The specially designed deposition nozzle facilitates optimized argon diffusion over the meltpool substantially reducing oxidation and enabling 3D printing of reactive metals in an open atmosphere environment. The Engine enables not only metal 3D printing of full density parts, but also an all-in-one additive manufacturing solution for repairing parts, laser cladding, laser welding (autogenous and with filler), laser cutting, laser texturing and polishing.