Industrial robot arm with attached advanced welding head. It can print lines of steel, stainless steel, aluminum, bronze or copper "in mid-air."
It's developed by Joris Laarman Lab in collaboration with the Institute for Advanced Architecture of Catalonia (IAAC).
MX3D Metal evolved from this project where they used thermosetting polymers only:
http://diy3dprinting.blogspot.com/2013/05/mataerial-thermosetting-polymers-3d.html
Source:
http://www.core77.com/blog/digital_fabrication/joris_laarmans_latest_anti-gravity_3d_printer_basically_conjures_metal_out_of_thin_air_26474.asp
