Comparative property analysis of fused filament fabrication PLA using fresh and recycled feedstocks

Manufacturing industries generate much waste, which can be converted into raw materials for other allied industries. Thermoplastic wastes can be recycled in many cases. Recently these recycled plastics have been used to manufacture the input filament necessary for material extrusion additive manufacturing (MEAM). Polylactic acid (PLA) is one of the most common and potentially useful engineering plastics that can be additively manufactured, but the effect of recycling on the effective properties is still not well known. In this study, the mechanical properties of MEAM-processed PLA were compared for virgin and recycled feedstock. The collected data were analyzed using a full-factorial design of experiments method, providing insight into the effects of layer thickness and infill density on the performance of the material before and after recycling. The results showed a notable degradation in properties after recycling, but this effect was moderated by modifying the studied parameters. This work and its conclusions will serve as a screening study to guide future efforts in this area and promote the wider use of recycled materials in additive manufacturing.