Because the lower receiver was made of plastic, it only lasted 6 rounds. But the article also notes:
In an industrial setting, though, 3D printing processes such as selective laser melting/sintering (SLM, SLS) are being used to create incredibly rugged parts out of metal. NASA, for example, is producing rocket parts with 3D printing. It is really only a matter of time until everyone has the hardware at home to print a complete firearm — or, well, any weapon really.