Abstract
As the absorption energy distribution is mainly determined by the heat source modelling, a heat source model capable of estimating precisely the distribution of absorbed laser energy is essential for the accuracy and reliability of computational simulations. In most existing mesoscale selective laser melting (SLM) modelling with ray tracing technology, laser energy has been treated as a surface heat source and laser energy absorption only occurs at reflection points in surface elements, leading to unphysical absorption energy distribution and localized temperature overestimation with extremely high peak. Here we propose a new heat source model incorporating both laser penetration and ray tracing, and accurately estimate the absorption energy distribution by calculating the laser energy attenuation during laser propagation in metal. The modified ray tracing scheme constructed here is capable of tracing ray propagation through different media and across interfaces. Computational simulations on SLM with different powder bed densities are carried out. Compared to the conventional surface heat source model in SLM simulations, our new heat source model reduces the high peak temperature of elements with low liquid volume fraction, guarantees the simulation success and eliminates the overestimation of the evaporation heat loss. Melt pool volume and depth as well as the recoil pressure is also characterized. A comparison between simulations and experimental results indicate that the proposed new heat source model is also capable of simulating the surface temperature of metal substrates upon heating pulse. In addition, keyhole morphologies from experimental observation and numerical simulations based on the proposed model are in good agreement.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call