US Marine Corps creates fabrication specialist role with 3D printing at its core
New MOS merges metal workers and machinists into a single designation built around additive manufacturing and remote parts production
The US Marine Corps is consolidating two existing engineering roles into a single new military occupational specialty (MOS) centered on additive manufacturing, taking effect October 1, 2026.
Metal Worker MOS 1316 and Machinist MOS 2161 will merge into Fabrication Specialist MOS 1321, as detailed in a message to the force issued in late May.
The restructured role reflects the Corps’ growing reliance on 3D printing technology at the unit level. The new training pipeline will place greater emphasis on additive manufacturing alongside traditional welding and machining.
Marines in the new MOS will also train on hybrid systems that combine 3D printing with conventional machining and milling methods, Marine Corps spokesperson Lt. Col. Melanie Salinas confirmed.
Reducing supply chain dependence in the field
A central objective of the new designation is equipping Marines to manufacture parts in remote or austere environments where access to conventional supply chains may be limited. Military services have increasingly turned to 3D printing in recent years to produce replacement components for equipment quickly and at lower cost — and in some cases, to fabricate entire drone airframes.
The active-duty fabrication specialist field will comprise approximately 390 Marines, drawn from the Corps’ current population of 236 metal workers and 157 machinists, Salinas said. Thirty-six Marines are already in the training pipeline and are projected to graduate before the merger is implemented.
Clearer promotion pathways
The consolidation also seeks to rebalance long-time career advancement obstacles within the two legacy specialties. Metal workers historically faced limited promotion opportunities beyond staff sergeant when competing against other engineering MOSs, while machinists encountered similar barriers at the gunnery sergeant level.
“Fabrication specialists (will) compete exclusively against their peers, ensuring an impartial promotion system and streamlined career options,” said Lt. Col. Salinas.
