Modelling energy source and powder properties for the development of a thermal FE model of the EBM additive manufacturing process

The combination of additive manufacturing principles and electron beam (EB) technology allows complex metal parts, featuring excellent quality material, to be produced, whenever traditional methods are expensive or difficult to apply. Today, the optimization of process parameters, for a given metal powder, is generally attained through an empirical trial and error approach. Process simulation can be used as a tool for decision-making and process optimization, since a virtual analysis can help to facilitate the possibility of exploring "what if' scenarios. In this work, a new type of modelling has been introduced for energy source and powder material properties and it has been included in a thermal numerical model in order to improve the effectiveness and reliability of Electon Beam Melting (EBM) FE simulation. Several specific subroutines have been developed to automatically calculate the powder properties as temperature functions, and to consider the position of the beam during scanning as well as the material state changes from powder to liquid in the melting phase and from liquid to solid during cooling. A comparison of the numerical results and experimental data taken from literature has shown a good forecasting capability. The average deviations of the simulation from an experimental scan line width have been found to be below about 15%. (C) 2017 Elsevier B.V. All rights reserved.