First steps of the melting of an amorphous polymer through a hot-end of a material extrusion additive manufacturing

The melting of an amorphous polymer filament through the hot end a material extrusion process is addressed using computational multiphase fluid dynamics coupled to heat transfer. Only flow block investigated. air gap between and interior extruder accounted for. polymer/air interface implicitly tracked by level-set method. system equations solved finite element method with time-marching Three velocities are For lowest velocity, after contact on nozzle, disappears time. transient regime lasts few tens seconds. two larger velocities, even if more reduced time, it persists for long extension increases velocity. feeding force needed push obtained integration tension surface extruder. After driven transfer, steady-state observed three velocities. Roughly, linearly A good agreement found experimental results smallest