Development of continous fibre liquid deposition modelling system

Abstract

Carbon fibre (CF) and carbon fibre reinforced polymer (CFRP) components are valued for their exceptional properties with applications across various industries. The growing demand for CFRP, driven by factors like sustainability and environmental regulations, is expected to result in a 6.5% compound annual growth rate. Despite its popularity, CFRP remains limited to high-performance applications due to complexity, cost, and low production volumes restricted by its primary choice of conventional production methods.

Additive manufacturing (AM) presents an opportunity to address these limitations with benefits in design flexibility, cost-effectiveness, and reduced lead times. However, AM is not without limitations, particularly with polymer part anisotropy. This paper discusses AM in the form of fused filament fabrication (FFF), vat polymerisation, and liquid deposition modelling (LDM) and each process’ limitations and challenges faced when modified for continuous fibre printing. Various formats of the processes and materials selection available were also considered for this writing.

Motivated by the need for improved CFRP fabrication and to overcome the limitations of existing AM techniques, this research explores a resin-based liquid deposition approach. A complete research guide is outlined from initial concept testing to process optimization, to develop a system capable of CCF printing using liquid resin as a driving force. The set-up in this study primarily centres around the use of an adaptor to allow the feed of dry CF directly to reduce the overall system complexity. However, it was found to be insufficient in preliminary studies and required the addition of other mechanical features to improve fibre-matrix impregnation. This study also placed focus on resin viscosity and curing behaviour as the primary variables to be analysed and found that resin in the range around 1000mPa.s are suitable for the liquid deposition approach. However, there is an observed need for further material characterisation to determine whether viscosity is the only variable at play in this set-up. Regardless, as a whole, a LDM approach for CCF printing remains feasible and requires more research efforts to attain.