Closing the Loop: Recycling PLA Waste from 3D Printing into Value-Added Filament at NC State University

Abstract

The rapid growth of 3D printing in university makerspaces has created a new but often overlooked waste stream: discarded polylactic acid (PLA) filament from failed prints, support structures, and design errors. Although PLA is a bio-based and recyclable thermoplastic, most of this material currently ends up in landfills. This paper outlines a pilot project at NC State University to close this loop by collecting, processing, and re-extruding PLA waste into new 3D printing filaments. The system, developed through collaboration between the D.H. Hill Makerspace and Hodges Lab, employs a straightforward four-step process—collection, sorting, grinding, and extrusion—thereby achieving over 90% material efficiency. Besides demonstrating technical feasibility, the project emphasizes how campus-scale circular systems can reduce waste, lower costs, and serve as educational models for sustainable manufacturing. This initiative provides a replicable framework for universities and small-scale fabrication facilities seeking to incorporate circular economy principles into their operations.