The Effect of a Phase Change During the Deposition Stage in Fused Filament Fabrication.

Additive Manufacturing Techniques such as Fused Filament Fabrication (FFF) produce 3D parts with complex geometries directly from a computer model without the need of using molding tools. Due to the rapid growth of these techniques, researchers have been increasingly interested in the availability of strategies, models or data that may assist process optimization. In fact, 3D parts often exhibit limited mechanical performance, which is usually the result of poor bonding between adjacent filaments. In turn, the latter is influenced by the temperature field history during deposition. This study aims at evaluating the influence of considering a phase change from the melt to the solid state on the heat transfer during the deposition stage, as undergone by semi-crystalline polymers. The energy equation considering solidification is solved analytically and then inserted in the MatLab® code previously developed by the authors to model cooling in FFF. The predictions of temperature evolution during the deposition of a simple 3D part demonstrate the importance of that thermal condition and highlight the influence of the type of material used for FFF.