Abstract: An apparatus (10) for producing three-dimensional work pieces comprises a process chamber (12) accommodating a carrier (16) and a powder application device (14) for applying a raw material powder onto the carrier (16) and being provided with a gas inlet (30) and a gas outlet (32). The apparatus (10) further comprises an irradiation device (18) for selectively irradiating electromagnetic or particle radiation onto the raw material powder applied onto the carrier (16) in order to produce a work piece made of said raw material powder by an additive layer construction method. A gas circuit (34) of the apparatus (10) comprises a circulation line (36) connecting the gas outlet (32) of the process chamber (12) to the gas inlet (30) of the process chamber (12) and a filter system (40) arranged in the circulation line (36). Furthermore, a cyclone separator system (42) is arranged in the circulation line (36) upstream of the filter system (40).

Abstract: An apparatus (10) for producing three-dimensional work pieces comprises a process chamber (12) accommodating a carrier (16) and a powder application device (14) for applying a raw material powder onto the carrier (16). The apparatus (10) further is equipped with an irradiation device (18) for selectively irradiating electromagnetic or particle radiation onto the raw material powder applied onto the carrier (16) in order to produce a work piece made of said raw material powder by an additive layer construction method. A gas circuit (34) comprises a circulation line (36) adapted to supply gas to the process chamber (12) and to discharge gas loaded with particulate impurities from the process chamber (12), and a raw material powder circuit (42) comprises a circulation line (44) adapted to supply raw material powder to the process chamber (12) and to discharge excess raw material powder from the process chamber (12).