An estimated 33 tonnes of polypropylene (PP) plastic boxes are discarded from NUS laboratories each year, representing a valuable material resource that could be put to new use. EcoSpool aims to close this plastic loop by transforming discarded PP into functional 3D-printing filament, extending the material's useful life and creating new possibilities for reuse within NUS.

Recycling PP into consistent filament presents significant engineering challenges. Its material properties can lead to unstable extrusion and uneven shrinkage, resulting in variations in filament diameter and shape. EcoSpool addresses these challenges through an optimised extrusion system incorporating a 3.5:1 compression screw, multi-zone resistance heaters for gradual heating, and an Omni-Flow wind tunnel that provides gradual and even circumferential cooling.

The developed system achieved a22% reduction in diameter fluctuation and a 34% improvement in circularity, reaching a mean circularity of 94.8%. Most importantly, the recycled PP filament was successfully used for 3D printing, demonstrating how thoughtful engineering can turn laboratory plastic waste into a useful manufacturing resource and contribute towards a more circular approach to materials use on campus.