The quality of parts built with powder bed fusion (PBF) additive manufacturing method crucially depends on solidified material properties and defects (such as porosity), which is determined by the details of the process at the mesoscale level. We have developed a high-throughput simulation package for additive manufacturing (KiSSAM) which accurately captures the diverse physical phenomena occuring during PBF at the mesoscale such as powder layer formation, energy absorption and melt pool dynamics and solidification. At the core of KiSSAM lies the lattice Boltzmann method (LBM) optimized for Graphical Processing Units GPU; a dynamic mesh for the melt pool; an adaptive mesh for the heat solver; a GPU-powered ray tracer and Monte-Carlo scattering solver for beam absorption, and a high-performance discrete element method (DEM) solver for powder bed deposition. High degree of algorithm optimization results in significant gains in simulation speed, allowing us to complete simulations in a few hours and even faster (less than half an hour for single tracks).
The high performance of KiSSAM enables multilayer simulations without compromising the accuracy of the description of the PBF process at the mesoscale level, helping gain insights into how evolution of single track morphology affects the morphology of a multilayer part. High-throughput parametric sweeps of single track simulations allowed formulating the criteria for the lack of fusion during Laser PBF with an increased layer thickness, which is expected to provide a scientific basis for the analysis of the maximum layer thickness via simulation to increase the performance of the technology.
Other applications of KiSSAM to intensive PBF process simulations, presented in this contribution, include simulation of overhangs and porous multilayer samples. Moreover, implementation of the mulitcomponent evaporation model allows modeling variation of the alloy composition during multilayer builds.