Factors Affecting Ultimate Tensile Strength and Impact Toughness of 3D Printed Parts Using Fractional Factorial Design

Abstract This paper aims to investigate the mechanical properties of spec- imens printed by 3D open-source printers. It discusses the effect of five fac- tors (part/print orientation, layer height, extrusion width, nozzle diameter, and filament temperature) on the ultimate tensile strength and the impact toughness of the 3D-printed samples. A 2 6-1 resolution V fractional factorial experiment was run with the 16 samples printed on a Prusa I3 MK3S in PLA. Tensile strength and impact toughness were tested using Instron 3367 and Tinius Olsen 66 testers, respectively. In analyzing the data, a normal proba- bility plot complimented with ANOVA (Analysis Of Variance) revealed that only part/print orientation was statistically significant at p = 0.05. Regression equations were used to predict the ultimate tensile strength and the impact toughness as a function of the part/print orientation. Both the toughness re- sponse and the tensile strength response are maximized with horizontal part orientation. Verification experiments have been implemented to validate the adopted regression equations’ predictions under different circumstances and the results of those experiments appear to confirm the model.