Increasing perpendicular alignment in extruded filament by an orifice embedded 3D printing nozzle

ABSTRACT

The mixing of fibrous additives in the polymer base is being widely investigated for improving the mechanical properties of printed parts using fused filament fabrication (FFF). In this study, flow visualisation experiments and computational fluid dynamics (CFD) analysis were conducted on the flow channel of a nozzle with an orifice for enhancing the through-layer physical properties of the printed parts. Flow visualisation experiments were conducted on the flow channels of nozzles installed with orifices of various shapes. Using ball-milled carbon fibre in high-viscosity polydimethylsiloxane (PDMS) that imitates filament flow in FFF, the fibre angles were measured for different internal and external locations of the nozzle. The distribution of the fibre angles inside the nozzle was compared with the gradient of the flow field calculated for the same shape by CFD analysis. It was found that the orifice structure inside the nozzle increases the vertical alignment of the fibre. An abrupt increase in the extension rate at the exit of the orifice is considered to be the reason behind the rotation and vertical orientation of fibres inside the nozzle channel. Results presented in this work provide the basis for achieving improved through-plane physical properties of FFF printed parts through fibre alignment.

KEYWORDS:

• Additive manufacturing
• fibre alignment control
• flow visualisation
• orifice embedded nozzle
• CFD analysis

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Notes on contributors

Do-In Jeong

Do-In Jeong is currently pursuing Master's degree at the Department of Mechanical Engineering at Chosun University, Korea. His research interests include understanding the alignment of additives inside polymer medium during the additive manufacturing process.

Ankur Jain

Ankur Jain is an Associate Professor in the Mechanical and Aerospace Engineering Department at the University of Texas at Arlington. He has published 96 journal papers on topics related to theoretical and applied heat transfer, including in additive manufacturing, batteries and microelectronics. He is a recipient of the NSF CAREER Award in 2016, UT Arlington College of Engineering Outstanding Early Career Award in 2017 and Lockheed Martin Aeronautics Excellence in Teaching Award in 2018. He received his Ph.D. from Stanford University in 2007.

Dong-Wook Oh

Dong-Wook Oh is an Associate Professor in the Department of Mechanical Engineering at Chosun University, Korea. He received his Ph.D. from Seoul National University in 2008. Prior to joining Chosun University, he worked as a Senior Researcher at the Department of Extreme Thermal Systems, Korea Institute of Machinery and Materials and a Post-Doctoral Associate at the Department of Material Science and Engineering, University of Illinois at Urbana-Champaign. His current research is focused on thermal characterisation and application of polymer composites.