Using metallurgical powders with a precision depositing feeder, layout a layer at a time (obviously) of the part you want to develop within a certain size parameter. Lower the layer into an induction heater coil to raise the temperature of the powder to just below the melting point then hit it with a low power laser to melt the powder together to make the part, again layer by layer. Theoretically removing the need for high power lasers and either a vacuum chamber running constantly or a constant stream of shielding gas.
Edit: You apply a vacuum or shielding gas only during the fusion cycle, hence the induction furnace. Removes the need for expensive vacuum chambers or heavy use of shielding.