Meet RAMBO: Rapid Additively Manufactured Ballistics Ordnance
David Szondy reports: The US Army’s Armament Research, Development and Engineering Center (ARDEC) has successfully fired the first 3D-printed grenade from a 3D-printed grenade launcher. Part of a demonstration of how such technology can be used to greatly speed up prototyping and modification of weapons while lowering costs, the grenade launcher, called RAMBO (Rapid Additively Manufactured Ballistics Ordnance), was based on an M203A1 grenade launcher and every component, with the exception of the springs and fasteners, was manufactured using additive manufacturing.
Although the parts used to create RAMBO were made using 3D printing, some additional processing was required based on the material and complexity of the individual components. For example, the aluminum barrel and receiver were made using direct metal laser sintering (DMLS), where a layer of aluminum powder is laid down, then fused into solid metal with a laser beam guided by a digital CAD file. A second layer is them laid down and the process continues until complete. The excess powder is blown away, any support structures are removed, and the part is buffed smooth. However, for the barrel and receiver, some additional machining and tumbling was needed.
One of the advantages of this approach is that the rifling in the barrel was printed directly into the barrel instead of milled out later. The barrel and receiver were then hardened by applying hard-coat anodizing to form a hard, abrasion-resistant outer layer.
ARDEC says that the cost of producing the barrel and receiver was about US$100 per pound. The agency conceded that this is not cheap, but pointed out that the process only took 75 hours, that there was no scrap, and a skilled machinist wasn’t needed to fabricate the parts, resulting in considerable cost savings. … (read more here)