Electron beam melting
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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 by layer with an electron beam in a high vacuum. Unlike some metal sintering techniques, the parts are fully dense, void-free, and extremely strong.
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. Compared 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.
Titanium alloys are widely used with this technology which makes it a suitable choice for the medical implant market.
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.
See also 
- “A Year Filled With Promising R&D”. Wohlers Associates, Inc. November/December 2002
Further reading 
- Manufacturing Engineering and Technology Fifth Edition. Serope Kalpakjian.