Advanced RSM-Driven Optimisation for Enhancing the Mechanical Performance of FDM-Printed PETG: A Correlated Microstructural and Mechanical Property Investigation

Fused deposition modelling (FDM) has become a cost-efficient and highly effective technique in 3D printing. Polyethylene terephthalate glycol (PETG) is a prevalent thermoplastic biofilament, and it exhibits resistance to water, heat, and chemicals. It is often regarded as waterproof and possesses exceptional thermal resistance. This study aimed to improve the mechanical properties of PETG by employing a 50% infill density along with certain infill patterns and raster angles for the top, bottom, and interstitial layers. Initially, Response Surface Methodology (RSM) was used to create the regression model by using various parameters; then, it was used to examine the experimental data and find the factors that have a significant impact on mechanical properties. The structural load-carrying behaviour of the specimen was analysed using a Scanning Electron Microscope (SEM). The tensile results showed that the maximum tensile strength attained was 43.09 MPa and the modulus value was 1.18 GPa and the yield strength was 21.01 MPa. The compressive properties showed that the highest strength was 25.90 MPa, and a modulus of 2.87 GPa was attained. The combination of a rectilinear and concentric infill pattern obtained more strength than the other combinations, and the raster angle acted as the most crucial factor on the strength of the specimen. A determination (R²) value over 90% signified strong suitability, while the error percentage between estimated and experimental data remained below 5%, showing that the regression values were satisfactory.