Influence of the Process Parameters on the Mechanical Properties of the FDM 3D Printed Samples

This research analyses the impact of infill density and layer thickness on the tensile strength of test samples fabricated using FDM 3D printing, with a particular focus on comparing samples produced with and without an adhesion layer. A two-factor factorial experimental design was employed, consisting of two levels and three replications. The infill density (20% and 50%) and layer thickness (0.1 mm and 0.2 mm) were defined as input variables, while tensile strength served as the output variable. Statistical methods, such as ANOVA, were used to analyse the experimental data and evaluate the significance of the individual factors and their interactions. The results revealed that for samples with an adhesion layer, the infill density, layer thickness, and their interaction had a statistically significant effect on tensile strength. In contrast, for samples without an adhesion layer, a significant effect was observed only for individual factors, with no significant interaction. The regression models exhibited high coefficients of determination (R²) for both sample sets, confirming their strong reliability in predicting tensile strength. Furthermore, the t-test results indicated no statistically significant difference in tensile strength between samples manufactured with and without an adhesion layer.