Experimental validation of a numerical thermal model of the EBM process for Ti6Al4V

Abstract

Electron Beam Melting (EBM) is an additive manufacturing (AM) process that uses an electron beam to melt metallic powders. Although the use of an electron beam in the AM field is relatively recent, several applications are already available in the aerospace and medical fields. To increase the applicability of the EBM process and to make it more reliable, different modelling techniques will be helpful tools. Modelling may have the potential to reduce the optimization time when compared with experimental trial and error approaches. In fact, by means of numerical modelling, process stability could be reached by exploring virtually what-if scenarios. However, experimental validation is necessary to ensure the accuracy of the modelling. The aim of this paper is to provide a validation of the effectiveness and reliability of a Finite Element (FE) thermal model by comparing numerical results and experimental measurements.Two different scanning strategies were studied: MultiBeam and continuous line melting. In MultiBeam melting, separated short melt lines (MultiBeam lines) are activated at different points along the predefined melt track. The electron beam jumps sequentially between the short lines until a complete melt track is finished. Continuous line melting means that the complete predefined melt track is melted from the start point to the stop point in one single sequence. The following parameters were investigated: beam speed, beam size and length of MultiBeam lines. A novel experimental setup was used in which single line tracks were melted in an Arcam Q10 system. Standard Arcam Ti6Al4V powder was used and the layer thickness was set to 0.05 mm. Microscope images were used to acquire the width of the melt pool at different positions along the melt tracks. The experiments were replicated by numerical simulations and a good agreement between simulations and experimental data was found.