Upper bound of feed rates in thermoplastic material extrusion additive manufacturing

In this work, we develop a simple model to determine the upper bound of feed rates that do not cause jamming in material extrusion additive manufacturing, also known as fused deposition modeling (FDM)(TM) or fused-filament fabrication (FFF). We first derive a relation between the tube temperature and Peclet number for the solid portion of polymer filaments. We focus on the boundary between the solid and molten polymer in the heated portion of the tube. We find the Peclet number that corresponds to the point at which this boundary makes contact with the nozzle, and identify this as the upper bound of the feed rate. We compare our predictions to experimental results. We find good agreement for tube temperatures sufficiently above the glass-transition temperature, which is the temperature region of typical additive manufacturing.