Electron-beam additive manufacturing

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.{{cite web|title=Electron Beam Melting |url=https://thre3d.com/how-it-works/powder-bed-fusion/electron-beam-melting-ebm |publisher=Thre3d.com |access-date=28 January 2014 |url-status=dead |archive-url=https://web.archive.org/web/20140203071900/https://thre3d.com/how-it-works/powder-bed-fusion/electron-beam-melting-ebm |archive-date=3 February 2014 }} 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.{{cite journal | last1 = Sames | display-authors = etal | year = 2014| title = Thermal effects on microstructural heterogeneity of Inconel 718 materials fabricated by electron beam melting | doi = 10.1557/jmr.2014.140 | journal = Journal of Materials Research| volume = 29| issue = 17| pages = 1920–1930| bibcode =2014JMatR..29.1920S| s2cid = 136814896 }}

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|date=October 2013}}

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

Recent work has been published by ORNL, demonstrating the use of EBM technology to control local crystallographic grain orientations in Inconel.{{cite web |url=http://www.ornl.gov/ornl/news/news-releases/2014/ornl-research-reveals-unique-capabilities-of-3-d-printing- |title=ORNL research reveals unique capabilities of 3-D printing | ornl.gov |access-date=2014-10-29 |url-status=dead |archive-url=https://web.archive.org/web/20141030041528/http://www.ornl.gov/ornl/news/news-releases/2014/ornl-research-reveals-unique-capabilities-of-3-d-printing- |archive-date=2014-10-30 }} 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. {{cite journal |last1=Guo |first1=Qianying |last2=Kirka |first2=Michael |last3=Lin |first3=Lianshan |last4=Shin |first4=Dongwon |last5=Peng |first5=Jian |last6=Unocic |first6=Kinga A. |title=In situ transmission electron microscopy deformation and mechanical responses of additively manufactured Ni-based superalloy |journal=Scripta Materialia |date=September 2020 |volume=186 |pages=57–62 |doi=10.1016/j.scriptamat.2020.04.012|s2cid=219488998 }} 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.{{Cite journal |last=Li |first=Ye |last2=Wang |first2=Yan |last3=Niu |first3=Jingzhe |last4=Liu |first4=Shifeng |last5=Lin |first5=Yan |last6=Liu |first6=Nan |last7=Ma |first7=Jun |last8=Zhang |first8=Zhaohui |last9=Wang |first9=Jian |date=2023-01-18 |title=Microstructure and mechanical properties of M2 high speed steel produced by electron beam melting |url=https://www.sciencedirect.com/science/article/pii/S0921509322017075 |journal=Materials Science and Engineering: A |volume=862 |pages=144327 |doi=10.1016/j.msea.2022.144327 |issn=0921-5093|url-access=subscription }} Other notable developments have focused on the development of process parameters to produce parts out of alloys such as copper,{{cite web |url=http://www.asminternational.org/documents/10192/19735983/amp17207p20.pdf/2a87d5ae-86ec-4f27-bdd1-f74af1a2f523 |format=PDF |title=Fabricating Copper Components with Electron Beam Melting |website=Asminterinternational.org |access-date=2017-04-26 |archive-date=2017-01-14 |archive-url=https://web.archive.org/web/20170114081732/http://www.asminternational.org/documents/10192/19735983/amp17207p20.pdf/2a87d5ae-86ec-4f27-bdd1-f74af1a2f523 |url-status=dead }} niobium,{{cite journal | last1 = Martinez | display-authors = etal | year = 2013| title = Microstructures of Niobium Components Fabricated by Electron Beam Melting | journal = Metallography, Microstructure, and Analysis| volume = 2| issue = 3| pages = 183–189| doi=10.1007/s13632-013-0073-9| doi-access = free}} Al 2024,{{cite journal|bibcode=2009PhDT.......262M |title=Electron beam melting of advanced materials and structures |url=http://Adsabs.harvard.edu |last1=Mahale |first1=Tushar Ramkrishna |year=2009 }} bulk metallic glass,{{cite web |url=https://www.sciencedaily.com/releases/2012/11/121119114157.htm |title=Unique breakthrough in bulk metallic glass manufacturing |access-date=2014-10-29 |url-status=dead |archive-url=https://web.archive.org/web/20141029213540/https://www.sciencedaily.com/releases/2012/11/121119114157.htm |archive-date=2014-10-29 }} stainless steel, and titanium aluminide. Currently commercial materials for EBM include commercially pure Titanium, Ti-6Al-4V,{{cite web |url=http://www.arcam.com/technology/electron-beam-melting/materials/ |title=EBM-Built Materials - Arcam AB |website=Arcam.com |date=2013-01-24 |access-date=2017-04-26 |archive-date=2017-05-15 |archive-url=https://web.archive.org/web/20170515194827/http://www.arcam.com/technology/electron-beam-melting/materials/ |url-status=dead }} CoCr, Inconel 718,{{cite web|url=http://www.programmaster.org/PM/PM.nsf/ViewSessionSheets?OpenAgent&ParentUNID=733A03EC3B3DE9B485257C5A00064CE6 |title=8th International Symposium on Superalloy 718 and Derivatives: Novel Processing Methods |website=Programmaster.org |access-date=2017-04-26}} and Inconel 625.{{cite web |url=http://www.jmrt.com.br/en/fabrication-of-metal-and-alloy/articulo/90195169/ |title=Journal of Materials Research and Technology |access-date=2014-10-29 |url-status=dead |archive-url=https://web.archive.org/web/20141029220530/http://www.jmrt.com.br/en/fabrication-of-metal-and-alloy/articulo/90195169/ |archive-date=2014-10-29 }}

Another approach is to use an electron beam to melt welding wire onto a surface to build up a part.{{cite web |url=http://www.mmsonline.com/videos/video-electron-beam-direct-manufacturing |title=Video: Electron Beam Direct Manufacturing : Modern Machine Shop |publisher=Mmsonline.com |access-date=10 October 2013 |archive-date=9 June 2013 |archive-url=https://web.archive.org/web/20130609234015/http://www.mmsonline.com/videos/video-electron-beam-direct-manufacturing |url-status=dead }} 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{{e|-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.{{cite web |title=What is Directed Energy Deposition (DED) 3D Printing? |url=https://www.sciaky.com/additive-manufacturing/what-is-ded-3d-printing |website=Sciaky.com |publisher=Sciaky, Inc. |access-date=16 May 2021}}

Depending on the part being manufactured, deposition rates can range up to {{convert|200|in3}} per hour. With a light alloy, such as titanium, this translates to a real-time deposition rate of {{convert|40|lb}} 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|date=October 2015}}

{{See|Electron-beam freeform fabrication}}

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|date=October 2014}}

The U.S. implant manufacturer Exactech has also received FDA clearance for an acetabular cup manufactured with the EBM technology. {{Citation needed|date=October 2014}}

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.{{cite web |url=http://3dprint.com/12262/ge-ebm-3d-printing/ |title=GE Uses Breakthrough New Electron Gun for 3D Printing – 10X's More Powerful Than Laser Sintering |access-date=2014-10-29 |url-status=dead |archive-url=https://web.archive.org/web/20141205063000/http://3dprint.com/12262/ge-ebm-3d-printing/ |archive-date=2014-12-05 |date=2014-08-18 }}

The first EBM machine in the United States is housed by the Department of Industrial and Systems Engineering at North Carolina State University. {{Cite web | url=https://www.ise.ncsu.edu/research/advanced-manufacturing/ | title=Advanced Manufacturing | Industrial Engineering}}

• 3D printing
• Electron-beam technology
• Electron-beam welding

{{Reflist|30em}}

• Manufacturing Engineering and Technology Fifth Edition. Serope Kalpakjian.

• [http://gyges3d.com/videos/58/Electron-Beam-MeltingEBM/most_recent/all_time/ Watch and Learn about electron beam melting]
• [https://web.archive.org/web/20080124120258/http://www.engineershandbook.com/RapidPrototyping/ebm.htm Engineer's Handbook]
• [https://archive.today/20130117100939/http://www.automotivedesignline.com/howto/chassisandsuspension/198702147 Automotive DesignLine]
• [https://web.archive.org/web/20111003181418/http://www.rm-platform.com/index2.php?option=com_docman&task=doc_view&gid=651&Itemid=1 Arcam process presentation (pdf)]
• [https://www.youtube.com/watch?v=M_qSnjKN7f8 Direct Manufacturing: ARCAM, Video Describing EBM Process]
• [https://hackaday.io/project/183736-3d-metal-printer Open Source Electron beam additive manufacturing]

{{3d printing}}

Category:Electron beams in manufacturing

Category:3D printing processes