Experimental Analysis of Layer Orientation Effects in Fused Filament Fabrication (FFF) with PETG: Comparative Evaluation of Two 3D Printers

3D printing using fused filament fabrication (FFF) has emerged as a key manufacturing tool due to its versatility, efficiency, and ability to produce complex geometries. However, ensuring consistent mechanical performance remains challenging, as reported properties often depend not only on process parameters but also on system-level characteristics of the printing platform. This study evaluates the tensile performance of PETG specimens fabricated using two open-frame FFF printers, treating the extrusion system architecture as an explicit experimental variable under controlled conditions: a Bowden-driven Ender 3 Pro and a direct-drive Insol Printer 4. ASTM D638 Type I specimens were printed at three raster orientations (0°, 45°, and 90°), with two replicates per condition (n = 2), using identical material, slicing parameters, and testing procedures. Build orientation dominated the tensile response, with 0° specimens exhibiting the highest strength and 90° the lowest. Beyond this established trend, a consistent printer-dependent difference was observed. At 0° orientation, the Insol Printer 4 reached a maximum ultimate tensile strength of 36.99 MPa, compared to 35.06 MPa for the Ender 3 Pro, representing an increase of approximately 5.5%. Similar trends were observed at 45°, while differences at 90° were less pronounced. Although the limited sample size restricts statistical generalization, these results provide controlled quantitative evidence that extrusion system architecture can influence PETG tensile performance alongside build orientation.