An insight into the effect of printing orientation on tensile strength of multi-infill pattern 3D printed specimen: Experimental study

Abstract

This research aims to investigate printing orientation effect on tensile properties of Multi-Infill Pattern (MIP) specimens fabricated by Fused Deposition Modelling (FDM). The material selected for fabrication of specimen is Poly-lactic Acid (PLA), and the thermal stability of PLA material was examined using Thermal Gravimetric Analysis (TGA). The print orientation selected in this study were flat and on-edge orientation. The up-right orientation was not considered because, in this orientation, the parts are built along the z-axis, which results in minimum strength. The MIP consists of honeycomb, triangular and rectilinear patterns fabricated with 25%, 50%, 75% and 100% infill density. The tensile specimen has been designed as per the ASTM D638 standard. The result represents that the printing orientation has influenced the tensile strength of MIP specimen. Higher tensile strength and tensile strength/mass ratio are observed in the on-edge orientation of MIP specimen. The specimen in on-edge orientation with 100% infill density has resulted in higher tensile strength of 30.91 MPa and tensile strength/mass ratio of 3.87 MPa/g. Based on the literature study, the tensile strength of rectilinear, honeycomb and triangular infill pattern PLA specimen with 80% infill density was 10.48 MPa, 10.72 MPa and 20.39 MPa respectively. Hence it can be concluded that the specimen with a MIP has more tensile strength compared to a single infill pattern specimen. Also, trans-layer failure was observed in MIP specimens printed in both orientations.