Additive manufacturing of PEEK-based continuous fiber reinforced thermoplastic composites with high mechanical properties

Continuous fiber-reinforced thermoplastic (CFRTP) printing is a promising method to increase the mechanical properties of FDM printed parts. In this study, it was aimed to achieve high mechanical properties using PEEK as a matrix and carbon fiber as support material. For this purpose, a novel production line was used to achieve CFRTP filaments with adjustable fiber volume fractions, and samples were additively manufactured. Further-more, an infrared heater was utilized to improve the interlaminar bonding of the printed samples. Although not affecting the tensile properties, usage of an infrared heater yielded a significant improvement in three-point bending tests due to shear forces. Furthermore, increasing the fiber volume fraction excessively showed a decrease in the flexural strength of the printed parts because of the insufficient wetting of the fibers and po-rosities occurring during the printing process. Lastly, failure surfaces of the printed parts and printed part cross-sections were examined.