Electron-beam additive manufacturing, or electron-beam melting (EBM) is a type of

additive manufacturing 3D printing, or additive manufacturing, is the construction of a three-dimensional object from a CAD model or a digital 3D model. It can be done in a variety of processes in which material is deposited, joined or solidified under computer ...

, or

3D printing 3D printing, or additive manufacturing, is the construction of a three-dimensional object from a CAD model or a digital 3D model. It can be done in a variety of processes in which material is deposited, joined or solidified under computer ...

, for metal parts. The raw material (metal powder or wire) is placed under a vacuum and fused together from heating by an electron beam. This technique is distinct from

selective laser sintering Selective laser sintering (SLS) is an additive manufacturing (AM) technique that uses a laser as the power and heat source to sinter powdered material (typically nylon or polyamide), aiming the laser automatically at points in space defined ...

as the raw material fuses have completely melted. Selective Electron Beam Melting (SEBM) emerged as a powder bed-based additive manufacturing (AM) technology and was brought to market in 1997 by Arcam AB Corporation headquartered in Sweden.

Metal powder-based systems

Metal powders can be consolidated into a solid mass using an electron beam as the heat source. Parts are manufactured by melting metal powder, layer by layer, with an electron beam in a high vacuum. This powder bed 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 process is known to operate at higher temperatures (up to 1000 °C), which can lead to differences in phase formation though

solidification Freezing is a phase transition in which a liquid turns into a solid when its temperature is lowered below its freezing point. For most substances, the melting and freezing points are the same temperature; however, certain substances possess dif ...

and solid-state phase transformation. The powder feedstock is typically pre-alloyed, as opposed to a mixture. That aspect allows classification of EBM with

selective laser melting Selective laser melting (SLM) is one of many proprietary names for a metal Additive Manufacturing, additive manufacturing (AM) technology that uses a bed of powder with a source of heat to create metal parts. Also known as direct metal laser sin ...

(SLM), where competing technologies like

SLS SLS may refer to the Space Launch System, a launch vehicle developed by NASA. It may also refer to: Education * Stanford Law School, California, U.S. * Sydney Law School, Australia * Symbiosis Law School, India * Same language subtitling, of ...

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. File:Arcam_S12.jpg, Arcam S12 File:Arcam_A2.jpg, Arcam A2 File:Arcam_Q10.jpg, Arcam Q10 File:Arcam_Powder_Recovery_System.jpg, System for recovering metal powders used in EBM additive manufacturing

Research developments

Recent work has been published by ORNL, demonstrating the use of EBM technology to control local

crystallographic Crystallography is the branch of science devoted to the study of molecular and crystalline structure and properties. The word ''crystallography'' is derived from the Ancient Greek word (; "clear ice, rock-crystal"), and (; "to write"). In J ...

grain orientations in

Inconel Inconel is a nickel-chromium-based superalloy often utilized in extreme environments where components are subjected to high temperature, pressure or Mechanical load, mechanical loads. Inconel alloys are oxidation- and corrosion-resistant. When he ...

. After testing in the transmission electron microscope by the state-of-the-art in-situ technique, the EBM Inconel alloy has been proved to exhibit similar mechanical property comparing to a wrought Inconel alloy. Numerous investigations have been conducted in recent times, exploring the microstructure and characteristics of various steel grades (including austenitic, martensitic, dual-phase, and ferritic) tailored for EBM process. Other notable developments have focused on the development of process parameters to produce parts out of alloys such as

copper Copper is a chemical element; it has symbol Cu (from Latin ) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkish-orang ...

niobium Niobium is a chemical element; it has chemical symbol, symbol Nb (formerly columbium, Cb) and atomic number 41. It is a light grey, crystalline, and Ductility, ductile transition metal. Pure niobium has a Mohs scale of mineral hardness, Mohs h ...

, Al 2024, bulk metallic glass,

stainless steel Stainless steel, also known as inox, corrosion-resistant steel (CRES), or rustless steel, is an iron-based alloy that contains chromium, making it resistant to rust and corrosion. Stainless steel's resistance to corrosion comes from its chromi ...

, and titanium aluminide. Currently commercial materials for EBM include commercially pure Titanium,

Ti-6Al-4V Ti-6Al-4V (UNS designation R56400), also sometimes called TC4, Ti64, or ASTM Grade 5, is an alpha-beta titanium alloy with a high specific strength and excellent Corrosion, corrosion resistance. It is one of the most commonly used titanium alloys a ...

, CoCr, Inconel 718, and

Inconel 625 Inconel Alloy 625 (UNS designation N06625) is a nickel-based superalloy that possesses high strength properties and resistance to elevated temperatures. It also demonstrates remarkable protection against corrosion and oxidation. Its ability to wi ...

Metal wire-based systems

Another approach is to use an electron beam to melt welding wire onto a surface to build up a part. This is similar to the common 3D printing process of

fused deposition modeling Fused filament fabrication (FFF), also known as fused deposition modeling (with the trademarked acronym FDM), or ''filament freeform fabrication'', is a 3D printing process that uses a continuous filament of a thermoplastic material. Filament is ...

, but with metal, rather than plastics. With this process, an electron-beam gun provides the energy source used for melting metallic feedstock, which is typically wire. The electron beam is a highly efficient power source that can be both precisely focused and deflected using electromagnetic coils at rates well into thousands of hertz. Typical electron-beam welding systems have high power availability, with 30- and 42-kilowatt systems being most common. A major advantage of using metallic components with electron beams is that the process is conducted within a high-vacuum environment of 1

torr The torr (symbol: Torr) is a Pressure#Units, unit of pressure based on an absolute scale, defined as exactly of a standard atmosphere (unit), atmosphere (101325 Pa). Thus one torr is exactly (≈ ). Historically, one torr was intended to be ...

or greater, providing a contamination-free work zone that does not require the use of additional inert gases commonly used with laser and arc-based processes. With EBDM, the feedstock material is fed into a molten pool created by the electron beam. Through the use of computer numeric controls (CNC), the molten pool is moved about on a substrate plate, adding material just where it is needed to produce the near net shape. This process is repeated in a layer-by-layer fashion until the desired 3D shape is produced. Depending on the part being manufactured, deposition rates can range up to per hour. With a light

alloy An alloy is a mixture of chemical elements of which in most cases at least one is a metal, metallic element, although it is also sometimes used for mixtures of elements; herein only metallic alloys are described. Metallic alloys often have prop ...

, such as

titanium Titanium is a chemical element; it has symbol Ti and atomic number 22. Found in nature only as an oxide, it can be reduced to produce a lustrous transition metal with a silver color, low density, and high strength, resistant to corrosion in ...

, this translates to a real-time deposition rate of per hour. A wide range of engineering alloys are compatible with the EBDM process and are readily available in the form of welding wire from an existing supply base. These include, but are not limited to, stainless steels,

cobalt Cobalt is a chemical element; it has Symbol (chemistry), symbol Co and atomic number 27. As with nickel, cobalt is found in the Earth's crust only in a chemically combined form, save for small deposits found in alloys of natural meteoric iron. ...

alloys,

nickel Nickel is a chemical element; it has symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel is a hard and ductile transition metal. Pure nickel is chemically reactive, but large pieces are slo ...

alloys,

nickel alloys,

tantalum Tantalum is a chemical element; it has Symbol (chemistry), symbol Ta and atomic number 73. It is named after Tantalus, a figure in Greek mythology. Tantalum is a very hard, ductility, ductile, lustre (mineralogy), lustrous, blue-gray transition ...

, titanium alloys, as well as many other high-value materials.

Market

Titanium Titanium is a chemical element; it has symbol Ti and atomic number 22. Found in nature only as an oxide, it can be reduced to produce a lustrous transition metal with a silver color, low density, and high strength, resistant to corrosion in ...

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 Corporate. 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 Rutherford rocket engine. The EBM process has been developed for manufacturing parts in gamma titanium aluminide and is currently being developed by Avio S.p.A. and

General Electric General Electric Company (GE) was an American Multinational corporation, multinational Conglomerate (company), conglomerate founded in 1892, incorporated in the New York (state), state of New York and headquartered in Boston. Over the year ...

Aviation for the production of turbine blades in γ-TiAl for gas-turbine engines. The first EBM machine in the United States is housed by the Department of Industrial and Systems Engineering at

North Carolina State University North Carolina State University (NC State, North Carolina State, NC State University, or NCSU) is a public university, public Land-grant university, land-grant research university in Raleigh, North Carolina, United States. Founded in 1887 and p ...

References

External links

Watch and Learn about electron beam meltingAutomotive DesignLineArcam process presentation (pdf)Direct Manufacturing: ARCAM, Video Describing EBM ProcessOpen Source Electron beam additive manufacturing
{{3d printing Electron beams in manufacturing 3D printing processes