Impact of printing parameters on in-plane tensile and fracture toughness of fused filament fabricated PEEK

In this study, we explore the effect of various FFF parameters on the in-plane tensile properties and fracture toughness of 3D-printed poly-ether-ether-ketone (PEEK). In particular, tensile test of dog bone specimens produced with different zone heater temperatures was conducted to determine the values of elastic modulus and tensile strength. Whereas, three point bending of single-edge notched beam (SENB) printed with different printing configuration, and zone heater temperatures were used to evaluate the mode-I critical strain energy release rate. Crack mouth opening displacement (CMOD) and strain fields induced in SENB specimens by crack propagation were captured with digital image correlation (DIC) technique. It was concluded that increasing zone heater temperature improved the tensile strength of the 3D-printed PEEK samples while the elastic modulus reduced. Moreover, zone heater temperature exhibits a ductile behavior with improving the interlaminar fracture toughness compared to high zone heater temperature. Instead, the on-edge printing pattern results in a low interlaminar toughness with transverse crack propagation as shown by the DIC images.