An analytical model for rapid predicting molten pool geometry of selective laser melting (SLM)

Eliminating defects related to molten pool geometry such as lack of fusion and keyhole effects, is an urgent issue in selective laser melting (SLM). A practical and effective method for predicting molten pool geometry becomes necessary to optimize process conditions and upgrade printing quality. In this study, a novel analytical model predicting molten pool geometry of SLM is proposed. The key of the model is to establish a heat balance within the front part of the molten pool based on a few assumptions supported by previous experimental and simulation discoveries. Compared with previous analytical models, the new model considers the specific molten pool configuration under the mutual action of recoil pressure and flow of melted metal. Experiments and numerical simulations of single-track SLM are carried out to validate analytical calculations. The results show good consistency when the input energy density is in the medium range. Correlations between the analytical predicted molten pool geometry and the defect thresholds of the inadequate fusion and the keyhole transition are investigated. The potential of the analytical model to rapidly predict molten pool cross-section geometry and determining the process window is demonstrated as well. (c) 2020 Elsevier Inc. All rights reserved.

Automated summary

The study introduces a new analytical model to predict the molten pool geometry in SLM, focusing on establishing heat balance assumptions and considering the interaction between recoil pressure and melted metal flow. Experimental validations show good accuracy of the model at medium energy density, exploring correlations between predicted geometry and defect thresholds.