Additive Manufacturing: Electron Beam Freeform Fabrication
This post was originally written in January of 2017.
With all the buzz about Additive Manufacturing, or 3D Printing, in the manufacturing world today, there is a lot of mystery and confusion surrounding common practices and techniques. This week’s blog post will address a common type of 3D printing known as Electron Beam Freeform Fabrication (EBF³) .
What is Electron Beam Freeform Fabrication?
It is actually part of a broader category, commonly referred to as a Filament Extrusion Techniques. Filament extrusion techniques all utilize a thin filament or wire of material. The material, typically a thermoplastic polymer, is forced through a heating element, and is extruded out in a 2D cross-section on a platform. The platform is lowered and the process is repeated until a part is completed. In most commercial machines, and higher-end consumer grade machines, the build area is typically kept at an elevated temperature to prevent part defects. The most common, and the first, technology of this type to be developed is Fused Deposition Modeling.
The Fused Deposition Modeling Technique was developed by S. Scott Crump, co-founder of Stratasys, Ltd. in the late 1980s. The technology was then patented in 1989. The patent for FDM expired in the early 2000s. This helped to give rise to the Maker movement by allowing other companies to commercialize the technology.
Electron Beam Freeform Fabrication, or EBF³ is one of the newest forms of rapid prototyping. This technique is performed with a focused electron beam and a metal wire or filament. The wire is fed through the electron beam to create a molten pool of metal. The material solidifies instantaneously once the electron beam passes through, and is able to support itself (meaning support structures generally aren’t required). This entire process must be executed under a high vacuum.
Pioneered by NASA Langley Research Center, this process is capable of producing incredibly accurate parts at full density (other additive manufacturing techniques have trouble achieving, or require secondary operations to achieve similar results). This is also one of the only techniques that can be successfully performed in zero gravity environments.
What Are the Advantages of this Process?As mentioned previously, this is one of the only additive manufacturing techniques that yields full density parts; this means parts created with EBF³ will have similar properties to parts created using traditional manufacturing processes. Another advantage of the material bed is the ability to stack multiple parts into the build envelope. This can greatly increase the throughput of an EBF³ machine.
EBF³ is also the only additive manufacturing technique that can be performed in a zero gravity environment. This has great implications for use outside of our atmosphere.
What Are the Disadvantages of this Process?
Of the commercially available rapid prototyping machines, those that use this technique have by far the largest price tag. This is due to the accuracy of these machines. Creating accurate parts can be quite expensive!
Unlike other manufacturing processes, EBF³ limits each part to a single material. This means parts printed on EBF³ machines will be limited to those with uniform material properties throughout.
In addition, these machines aren’t yet commercially available, as this is still a developing technology.
There are quite a few different ways to 3D print a part, with unique advantages and disadvantages to each method. This post is the final part of a series discussing the different techniques; check out part 1 here if you haven’t already. Thanks for reading!