Continuous glass fiber-reinforced polycaprolactone composite produced in a conventional fused filament fabrication equipment: Process modeling and parameters adjustment

Polymer composites with continuous fibers are expected to exhibit good mechanical performance due to orientation and high aspect ratio of fillers. Fused filament fabrication (FFF) provides an affordable method for processing these materials as products with tunable architecture. By incorporating continuous bioactive fibers coated with biodegradable polymer, the degradation rate of printed scaffolds may vary over time. As proof of concept, macroporous composites were 3D printed using continuous glass fiber-reinforced polycaprolactone filament. Parametrization and challenges associated with printing on non-dedicated equipment are discussed. A model describing the melt flow was employed to evaluate the velocity and shear rate profiles. Although the maximum velocity is approximately 18 mm s-1 for both neat and reinforced polymer, the obstruction caused by fibers results in higher shear rate, up to 481 s-1, higher pressure gradient, 1.95 MPa mm-1, and higher velocity gradient, conditions that limit print quality. Additionally, it was also possible to determine the shear stress experienced by the fiber bundle, 300 KPa, and the influence of different processing conditions. This investigation advances the development and understanding of manufacturing of continuous fiber-reinforced polymers via FFF. Melt flow during 3D printing of continuous fiber-reinforced polymer was investigated using a model for pseudoplastic annular flow. The presence of fibers results in high shear rate, pressure gradient, and velocity gradient, limiting print quality. The model can be applied to elucidate the influence of processing parameters on the quality of continuous fiber-reinforced polymer products obtained via fused filament fabrication. image