Interactive influence of in-situ annealing temperature and thermal processing parameters on defect minimization and strength enhancement in FDM-printed PEEK

Abstract

Abstract PolyEther Ether Ketone (PEEK) fused deposition modelling (FDM) has become a viable manufacturing technique for creating high-performance parts utilised in high-temperature engineering, biomedical, and aerospace applications. However, poor heat control during FDM printing frequently results in internal flaws like cavities and poor interlayer bonding, which seriously impair the printed components’ structural integrity and load-bearing ability. This study examines the combined effects of chamber temperature (80, 100, and 120 °C), in-situ annealing temperature (200, 260, and 320 °C), and layer thickness (0.15, 0.2, and 0.3 mm) on the mechanical performance and defect formation of FDM-printed PEEK components in order to address these issues. The individual and combined impacts of the process parameters were assessed using the multi-criteria decision-making method Weighted Aggregated Sum Product Assessment (WASPAS), coupled with Criteria Importance Through Intercriteria Correlation (CRITIC) and ANOVA. The findings show that an in-situ annealing temperature of 320 °C greatly improves interlayer consolidation and thermal diffusion, lowering internal cavity content to as low as 0.82% as opposed to values surpassing 9% at lower thermal settings. Flexural and compressive strengths improved by 30.2% and 40.2%, respectively, to 91.14 MPa and 135.58 MPa under ideal conditions of 320 °C annealing temperature, 100 °C chamber temperature, and 0.2 mm layer thickness. These results demonstrate the great potential of thermally optimised FFF-printed PEEK for challenging applications where high strength and flawless performance are essential, such as load-bearing orthopaedic implants and aerospace structural brackets.