An investigation into 3D printing of fibre reinforced thermoplastic composites

Abstract

General rightsThis document is made available in accordance with publisher policies. Please cite only the published version using the reference above. Full terms of use are available: http://www.bristol.ac.uk/pure/about/ebr-terms A B S T R A C TFused filament fabrication (FFF) is a 3D printing technique which allows layer-by-layer build-up of a part by the deposition of thermoplastic material through a nozzle. The technique allows for complex shapes to be made with a degree of design freedom unachievable with traditional manufacturing methods. However, the mechanical properties of the thermoplastic materials used are low compared to common engineering materials. In this work, composite 3D printing feedstocks for FFF are investigated, wherein carbon fibres are embedded into a thermoplastic matrix to increase strength and stiffness. First, the key processing parameters for FFF are reviewed, showing how fibres alter the printing dynamics by changing the viscosity and the thermal profile of the printed material. The state-of-the-art in composite 3D printing is presented, showing a distinction between short fibre feedstocks versus continuous fibre feedstocks. An experimental study was performed to benchmark these two methods. It is found that printing of continuous carbon fibres using the MarkOne printer gives significant increases in performance over unreinforced thermoplastics, with mechanical properties in the same order of magnitude of typical unidirectional epoxy matrix composites. The method, however, is limited in design freedom as the brittle continuous carbon fibres cannot be deposited freely through small steering radii and sharp angles. Filaments with embedded short carbon microfibres (∼100 μm) show better print capabilities and are suitable for use with standard printing methods, but only offer a slight increase in mechanical properties over the pure thermoplastic properties. It is hypothesized that increasing the fibre length in short fibre filament is expected to lead to increased mechanical properties, potentially approaching those of continuous fibre composites, whilst keeping the high degree of design freedom of the FFF process.

Development and Mechanical Properties of Basalt Fiber-Reinforced Acrylonitrile Butadiene Styrene for In-Space Manufacturing Applications

“…Most of the research in composite material 3D printing is related to a thermoplastic with a fiber reinforcing material [15][16][17][18][19][20]. Most of these materials have focused on short discontinuous fibers because this is a much simpler and less expensive method for FFF printing.…”

The Use of Composite Materials in 3D Printing

“…An observed lack was the limitation in design freedom, due to the difficult deposition of the brittle continuous carbon fibers through the small steering radii and sharp angles. They also recorded that filaments with embedded short carbon microfibers showed better print capabilities but offered a slight increase in mechanical properties over the pristine thermoplastic [25].…”

Performance of 3D-Printed Continuous-Carbon-Fiber-Reinforced Plastics with Pressure

“…Dickson et al assessed the performance of continuous carbon-, Kevlar-, and glass-fiber-reinforced composites by MarkOne [27]. However, 3D printers are simple in design and use but lack the ability to apply additional pressure and heat to the part compared to the ATP machines [32]. Zhang et al proposed a The other strategy is to manufacture the CCFRPs and then print parts with the CCFRPs on a FDM printer, which is a multi-step process, as shown in Figure 1b.…”