Developing a novel technique for the fabrication of PLA-graphite composite filaments using FDM 3D printing process

Abstract

Developing a uniform polymer-based composite filament is a critical factor for a successful 3D printing process. In this regard, a novel technique for the fabrication of PLA-graphite filament with the potential to be applied to other PLA-based composite filaments was proposed and compared to the solvent casting method. This modified mixing technique involves partial dissolution of the PLA pellets surface by dichloromethane (DCM), which creates a sticky surface for the strong adhesion of reinforcement powders. The manufactured composite filament by this method exhibited excellent structural features, while the solvent casting method yielded a heterogeneous filament with a non-uniform diameter and numerous voids. In addition, graphite, as a cost-effective carbon-based filler for polymer matrix composites, could effectively act as a reinforcement phase, leading to noticeable mechanical strength enhancement of PLA. Furthermore, significantly enhanced printability and mechanical properties of 3D-printed PLA-graphite composite specimens indicate the efficiency of the modified mixing method as a practical and time-saving technique for developing uniform PLA-based composite filaments for the extrusion-based additive manufacturing techniques such as FDM.