Direct deposition is an 'additive manufacture' technology that deposits molten metal droplets onto a build platform.
Please visit the Direct Deposition Forum here for further discussions.
Direct Deposition printers are similar in operation to selective laser sintering in that an object is 'grown' by depositing successive layers of metal, one on top of the other. The process works either by firing tiny droplets of metal onto a build platform, or melting a piece of metal with high energy lasers (or other heat sources) and allowing gravity to pull the metal down onto the build platform. The build platform is moved in an X-Y fashion allowing a 'cross section' of the object to be fabricated.
Limitations include an inability to print overhangs. Stress fractures in the printed parts may also form because of the rapid heating and cooling the droplets.
The most notable direct deposition metal printer currently being developed for commercial use is the 'Liquid Metal Jet Printer' (LMJP).
Quote from the Vader Systems Website...
"Using a head much like that of an ink jet on a paper printer, the machine lays down droplets in layers of molten aluminum that build up gradually. At the end of the process, an object of great complexity can be created with no labor and no energy on the part of the maker. This innovation eliminates having to choose between cost and functionality. This is the Do-er that we're creating at Vader Systems, and it's here that our dream diverges from Summers."
Wire Melting Assembly
Zhivko has been working on a wire melting assembly that uses a high energy laser to melt wire as it is fed into the machine.
Zhivko's project can be found here: Zhivko's Projects
To discuss the project please look here: Forum Thread
Welding 3D Printer
Professor Joshua M. Pearce is heading a team from Michigan Tech that are currently working on an open source 3D Metal printer.
More information on the project can be found here: Michigan 3D Metal Printer
To discuss the project please comment here: Forum Thread
The StarJet uses a melt pool and micro nozzle made of silicone to deposit small (~50um) drops onto the build platform.
Here is a PDF document detailing the operation of the StarJet StarJet
You can find a discussion on the StarJet here: http://www.metalbot.org/forum/viewtopic.php?f=13&t=115