PRODUCTION OF CARBON FIBER 3D PRINT FILAMENT WITH CONSISTANT FIBER LENGTH

• Benjamin Yaroch, Mechanical Engineering, University of Delaware

• Suresh Advani, Mechanical Engineering, University of Delaware

Additive manufacturing using carbon PLA filament is very reliant on the orientation and length of the carbon fibers suspended in the part. When printing, the curves and edges of the part result in different orientations of the filament’s fibers and being able to control these values would allow for stronger, more consistent parts to be made.  The development of carbon fiber-reinforced PLA (Carbon PLA) filament for 3D printing faces a persistent challenge due to inconsistent fiber lengths—often a result of high shear mixing during commercial production. These commercial filaments have fiber length ranging from 30-300 um This project presents an in-house approach to fabricate Carbon PLA filament with improved uniformity in fiber length and distribution, leading to enhanced mechanical performance and print quality. The process involves chemically dissolving PLA in ethyl acetate to uniformly integrate carbon fibers, followed by solvent evaporation and controlled extrusion using a low-shear, single-screw extruder. The extrusion system is complemented by a custom-built guiding and tensioning setup with Arduino-controlled motors to ensure consistent filament diameter. Post-production results include laser microscopy for fiber length validation and orientation analysis using printed sine wave geometries. The results of this process demonstrate improved fiber length and consistency throughout the filament. This work enables more precise material testing especially for orientation analysis in cross-sectioned parts.