Enhanced interlayer adhesion and regulated tribological behaviors of 3D printed poly(ether ether ketone) by annealing

Most of the current poly(ether ether ketone) (PEEK) parts manufactured via fused deposition modeling (FDM) printing are suffering for weak interlayer adhesion and low mechanical strength. Herein, a simplified tactic is adopted, which combined FDM printing with annealing post-treatment, to realize a better mechanical strength, interlayer adhesion and wear resistance of 3D printed PEEK. The freeze-fracture surface of PEEK annealed at 190 ℃ was dense. At the normal load of 30 N, the wear rate of annealed PEEK reached the minimum value of 2.83 × 10⁻⁵ mm³/(N·m), with a 34 % reduction. At a higher load of 70 N, the annealed PEEK at 170 ℃ still maintained a low wear rate. Moreover, the annealed PEEK exhibited excellent manufacturing precision and fidelity. The PEEK annealed at 170 ℃ was used to simulate wear within knee-joint cavity and planetary gears were printed for demonstration, which run stably at different working conditions. These findings highlight the significant potential of 3D printed PEEK combined with annealing post-treatment in the applications of heavy-load gear and bionic joint.