Additive manufacturing (AM), or 3D printing, is a process whereby a 3D object is created through successive depositions of matter. Such an object is designed using CAD software. 3D printers, which have been developed over the past 25 years, were originally found only in laboratories . Their numbers have been increasing briskly since in 2000. Their price, in free fall, makes them accessible to more and more businesses. Personal 3D printers are even available. Thanks to miscellaneous materials, 3D printing technology is being used in aerospace, automotive parts, medical equipment, electronics, industrial design and numerous other fields. Already used in industry and design for prototypes, 3D printers are coming out of this niche and may upset production. 3D printers will impact over defense and security by significantly changing to production and supply lines, through bringing manufacturing closer to actual use. They may also decrease costs, manufacturing time and the need for skilled personnel. They also make custom production possible, through printing of complex parts which hitherto were difficult, if not impossible, to make using traditional molding techniques. Quick development of this technology, and potential high-stake challenges in terms of security and defense, require work to understand and anticipate risks to control, in particular through export control.