Additive Manufacturing: Electron Beam Melting
This post was originally created in January 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 the common practices and techniques. So, this week’s blog post will address a common type of 3D printing known as Electron Beam Melting (EBM).
What is Electron Beam Melting?
It is actually part of a broader category, commonly referred to as a Granular Based Technique. All granular based additive manufacturing techniques start with a bed of powdered material. A laser beam or bonding agent joins the material in a cross section of the part. Then the platform beneath the bed of material is lowered, and a fresh layer of material is brushed over the top of the cross section. The process is then repeated until a complete part is produced. The first commercialized technique of this category is known as Selective Laser Sintering.
The Selective Laser Sintering Technique was developed in the mid-1980s by Dr. Carl Deckard and Dr. Joseph Beaman and the University of Texas at Austin, under DARPA sponsorship. As a result of this, Deckard and Beaman established the DTM Corporation with the explicit purpose of manufacturing SLS machines, and in 2001 DTM was purchased by their largest competitor, 3D systems.
Electron Beam Melting is very similar to Selective Laser Melting, though there are a few distinct differences. EBM uses an electron beam to create a molten pool of material, to create cross-sections of a part. The material solidifies instantaneously once the electron beam passes through it. In addition, this technique must be performed in a vacuum. This is one of the few additive manufacturing techniques that can create full density parts.
What Are the Advantages of this Process?
EBM is quick; it’s one of the fastest rapid prototyping techniques (though, relatively speaking, most techniques are fast). In addition, it can potentially be one of the most accurate rapid prototyping processes, the major limiting factor being the particle size of the powdered material.
As mentioned previously, this is one of the only additive manufacturing techniques that yields full-density parts; this means parts created with EBM 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 EBM machine.
What Are the Disadvantages of this Process?
Of the commercially available rapid prototyping machines, those that use the Electron Beam Melting technique by far have the largest price tag. This is due to the accuracy of these machines. Creating accurate parts can be quite pricey!
EBM can be very messy. The material used is a bed of powdered material and, if not properly contained, will get EVERYWHERE. In addition, breathing in powdered metals can potentially be very hazardous to one’s health. Though most machines account for this, it is certainly something to be cognizant of when manufacturing.
Unlike other manufacturing processes, EBM limits each part to a single material. This means parts printed on EBM machines will be limited to those with uniform material properties throughout.
There are quite a few different ways to 3D print a part, with unique advantages and disadvantages of each process. This post is part of a series discussing the different techniques. Thanks for reading!