Magnetic field assisted 3D printing of short carbon fibre-reinforced polymer composites

This paper investigates and discusses the outcomes from an ongoing feasibility research being conducted at Advanced Composites Research Focused Group on 3D printing polymers and carbon composites subjected to localised magnetic field force lines. Magnetic equipped composite processes are starting to become an important new development for structural applications. Specific to this paper, in-situ alignment of short carbon fibres (∼1 mm length) in thermoplastic polymer filaments (Onyx FR, a Nylon base with micro carbon-fibres with a flame retardant additive supplied by Markforged) during a fused deposition modelling (FDM) based 3D printing (MakerBot Replicator 2). An experiment took place in which samples of PLA and onyx were printed, both with and without a magnetic field present. This was done to see what effects, if any, the magnetic field had on the flow orientation of these materials when printed. The results from using a high-resolution optical microscopy and scanning electron microscopy showed that while carbon fibres within the Onyx had aligned in response to the magnetic field, the PLA samples were visibly unchanged by the magnetic field. The observations have been partially supported by theoretical calculations utilizing Multiphysics constitutive equations.