ORIGINAL ARTICLE Electron beam melting of gamma titanium aluminide and investigating the effect of EBM layer orientation on milling performance Saqib Anwar 1 & Naveed Ahmed 1,2,3 & Basem M. Abdo 1 & Salman Pervaiz 4 & M. A. K. Chowdhury 1 & Abdulrahman M. Alahmari 1,2 Received: 13 September 2017 /Accepted: 13 February 2018 # Springer-Verlag London Ltd., part of Springer Nature 2018 Abstract Electron beam melting (EBM) is one of the growing processes of additive manufacturing technology (AMT) to fabricate 3D parts from various difficult-to-process materials such as titanium alloys. A major limitation of the EBM process is the poor surface finish of the produced parts which ultimately demands a subsequent subtractive method (secondary finishing operation) to improve the surface finish for shaping the part to be fit for-end use applications where high surface finish is commonly required. With respect to the EBM layer build direction, the fabricated part has different orientations with varying surface characteristics. Therefore, in order to perform secondary finishing operation (e.g., milling) there are different choices of EBM part orientation to select the direction of tool feed. In this research, 3D parts of titanium alloy (gamma titanium aluminide; γ-TiAl) are additively manufactured through EBM process. The effect of EBM layer/part orientation on the milling performance is further investigated in terms of surface finish improvement and edge chipping evaluation. It has been observed that the EBM layer/part orientation with respect to milling tool feed direction (TFD) plays a vital role in milling performance. Thus, a care must be taken to select the appropriate tool feed direction and layer/part orientation in order to achieve maximum surface finish with minimum edge chipping. The results revealed the vertical milling can be adopted as a secondary finishing operation to be performed on EBM produced parts of γ-TiAl and it allows to significantly improve the poor surface finish generated by EBM (R a 31 μm). Furthermore, among the available part orientation choices, the part orientation in which the milling tool is fed across the EBM layer build direction is the best orientation resulting into high surface finish (R a 0.12 μm) with relatively smooth edges (minimum chipping-off). Keywords Electron beam melting (EBM) . γ-TiAl, layer orientation . Vertical milling . Tool feed direction . Surface roughness . Edge chipping 1 Introduction Gamma titanium aluminides (γ-TiAl) intermetallic alloys have numerous benefits such as oxidation resistance, stability at elevated temperatures, high specific strength, and rigidity etc. These attributes of γ-TiAl alloys have a strong dependen- cy on its microstructure and the processing history [1]. Based on the processing and chemical composition, titanium * Saqib Anwar sanwar@ksu.edu.sa Naveed Ahmed anaveed@ksu.edu.sa Basem M. Abdo babdo@ksu.edu.sa Salman Pervaiz sxpcad@rit.edu M. A. K. Chowdhury mchowdhury@ksu.edu.sa Abdulrahman M. Alahmari alahmari@ksu.edu.sa 1 Industrial Engineering Department, College of Engineering, King Saud University, Riyadh, Saudi Arabia 2 Princess Fatima Alnijiris’ s Research Chair for Advanced Manufacturing Technology (FARCAMT Chair), Advanced Manufacturing Institute, King Saud University, Riyadh, Saudi Arabia 3 Department of Industrial and Manufacturing Engineering, University of Engineering and Technology, Lahore, Pakistan 4 Department of Mechanical and Industrial Engineering, Rochester Institute of Technology, Rochester, NY 14623, USA The International Journal of Advanced Manufacturing Technology https://doi.org/10.1007/s00170-018-1802-7