Effects of processing parameters and annealing on the mechanical properties of polyether ether ketone(PEEK) via fused deposition modeling(FDM)

Fused deposition modeling (FDM) has been recognized as a predominant additive manufacturing technique for polymer 3D print. Polyether ether ketone (PEEK) has been widely used as a high-performance commercial polymer in biomedical fields. In this work, the tensile and flexural properties of PEEK processed by FDM were studied. Nozzle temperature, print speed and platform temperature were optimized using the orthogonal method. In terms of tensile strength, the best performing specimen was 82 MPa, which was printed at an optimal parameter combination of nozzle temperature 420°C, print speed 20 mm/s and platform temperature 100°C. As for flexural strength, the optimal levels were nozzle temperature 420°C, print speed 20 mm/s, and platform temperature 140°C, and reached a maximum value of 141 MPa. The fracture morphology of the tensile specimens indicated that the interfacial bonding between layers and defects was the main factor affecting the tensile strength. It was also found that the tensile strength was significantly improved by annealing post-processing. After annealing at 200 °C for 2 h, the tensile strength of the specimen reached a maximum value of 104 MPa, increased by 28.0% compared with the un-annealed ones. Moreover, the increase of crystallinity was the main reason for the improvement of the tensile strength. Simultaneously, the chemical structure was not affected by the annealing treatment according to the FTIR spectra.