Three-dimensional CFD simulation of the sintering process focusing on Metal Binder Jetting (MBJ)

Purpose and goal: The project is performed as SME-support within the frame of CAM2 Competence center.

MBJ is the fastest and cheaper 3D printing technology but depends on sintering. The project aim was to provide advanced 3D CFD simulation with an innovative software Simtec to better understand the sintering process and allow control process parameters to achieve desirable properties later. 3D CFD simulations of an MB specimen under sintering operational conditions were performed.

This method allows a well 3D simulation of all important processes including gas flow, thermal radiation, convection, and conjugate heat transfer in solids and liquids during the sintering processes. Expected results and effects:

Unique and world-leading comprehensive full-scale CFD simulations of MBJ specimen sintering were successfully conducted. The simulated sintering process was an about 15 hours full cycle with all the heating, holding and cooling stages. An extra simulation with a different orientation was also performed, to study the effect of gravity and thus buoyant flow.

Detailed transient thermal data regarding temperature and heat flux distributions, etc., were obtained as expected, which will be used to optimize the sintering process and thus enhance the postprocessing of MBJ. Approach and implementation:

CFD simulations were made using Simtec based on numerical solutions of partial differential governing equations for mass, momentum and energy conservation. All important processes of fluid flow, thermal radiation, convection, and conjugate heat transfer in solid and fluid were coupled-computed. The complex geometry was directly imported from CAD.

The computations were made with 14683660 finite volume cells and 4138272 wall surface cells to provide necessary and sufficient numerical resolution. Parallel computing was employed using 6 processors to speed up the computation.