Effects of nozzle temperature and building orientation on mechanical properties and microstructure of PEEK and PEI printed by 3D-FDM

Poly-ether-ether-ketone (PEEK) and polyetherimide (PEI) are typical representatives of special engineering plastics with high heat-resistance and great mechanical properties. The printing parameters during the fused deposition modeling (FDM) process can affect their mechanical properties of printed parts directly or indirectly. In this paper, PEEK and PEI were printed to investigate the relationship of nozzle temperature, building orientation and material properties by analyzing the morphology, chemical composition and SEM. Because of the crystallinity of PEEK material, its printed parts exhibit plasticity, while the printed PEI parts become brittle due to its non-crystallinity, which is reflected in tensile, flexural and impact test. On the one hand, the mechanical properties of their printed parts were deteriorated due to the formation of air pores. On the other hand, PEEK exhibited the better toughness than PEI. All properties of PEEK and PEI parts printed after optimization can reach about 80% of injection molding parts.