An additive manufacturing facility operating in an automated and contained manner. The facility includes a containment chamber inside which a plurality of additive manufacturing machines is installed, each machine comprising a manufacturing chamber, inside the containment chamber, a supply device and a supply circuit for supplying the various machines of the facility with an additive manufacturing powder, a conveying device for conveying additive manufacturing container/tray assemblies comprising at least one conveying chamber circulating between the various machines, and (4) a cleaning device comprising at least one cleaning chamber for cleaning, in an automated and contained manner, the additive manufacturing trays in the cleaning chamber.