  In this paper we outline the development of a scalable PBF thermal history
simulation built on CAPL and based on melt pool physics and dynamics. The new
approach inherits linear scalability from CAPL and has three novel ingredients.
Firstly, to simulate the laser scanning on a solid surface, we discretize the
entire simulation domain instead of only the manufacturing toolpath by
appending fictitious paths to the manufacturing toolpath. Secondly, to simulate
the scanning on overlapping toolpaths, the path-scale simulations are
initialized by a Voronoi diagram for line segments discretized from the
manufacturing toolpath. Lastly, we propose a modified conduction model that
considers the high thermal gradient around the melt pool. We validate the
simulation against melt pool images captured with the co-axial melt pool
monitoring (MPM) system on the NIST Additive Manufacturing Metrology Testbed
(AMMT). Excellent agreements in the length and width of melt pools are found
between simulations and experiments conducted on a custom-controlled laser
powder bed fusion (LPBF) testbed on a nickel-alloy (IN625) solid surface. To
the authors' best knowledge, this paper is the first to validate a full
path-scale thermal history with experimentally acquired melt pool images.
Comparing the simulation results and the experimental data, we discuss the
influence of laser power on the melt pool length on the path-scale level. We
also identify the possible ways to further improve the accuracy of the CAPL
simulation without sacrificing efficiency.
