"Raytheon .. says that they have 3D printed just about every component needed for a guided [missile]. This includes the 3D printing of the rocket engines, the parts for the guidance and control systems, the fins on the missiles themselves, and more. Moreso, Jeremy Danforth, an engineer at Raytheon, says that the potential is there for missiles to be 3D printed on demand in the field, as needed."
https://3dprint.com/81850/3d-printed-guided-missiles/
https://3dprint.com/81850/3d-printed-guided-missiles/