Device and method for additive manufacturing under protective gas

An apparatus for additive manufacturing of workpieces under protective gas which is provided with a manufacturing chamber in which a workpiece is producible under protective gas by selective sintering or melting of a pulverulent starting material through introduction of energy, wherein the manufacturing chamber is in the form of a pressure chamber and is fluidically connected to a pressure vessel via a gas withdrawal conduit fitted with a vacuum pump and via a gas return conduit;

• wherein a first valve is provided in the gas withdrawal conduit between the manufacturing chamber and the pressure vessel, the first valve being configured to selectively permit flow of the protective gas from the manufacturing chamber into the pressure vessel;
• wherein a second valve is provided in the gas return conduit between the pressure vessel and the manufacturing chamber, the second valve being configured to selectively permit flow of the protective gas from the pressure vessel into the manufacturing chamber;
• and
• wherein the pressure vessel is configured to store the protective gas at a pressure between 2 and 5 bar (g), which pressure is a result of the vacuum pump pumping the protective gas into the pressure vessel via the gas withdrawal conduit.