Additive manufacturing of flexible electrically conductive polymer composites via CNC-assisted fused layer modeling process

Abstract

The applications of electrically flexible conductive polymer composites are rapidly growing over the time due to their widespread use in fabrication of health monitoring devices, sensors, and flexible displays fabrication, etc. Various techniques have been explored to develop electrically conductive polymer composites. In the recent past, fused deposition modeling (FDM) process has been gained tremendous attention to fabricate electrically conductive parts considering rigid polymers along with conductive filler particles. This allows to avail all advantages and benefits of additive manufacturing in the fabrication of complex electrically conductive parts. However, FDM process faces challenges of filament buckling while fabricating flexible parts. Hence, there is need to develop an economically viable and simplified process to fabricate the flexible electrically conductive polymer composite objects. In the present study, fabrication of flexible electrically conductive polymer composite objects has been attempted by developing a novel CNC assisted fused layer modeling process. The developed process uses the material in pellet form instead of a filament, which eliminates the issues of filament buckling and allows flexible object fabrication. The ethylene vinyl acetate (EVA) and graphite (Gr) particles have been used as the polymer matrix and conductive filler material respectively. Solvent and melt blending techniques have been employed to develop EVA/Gr composites. Three-dimensional flexible electrically conductive objects have been fabricated successfully. The experimental result shows the remarkable improvements in electrical conductivity of EVA polymer by incorporation of graphite particles. The outcome of the presented approach may help to fabricate flexible electrically conductive complex structures for soft robotics and electronics applications.