Effects of Printing Speed and Thermal Post-processing Treatments on the Mechanical Properties of PEEK Processed by Fused Deposition Modeling

Polyether ether ketone (PEEK) is a thermoplastic polymer that presents notable thermal resistance, high mechanical strength, biocompatibility, durability, chemical resistance, and low density. PEEK can be additively manufactured by Power Bed Fusion (PBF) and Material Extrusion (ME) techniques. However, the latter is easier to operate and less expensive than the first solution. Printing parameters and thermal post-processing are fundamental aspects to improve the mechanical and thermal properties of the printed part. In the present study, the effects of two distinct thermal post-processing treatments and three different printing speeds on the mechanical properties of PEEK samples produced by ME were investigated. 45 specimens were manufactured, 15 for each printing speed and 5 for each thermal treatment. The results demonstrated that for the as-printed condition, higher printing speeds produced the greatest outcomes in terms of ultimate tensile strength and elastic modulus, whereas the lowest printing speed produced the maximum strain at break. The thermal post-processing treatments revealed that the one carried out at lower temperatures resulted in negligible changes, while the other significantly improved the mechanical performance of the material. The study's findings provide a solid foundation for printing and post-processing a cutting-edge polymer like PEEK to maximize its potential.