Mixing device for producing a powder mixture

1 . A mixing device for producing a powder mixture of a first powder component and at least one second powder component for an additive manufacturing device in which a three-dimensional object can be produced by layer-wise selective solidification of a building material comprising the powder mixture, the mixing device comprising:

a first container for receiving the first and/or the second powder component, wherein the first container provides a discharge opening for discharging the first and/or the second powder component at a bottom of the first container;

a second container for receiving the first and/or the second powder component, wherein the second container is arranged within the first container; and

a powder conduit that connects to the discharge opening at the bottom of the first container and is guided through the top of the second container into the second container:

wherein the second container is designed to be at least partially open at its top; and

wherein the first container comprises at least one fluidization zone for introducing a gas into the first container.

2 . The mixing device of claim 1 , wherein the first container is closable towards an upper side by a container lid and wherein the second container is provided within the first container such that an upper boundary of the second container is spaced apart from the container lid of the first container and wherein the powder conduit extends through the container lid of the first container into the second container.

3 . The mixing device of claim 1 , wherein the second container provides a powder opening for discharging the first and/or the second powder component at a lower boundary of the second container.

4 . The mixing device of claim 3 , further comprising at least a first closure device that is designed to close and/or open the discharge opening of the first container, and/or at least a second closure device that is designed to close and/or open the powder opening of the second container.

5 . The mixing device of claim 4 , wherein the first closure device and the second closure device are designed to close and/or open the respective discharge opening or powder opening depending on an operating state of respective other closure device and/or depending on a defined operating mode of the mixing device.

6 . The mixing device of claim 5 , wherein the mixing devices defines at least one of following operating states:

a first state in which the discharge opening of the first container is open and the powder opening of the second container is closed;

a second state in which the discharge opening of the first container is closed and the powder opening of the second container is open; and/or

a third state in which the discharge opening of the first container and the powder opening of the second container are both closed or both open.

7 . The mixing device of claim 1 , wherein the bottom of the first container and/or a lower boundary of the second container is/are funnel-shaped at least in sections thereof, and wherein the discharge opening connects to a conveyor module.

8 . The mixing device of claim 1 , wherein the second container is coupled to at least on one wall of the first container.

9 . The mixing device of claim 1 ,

wherein the second container provides at least one deflecting element extending substantially from an upper boundary of the second container in a direction of at least one nearest wall of the first container; and

wherein the deflecting element is inclined from the upper boundary of the second container towards the bottom of the first container.

10 . The mixing device of claim 1 ,

wherein the first and/or second container can be filled manually or and/or partially automatically and/or automatically, via the powder conduit, and/or

wherein the powder conduit is connected to a removal conduit for removing the powder mixture from the mixing device.

11 . The mixing device of claim 1 , further comprising a moistening device designed and/or arranged and/or adjusted for moistening the first and/or second powder component, in the powder conduit and/or in the fluidization zone.

12 . An additive manufacturing device for manufacturing a three-dimensional object by selective solidification of a building material layer by layer,

wherein the building material comprises the powder mixture provided by the mixing device of claim 1 ; and/or

wherein the manufacturing device comprises and/or is connected to the mixing device of claim 1 .

13 . A mixing device for producing a powder mixture of a first powder component and at least one second powder component for an additive manufacturing device in which a three-dimensional object can be produced by layer-wise selective solidification of a building material comprising the powder mixture, the mixing device comprising:

a first container for receiving the first and/or the second powder component, wherein the first container provides a discharge opening for discharging the first and/or the second powder component at a bottom of the first container;

a second container for receiving the first and/or the second powder component; and

a powder conduit that connects to the discharge opening of the first container and is guided into the second container,

wherein the second container is designed to be at least partially open towards an upper side; and

wherein the first container comprises at least one fluidization zone for introducing a gas into the first container, the at least one fluidization comprising a cavity and a porous plate or a grid for passing the gas from the cavity into the first container.

14 . A mixing device for producing a powder mixture of a first powder component and a second powder component for an additive manufacturing apparatus producing objects by layer-wise solidification of the powder mixture, the mixing device comprising:

a first container and a second container, the first container having a first container interior receiving the first powder component;

the second container having a second container interior receiving the second component;

a mixing conduit connecting the first and second container interiors, the mixing conduit extending from a first outlet in a bottom of the first container interior to the second container interior;

a drive moving powder through the mixing conduit;

a fluidizing mechanism communicating with the second container interior, the fluidizing mechanism percolating gas through first and second powder components in the second container interior to intermingle the first and second powder components;

a second outlet in a bottom of the second container interior;

a first valve opening and closing the first container outlet;

a second valve opening and closing the second outlet, the second valve communicating with the first container interior; and

a third valve located in the mixing conduit, the third valve having a mixing position wherein powder material flows through to the second container interior, and a mixed powder transfer position wherein mixed powder material is transferred out of the mixing device.

15 . The mixing device of claim 14 , wherein the second container is located within the first container interior, the second valve emptying into the first container adjacent the bottom of the first container interior.

16 . The mixing device of claim 15 , wherein the fluidizing mechanism comprises a second container zone within the second container interior having a plurality of outlets for gas to pass out of the second container zone.

17 . The mixing device of claim 16 , wherein the fluidizing mechanism further includes a first container zone within the first container interior having a plurality of outlets for gas to pass out of the first container zone.

18 . The mixing device of claim 16 , wherein the second container zone fluidizes the first powder component and the second powder component to exit the second container through an opening in a top of the second container and into the first container interior.

19 . The mixing device of claim 18 , further including a deflator plate spaced above the opening, a deflector plate arranged to direct the first powder component and the second powder component into the first container interior.