A semi-analytical approach for analysis of thermal behaviors coupling heat loss in powder b e d fusion

The build-up of the heat losses induced by a high-temperature gradient during laser additive manufactur-ing process has a significant effect on the thermal behaviors and the formation of parts' defect. In this pa-per, considering heat losses caused by conduction, convection and radiation, a semi-analytical model for predicting three-dimensional transient temperature field distributions is established, which is verified by comparison with results from the literature. The temperature distributions coupled with heat losses for typical surface and volumetric heat source models are obtained by using the separation of variables. The effect of process parameters and heat source model on peak temperature, temperature gradient, molten pool dimensions and heat losses is analyzed. In addition, the effect of the surface and volumetric heat source model on formation quality during the powder bed fusion (PBF) process is discussed in detail. The results show that higher average temperature and lower heat losses occur for the volumetric heat source model. Moreover, heat losses increase as the power, energy absorptivity and effective radius of the laser beam, while decrease with a decrease of scan speed. The results could be helpful to enable process optimization of the PBF to improve as-built parts quality. (c) 2022 Published by Elsevier Ltd.

Automated summary

In this paper, a semi-analytical model is established to predict the three-dimensional transient temperature field distributions during laser additive manufacturing process. The model considers heat losses caused by conduction, convection, and radiation. The effect of process parameters and heat source model on peak temperature, temperature gradient, molten pool dimensions, and heat losses is analyzed. It is found that the volumetric heat source model results in higher average temperature and lower heat losses, and heat losses increase with increasing laser power, energy absorptivity, and effective radius of the laser beam.