We've seen a lot of metal 3D printers come about recently, but now researchers at Virginia Tech University have created a binder-jet 3D printer that prints copper objects using copper powder and a special glue. Once an object is printed, it is then put into a furnace to heat and sinter it. Currently the researchers are working on a method of filling in the small air pockets that form between pieces of powder so that the parts and components can be as strong as traditional machined copper parts. Read and see more at: http://3dprint.com/86321/3d-print-copper-virginia-tech/