A high-speed 3D printer is being tested by the US Army for producing spare steel parts near the front lines – it could also make airplane parts or weapons
Source:
https://www.newscientist.com/article/2240724-the-us-army-has-a-3d-printer-for-ultra-strong-steel-gear-and-weapons/?utm_campaign=RSS%7CNSNS&utm_source=NSNS&utm_medium=RSS&utm_content=home