Estimations of Interlayer Contacts in Extrusion Additive Manufacturing Using a CFD Model

Numerical modeling is one of the key components in the development of digital twins of Additive Manufacturing (AM) processes, encompassed in the concept of Industry 4.0. Numerical simulations also have a role to play in the improvement of contemporary AM techniques, among which material extrusion is very popular. Computational Fluid Dynamics (CFD) models have recently proven successful for simulating the deposition flow in extrusion AM. Previous modeling works using CFD have been able to predict the influence of processing parameters on the cross-sectional shape of the printed strand, as well as the mesostructure formation resulting from their deposition and fusing. The present study focuses on using CFD simulations to quantify the waviness of a strand extruded on top of a previous layer with an orthogonal print direction, which often occurs when printing a part with a rectilinear infill pattern and alternate 0°/90° raster angles from layer to layer. The variations in the strand width and thickness of the second layer were found to depend on the strand-to-strand gap in the first layer. The CFD model was also used to determine the interlayer penetration depth, which enhances mechanical performances.