Fabrication of Recycled Polymer Filament for 3D Printing

Lu, En Kang (2025) Fabrication of Recycled Polymer Filament for 3D Printing. Final Year Project (Bachelor), Tunku Abdul Rahman University of Management and Technology.

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Abstract

The increasing prevalence of plastic waste, particularly high-density polyethylene (HDPE), presents significant environmental challenges. This research aims to address this issue by developing a sustainable 3D printing filament made from recycled HDPE (rHDPE), sourced from post-consumer HDPE bottles. The objective is to provide an eco-friendly alternative to commonly used 3D printing materials like polylactic acid (PLA) and acrylonitrile butadiene styrene (ABS), which are typically derived from virgin resources. In this study, post-consumer HDPE bottles were cleaned, shredded, and extruded into filaments at varying extrusion speeds (16, 17, and 18 rpm). The resulting filaments were evaluated for mechanical properties, printability, and dimensional consistency. The findings indicated that an extrusion speed of 17 rpm produced the most consistent filament, with minimal diameter deviations and the best dimensional stability, as measured by ovality tests. Visual inspection revealed minor defects, such as blobs and impurities, which were attributed to inconsistencies in the extrusion process and contamination in the recycled feedstock. Printability testing showed that rHDPE filaments faced challenges with bed adhesion and warping during printing, particularly on standard PEI print beds. However, successful adhesion was achieved with an HDPE-specific print bed. Tensile testing revealed that while higher extrusion speeds (18 rpm) produced filaments with higher tensile strength, the material exhibited reduced ductility. In contrast, filaments extruded at 17 rpm demonstrated superior elongation but with greater variability, suggesting a trade-off between strength and flexibility. This research demonstrates the potential of rHDPE as a sustainable alternative material for 3D printing, highlighting the importance of optimizing the extrusion process and improving material consistency. The study also emphasizes the need for further exploration of extrusion parameters, bed adhesion techniques, and the incorporation of scanning electron microscopy (SEM) to better understand the filament’s microstructure and improve the material’s performance. Ultimately, this work contributes to the broader goal of reducing plastic waste and promoting sustainable manufacturing practices in the 3D printing industry.