Electron-beam additive manufacturing

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Electron-beam additive manufacturing, or electron-beam melting (EBM) is a type of additive manufacturing, or 3D printing, 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 as the raw material fuses have completely melted. [1] 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 [2] .

Contents

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. [3] The process is known to operate at higher temperatures (up to 1000 °C), which can lead to differences in phase formation though solidification and solid-state phase transformation. [4]

The powder feedstock is typically pre-alloyed, as opposed to a mixture. 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.[ citation needed ]

Research developments

Recent work has been published by ORNL, demonstrating the use of EBM technology to control local crystallographic grain orientations in Inconel. [5] 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. [6] 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 [7] . Other notable developments have focused on the development of process parameters to produce parts out of alloys such as copper, [8] niobium, [9] Al 2024, [10] bulk metallic glass, [11] stainless steel, and titanium aluminide. Currently commercial materials for EBM include commercially pure Titanium, Ti-6Al-4V, [12] CoCr, Inconel 718, [13] and Inconel 625. [14]

Metal wire-based systems

Another approach is to use an electron beam to melt welding wire onto a surface to build up a part. [15] This is similar to the common 3D printing process of fused deposition modeling, 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 1×10−4 Torr 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. [16]

Depending on the part being manufactured, deposition rates can range up to 200 cubic inches (3,300 cm3) per hour. With a light alloy, such as titanium, this translates to a real-time deposition rate of 40 pounds (18 kg) 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 alloys, nickel alloys, copper nickel alloys, tantalum, titanium alloys, as well as many other high-value materials.[ citation needed ]

Market

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 Corporate.[ citation needed ]

The U.S. implant manufacturer Exactech has also received FDA clearance for an acetabular cup manufactured with the EBM technology. [ citation needed ]

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 Aviation for the production of turbine blades in γ-TiAl for gas-turbine engines. [17]

The first EBM machine in the United States is housed by the Department of Industrial and Systems Engineering at North Carolina State University. [18]

See also

Related Research Articles

<span class="mw-page-title-main">Metallurgy</span> Field of science that studies the physical and chemical behavior of metals

Metallurgy is a domain of materials science and engineering that studies the physical and chemical behavior of metallic elements, their inter-metallic compounds, and their mixtures, which are known as alloys.

<span class="mw-page-title-main">Powder metallurgy</span> Process of sintering metal powders

Powder metallurgy (PM) is a term covering a wide range of ways in which materials or components are made from metal powders. PM processes can reduce or eliminate the need for subtractive processes in manufacturing, lowering material losses and reducing the cost of the final product.

Since the mid-20th century, electron-beam technology has provided the basis for a variety of novel and specialized applications in semiconductor manufacturing, microelectromechanical systems, nanoelectromechanical systems, and microscopy.

<span class="mw-page-title-main">3D printing</span> Additive process used to make a three-dimensional object

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 control, with the material being added together, typically layer by layer.

<span class="mw-page-title-main">Inconel</span> Austenitic nickel-chromium superalloys

Inconel is a nickel-chromium-based superalloy often utilized in extreme environments where components are subjected to high temperature, pressure or mechanical loads. Inconel alloys are oxidation- and corrosion-resistant. When heated, Inconel forms a thick, stable, passivating oxide layer protecting the surface from further attack. Inconel retains strength over a wide temperature range, attractive for high-temperature applications where aluminium and steel would succumb to creep as a result of thermally-induced crystal vacancies. Inconel's high-temperature strength is developed by solid solution strengthening or precipitation hardening, depending on the alloy.

Titanium alloys are alloys that contain a mixture of titanium and other chemical elements. Such alloys have very high tensile strength and toughness. They are light in weight, have extraordinary corrosion resistance and the ability to withstand extreme temperatures. However, the high cost of both raw materials and processing limit their use to military applications, aircraft, spacecraft, bicycles, medical devices, jewelry, highly stressed components such as connecting rods on expensive sports cars and some premium sports equipment and consumer electronics.

<span class="mw-page-title-main">Microstructure</span> Very small scale structure of material

Microstructure is the very small scale structure of a material, defined as the structure of a prepared surface of material as revealed by an optical microscope above 25× magnification. The microstructure of a material can strongly influence physical properties such as strength, toughness, ductility, hardness, corrosion resistance, high/low temperature behaviour or wear resistance. These properties in turn govern the application of these materials in industrial practice.

Laser powder forming, also known by the proprietary name is an additive manufacturing technology developed for fabricating metal parts directly from a computer-aided design (CAD) solid model by using a metal powder injected into a molten pool created by a focused, high-powered laser beam. This technique is also equivalent to several trademarked techniques that have the monikers direct metal deposition (DMD), and laser consolidation (LC). Compared to processes that use powder beds, such as selective laser melting (SLM) objects created with this technology can be substantially larger, even up to several feet long.

<span class="mw-page-title-main">Cold spraying</span> Coating deposition method

Gas dynamic cold spraying or cold spraying (CS) is a coating deposition method. Solid powders are accelerated in a supersonic gas jet to velocities up to ca. 1200 m/s. During impact with the substrate, particles undergo plastic deformation and adhere to the surface. To achieve a uniform thickness the spraying nozzle is scanned along the substrate. Metals, polymers, ceramics, composite materials and nanocrystalline powders can be deposited using cold spraying. The kinetic energy of the particles, supplied by the expansion of the gas, is converted to plastic deformation energy during bonding. Unlike thermal spraying techniques, e.g., plasma spraying, arc spraying, flame spraying, or high velocity oxygen fuel (HVOF), the powders are not melted during the spraying process.

Arcam AB manufactures electron beam melting (EBM) systems for use in additive manufacturing, which create solid parts from metal powders. Arcam also produces metal powder through AP&C and medical implants through DiSanto Technologies.

Electron-beam freeform fabrication (EBF3) is an additive manufacturing process that builds near-net-shape parts. It requires far less raw material and finish machining than traditional manufacturing methods. EBF3 is done in a vacuum chamber where an electron beam is focused on a constantly feeding source of metal, which is melted and applied as called for by a three-dimensional layered drawing - one layer at a time - on top of a rotating metallic substrate until the part is complete.

<span class="mw-page-title-main">Ultrasonic consolidation</span>

Ultrasonic Consolidation (UC) or Ultrasonic Additive Manufacturing (UAM) is a low temperature additive manufacturing or 3D printing technique for metals.

<span class="mw-page-title-main">Selective laser melting</span> 3D printing technique

Selective laser melting (SLM) is one of many proprietary names for a metal 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 sintering (DMLS), the ASTM standard term is powder bed fusion (PBF). PBF is a rapid prototyping, 3D printing, or additive manufacturing technique designed to use a high power-density laser to melt and fuse metallic powders together.

<span class="mw-page-title-main">Powder bed and inkjet head 3D printing</span> 3D printing technique

Binder jet 3D printing, known variously as "Powder bed and inkjet" and "drop-on-powder" printing, is a rapid prototyping and additive manufacturing technology for making objects described by digital data such as a CAD file. Binder jetting is one of the seven categories of additive manufacturing processes according to ASTM and ISO.

Sciaky, Inc. is an American manufacturer of metal 3d printing systems and industrial welding systems, founded in 1939 and headquartered in Chicago, Illinois. It specializes in electron beam welding systems and services for aerospace manufacturers.

<span class="mw-page-title-main">3D printing processes</span> List of 3D printing processes

A variety of processes, equipment, and materials are used in the production of a three-dimensional object via additive manufacturing. 3D printing is also known as additive manufacturing, because the numerous available 3D printing process tend to be additive in nature, with a few key differences in the technologies and the materials used in this process.

Cold spray additive manufacturing (CSAM) is a particular application of cold spraying, able to fabricate freestanding parts or to build features on existing components. During the process, fine powder particles are accelerated in a high-velocity compressed gas stream, and upon the impact on a substrate or backing plate, deform and bond together creating a layer. Moving the nozzle over a substrate repeatedly, a deposit is building up layer-by-layer, to form a part or component. If an industrial robot or computer controlled manipulator controls the spray gun movements, complex shapes can be created. To achieve a 3D shape, there are two different approaches. First, to fix the substrate and move the cold spray gun/nozzle using a robotic arm; the second one is to move the substrate with a robotic arm, and keep the spray-gun nozzle fixed. There is also a possibility to combine these two approaches either using two robotic arms or other manipulators. The process always requires a substrate and uses only powder as raw material.

Research on the health and safety hazards of 3D printing is new and in development due to the recent proliferation of 3D printing devices. In 2017, the European Agency for Safety and Health at Work has published a discussion paper on the processes and materials involved in 3D printing, potential implications of this technology for occupational safety and health and avenues for controlling potential hazards.

AlSi10Mg is a lightweight, high-strength aluminium alloy that is widely used in the aerospace, automotive, and medical industries. Its unique combination of aluminium, silicon, and magnesium makes it an ideal material for additive manufacturing processes, such as 3D printing.

Laser metal deposition (LMD) is an additive manufacturing process in which a feedstock material is melted with a laser and then deposited onto a substrate. A variety of pure metals and alloys can be used as the feedstock, as well as composite materials such as metal matrix composites. Laser sources with a wide variety of intensities, wavelengths, and optical configurations can be used. While LMD is typically a melt-based process, this is not a requirement, as discussed below. Melt-based processes typically have a strength advantage, due to achieving a full metallurgical fusion.

References

  1. ↑ "ASTM F2792 - 12a Standard Terminology for Additive Manufacturing Technologies, (Withdrawn 2015)". Astm.org. Retrieved 2017-04-26.
  2. ↑ Körner, C. (2016-07-03). "Additive manufacturing of metallic components by selective electron beam melting — a review". International Materials Reviews. 61 (5): 361–377. doi:10.1080/09506608.2016.1176289. ISSN   0950-6608.
  3. ↑ "Electron Beam Melting". Thre3d.com. Archived from the original on 3 February 2014. Retrieved 28 January 2014.
  4. ↑ Sames; et al. (2014). "Thermal effects on microstructural heterogeneity of Inconel 718 materials fabricated by electron beam melting". Journal of Materials Research. 29 (17): 1920–1930. Bibcode:2014JMatR..29.1920S. doi:10.1557/jmr.2014.140. S2CID   136814896.
  5. ↑ "ORNL research reveals unique capabilities of 3-D printing | ornl.gov". Archived from the original on 2014-10-30. Retrieved 2014-10-29.
  6. ↑ Guo, Qianying; Kirka, Michael; Lin, Lianshan; Shin, Dongwon; Peng, Jian; Unocic, Kinga A. (September 2020). "In situ transmission electron microscopy deformation and mechanical responses of additively manufactured Ni-based superalloy". Scripta Materialia. 186: 57–62. doi:10.1016/j.scriptamat.2020.04.012. S2CID   219488998.
  7. ↑ Li, Ye; Wang, Yan; Niu, Jingzhe; Liu, Shifeng; Lin, Yan; Liu, Nan; Ma, Jun; Zhang, Zhaohui; Wang, Jian (2023-01-18). "Microstructure and mechanical properties of M2 high speed steel produced by electron beam melting". Materials Science and Engineering: A. 862: 144327. doi:10.1016/j.msea.2022.144327. ISSN   0921-5093.
  8. ↑ "Fabricating Copper Components with Electron Beam Melting". Asminterinternational.org. Archived from the original (PDF) on 2017-01-14. Retrieved 2017-04-26.
  9. ↑ Martinez; et al. (2013). "Microstructures of Niobium Components Fabricated by Electron Beam Melting". Metallography, Microstructure, and Analysis. 2 (3): 183–189. doi: 10.1007/s13632-013-0073-9 .
  10. ↑ Mahale, Tushar Ramkrishna (2009). "Electron beam melting of advanced materials and structures". Bibcode:2009PhDT.......262M.{{cite journal}}: Cite journal requires |journal= (help)
  11. ↑ "Unique breakthrough in bulk metallic glass manufacturing". Archived from the original on 2014-10-29. Retrieved 2014-10-29.
  12. ↑ "EBM-Built Materials - Arcam AB". Arcam.com. 2013-01-24. Archived from the original on 2017-05-15. Retrieved 2017-04-26.
  13. ↑ "8th International Symposium on Superalloy 718 and Derivatives: Novel Processing Methods". Programmaster.org. Retrieved 2017-04-26.
  14. ↑ "Journal of Materials Research and Technology". Archived from the original on 2014-10-29. Retrieved 2014-10-29.
  15. ↑ "Video: Electron Beam Direct Manufacturing : Modern Machine Shop". Mmsonline.com. Archived from the original on 9 June 2013. Retrieved 10 October 2013.
  16. ↑ "What is Directed Energy Deposition (DED) 3D Printing?". Sciaky.com. Sciaky, Inc. Retrieved 16 May 2021.
  17. ↑ "GE Uses Breakthrough New Electron Gun for 3D Printing – 10X's More Powerful Than Laser Sintering". 2014-08-18. Archived from the original on 2014-12-05. Retrieved 2014-10-29.
  18. ↑ "Advanced Manufacturing | Industrial Engineering".

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