Electron beam additive manufacturing (EBAM) is a high-speed metal 3D printing process that uses an electron beam to melt metal powder feedstock or metal wire in a high vacuum, building metal parts layer-by-layer.
Methods include electron-beam melting (EBM) (also known as selective electron beam melting (SEBM), which typically refers to powder bed-based fusion of smaller, intricate parts, while EBAM often refers to larger-scale, wire-fed systems. All of these processes are different from selective laser sintering (SLS), as the raw material is completely melted during fusion.
Because EBAM processes are conducted under vacuum they can be used with reactive materials with a high affinity for oxygen, such as titanium.
Electron beam additive manufacturing systems differ slightly according to whether they are powder-based or wire-based:
Metal Powder-based Systems
Metal powder systems use an electron beam to melt the powders in accordance with data from a CAD model to build up a part layer by layer. The high energy density and scanning methods used by these systems lead to high deposition rates, while the vacuum helps maintain the mechanical property of the materials without contamination.
Metal Wire-based Systems
This method uses a high power electron beam in a high vacuum environment to create near net shape parts from metal wire that is fed into a molten pool created by the electron beam gun, in a similar manner to similar laser and arc-based processes. The vacuum keeps the part free from contaminants as the molten pool is moved around on a substrate plate in accordance to computer numeric controls (CNC) and the wire material is fed into the pool as required. Repeating the process allows parts to be built layer by layer.
Advantages and Applications
The advantages of electron beam additive manufacturing include the ability to produce fully dense, high strength parts with excellent mechanical properties at high rates of deposition. Because the process occurs at high temperatures, the parts produced have low levels of residual stress and require fewer supports. Because the process uses an electron beam it creates high temperatures that result in improved material compatibility for crack-prone alloys compared to selective laser melting, although it also results in a rougher surface finish.
Applications include critical, large-scale and complex parts for industries including aerospace, automotive, defence, medical and space, such as turbine blades or implants.