City Research Online

Abstract

The development of efficient, energy saving, eco-friendly and automated manufacturing of free-form variable-thickness polymer composite components has created a step-change and enabling technology for the composites industry seeking geometry tailoring during a mouldless and/or additive manufacturing such as that in 3D printing. The current article presents ongoing research on the 3D printing of polymer nanocomposites embedded with ferromagnetic iron particles. This research involves exposing the nanocomposite to a magnetic field remotely during the fabrication process. The magnetic field is applied unidirectionally by using constant-strength magnets placed on a fused deposition method (FDM) based 3D printing platform. The magnets are symmetrically fixed on both sides of the printed nanocomposite. A high-performance polylactic acid (PLA) grade polymer was selected, which is commonly used for rigid structures. The setup utilised Neodymium magnets with a constant strength below 1T. The printing process maintained a consistent temperature of 220°C for the nozzle and 40°C for the bed. Observations have shown that the nanocomposites being printed undergo permanent macro-scale deformations caused by the extrinsic strains induced by the surrounding iron particles in response to the relatively low magnetic field (<1T). To provide a theoretical understanding of these induced strains, a Multiphysics constitutive equation has been developed. This equation aims to describe the micromechanics of the field-induced strains and study the evolution of magnetisation within a relatively thick nanocomposite (5mm thickness). Experimental measurements have quantified the macro-scale geometric variations achieved during printing, and a correlation has been established between these variations and the extrinsic strains derived from the theoretical solution, i.e. induced 1.3 mm. The theoretical solution accurately provides the description of the actual field induced strains during the 3D printing process provided that precise temperature values for the layers are accounted for. The theory also predicts a high sensitivity of field induced deformation to such temperatures and interconnects the Multiphysics parameters in explicit expressions for the phenomenon occurring. The results demonstrate a viable and disruptive magnetic field equipped fabrication approach with ability to extend to geometry control during its process.

Publication Type:	Article
Additional Information:	© 2023 The Authors. Macromolecular Materials and Engineering published by Wiley-VCH GmbH This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Publisher Keywords:	3D printing, magnetic polarisation, polymer nanocomposite, ferromagnetic particles, composite manufacturing
Subjects:	Q Science > QD Chemistry T Technology > TA Engineering (General). Civil engineering (General)
Departments:	School of Science & Technology > Engineering
SWORD Depositor:	Symplectic Administrator

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