Researchers in Japan have developed a multi-material 3D printing technique for lightweight, strong parts for cars.

Others require many additional parts, which are often metal. For example, many 3D-printed gun blueprints focus on a weapon’s lower receiver, which is basically the chassis of a firearm.

Building vehicle parts is just one use for additive ... Of course, these 3D printing companies needed to be able to print with metal, otherwise the subs' integrity wouldn't hold.