Electron-beam freeform fabrication (EBF
3) is an
additive manufacturing process that builds
near-net-shape
Near-net-shape is an industrial manufacturing technique. As the name implies, the initial production of the item is very close to the final, or ''net'', shape. This reduces the need for surface finishing. By minimizing the use of finishing methods ...
parts. It requires far less
raw material
A raw material, also known as a feedstock, unprocessed material, or primary commodity, is a basic material that is used to produce goods, finished goods, energy, or intermediate materials that are feedstock for future finished products. As feedst ...
and finish machining than traditional manufacturing methods. EBF
3 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
Substrate may refer to:
Physical layers
*Substrate (biology), the natural environment in which an organism lives, or the surface or medium on which an organism grows or is attached
** Substrate (locomotion), the surface over which an organism lo ...
until the part is complete.
History
The use of electron beam welding for additive manufacturing was first developed by Vivek Davee in 1995 as part of his PhD thesis at
MIT. The process was referred to as electron beam solid freeform fabrication (EBSFF). A team at
NASA Langley Research Center (LaRC) led by Karen Taminger developed the process, calling it electron beam freeform fabrication (EBF
3). EBF
3 is a NASA-patented additive manufacturing process designed to build near-net-shape parts requiring less raw material and finish machining than traditional manufacturing methods. EBF
3 is a process by which NASA plans to build metal parts in
zero-gravity environments; this layer-additive process uses an electron beam and a solid wire
feedstock
A raw material, also known as a feedstock, unprocessed material, or primary commodity, is a basic material that is used to produce goods, finished goods, energy, or intermediate materials that are feedstock for future finished products. As feedst ...
s to fabricate metallic parts. Future astronauts stationed on
the Moon or
Mars may be able to employ EBF3 to produce replacement parts locally rather than relying on parts launched from Earth, possibly even mining feedstock from the surrounding soils. The aviation industry has the most potential for the procedure, say experts at the NASA LaRC, because there should be significant progress made in reducing machining waste byproducts. Typically, an aircraft maker would start with a 6,000-pound block of titanium and use thousands of litres of cutting fluid to reduce it to a 300-pound item, leaving 5,700 pounds of material that needed to be recycled. According to Taminger, "With EBF3 you can build up the same part using only 350 pounds of titanium and machine away just 50 pounds to get the part into its final configuration. And the EBF3 process uses much less electricity to create the same part." 30 years ago.
Process
The operational concept of EBF
3 is to build a near-net-shape metal part directly from a
computer-aided design
Computer-aided design (CAD) is the use of computers (or ) to aid in the creation, modification, analysis, or optimization of a design. This software is used to increase the productivity of the designer, improve the quality of design, improve c ...
(CAD) file. Current computer-aided machining practices start with a CAD model and use a post-processor to write the machining instructions (G-code) defining the cutting tool paths needed to make the part. EBF
3 uses a similar process, starting with a CAD model, numerically reducing it into layers, then using a post-processor to write the G-code defining the deposition path and process parameters for the EBF
3 equipment. It uses a focused electron beam in a vacuum environment to create a molten pool on a metallic substrate. The beam is translated by the surface of the substrate while the metal wire is fed into the molten pool. The deposit solidifies immediately after the electron beam has passed, having sufficient structural strength to support itself. The sequence is repeated in a layer-additive manner to produce a near-net-shape part needing only finish machining. The EBF
3 process is scalable for components from fractions of an inch to tens of feet in size, limited mainly by the size of the vacuum chamber and the amount of wire feedstock available.
See also.
*
Electron-beam additive manufacturing
References
External links
Video: EBF3 – Electron Beam Free Form FabricationElectron Beam Freeform Fabrication for Cost Effective Near-Net ShapeElectron-Beam Free-Form Fabrication SystemDevice like ‘Star Trek’ replicator is in the works
{{3d printing
Electron beams in manufacturing
NASA programs
3D printing processes
2000 introductions
American inventions
2000 establishments in the United States