A couple days ago I read a cheeky article about NASA's plans to use 'Star Trek' replicators to create parts and tools in space (No offense meant, Mr. Hsu -- although the phrase was from Karen Taminger, anyway). The technology is a portable electron beam freeform fabrication (EBF3) device. Basically the EBF3 uses an electron beam to create a molten pool in a metallic substrate. The whole object is moved so that the fixed electron beam deposits material in the desired pattern. Doing this, they are able to create objects using a layer additive process. The concept is similar in general concept to the FAB@home projects.
Non-portal EBF3 has been used previously in the welding industry. Companies such as Sciaky create big machines that use a similar process.
Here's a neat video describing the work that Karen Taminger has done with portable EBF3.
Here's another one styled for the kids...
So what's so neat about EBF3?
For one, it is another method to produce things in zero gravity. Ie. It helps make space a commercially viable option.
Darpa is interested in the project because it would allow them to create large items in space. They would be able to create items in space which are too big to launch. Presumably, they would also be able to create items with less 'eyes'. EBF3 would enable DARPA to beam the CAD files directly to an EBF3 in space. Only a very small team of people would need to know what the item actually is.
NASA is looking to use EBF3 to create tools needed to complete missions. Dropped the last hammer into the vacuum of space? No problem. Being able to create tools in space would also allow astronauts to overcome unexpected obstacles in space - which would be essential for extra-planetary operations on the Moon or Mars.
Boeing, Lockheed Martin, Pratt & Whitney also provided support for the project. While it wasn't stated directly, Karen Taminger displayed a different construction for airplane supported using curves supports rather than squared supports. These would make the planes lighter, quieter and cheaper to produce.
Who's doing what?
University of Tennessee -- modeling to improve the process.
Virginia Tech -- design optimization and analysis tools.
Modern Computational Technologies (MCT) -- computational analysis to improve the process.