Modelling bead deposition in material extrusion using the smoothed particle hydrodynamics framework PySPH

Parts manufactured using the additive Material Extrusion (MEX) process comprise a small-scale mesostructure of beads and voids. In this work, a numerical model is created with the goal of predicting the formation of this mesostructure. Therefore, the Smoothed Particle Hydrodynamics (SPH) framework PYSPH is extended with a thermal model and used to simulate the extrusion of multiple beads. The SPH method is well suited to model the complex evolution of free surfaces. While the implemented conductive heat transport model agrees well with a thermal Finite Element model, the heat losses at the surface due to radiation and convection are significantly overestimated. An extrusion of multiple layers of beads shows that the inability of the used SPH-scheme to capture the fluid’s incompressibility and high viscosity prevents it from accurately predicting the formation of the mesostructure.