Effect of input variables on the mechanical properties of additively manufactured PEEK thermoplastics

Abstract

Additive manufacturing of Polyetheretherketone (PEEK) thermoplastics offer significant advantages for advanced engineering applications, e.g., in the aerospace and biomedical fields, due to its remarkable strength, resistance to high temperatures and low thermal expansion. Moreover, using Fused Filament Fabrication 3D printing for PEEK thermoplastic allows for greater design flexibility and cost-effectiveness in comparison to traditional manufacturing methods. The significance of 3D printer input variables for improving the mechanical properties of additively fabricated PEEK thermoplastics is addressed in this research. In this regard, to investigate the impact of nozzle temperature and printing speed on the mechanical properties of 3D printed PEEK thermoplastics, a design-of-experiments methodology with a full factorial design (two factors and three levels) coupled with analysis of variance was employed. The printer speed varied between 15 and 25 mm/s, while the nozzle temperature ranged from 400 to 440 °C. Tensile tests and scanning electron microscopy were used to evaluate the mechanical properties and microstructure. The results show that the mechanical strength of the PEEK samples reduced as nozzle temperature and printing speed increased. These outcomes are due to the thermal degradation and inadequate cooling time during the printing process.