Group of students on Delft University of Technology made a DIY metal 3d printer based on MIG welder and Prusa i3. Their goal is to get a better DIY metal 3d printer and improve current welder based designs. There are several MIG welder projects like Michigan Tech's Delta this project is based on, but non of them was based on common 3d printer design like Prusa i3.
The project is under development and they will publish the results in a paper.
Project homepage: http://metal2014.weblog.tudelft.nl/
The group also released some files and settings for this metal printer if you want to explore them:
|Here is a close-up of the heat shields constructions on the "printhead" and print bed since metal melts around 1400 C.|