Simulation of Planar Deposition Polymer Melt Flow and Fiber Orientation in Fused Filament Fabrication

Heller, B.P.
Smith, D.E.
Jack, D.A.
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University of Texas at Austin

Mechanical and thermal properties of a 3D printed part are improved by adding discrete carbon fibers to the Fused Filament Fabrication (FFF) polymer feedstock. The properties of the fiber-filled composite are significantly influenced by the orientation of the carbon fibers within the extruded bead where fiber orientation in the bead is affected by the nozzle internal flow geometry, extrudate swell, and the deposition flow during the FFF process. In this work, a 2D Stokes flow finite element analysis is performed to evaluate FFF extrusion for a large-scale deposition extruder where special attention is given to the deposition of polymer melt on the moving platform below the nozzle. The shape of the extruded polymer is computed using a free surface normal velocity minimization technique. Once the velocity field and flow boundary is computed for the bead deposition process, fiber orientation and the resulting mechanical properties of the solidified composite are computed within the printed bead.