Investigating the Influence of Fabrication Parameters on the Flexural Properties of 3D-Printed Recycled PLA Filament

Polylactic acid (PLA), recognized for its biodegradable and biocompatible attributes, serves as a popular choice for 3D printing filaments. However, its properties undergo transformations upon recycling. This study aimed to elucidate the specific effects of varying extrusion temperatures and screw speeds on the mechanical strength and dimensional properties of recycled PLA filaments. For the purpose of this study, recycled PLA pellets (3D850D) were processed using a single filament extruder machine, with the extrusion temperature set between 145 and 165 °C, and the screw speed ranging from 2 to 6 rpm. The produced filaments were then 3D printed into test samples using a 0° raster angle, line infill pattern, and a complete, 100% infill density. These samples were then tested in compliance with ASTM D790 mechanical standards. The study's findings unveiled a significant correlation between extrusion parameters (extrusion temperature and screw speed) and the filament's ultimate flexural strength, yield strength, and diameter. It was found that an extrusion temperature of 155 °C coupled with a screw speed of 5 rpm led to the highest mechanical strengths. Moreover, these conditions also yielded filament diameters most comparable with commercial standards. These findings underscore the potential for enhancing the properties of recycled PLA filaments through the precise control of extrusion parameters. As a result, this study bolsters the prospect of using recycled PLA filaments in the 3D printing industry as a sustainable, performance-optimized material, marking a significant step toward eco-friendly additive manufacturing practices.