Abstract

This study investigates the influence of build orientation on the mechanical performance of Polylactic Acid (PLA) components fabricated using Fused Granular Fabrication (FGF), a pellet-based additive manufacturing method, and benchmarks these results against Fused Deposition Modeling (FDM). Although orientation-dependent mechanical behavior has been widely studied in filament-based extrusion, there remains a critical gap in understanding how these effects appeared in pellet-based fabrication. To address this gap, PLA tensile and compression specimens were fabricated using both FGF and FDM under identical geometries, processing parameters, and preparation procedures, ensuring that any differences in performance arise solely from the manufacturing method and build orientation rather than external variables. Three orientations were selected which are Flat, On-edge, and Upright. The test was conducted according to ASTM D638 for tensile testing and ASTM D695 for compression testing, with five specimens produced per orientation for each manufacturing process. The findings showed that build orientation significantly affects the mechanical behavior of PLA in both processes, but in different ways. FGF achieved consistently higher tensile strength and stiffness across all orientations, whereas FDM demonstrated superior ductility and toughness, particularly in the Flat orientation. In compression, FDM generally exhibited higher stiffness, yet FGF printed in the Upright orientation produced the highest ultimate compressive strength among all samples tested. Within FGF, Flat and On-edge orientations yielded the best tensile properties, while Upright, despite having the lowest tensile strength, exhibited the highest stiffness. Orientation effects in compression were less pronounced, though Upright again provided the highest strength for FGF. When comparing the two processes directly, orientation-dependent trends showed inconsistencies: the Upright orientation was stiffest in FGF, whereas the Flat orientation was stiffest in FDM. However, both methods followed the same tensile strength ranking of On-edge > Flat > Upright.

Publication Date

12-2025

Document Type

Thesis

Student Type

Graduate

Degree Name

Mechanical Engineering (MS)

Advisor

Wael Abdel Samad

Advisor/Committee Member

Salman Pervaiz

Advisor/Committee Member

Umer Javed

Campus

RIT Dubai

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