Figure 3: Additive manufacturing using pre-alloyed powder in electron beam melting system. (a) Pre-alloyed Ti-6Al-4V powder observed in the scanning electron microscope (SEM). (b) Energy-dispersive X-ray spectrum for powder in (a). (c) Electron beam melting (EBM) system: Arcam A2. Components highlighted include the electron gun (1), beam forming lenses and scan coils (2), powder cassettes (3), powder bed/layer rake system (4), building component (5). The system maintain a vacuum of ~10-5Torr, often with a helium gas bleed in the build area to facilitate component cooling.