Optimizing tribological properties of 3D-printed thermoplastics through process parameters and microstructural insights

The process of additive manufacturing (AM) and fuzed deposition modeling (FDM, in particular), has become a promising approach to manufacturing complex products with biodegradable materials like polylactic acid (PLA). Nevertheless, the tribological performance of FDM-printed PLA components is still a severe limitation of functional use. This research experimentally studied the tribological performances of the PLA + and carbon-fiber-reinforced PLA (PLA Pro CF) fabricated through FDM. Pin-on-disk tribometer A group trial of cylindrical specimens was conducted in line with the standards of ASTM G99- 04. Five key printing parameters, layer thickness, raster angle, material type, infill pattern, and infill percentage were varied across 24 experimental runs. ANOVA and multi-criteria decision-making using the Combined Compromise Solution (CoCoSo) method wase employed to analyze surface roughness, frictional force, coefficient of friction (COF), and wear. The results indicate that raster angle (26.36%) and infill percentage (17.01%) are the most influential parameters affecting tribological performance. The optimal parameter combination, layer thickness of 0.2 mm, raster angle of 30°, PLA + material, full honeycomb infill pattern, and 50% infill, resulted in a 40.28% reduction in surface roughness, 22.21% reduction in frictional force, 28.22% reduction in coefficient of friction (COF), and 9.17% reduction in wear compared to the average of all experimental runs. This optimal configuration represents the best compromise among all considered performance responses. FESEM analysis showed that PLA + had an abrasive-adhesive wear whereas PLA Pro CF had enhanced wear resistance owing to the strength of carbon fiber. The findings demonstrate that carbon fiber reinforcement significantly enhances the tribological performance of FDM-printed PLA components.