Abstract: A method of filtering gas in a powder bed fusion apparatus, wherein an object is built layer-by-layer by selective solidification of a powder bed, and a powder bed fusion apparatus for executing the method. The apparatus includes a build chamber housing the powder bed, a gas circuit for recirculating the gas, including passing the gas over the powder bed within the build chamber, multiple filter assemblies in the gas circuit for filtering process emissions from the recirculated gas and a valve system regulating gas flow to each filter assembly. The method may include controlling the valve system to divide the gas flow between the filter assemblies. The method includes controlling the valve system such that a first one of the filter assemblies is connected with at least one second one of the filter assemblies such that the gas passes through the filter elements of both filter assemblies.

Abstract: A method of filtering gas in a powder bed fusion apparatus, wherein an object is built layer-by-layer by selective solidification of a powder bed, and a powder bed fusion apparatus for executing the method. The apparatus includes a build chamber housing the powder bed, a gas circuit for recirculating the gas, including passing the gas over the powder bed within the build chamber, multiple filter assemblies in the gas circuit for filtering process emissions from the recirculated gas and a valve system regulating gas flow to each filter assembly. The method may include controlling the valve system to divide the gas flow between the filter assemblies. The method includes controlling the valve system such that a first one of the filter assemblies is connected with at least one second one of the filter assemblies such that the gas passes through the filter elements of both filter assemblies.

Abstract: A method of filtering gas in a powder bed fusion apparatus, wherein an object is built layer-by-layer by selective solidification of a powder bed, and a powder bed fusion apparatus for executing the method. The apparatus includes a build chamber housing the powder bed, a gas circuit for recirculating the gas, including passing the gas over the powder bed within the build chamber, multiple filter assemblies in the gas circuit for filtering process emissions from the recirculated gas and a valve system regulating gas flow to each filter assembly. The method may include controlling the valve system to divide the gas flow between the filter assemblies. The method includes controlling the valve system such that a first one of the filter assemblies is connected with at least one second one of the filter assemblies such that the gas passes through the filter elements of both filter assemblies.