Improvement of the layer-layer adhesion in FFF 3D printed PEEK/carbon fibre composites

Improvement of the mechanical properties of FFF 3D printed CF/PEEK composites was achieved by printing under favorable crystallization conditions. It was possible to improve the layer-layer tensile strength more than fivefold from 6.96 MPa to 36.28 MPa by printing in a specially customised, low cost printer operated with a heated print chamber at 230℃. The influence of the chamber temperature on the mechanical and crystalline structure was investigated to determine the best conditions. A maximum flexural modulus of 14 946 MPa and flexural stress at break of 248.9 MPa were achieved. A proof of concept study involved the 3DP of a CF/PEEK mould tooling insert for injection moulding. This insert replaced a costly traditional metal insert to print short production runs of ABS and HIPS polymers. This work offers a low cost and rapid means to produce effective tooling inserts for the injection moulding industry.