Electron beam melting (EBM) is a type of additive manufacturing for metal parts. It is often classified as a rapid manufacturing method. The technology manufactures parts by melting metal powder layer per layer with an electron beam in a high vacuum. Unlike some metal sintering techniques, the parts are fully dense, void-free, and extremely strong.
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This solid freeform fabrication method produces fully dense metal parts directly from metal powder with characteristics of the target material. The EBM machine reads data from a 3D CAD model and lays down successive layers of powdered material. These layers are melted together utilizing a computer controlled electron beam. In this way it builds up the parts. The process takes place under vacuum, which makes it suited to manufacture parts in reactive materials with a high affinity for oxygen, e.g. titanium.
The melted material is from a pure alloy in powder form of the final material to be fabricated (no filler). For that reason the electron beam technology doesn't require additional thermal treatment to obtain the full mechanical properties of the parts. That aspect allows classification of EBM with selective laser melting (SLM) where competing technologies like SLS and DMLS require thermal treatment after fabrication. Comparatively to SLM and DMLS, EBM has a generally superior build rate because of its higher energy density and scanning method.
The EBM process operates at an elevated temperature, typically between 700 and 1.000 °C, producing parts that are virtually free from residual stress, and eliminating the need for heat treatment after the build.
Melt rate: up to 80 cm3/h. Minimum layer thickness: 0.05 millimetres (0.0020 in). Tolerance capability: +/- 0.2 mm.
This technology was developed by Arcam AB in Sweden.[1]
Titanium alloys are widely used with this technology which makes it a suitable choice for the medical implant market.
CE-certified acetabular cups are in series production with EBM since 2007 by two European orthopedic implant manufacturers, Adler Ortho and Lima-Lto. The acetabular cups are manufactured with integrated, engineered trabecular structures for enhanced osseointegration, and more than 20.000 cups have been implanted to date.
The U.S. implant manufacturer Exactech has also received FDA clearance for an acetabular cup manufactured with the EBM technology.
Aerospace and other highly demanding mechanical applications are also targeted.
The EBM process was recently developed for manufacturing parts in gamma titanium aluminide, and is currently used by Avio S.p.A. for the production of turbine blades in γ-TiAl for aero engines.