Investigation About the Impact of Nozzle and Chamber Temperatures and Infill Orientation on the Mechanical Behavior of 3D Printed PEEK Specimens

Polyether EtherKetone (PEEK) is a high-performance polymerwidely used in several fields due to its excellent material and chemical strength properties also at high operating temperatures. The processing conditions used to fabricate PEEK parts can significantly influence the crystallinity and, hence, mechanical properties. Manufacturing difficulties are further amplified when PEEK is produced by Additive Manufacturing (AM), since it requires high processing temperatures, which only a few 3D printers available on the market can guarantee. In this paper, a Design of Experiment (DoE) was employed to investigate the mechanical properties of PEEK produced by Fused Filament Fabrication (FFF). Nozzle Temperature (390 °C and 420 °C), Chamber Temperature (80 °C and 100 °C) and Infill orientations (0° and 45°)were involved in the experiment through a 2-level full factorialDoE.Young’s modulus,Yield Stress, Ultimate Tensile Stress and elongation at fracture were investigated. Through ANOVA analysis it was found that the three parameters do not influence Young modulus (2.6 ÷ 3.2 GPa), while their combinations influence yield stress (36 ÷ 46 MPa), tensile strength (45 ÷ 74 MPa) and elongation at fracture (2.1 ÷ 16%). As expected, the optimal values for the best mechanical properties are the highest levels of nozzle and chamber temperatures and 0° infill orientation.