A relativistic approach towards macro-scale modelling: implementation on laser re-melting and powder bed fusion (PBF-LB/M) AM processes

Simulation of laser-based processes is a computational intensive task; its efficiency strongly depends on the determination of the process phenomena and mechanisms that are of key importance. A major challenge in the macro-scale simulation of these processes is the large separation between the workpiece and laser beam dimensions resulting in a need for enormous lattices. In this work, this problem is bypassed via the introduction of an inhomogeneous lattice that is attached to the laser head, which combined with the enthalpy method enables a finite differences fast-running algorithm. Since the lattice moves relatively to the workpiece, the method requires appropriate adaptation of the physical governing equations. To validate the capabilities of this model, the laser re-melting and powder bed fusion (PBF-LB/M) processes are simulated and the results are compared with an experimentally verified modelling approach, indicating the adaptability of the workflow irrespective of the type of feedstock. Additionally, this approach facilitates the beam shaping investigation leveraging the stationary head relatively to the grid.