Prediction of melt pool depth and dilution in laser powder deposition

Abstract

This paper presents a mathematical model of laser powder deposition (LPD) to predict temperature field, melt pool depth and dilution. The model validated by experiments is developed using the moving heat source method. In this method, the temperature distribution inside the clad and the substrate is obtained using the superposition principle and the solution of the heat diffusion due to a point heat source. The model, which can be used in real-time applications, predicts the melt pool depth and dilution as a function of clad height and clad width, which in practice can be measured by a vision system. Numerical and experimental analyses show a non-linear behaviour of the melt pool depth as a function of process speed. This indicates that the melt pool depth has a maximum at a certain process speed. The comparisons between the numerical and experimental results show that this model is capable of predicting the characteristics of the LPD process accurately. Using the model, some general curves that show the behaviours of the melt pool depth and dilution as a function of clad height, scanning speed and laser power are illustrated.