From The Register:

The one thing that made 3D printed guns tolerable to the non-gun-owning community was that they were made of plastic, because metal 3D printers were costly. Now, a bunch of scientists from Michigan Tech are showing off a cheap 3D printer that fabricates in metal.

Metal 3D printing isn’t new, but it’s been expensive until now. The open-source Michigan project, here, offers a bill of materials costing just under $1,200 to build the 3D printer, controlled by a Linux computer.

More at the link, including other links.