The Influence of Recycling on the Tensile Properties of PLA Variants through Fused Granule Fabrication and Injection Molding Processes.

Abstract

This study looks at how the recycling sequence and processing method affect the mechanical characteristics of two commercially available PLA variants: injection moulding grade PLA and CR wood PLA. Recycled material was processed in various ways, including fused granule fabrication (FGF) and injection moulding. Six configurations were created and tensile tested to determine stiffness, yield strength, and strain at break. The CR wood PLA was recycled twice, with shredding and reprinting between cycles, whereas the injection moulding grade PLA was recycled only once. The results showed that moulded samples consistently had higher stiffness and yield strength than printed samples, and that performance declined when the final processing step was printing. The best strain at break was found in printed virgin material, while the worst was discovered in twice processed printed CR wood PLA. Secondary factors such as moisture retention, granule size, and infill percentage were found to have a significant impact on the results. The study confirms that processing order is critical in maintaining mechanical reliability in recycled PLA and emphasizes the difficulties of structural reuse with low pressure printing methods.