fractures within the layer. Adopting this advanced approach could address the current limitations of FFF 3D printing in manufacturing and enable FFF to serve fields that require mechanical strength and small-batch production. This technique has the potential to extend polymer additive manufacturing to fields requiring high-temperature, high-strength composites, such as in-space manufacturing/assembly, small-batch production for aerospace parts, medical components, and prototypes.