(193i) Computational Fluid Dynamics Simulation of the Fused Deposition Modeling Process Using a Viscoelastic Model
Fused Deposition Modeling (FDM) is one of the most common additive manufacturing techniques. FDM builds a 3D object by extruding strands of polymer melts, layer by layer, on a platform. Despite extensive experimental studies, numerical modeling of FDM process, particularly for viscoelastic polymer melts, is yet to be done. Many issues related to FDM like surface roughness and die swell are originated from the viscoelastic behavior of polymer melts. In the present work, 3D computational fluid dynamics (CFD) simulation of the FDM process is performed based on the Finite Volume Method. The polymer melt is simulated as a Newtonian fluid and a viscoelastic fluid. Oldroyd-B model, one of the most common models for viscoelastic fluids, is used to predict the viscoelastic behavior of the polymer melt. The effects of geometrical parameters (e.g., cross-section shape and area, nozzleâs wall thickness) and the flow characteristics (e.g., nozzle and moving substrate velocities, the relaxation time and viscosity) on the deposition of layers on the moving substrate are investigated. Additionally, the thickness of the extruded strands is related to dimensionless numbers of the systems (i.e., Re and Wi). The results from both the Newtonian and the viscoelastic fluid simulations are also compared with experimental results. For experimental investigation, Polylactic Acid (PLA) filaments are utilized for extrusion in a Prusa 3D printer.