Effect of 3D Printing Orientation on the Mechanical Properties of PA, PETG, and PLA Materials

Abstract

This study investigates the influence of print orientation, specifically raster angles of 0/90° and ±45°, on the mechanical properties of three widely used FDM (Fused Deposition Modeling) thermoplastics: Polylactic Acid (PLA), Polyethylene Terephthalate Glycol (PETG), and Polyamide (PA/Nylon). Standard tensile test specimens (ASTM D638 Type I) were fabricated with consistent slicer parameters (0.2 mm layer height, 100% infill). The experimental results demonstrate a significant performance advantage for the ±45° orientation across all materials. PLA exhibited a 145% increase in Ultimate Tensile Strength (UTS), while PETG and PA showed increases of 72% and 107%, respectively. The ±45° orientation, characterized by the "scissor effect," promotes filament realignment under load, enhancing ductility and toughness. Notably, PA in the ±45° orientation achieved an elongation of over 300 mm, compared to only 27 mm in the 0/90° orientation. The toughness (area under the stress–strain curve) of PA increased by more than 22 times in the ±45° configuration. This research highlights the critical role of print orientation in optimizing the structural performance of 3D-printed components and provides practical engineering recommendations for material and orientation selection.