Additive manufacturing of continuous fiber composites using fused filament fabrication

Additive manufacturing of continuous fiber composites have extensively been investigated as a key technology of advanced composites in past two decades. Fused filament fabrication (FFF) or Fused deposition modelling (FDM) has attacked great attention in research community because of its capability for manufacturing continuous fiber composite parts with optimization of topologically designed configurations. Successful fabrication of high-quality continuous fiber composite parts using FFF is secured by completion of a few key processes such as precise deposition of a filament and fusion between a depositing filament and filaments deposited in previous steps, while the fusion is modulated by two key mechanisms, i.e., “intimate contact” and “autohesion”. This presentation summarizes some recent results in additive manufacturing of comtinuous CF/PA composites. Mechanistic models are developed to describe “intimate contact” and “autohesion” processes during an “interlaminar” deposition mode without or with overlapping, equipped with parameters such as surface profile of filaments, temperature of depositing head, contact duration between filaments, contact pressure between filaments, while the latter is measured by a high precision 3D dynamometer instrumented on a 3D printing platform. It is concluded that a high quality pre-impregnated filament of a precise diameter and high precision deposition of the filament in a defined path with a tailored processing window of deposition temperature, depositing speed, and deposition pressure are the keys for the successful fabrication of high quality continuous fiber composite parts.