Additive manufacturing of heat-sensitive polymer melt using a pellet-fed material extrusion

Zhou, Zuoxin; Salaoru, Iulia; Morris, Peter; Gibbons, Gregory J.

Abstract

The most common method for Additive Manufacturing (AM) of polymers is melt extrusion, which normally requires several pre-processing steps to compound and extrude filament feedstock, resulting in an overall long melt residency time. Consequently a typical melt extrusion-based AM process is time/cost consuming, and limited in the availability of materials that can be processed. Polyvinyl alcohol (PVOH) is one of the heat-sensitive polymers demonstrating a thermal decomposition temperature overlapping its processing window. This study proposed to use a pellet-fed material extrusion technique to directly process PVOH granules without the necessity of using any pre-processing steps. The approach essentially combined compounding, extrusion and AM, allowing multi-material printing with minimum exposure to heat during the process. The processing parameters were determined via thermal and rheological characterisation of PVOH. Effects of processing temperature and time on the thermal decomposition of PVOH were demonstrated, which further affected the tensile properties and solubility. An increase in Young’s modulus, stress at 2% strain, and Ultimate Tensile Stress were 98 ± 4%, 40 ± 5%, and 20 ± 2%, respectively, was observed when PVOH residency time was reduced from 25 min to 14 min. The pellet-fed material extrusion technology demonstrated good 3D printability, multi-material printing capability, and great versatility in processing polymer melts.

Citation

Zhou, Z., Salaoru, I., Morris, P., & Gibbons, G. J. (2018). Additive manufacturing of heat-sensitive polymer melt using a pellet-fed material extrusion. Additive Manufacturing, https://doi.org/10.1016/j.addma.2018.10.040

• Journal Article Type: Article
• Acceptance Date: Oct 23, 2018
• Online Publication Date: Oct 28, 2018
• Publication Date: Oct 28, 2018
• Deposit Date: Oct 29, 2018
• Publicly Available Date: Oct 29, 2019
• Journal: Additive Manufacturing
• Print ISSN: 2214-7810
• Electronic ISSN: 2214-8604
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• DOI: https://doi.org/10.1016/j.addma.2018.10.040
• Keywords: Additive Manufacturing; Three-Dimensional Printing; Polyvinyl alcohol; Thermal decomposition; Material extrusion
• Public URL: https://nottingham-repository.worktribe.com/output/1205550
• Publisher URL: https://www.sciencedirect.com/science/article/pii/S2214860418303683
• Contract Date: Oct 29, 2018