EP3972819A1

EP3972819A1 - Powder output module for an additive manufacturing device, additive manufacturing device and method for applying a powder layer

Info

Publication number: EP3972819A1
Application number: EP20734902.8A
Authority: EP
Inventors: Stefan Grünberger; Stefan Kneisel; Gabriel Schneider; Stefanie MARKL; Stefan Paternoster
Original assignee: EOS GmbH
Current assignee: EOS GmbH
Priority date: 2019-07-09
Filing date: 2020-06-24
Publication date: 2022-03-30
Also published as: DE102019210120A1; CN114126846A; WO2021004794A1; US20220266346A1

Abstract

The invention relates to a powder output module for a coating device (16) of a device (1) for additively manufacturing a three-dimensional object (2) via the layer-by-layer application of powder-type construction material and the selective solidifying of the applied layers at points, according to the respective cross-section of the three-dimensional object (2) in the respective layer, wherein the coating device (16) for the layer-by-layer application of the construction material is provided in the device such that it can be moved in at least one movement direction (B) over a working plane (7) of the device (1). The powder output module (18) comprises a powder container (30) for receiving the powder-type construction material and the powder container (30) comprises a supply opening (33) for supplying the powder-type construction material to the powder container (30) and a discharge region (31) facing the working plane (7) during the intended operation of the coating device (16), wherein the discharge region (31) has at least one first output unit (36a, 36b) for outputting powder-type construction material and at least one fluidisation zone (40, 41a, 41b) for the fluidisation of the powder-type construction material using a gas in the the powder container (30). The powder container (30) also comprises at least one first flow reduction element (50a, 50b) provided in the powder container (30).

Description

Powder discharge module for an additive manufacturing device, additive manufacturing device and method for applying a powder layer

The present invention relates to a powder discharge module for a device for the additive manufacture of a three-dimensional object by layer-by-layer application and selective solidification of a powdery building material and to such an additive manufacturing device, as well as to a method for applying at least one layer of a powdery building material as part of a Ver Driving for the production of a three-dimensional object by layer-by-layer application and selective solidification of a powdery build-up material and such an additive manufacturing process.

Devices and methods of this type are used, for example, in rapid prototyping, rapid tooling or additive manufacturing. An example of such a process is known by the name of "selective laser sintering or laser melting". A thin layer of the powdery build-up material is repeatedly applied and the build-up material is selectively solidified in each layer by selective irradiation of a point corresponding to the cross-section of the object to be manufactured with a laser beam.

To apply a layer of the powdery building material, a coating device provided in the device is moved over a building field, for example. During the movement of the coating device over the construction field, powdery build-up material is discharged through a discharge device of the coating device, for example an output gap, and is applied to form a uniform layer by an application element of the coating device. pulled. By introducing a gas into the build-up material stored in the coating device, it can be fluidized, ie put into a fluidized bed or fluidized bed-like or fluid-like state in order to improve the powder discharge.

In particular, at the beginning and at the end of a layer application, the coating device and thus also the powder stored in it are accelerated. Due to the acceleration forces that are provided in the coating device, the fluidized powdery building material is set in motion, which is also referred to as "sloshing" of the building material. Such a sloshing of the build-up material, that is, a chaotic and therefore difficult to control action of a turbulent flow of the fluid build-up material, can cause an uneven distribution of the build-up material in the coating device, which can negatively affect the quality of the applied powder layer. In addition, the sloshing can cause undesirable forces on the powder container, which can also negatively affect the quality of the applied layer. Fine powder particles can also be carried out by the sloshing and / or fluidizing of the powder, which can lead to contamination of components of the coating device and / or the manufacturing device.

From WO 2017/102242 A1 a powder discharge device for a coating device is known, which comprises a powder container and a filling shaft formed separately from the powder container and connected to the powder container via an opening in a partition wall. The powdery build-up material can be fluidized independently of one another in the powder container and in the filling shaft.

The object of the present invention is to provide an alternative or improved powder discharge module or an alternative or improved additive manufacturing device or an alternative or improved method for applying at least one powder layer or an alternative or improved additive manufacturing Provide treatment method in which, in particular, a movement of the fluidized powder in the powder discharge module of the coating device is at least reduced and / or the powdery build-up material can be better fluidized.

This object is achieved by a powder discharge module according to claim 1, a manufacturing device according to claim 11, a method for applying at least one layer according to claim 12 and a manufacturing method according to claim 15. Further developments of the invention are each specified in the dependent claims. The methods can also be further developed by the features of the devices below or in the subclaims, or vice versa, or the features of the devices and the method can also be used in each case for further development.

A powder discharge module according to the invention is used for a coating device of a device for the additive manufacture of a three-dimensional object by applying powdery build-up material in layers and selective solidification of the applied layers at points that correspond to the respective cross-section of the three-dimensional object in the respective layer, the coating device for Layer-by-layer application of the building material in at least one direction of movement over a working plane of the device is provided movably in the device. The powder discharge module has a powder container for receiving the powdery build-up material. The powder container comprises a feed opening for supplying the powdery build-up material to the powder container, an output area facing the working level when the coating device is in normal operation, the output area at least one first discharge device for discharging powdery build-up material and at least one fluidization zone for fluidizing the powdery build-up material using a gas in the powder container, and at least one first flow reduction element provided in the powder container. The powder discharge module can, for example, be formed integrally with the coating device or be provided on it such that it can be replaced. The powder discharge module and / or the coating device can for example further at least one application element, for example an applicator roller and / or an applicator blade and / or a flexible applicator element, e.g. B. a flexible rubber lips or a brush, which is arranged in the direction of movement of the coating device behind the discharge device to hen the discharged from the discharge device powdery building material to a uniform layer and / or to compact an applied layer.

Preferably, the output area is a downward direction of the powder container when the coating device is being used as intended or when the powder discharge module is used as intended, ie. H. in the direction of the working level or the construction field, the final area of the powder container. The output area of the powder container can be, for example, a container bottom of the powder container, i. H. the entire container base or one or more zones of the container base. However, it can also be another area of the powder container, e.g. in the vicinity of the container floor, for example an intermediate floor, which is essentially turned towards the construction field or the work level when the coating device is used as intended or when the powder discharge module is used as intended. The intended use of the powder discharge module preferably means a state and / or an arrangement or alignment of the powder discharge module in the additive manufacturing device or in the coating device in which the powder discharge module is suitable for dispensing powdery build-up material for applying a layer , d. H. in particular, the coating device is moved over the construction field or the work plane.

Proper operation of the coating device preferably denotes a state of the coating device in which it is arranged and / or aligned and / or controlled in the additive manufacturing device in such a way that it is at least suitable for at least one layer of the powdery building material in the working plane or to be applied to the construction field, in particular in accordance with a method according to the invention described in more detail below. The Intended use of the powder discharge module preferably denotes a state in which the powder discharge module is suitably attached to the coating device or is provided integrally with it and the coating device is in its intended operation.

The at least one discharge device is designed to discharge the construction material stored in the powder container, in particular downwards, i.e. downwards. H. in the direction of the working level or the construction site. The building material discharged in this way can then, for example, be drawn out into a uniform layer. The support device can for example be designed as a recess in the output area. Next, one or more Beschich terelements, z. B. a slide and / or a metering roller, can be provided for partially and / or completely closing the recess. With such coating elements it is possible, for example, to control the amount of powder discharged or a volume flow of the powder discharged.

With respect to the direction of movement of the coating device, the feed opening is preferably provided at a distance from a lateral wall of the powder container, in particular in a central region of the powder container with respect to the direction of movement. A closing element, for example a cover, is preferably also provided on the feed opening, by means of which the feed opening can be closed.

The at least one fluidization zone can be formed, for example, by a cavity in or outside the dispensing area, which is connected to a supply line for supplying the gas and by a gas inlet element, for example a perforated plate and / or a porous plate, from the interior of the powder container holder is separated. The holes or pores of the gas inlet element are preferably designed in such a way that they allow the gas to pass, but do not allow any powder grains of the powdery build-up material to pass through. For example, the powder stored in it can be fluidized by introducing a gas into the powder container. the, ie in a fluidized bed-like or fluid-bed-like or fluid-like to stand. The at least one fluidization zone is preferably used to introduce a gas into the powder container.

Here and in the following, a flow reducing element is preferably understood to mean a structural element which on average reduces a flow in the powder container, in particular a flow of the fluidized build-up material in the powder container. The flow reduction element can have at least one powder opening (for example a hole), the flow reduction element to be understood in such a way that the flow in the center of the hole passage is initially, but under certain circumstances, not influenced. The flow of the fluidized build-up material can generally be understood as a movement of the fluidized build-up material, that is to say put into a fluidized bed-like or fluidized-bed-like state. Such a movement can in particular be caused by an increase and / or decrease in speed, i.e. an acceleration, of the coating device as part of a layer application and, as soon as it has reached chaotic quality in terms of its own dynamics, can no longer be regulated by simple countermeasures than "Sloshing" denotes the fluidized build material. Without acceleration, ie when the coating device is at rest or moving at a constant speed, the flow-reducing element is preferably at least partially permeable to the powdery build-up material. As a result, for example, when the powder container is filled with building material and / or after a layer application, the building material can be distributed in the container or improved. The at least one flow-reducing element is preferably provided separately from and at a distance from a wall of the powder container and / or protrudes into the interior of the powder container. It he preferably stretches in the direction of movement of the coating device over a thickness that is several times smaller than a longitudinal extent and a vertical extent of the flow reducing element, ie the flow reducing element is designed as a flat body with a small depth. For example, it can be formed as a thin plate or a thin sheet of metal. By providing at least one flow-reducing element in the powder container, sloshing of the fluidized build-up material can for example be prevented or at least reduced. As a result, the distribution of the building material in the powder container can be improved and / or forces acting on the powder container, which are / would be caused by sloshing building material, can be reduced.

The powder container preferably has the first flow-reducing element on at least one upper container area, it essentially extending from the at least one upper container area in the direction of the dispensing area. Alternatively or additionally, the first flow reduction element extends preferably at least over 50%, more preferably over at least 70%, even more preferably over at least 90% of a distance between an upper container area and the output area. Alternatively or additionally, the first flow-reducing element is preferably provided in the powder container at a distance from the dispensing area.

The upper container area of the powder container is preferably defined by a delimitation of the powder container at the top, for example a container ceiling or an intermediate container ceiling. The distance between the upper container area and the dispensing area can also be referred to as the height of the interior of the powder container. The distance does not have to be the same in all areas of the powder container, but can vary, for example, across areas of the powder container. Therefore, the distance between the upper container area and the output area can also be a local distance, for example. Alternatively, the flow reducing element can extend over the entire distance of the upper container region from the dispensing region. In this case it is adjacent to both the upper container area and the output area, ie it extends over the entire height of the interior of the powder container. The term "upper container area" or "upper boundary" means an area or boundary of the powder container facing away from the working level or the construction field. Preferential wise, an interior of the powder container is located between the dispensing area and the upper container area of the powder container and is at least partially bounded by these.

Due to the height extension of the flow reducing element over at least 50% of the distance between the upper container area and the output area, a sufficient effect of the flow reducing element can be achieved even at lower fill level heights.

Preferably, the first flow reducing element extends essentially in a longitudinal direction transversely, more preferably perpendicularly, to the intended direction of movement of the coating device and extends preferably in the longitudinal direction essentially over an entire dimension of an interior of the powder container.

Similarly, the first and / or second discharge device, which is described in more detail below, and / or the feed opening and / or the at least one fluidization zone extends essentially in a longitudinal direction transversely, preferably perpendicularly, to the intended direction of movement of the coating device. More preferably, the first and / or second discharge device (see below) and / or the feed opening and / or the at least one fluidization zone extends in the longitudinal direction essentially over the entire dimension of the interior of the powder container. The term “essentially” expresses the fact that the respective element extends over at least 80% of the dimensions of the interior of the powder container in the longitudinal direction. This makes it possible, for example, to use the largest possible area of the powder container for powder supply or discharge or powder fluidization or, if the flow reducing element is formed over essentially the entire length of the interior of the powder container, a good reduction in flow can be achieved be achieved.

The first flow-reducing element preferably has at least one, preferably a plurality of structures, the structure (s) being further preferred has one or a plurality of powder opening (s) penetrating the flow-reducing element.

A "powder opening penetrating the flow reducing element" preferably means that the powdery build-up material can pass through the powder opening from one side of the flow-reducing element to the opposite side, in particular when the fluidized build-up material is essentially not exposed to any acceleration. This enables, for example, a good distribution of the powdery building material in the powder container.

The flow reducing element can, for example, also have structures other than holes or powder openings, e.g. B. it can have one or more ribs and / or fins. In general, the structure (s) is or are preferably designed, as described above, to reduce a flow in the powder container in the middle. Thus, for example, various possibilities for the formation of the flow reducing element are provided.

More preferably, the at least one powder opening of the flow reducing element is designed as an adjustable and / or changeable powder opening, ie the geometric shape and / or the opening area of the powder opening (s) can be set or changed. This can be implemented, for example, by one or more diaphragms provided on the powder opening, the diaphragm (s) being or are designed to partially and / or completely close the at least one powder opening. Such adjustable or changeable powder opening (s) of the flow reducing element makes it possible, for example, to use the powder container or flow reducing element for different powdery building materials, in particular building materials with different grain size distributions. Alternatively or in addition, the powder openings are further preferably spaced from one another, even more preferably regularly spaced from one another, provided in the flow-reducing element, the powder openings preferably being arranged in mutually offset rows.

The powder openings can be spaced apart from one another in a longitudinal direction and / or a height direction of the flow reducing element and / or diagonally. Alternatively or additionally, the arrangement of the powder openings can be formed symmetrically, for example in the longitudinal direction and / or the height direction. The powder openings are further preferably arranged in rows and / or in columns, in particular in rows and / or columns that are offset from one another.

The powder openings are preferably provided essentially over the entire extent of the flow reducing element along its vertical extent and / or essentially over the entire extent of the flow reducing element along its longitudinal extent, the height extent and the longitudinal extent of the flow reducing element each being transverse, preferably perpendicular, to the direction of movement the coating device run ver.

The powder openings are preferably designed and arranged such that powdery build-up material can pass the powder openings at least when the coating device is at a standstill and / or the coating device is moving at constant speed. For example, the powder openings can have an opening diameter or a maximum extension of the opening which is at least one hundred times a grain diameter assigned to the powder grains of the building material, for example a maximum grain diameter or a grain diameter of a defined characteristic value of the powder size distribution. An opening diameter of the powder openings can for example be in the range between 5 mm and 10 mm. A mean grain diameter of the powdery building material can be, for example, in the range of 50 μm +/- 20% deviation. The closed, ie not penetrated by powder openings, regions of the flow reducing element are preferably dimensioned such that a flow in the powder container is at least reduced. For example, a ratio of the total opening area of all powder openings to the remaining closed area of the flow reducing element can be at least 30% and / or at most 40%, preferably between 30% and 40%.

The flow reducing element formed in this way, which is also referred to as a baffle plate or baffle plate, for example, can reduce movement (sloshing) of the fluidized build-up material in the powder container particularly well.

Preferably, at least one second flow reducing element is provided in the powder container, which more preferably has an orientation corresponding to the first flow reducing element in the powder container, and is even more preferably arranged parallel to this first flow reducing element. The first and second flow reduction elements are preferably designed and / or arranged in the powder container such that the powder openings of the first and second flow reduction elements are at least partially offset from one another in a projection of the first flow reduction element onto the second flow reduction element. Alternatively or additionally, the first flow reducing element and the second flow reducing element are preferably arranged in the powder container at a distance from one another in the direction of movement of the coating device, and the feed opening of the powder container is provided between the flow reducing elements in the direction of movement of the coating device.

It is thus possible, for example, to reduce the flow in the powder container particularly well. By providing a second flow reducing element in the powder container, with the feed opening being provided in an area between the two flow reducing elements, it is also possible, for example, to effect a functional separation of the container interior, which che is further promoted by the provision of different fluidization zones described below. The offset perforation of the two flow reducing elements to one another can, for example, reduce or prevent the formation of powder waves during the acceleration phases of the coating device and / or enable rapid and / or homogeneous powder distribution in the interior of the powder container.

A first discharge fluidization zone for fluidizing the powdery build-up material using a gas is preferably provided in the powder container in a first area of the dispensing area, which is an area of the dispensing area adjoining the first dispensing device, and / or in a second area of the dispensing area, which is a is from the first Austrageinrichtung device spaced region of the output area, a central fluidization zone is provided for fluidizing the powdery building material using a gas in the powder container.

By providing different fluidization zones, it is possible, for example, to fluidize the powdery build-up material differently in the powder container locally, ie in accordance with the first and second areas of the output area, or to fluidize it only in one of the areas. In contrast to a large-area fluidization of the build-up material, less build-up material is fluidized overall, which can lead to a lower discharge of fine powder particles and / or reduce or prevent a flow or sloshing of the fluidized build-up material in the powder container. For this purpose, the discharge fluidization zone and the central fluidization zone are preferably designed as two independently controllable zones. Two fluidization zones that can be controlled independently of one another are to be understood in particular to mean that a volume flow of the gas introduced into the powder container through the respective fluidization zone can be set independently of the other fluidization zone. A volume flow of the gas introduced can also be zero. Furthermore, the provision of different fluidization zones makes it possible, for example, to assign different tasks or functions to the different fluidization zones. The fluidization zones can be activated in a specific order, for example and / or have a different flow rate and / or a different activation frequency and / or a different activation duration. In this way, for example, the flexibility of the powder discharge module or a method that can be carried out with it for applying at least one powder layer can be increased.

The powder container further preferably has at least one upper container area on which the supply opening is provided, the supply opening being provided in a projection of the at least one upper container area onto the output area, even more preferably essentially in an area of the central fluidization zone.

This makes it possible, for example, to fluidize the construction material in the powder container in a targeted manner in certain areas, according to different process steps such as. B. a filling step in which the powder container is supplied through the supply opening building material, and / or an application step in which a layer of powdery building material is applied to the construction field or in the work plane.

Alternatively or additionally, the output area further preferably has a second discharge device, a second discharge fluidization zone for fluidizing the powdery build-up material using a gas in the powder container in a third area of the output area, which is an area of the output area adjacent to the second discharge device is provided. Even more preferably, the first and the second discharge area are spaced apart from one another in the direction of movement, and the first and the second discharge fluidization zone are provided between the two discharge areas. Even more preferably, as an alternative or in addition, the central fluidization zone is provided between the first and the second discharge fluidization zone.

By providing a second discharge device, it is possible, for example, to apply successive (partial) layers of the build-up material in the coating direction and its opposite direction, with a first being applied for the application (Partial) layer the powdery build-up material is discharged through one of the two discharge devices and the powdery build-up material is carried out through the other of the two discharge devices to apply a second (partial) layer.

The first and / or second discharge device preferably comprises a dispensing opening, in particular a slit-shaped dispensing opening, which extends in the direction of the construction field or the working plane over a thickness of the dispensing area, where the dispensing opening is at least partially funnel-shaped and / or at least one dispensing opening fluidization zone having. Further before given, a longitudinal direction of the slot-shaped dispensing opening extends transversely, in particular perpendicular, to the direction of movement of the coating device. With such a, in particular gap-shaped, dispensing opening, for example, a dispensing device that is easy to implement is provided. By providing at least one dispensing opening fluidization zone at the dispensing opening, the powder discharge can, for example, be further improved; H. clogging of the dispensing opening can be prevented. By providing an at least partially funnel-shaped section, the powder discharge can be improved, for example.

Preferably, at least one of the fluidization zones comprises a porous plate and / or a perforated plate with a plurality of gas outlet openings, the gas outlet openings being designed to be permeable to the gas but not permeable to powder, the porous plate or the perforated plate further preferably being made of a metal is formed and / or was manufactured in an additive manufacturing process by layer-wise selective solidification of a building material. More preferably, the porous plate and / or perforated plate, particularly preferably as a unit with a chamber, is designed as an exchangeable insert. The chamber is used to receive a supplied gas before it flows through the porous plate and / or perforated plate into the interior of the powder container. The insert is preferably sealed off from the dispensing area and / or further fluidization zones by means of one or more sealing elements. This makes it possible for example to use the Use for cleaning purposes and / or when using a different assembly material to remove and / or replace.

At least one of the fluidization zones preferably comprises a regulating device for setting a volume flow through the at least one fluidization zone.

In other words, the control device is preferably designed to set a volume flow of the gas flowing into the powder container through the fluidization zone during operation. This makes it possible, for example, to adjust the volume flow of the gas through the fluidization zone into the powder container independently of further fluidization zones of the powder container and thus to generate a local fluidization of the building material, which can be controlled by the control device. The control device can be designed, for example, as a mass flow controller (MFC) and / or as at least one switchable valve.

A powder discharge module according to a further aspect is used for a coating device of a device for additive Fierstellen a three-dimensional object by applying powdery build-up material in layers and selectively solidifying the applied layer in places corresponding to the respective cross-section of the three-dimensional object in the respective layer, the Be coating device for applying the building material in layers in at least one direction of movement over a working plane of the device is provided movably in the device. The powder discharge module has a powder container for receiving the powdery build-up material and the powder container comprises a feed opening for feeding powdery build-up material to the powder container and an output area facing the work plane when the coating device is in normal operation, the at least one first discharge device for discharging powdery build-up material having, in a first area of the dispensing area, which is an area of the dispensing area adjoining the first dispensing device, a discharge fluidization zone for fluidizing the powdery build-up material using a gas in the powder container and / or in a second area of the dispensing area, which is a spaced from the first discharge Be rich of the output area, a central fluidization zone for fluidizing the powdery building material is provided using a gas in the Pulverbehäl ter. Preferably, the powder discharge module further comprises at least one first flow reducing element provided in the powder container, the powder container further preferably having the flow reducing element on at least one upper container area and / or wherein the flow reducing element extends essentially from the at least one upper container area in the direction of the output area and / or wherein the flow-reducing element has at least one, preferably a plurality of flow-reducing structures, preferably powder openings penetrating the flow-reducing element.

With such a powder discharge module it is possible, for example, to fluidize the powdery building material in the powder container in different areas, in particular independently of one another. The powder discharge module according to the further aspect can be further developed by the features of the powder discharge module according to the invention described above or listed in the subclaims.

A device according to the invention is used for the additive manufacture of a three-dimensional object by applying powdery build-up material in layers and selectively solidifying the applied layer at points that correspond to the respective cross-section of the three-dimensional object in the respective layer, and comprises a coating device that is used to apply the layer by layer construction material is provided movable in at least one direction of movement over a working plane of the device in the device, wherein the coating device comprises a powder discharge module according to the invention described above and / or a powder discharge module according to the further aspect described above. Since it is possible, for example, to achieve the effects described above in relation to the powder discharge module also in an additive manufacturing device.

A method according to the invention for applying at least one layer of a pulverulent construction material can be carried out or is carried out in a device for the additive production of a three-dimensional object by layering Application of powdery build-up material and selective solidification of the applied layers at points corresponding to the respective cross-section of the three-dimensional object in the respective layer, a coating device for applying a layer of the powdery build-up material being moved in at least one direction of movement over a working plane of the device, with the coating device comprises a powder discharge module and wherein the powder discharge module has a powder container which receives powdery build-up material. The powder container comprises a supply opening for supplying the powdery build-up material to the powder container, an output area facing the working level when the coating device is in normal operation, the output area underneath at least one first discharge device for discharging powdery build-up material and at least one fluidization zone for fluidizing the powdery build-up material Having use of a gas in the powder container, and at least a first flow reducing element provided in the powder container. The powder discharge module preferably comprises in a first area of the output area, which is an area of the output area adjoining the first discharge device, a discharge fluidization zone for fluidizing the powdery build-up material using a gas in the powder container and in a second area of the output area, which an area of the output area spaced apart from the first discharge device is a central fluidization zone for fluidizing the powdery build-up material using a gas in the powder container, gas being introduced into the powder container at least temporarily through the discharge fluidization zone and / or the central fluidization zone. Preferably, in the method, at least intermittently, powdery building material is discharged from the first discharge device and gas is introduced into the powder container at least intermittently through at least one of the fluidization zones described above. This makes it possible, for example, to achieve the effects described above with regard to the powder discharge module in a method for applying at least one powder layer. Before moving the coating device over the working level and / or over the construction field, a filling step is preferably carried out in which the powder container is fed with powdery build-up material through the feed opening and in the gas at least through the central fluidization zone, preferably through the central fluidization zone and the Discharge fluidization zone, is introduced into the powder container, wherein in the filling step powdery build-up material is supplied up to a predetermined level in the powder container, which is preferably detected by means of a light barrier. By introducing a gas through the central fluidization zone, the build-up material can be fluidized in a central area of the powder container in relation to the coating direction, in which the feed opening is preferably provided, in order to enable, for example, a better distribution of the build-up material in the powder container. The distribution of the construction material in the powder container can also be further improved by introducing the gas through the discharge fluidization zone (s) to fluidize the construction material in these areas.

By defining a level of the powdery building material to be achieved in the powder container, it is possible, for example, to supply a reproducible amount of powder to the powder container or to achieve a reproducible amount of powder in the powder container. Alternatively or additionally, independently of the filling step, a filling level detection step can be carried out in which a current filling level of the powdery build-up material in the powder container is detected, for example by the light barrier.

Preferably, while moving the coating device over the working plane or over the construction field, gas is introduced into the powder container at least through the discharge fluidization zone, gas with a lower volume flow through the central fluidization zone than through the discharge fluidization zone and / or essentially no gas through the central fluidization zone is introduced into the powder container. Because the build-up material is fluidized in the area of the discharge device, ie the gas is introduced into the powder container through the discharge fluidization zone, a homogeneous powder discharge can be achieved, for example. In contrast to maximum fluidization, with gas too is introduced through the central fluidization zone with a large volume flow, e.g. B. in the filling step described above, overall less build-up material is fluidized by reducing the volume flow of the central fluidization zone, which results in the proportion of fine powder (st) discharge and / or sloshing of the build-up material, especially in a subsequent slowing step (braking from ) of the coating device.

As described below, the fluidization zones or the volume flows of the gas flowing through the respective fluidization zones can preferably be switched or controlled independently of one another. Such a control can for example be carried out depending on a currently executed function of the coating device (e.g. filling or layer application) and / or depending on an acceleration of the coating device (e.g. no acceleration, ie the coating device is stationary or moving at an essentially constant speed, or the coating device is accelerated (positive acceleration, ie increase in speed, or negative acceleration, ie decrease in speed)).

The targeted control of the fluidization zones described below makes it possible, for example, to keep a period of maximum fluidization (through all fluidization zones) as short as possible, for example only while the powder container is being filled, and thus to reduce or reduce the discharge of fine powder (st) discharge. to minimize. A filling process can, for example, only take a fraction of the time span of a coating and / or exposure process.

In general, it should also be noted that when the individual fluidization zones are controlled, at least one fluidization zone can be deactivated, i.e. no gas is introduced through this fluidization zone (volume flow is zero), or that the at least one fluidization zone is only operated at a reduced rate, i.e. so little Gas (small volume flow) is introduced through the fluidization zone so that the building material is only fluidized to a very small extent, especially if (depending on the material) a deactivation to restore a fluidized bed is more difficult should lead. The deactivation can, for example, bring about the formation of a compacted fixed bed (also referred to as a powder plug).

Preferably, during a reduction and / or an increase in the speed of the coating device, the volume flow of the gas introduced into the powder container through the discharge fluidization zone and / or the central fluidization zone is reduced. Alternatively or additionally, the volume flow of the gas introduced into the powder container through the discharge fluidization zone and / or the central fluidization zone is preferably increased at the start of the discharge of the powdery build-up material by the discharge device. By reducing the volume flow when reducing and / or increasing the speed, i. H. generally an acceleration, the coating device can be reduced or prevented, for example, a sloshing of the powdery build-up material in the Pulverbehäl ter. By increasing the volume flow at the start of the powder discharge, an improved (initial) powder discharge can be achieved, for example.

According to a further aspect, a method for applying at least one layer of a powdery build-up material is provided, which can be carried out or is carried out in a device for the additive setting of a three-dimensional object by applying powdery build-up material layer by layer and selectively solidifying the applied layers at points, accordingly the respective cross-section of the three-dimensional object in the respective layer, wherein a coating device for applying a layer of the powdery building material is moved in at least one direction of movement over a working plane of the device. The coating device comprises a powder discharge module and the powder discharge module has a powder container which holds powdery building material. The powder container comprises a supply opening for supplying powdery build-up material to the powder container and an output area facing the work plane when the coating device is operating as intended, the output area having at least one first discharge device for discharging powdery build-up material. In a first area of the dispensing area, which is an area of the dispensing area adjoining the first dispensing device, a dispensing fluidization zone for fluidizing the powdery build-up material using a gas is provided in the powder container and / or in a second area of the dispensing area, which is spaced apart from the first dispensing device Area of the output area, a central fluidization zone is provided for fluidizing the powdery build-up material using a gas in the powder container and gas is introduced at least temporarily through the discharge fluidization zone and / or the central fluidization zone into the powder container. The powder discharge module preferably further comprises at least one first flow reducing element provided in the powder container, the powder container further preferably having the flow reducing element at at least one upper container area and / or wherein the flow reducing element extends essentially from the at least one upper container area in the direction of the output area and / or wherein the flow-reducing element has at least one, preferably a plurality of flow-reducing structures, preferably powder openings penetrating the flow-reducing element.

This makes it possible, for example, to achieve the effects or similar effects described above in relation to the method according to the invention for applying at least one layer, even when using a powder discharge module without a flow-reducing element. The method for applying at least one powder layer according to the further aspect can be developed by the features of the method according to the invention for applying at least one powder layer described above or listed in the subclaims.

An inventive method of setting a three-dimensional object is used for the additive setting of a three-dimensional object in a device by applying powdery build-up material in layers and selective solidification of the applied layer at points that correspond to the respective cross-section of the three-dimensional object in the respective layer, with at least one layer of the layer being applied building material an above-described method according to the invention and / or a method described above according to the further aspect is carried out. This makes it possible, for example, to achieve the effects described above in relation to the method according to the invention for applying at least one layer of the pulverulent construction material and / or the method for applying at least one layer of the pulverulent construction material according to the further aspect in an additive manufacturing process .

Another method is used to control a coating device and can be carried out or is carried out in a device for the additive production of a three-dimensional object by applying powdery build-up material in layers and selectively solidifying the applied layers at points corresponding to the respective cross-section of the three-dimensional object in the respective Layer, wherein the coating device for applying a layer of the powdery build-up material is controlled in such a way that it is moved in at least one direction of movement over a working plane of the device. The coating device comprises a powder discharge module, the powder discharge module having a powder container which receives powdery build-up material. The powder container comprises a supply opening for supplying the powdery build-up material to the powder container and an output area facing the working plane when the coating device is in normal operation. The dispensing area has at least one first discharge device, which is controlled in such a way that it discharges building material in powder form at least at times. Furthermore, the output area has at least one fluidization zone, which is controlled in such a way that it at least temporarily fluidizes powdery building material using a gas in the powder container. The powder container further comprises at least one first flow reducing element provided in the powder container and / or in a first area of the output area, which is an area of the output area adjoining the first discharge device, there is a discharge fluidization zone for fluidizing the powdery build-up material using a gas in The powder container is provided and / or in a second area of the dispensing area, which is an area of the dispensing area spaced from the first dispensing device, is a central fluidization zone for fluidizing the powdery build-up material using a gas Powder container provided and wherein gas is at least temporarily passed through the discharge fluidization zone and / or the central fluidization zone into the powder container. In particular, the coating device can be controlled in such a way that it carries out a method described above for applying at least one powder layer.

Further features and usefulnesses of the invention will become apparent from the description of embodiments Be with reference to the accompanying drawings.

Fig. 1 is a schematic, partially sectioned view of a device for generative Fierstellen a three-dimensional object ge according to an embodiment of the present invention.

FIG. 2 is a schematic, sectional view of a powder discharge module of the device shown in FIG.

FIG. 3 is a schematic top view of an output area of the powder discharge module shown in FIG. 2 from above.

FIG. 4a is a schematic view of one in that shown in FIGS. 2 and 3

Powder discharge module provided flow reduction element and FIG. 4b shows the alignment of two flow reduction elements in the powder discharge module shown in FIGS. 2 and 3 in relation to one another.

5 is a schematic block diagram showing the steps of a method for applying a powder layer in the apparatus shown in FIG. 1 using the powder discharge module shown in FIGS. 2 and 3.

A first embodiment of the present invention is described below with reference to FIG. 1. The device shown in Fig. 1 is a laser sintering or Laser melting device 1. To build up an object 2, it contains a process chamber 3 with a chamber wall 4.

In the process chamber 3, an upwardly open container 5 with a container wall 6 is arranged. A working plane 7 is defined by the upper opening of the container 5, the area of the working plane 7 lying within the opening, which can be used to build the object 2, is referred to as construction field 8.

In the container 5 is a movable in a vertical direction V carrier 10 is arranged, on which a base plate 11 is attached, which closes the container 5 down and thus forms the bottom. The base plate 11 can be a plate formed separately from the carrier 10 and attached to the carrier 10, or it can be formed integrally with the carrier 10. Depending on the powder and process used, a construction platform 12 can also be attached to the base plate 11 as a construction base, on which the object 2 is built. The object 2 can, however, also be built on the base plate 11 itself, which then serves as a construction base. In Fig. 1, the object 2 to be formed in the container 5 on the construction platform 12 is shown below the working plane 7 in an intermediate state with several solidified layers, surrounded by building material 13 that has remained unsolidified. The vertical direction V defines the z-direction of a Cartesian coordinate system.

The laser sintering device 1 also contains a storage container 14 for a powdery building material 15 that can be solidified by electromagnetic radiation and a coating device 16 movable in at least one direction of movement B, which is also referred to as the coating direction, for applying the building material 15 within the building field 8. The direction of movement B is 1 shows a horizontal direction and defines the x-axis of the Cartesian coordinate system, the z-direction of which is defined by the vertical direction V of the carrier 10. The coating device 16 preferably extends transversely to its direction of movement B, ie in the y-direction or in FIG. 1 into the plane of the drawing, over the entire area to be coated. The coating device 16 comprises a powder discharge module 18, which will be described below with reference to FIGS. 2, 3, 4a and 4b is described in more detail and is not shown in FIG. Furthermore, the coating device 16 comprises at least one application element not shown in the figures, for example an applicator roller and / or an applicator blade and / or a flexible applicator element, for example a flexible rubber lip or a brush, for pulling out the powdery build-up material 15 to form a uniform layer and / or or compaction of an applied layer. The at least one application element can also be provided on the powder discharge module.

Various types of powder can be used as the building material, in particular special metal powder, plastic powder, ceramic powder, sand, filled, coated or mixed powder.

Optionally, a radiant heater 17 is arranged in the process chamber 3, which is used to heat the applied building material 15. An infrared radiator, for example, can be provided as the radiant heater 17.

The laser sintering device 1 furthermore contains an exposure device 20 with a laser 21 which generates a laser beam 22 which is deflected via a deflection device 23 and through a focusing device 24 via a coupling window 25 which is attached to the top of the process chamber 3 in the chamber wall 4, is focused on the working level 7.

The laser sintering device 1 also contains a control unit 29, via which the individual components of the device 1 are controlled in a coordinated manner to carry out the construction process. Alternatively, the control unit can also be attached partially or entirely outside the device. The control unit can contain a CPU, the operation of which is controlled by a computer program (software). The computer program can be stored separately from the device on a storage medium from which it can be loaded into the device, in particular into the control unit. During operation, in order to apply a powder layer, the carrier 10 is first lowered by a height which corresponds to the desired layer thickness. The coating device 16 first moves to the storage container 14 and takes from it a sufficient amount of the building material 15 to apply at least one layer into the powder discharge module 18 (not shown in FIG. 1; see, for example, FIG. 2). Then the coating device 16 moves over the construction field 8, brings there powdery construction material 15 on the construction base or an already existing powder layer and pulls it out to form a powder layer. The application takes place at least over the entire cross section of the object 2 to be produced, preferably over the entire construction field 8, that is to say the area delimited by the container wall 6. Optionally, the powdery building material 15 is heated to a working temperature by means of a radiant heater 17.

The cross-section of the object 2 to be produced is then scanned by the laser beam 22, so that the powdery building material 15 is solidified at the points that correspond to the cross-section of the object 2 to be produced. The powder grains are partially or completely melted at these points by means of the energy introduced by the radiation, so that they are connected to one another as solid bodies after cooling. These steps are repeated until the object 2 is completed and the process chamber 3 can be removed.

An exemplary embodiment of the powder discharge module 18 of the coating device 16 is described below with reference to FIGS. 2 and 3. The powder discharge module comprises a powder container 30 for receiving the powdery building material. Fig. 2 shows a view of the powder discharge module 18 or the powder container 30 in section, the section plane running essentially perpendicular to the working plane 7 and parallel to the direction of movement B of the coating device 16, ie parallel to the xz plane. Fig. 3 shows a plan view of an output range or container bottom 31 of the powder container 30 from above (parallel to the xy plane, that is, parallel to the direction of movement B). As can be seen from Fig. 2, the powder container 30 comprises as the upper (ie the working level 7 (see Fig. 1) facing away from the intended operation) container area a container ceiling 32, which limits the powder container 30 at the top and in which a feed opening 33 is provided for supplying the powdery building material 15 to the powder container 30. As the lower container area (ie facing working level 7 (see FIG. 1) in normal operation), the powder container 30 comprises an output area which is designed as a container bottom 31 and delimits the powder container 30 at the bottom. The powder container 30 is laterally bounded by a container wall, of which only the side wall 34b located at the front in the direction of movement B and the side wall 34a located at the rear in the direction of movement B are shown. A cover (not shown in the figures) for closing the feed opening 33 can be provided on the feed opening 33.

The interior of the powder container 30 extends between the container top 32 and the container bottom 31, i. H. in the z-direction, over a flea Fl and along the direction of movement B, d. H. in the x-direction, over a width A. perpendicular to its fleas Fl and the width A, d. H. in the y direction, the interior of the Pulverbehäl age 30 extends over a length L (see. Fig. 3).

As can be seen from FIG. 2, the container bottom 31 has a thickness d in the z-direction, ie parallel to the fleas F1 of the interior of the powder container 31. The thickness d is preferably smaller than the fleas Fl of the interior of the powder container 30. Furthermore, the container bottom 31 comprises two spaltför-shaped dispensing openings or dispensing devices designed as dispensing gaps 36a, 36b, which extend in the z-direction over the entire thickness d of the Extend the output area. They each form an output opening for discharging powder-form building material provided in the powder container 30 downwards, ie in the direction of the working plane 7 (not shown in FIG. 2; see FIG. 1 in this regard). Furthermore, a discharge element (not shown in detail in the figures) for regulating the amount of powder discharged through the discharge gap 36a, 36b and / or for at least partial opening and / or closing of the discharge gap 36a, 36b can be provided at at least one of the discharge gaps 36a, 36b. The discharge element (not shown in the figures) can for example be designed as a slide and / or a (metering) roller. The two output gaps 36a, 36b are provided in the direction of movement B, ie in the x direction, spaced from one another on the container bottom 31. In Fig. 2 the right output gap 36b is the output gap in the front in the (current) direction of movement B and the left output gap 36a is the output gap in the rear in the (current) direction of movement B. The dispensing gaps 36b, 36a are preferably provided on a delimitation of the container bottom 31 which is located at the front or rear in the direction of movement B.

In their areas adjoining the container bottom 31, the side walls 34a and 34b optionally each have an inclined section 35a and 35b, which is designed as a ramp and slopes downwards towards the respective dispensing gap 36a and 36b, i. H. is at least partially funnel-shaped. The inclined section 35a, 35b of the side wall 34a, 34b preferably merges into a substantially vertical wall section 37a or 37b of the container bottom 31, which connects the respective output gap 36a and 36b in the direction of movement B, i.e. H. limited in the x direction or the opposite direction. Alternatively, the inclined section 35a, 35b itself can move the respective output gap 36a or 36b in the direction of movement B, ie. H. in the x-direction, or at least partially limit the opposite direction, d. H. the container bottom 31 can also be provided without the vertical wall section 37a or 37b.

Furthermore, the container base 31 comprises a first region adjoining the discharge gap 36b at the front in the direction of movement B, in which a first discharge fluidization zone 41b is provided. The container bottom 31 further comprises a third area adjoining the discharge gap 36a at the rear in the direction of movement B, on which a second discharge fluidization zone 41a is provided. Between tween the first and the third area of the container bottom 31, a second loading area of the container bottom 31 is provided, which is spaced from the dispensing gaps 36a, 36b and on which a central fluidization zone 40 is provided. The first and second discharge fluidization zones 41 b, 41 a can be provided at a distance from the respective output gap 36 b, 36 a or each attached to them. boundaries (as shown in Fig. 2). The central fluidization zone 40 can be provided at a distance from the first and / or the second discharge fluidization zone 41 b, 41 a (as shown in FIG. 2) or adjoin them.

The first discharge fluidization zone 41b comprises a flask space 44b formed in the container bottom 31, which is separated from the interior of the powder container 30 by a porous plate and / or perforated plate 45b. The second discharge fluidization zone 41a and the central fluidization zone 40 each include a cavity 44a or 42 formed in the container bottom 31, which is separated from the interior of the powder container 30 by a porous plate and / or perforated plate 45a or 43. The cavities 42, 44a, 44b are each connected to a gas supply line, not shown in FIG. 2, for supplying a gas. The gas supply lines preferably each include a control device for adjusting the volume flow of the gas flowing through the gas supply lines. More preferably, the volume flows of the gas flowing into the cavities 42, 44a, 44b can be adjusted independently of one another by the respective control devices.

The porous plates and / or perforated plates 43, 45a, 45b each have a plurality of gas outlet openings which are designed or dimensioned such that they are permeable to the gas, but not to the powdery building material. The opening cross-sections of the gas outlet openings are therefore smaller than the cross-sectional areas of the powder grains of the building material, preferably smaller, more preferably several times smaller than a minimum cross-sectional area of the powder grains.

Optionally, one or more discharge opening fluidization zones (not shown in FIG. 2) can be provided on at least one of the inclined sections 35a, 35b of the side walls 34a, 34b and / or on at least one of the essentially vertical wall sections 37a or 37b of the container bottom 31 . A discharge opening fluidization zone preferably comprises, analogously to the discharge fluidization zones 41 a, 41 b and the central fluidization zone 40, a cavity formed in the inclined section 35a, 35b or the wall section 34a, 34b (in FIG not shown), which is separated from the interior of the powder container 30 by a porous plate and / or perforated plate (not shown in FIG. 2).

During operation of a fluidization zone 40, 41 a, 41 b (this also includes the discharge opening fluidization zones not shown in detail in the figures), gas flows through the respective gas supply line (not shown in FIG. 2) into the respective cavity 42, 44a, 44b and then flows through the respective porous plate and / or perforated plate 43, 45a, 45b into the interior of the powder container 30. With a sufficiently large gas volume flowing into the powder container 30 or a sufficiently large volume flow of the inflowing gas, the powdery build-up material is at least locally placed in a fluidized bed or fluidized bed-like state d. H. fluidized. The volume flow of the gas flowing into the powder container is preferably adjustable by the corresponding control device.

Furthermore, two flow-reducing elements designed as baffle plates or baffle plates 50a, 50b are provided in the powder container 30 shown in FIG. 2, which elements are hereinafter referred to as baffle plates. The baffles 50a, 50b are placed in the powder container 30, preferably on the container ceiling 32, for example by means of a respective fastening section 51a, 51b which runs essentially parallel to the container ceiling 32. The baffles 50a, 50b each extend essentially vertically downward from the container ceiling 32, i.e. H. in the direction of the container bottom 31. In the powder container 30 shown in Fig. 2, the baffles 50a, 50b are each provided at a distance from the Behäl terboden 31, d. H. they only extend over a portion of the height H, for example over 70% of the height H of the interior of the powder container 30. Alternatively, at least one of the baffles 50a, 50b can extend over the entire height H of the interior of the powder container 30, i.e. from the Be container ceiling 32 to the container bottom 31.

The baffles 50a, 50b are arranged in the powder container 30 at a distance from one another in the direction of movement B. In FIG. 2, the right baffle plate 50b is the baffle plate located in front in the (current) direction of movement B and the left baffle plate 50a is the baffle plate located at the rear in the (current) direction of movement B Baffle plate. The feed opening 33 of the powder container 30 is provided in the direction of movement B between the baffles 50a, 50b. The baffles 50a, 50b are further described in more detail below with reference to FIGS. 4a and 4b.

3 shows a plan view of the container bottom 31 from above. As can be seen from FIG. 3, the discharge gaps 36a, 36b, the discharge fluidization zones 41a, 41b and the central fluidization zone 40 each extend essentially in a longitudinal direction perpendicular to the direction of movement B, i.e. H. parallel to the length L of the interior of the powder container 30, and essentially over the entire length L of the interior of the powder container 30, but at least over 80% of the length L.

In a projection of the container top 32 onto the container bottom 31, the Zuführöff opening 33 is provided within the central fluidization zone 40, in FIG. 3 by the area between the dashed lines. The baffles 50a, 50b are also provided within the central fluidization zone 40 in a projection onto the container bottom 31, shown in FIG. 3 by the dash-dotted lines. In the projection, at least one of the baffles 50a, 50b can, however, also be provided outside the central fluidization zone 40 and / or at an edge of the central fluidization zone 40. As can be seen from FIG. 3, the feed opening 33 and the baffle plates 50a, 50b likewise in each case essentially in a longitudinal direction perpendicular to the direction of movement B, i. H. parallel to the length L of the interior of the powder container 30, and essentially over the entire length L of the interior of the powder container 30, but at least over 80% of the length L.

The baffles 50a, 50b are described in more detail below with reference to FIGS. 4a and 4b. As can best be seen from FIG. 4a, the front baffle 50b has a plurality of powder openings 52b penetrating the baffle 50b and the rear baffle 50a has a plurality of powder openings 52a penetrating the baffle 50a (FIG. 4a optionally shows the front baffle 50b or the rear baffle plate 50a). The powder openings 52a, 52b of the respective baffle plate 50a, 50b are each regularly spaced from one another. provided at a distance in the baffle plate 50a, 50b. In Fig. 4a, 4b the powder openings 52a, 52b are arranged in two offset rows of four powder openings each, but more than two rows and / or rows of more than four powder openings, for example 15 openings, can be provided. The rows also do not have to be offset from one another, or the powder openings can be arranged differently than in rows or columns. Preferably, the powder openings 52a, 52b are each essentially over the entire extent of the surge plate 50a, 50b in the direction of the height H of the powder container 30 (see FIG. 2) and essentially over the entire extent of the surge plate 50a, 50b in Direction of the length L of the powder container 30 (see Fig. 2, 3) is provided.

The powder openings 52a, 52b are designed or dimensioned and in the

Baffle plate 50a, 50b arranged so that powdery building material can pass the powder openings 52a, 52b at least when the coating device 16 or the powder discharge module 18 is at a standstill. For example, the powder openings 52a, 52b can have an opening diameter or a maximum extent of the opening which is at least one hundred times a grain diameter assigned to the powder grains of the build-up material, for example a maximum grain diameter or a grain diameter of a defined parameter of the powder size distribution. For example, an average grain diameter of the powdery building material can be in the range of 50 μm and the opening diameter or the maximum extension of the powder openings in the range of 5 mm or 10 mm. The cross-sectional shape of the powder openings can be designed as desired, preferably the powder openings have a regular cross-sectional shape, for example circular, as shown in FIGS. 4a and 4b, or square, triangular or slot-shaped.

Furthermore, the baffles 50a, 50b are designed to at least reduce or avoid sloshing of the fluidized build-up material when the coating device 16 or the powder discharge module 18 is moved. For this purpose, the closed areas of the baffles 50a, 50b between the powder openings 52a, 52b are sufficiently dimensioned to have a braking effect due to the loading acceleration of the coating device 16 or the powder discharge module 18 be moving fluidized build-up material. For example, a ratio of the total opening area of all powder openings 52a, 52b of a baffle 50a, 50b to the remaining closed area of baffle 50a, 50b can be between 30% and 40%, for example 36%.

In the direction of movement B (see FIG. 2), the baffles 50a, 50b have a thickness which is several times smaller than the extent of the baffles in the y-direction, ie. H. the longitudinal direction, and the z-direction, d. H. along the height.

As can best be seen from FIGS. 2, 3 and 4b, the baffles 50a, 50b are arranged essentially parallel to one another in the powder container 30. Furthermore, the baffles 50a, 50b are designed and arranged in the powder container 30 in such a way that their powder openings 52a and 52b are offset from one another in a projection on one another or on a common plane, at least in sections. In Fig. 4b a view of the surge plate 50a located at the rear in the direction of movement is shown, wherein through each of the powder openings 52a a portion of a powder opening 52b of the one behind it in the view of FIG. 4b (or in front of it in the direction of movement) front baffle 50b is visible.

In the figures, baffles 50a, 50b are shown with a plurality of powder openings 52a, 52b. Alternatively, at least one of the baffles 50a, 50b can also have only a single powder opening (not shown in the figures). For example, the one powder opening can be designed as a serpentine slot which extends, for example, in the longitudinal direction.

Optionally, the powder openings or the at least one powder opening of at least one baffle plate 50a, 50b are designed as adjustable and / or changeable powder opening (s), ie the geometric shape and / or the opening area of the powder opening (s) can be set or changed. The application of a layer of the powder-form building material is described below with reference to FIG. 5, reference being made to the previous FIGS. 1 to 4b. As already mentioned above with reference to FIG. 1, in a first step S1, which is also referred to as the filling step, the coating device 16 initially takes from the storage container 14 an amount of the build-up material 15 sufficient to apply at least one layer into the powder discharge module 18 . For this purpose, the cover of the supply opening 33 (not shown in the figures) is geöff net and the powdery material 15 is supplied from the storage container 14 through the supply opening 33 to the powder container 30. During the supply of the powdery build-up material, the powder container 30 is essentially in the same position below the storage container 14, which is also referred to as the filling position of the coating device 16, ie it or the coating device 16 does not move. The powder openings 52a, 52b of the baffles 50a, 50b are permeable to the powdery building material, so that the powdery building material is distributed in the powder container 30 starting from the area of the supply opening 33. While the powdery build-up material is being fed in, a gas is introduced into the powder container 30 at least through the central fluidization zone 40, preferably at least through the central fluidization zone 40 and the discharge fluidization zones 41 a, 41 b, further preferably also through the discharge opening fluidization zones, and the powdery build-up material in the powder container 30 thus fluidized, whereby the formation of a pouring cone is at least reduced ver and a distribution of the powdery building material over substantially union over the entire width A of the powder container 30 is favored.

Powdery building material is preferably fed to the powder container 30 until a previously determined fill level of the building material in the powder container 30 is reached. The fill level can be detected, for example, by means of a light barrier (not shown in the figures) arranged in the powder container.

After this filling step, the coating device 16 applies a layer of powder. For this purpose, in a second step S2, the coating device 16 is moved out of the filling position in the direction of movement B onto a, preferably previously fixed applied, accelerated travel speed. In a third step S3, the coating device 16 travels at a substantially constant speed, namely the preferably previously determined travel speed reached at the end of the second step S2, over the construction field 8, where powdery construction material 15 is applied to the construction substrate or an already existing one Powder layer and pulls it out into a powder layer. The application of the construction material in powder form takes place by discharging the construction material from the powder container 30 of the powder discharge module 18 through at least one of the output gaps 36a, 36b. The coating device 16 is then braked, ie accelerated (negative acceleration), in a fourth step S4.

During the movement of the coating device over the construction field in the third step S3, gas is introduced into the powder container 30 through at least one of the discharge fluidization zones 41 a, 41 b. This is preferably that discharge fluidization zone 41a, 41b which is closer to the discharge gap 36a, 36b through which build-up material is discharged in the third step. Preferably, gas is also discharged through the dispensing opening fluidization zones, which are provided on the inclined section 35a, 35b of the side wall 34a, 34b and on the essentially vertical wall sections 37a, 37b of the container bottom 31, of the dispensing space 36a, 36b, through the construction material becomes. The gas introduced through the discharge fluidization zone and optionally through the discharge opening fluidization zone can, for example, have a volume flow that is essentially the same as in the filling step S1. In step S3, gas with a lower volume flow is preferably introduced through the central fluidization zone 40 than through the discharge fluidization zone 41a, 41b and / or than in the filling step S1, or there is essentially no gas through the central fluidization zone 40 in the powder container 30 initiated. As a result, the powdery build-up material provided in the powder container 30 is essentially only fluidized in the area of the discharge gap 36a, 36b used for discharging the build-up material, or at least more fluidized in this area. Thus, less building material is fluidized, which reduces the amount of fine particles discharged from the powdery building material in the powder container 30. At the beginning of the powder discharge through the at least one discharge gap 36a, 36b in the third step S3, the volume flow of the fluidization zone 41a, 41b through the discharge and the discharge opening fluidization zones, preferably also that through the central fluidization zone 40, is preferably introduced into the powder container Increased gas in order to achieve an improved discharge of the powdery Aufbauma terials.

In the second step S2, in which the speed of the coating device 16 is increased, and / or in the fourth step S4, in which the speed of the coating device 16 is reduced, the volume flow of the through the at least one discharge fluidization zone 41a, 41b and optionally through the output opening fluidization zones, possibly also through the central fluidization zone 40, gas introduced into the powder container 30 is reduced in order to prevent or at least reduce sloshing of the powdery build-up material in the powder container 30 during the acceleration process.

In the powder discharge module 18 shown in Fig. 2, the first discharge fluidization zone 41b is provided in the direction of movement B behind the output gap 36b in the direction of movement and the second discharge fluidization zone 41a is provided in the direction of movement B in front of the output gap 36b that is rear in the direction of movement, so that the discharge fluidization zones 41a, 41b and the central fluidization zone 40 are provided in the direction of movement B between the discharge gaps 36a, 36b. The optional dispensing opening fluidization zone (s), which is or are provided on at least one inclined section 35a, 35b of a side wall 34a, 34b and / or on at least one of the essentially vertical wall sections 37a or 37b of the container bottom 31, are shown in FIG Direction of movement B is provided in front of the front output gap 36b or behind the rear output gap 36a, ie on the side of the respective output gap 36a, 36b opposite the respective discharge fluidization zone 41a, 41b.

Alternatively, at least one of the discharge fluidization zones 41 a, 41 b can also be provided in the direction of movement B in front of the front discharge gap 36b or behind the rear discharge gap 36a, in particular if at the discharge gap 36a, 36b no dispensing opening fluidization zone (s) is or are provided. Further fluidization zones can also be provided in the area of the container bottom 31, for example at least one of the fluidization zones can be formed by several fluidization zones formed separately from one another.

In general, the number of fluidization zones, discharge gaps, baffles and / or the feed opening can differ from the number described here. For example, the powder container can only be provided with the central fluidization zone 40 and the discharge fluidization zones 41a, 41b. As an alternative or in addition, the powder container can have only one discharge opening and / or only one baffle plate or more than two baffle plates and / or more than one, for example two, supply openings. The powder container can also be provided without surge plates.

The inclined section 35a and 35b of the side walls 34a and 34b described above with reference to FIG. 2, which can each comprise an output opening fluidization zone, can alternatively or additionally be designed as inclined sections of the respective output gap 36a, 36b itself. Further inclined or at least partially funnel-shaped areas can also be provided. The container bottom 31, which in FIG. 1 has an essentially flat surface facing the interior of the powder container 31, can, for example, also slope down towards the dispensing gaps 36a, 36b, i. H. be designed as an inclined section. Correspondingly, the porous plates and / or perforated plates 45a, 45b in FIG.

2, for example, also have a respective output gap 36a, 36b sloping down section. In general, such inclined sections are preferably formed without edges to any non-inclined or flat sections, for. B. by means of a suitable rounding.

In the embodiment described above, the flow-reducing element (s) are designed as baffles or baffles, ie as flat elements penetrated by at least one powder opening. Alternatively or additionally In addition, other flow-reducing structures than the powder openings described above can be provided on the flow-reducing element (s), e.g. B. one or more ribs and / or slats.

Even if the present invention has been described using a laser sintering or laser melting device, it is not limited to laser sintering or laser melting. It can be applied to any method for the generative production of a three-dimensional object by applying layers and selectively consolidating a powdery building material.

The imagesetter can, for example, comprise one or more gas or solid-state lasers or any other type of laser such as laser diodes, in particular VCSEL (Vertical Cavity Surface Emitting Laser) or VECSEL (Vertical External Cavity Surface Emitting Laser), or a line of these lasers. In general, any device can be used as an exposure device with which energy can be applied selectively as wave or particle radiation to a layer of the building material. Instead of a laser, it is possible, for example, to use another light source, an electron beam or any other energy or radiation source that is suitable for solidifying the building material. Instead of deflecting a beam, exposure with a movable line exposure unit can also be used. Also on selective mask sintering, in which an extended light source and a mask are used, or on high-speed sintering (HSS), in which a material is selectively applied to the building material that increases the absorption of radiation at the corresponding points (Absorption sintering) or reduced (inhibition sintering), and then unselectively exposed over a large area or with a movable line exposure unit, the invention can be used.

Instead of introducing energy, the selective solidification of the applied building material can also take place by means of 3D printing, for example by applying an adhesive. In general, the invention relates to the additive manufacturing of an object by means of layer-by-layer application and selective solidification of a powder-form building material, regardless of the manner in which the building material is solidified.

Claims

1 . Powder discharge module for a coating device (16) of a device (1) for the additive manufacture of a three-dimensional object (2) by applying powdery build-up material in layers and selectively solidifying the applied layers in places corresponding to the respective cross-section of the three-dimensional object (2) in the respective layer, the coating device (16) being provided in the device to be movable in at least one direction of movement (B) over a working plane (7) of the device (1) for applying the building material layer by layer, and

wherein the powder discharge module (18) has a powder container (30) for receiving the powdery building material and the powder container (30) comprises: a feed opening (33) for feeding the powdery building material to the powder container (30),

an output area (31) facing the working plane (7) when the coating device (16) is in normal operation, the output area (31) at least one first discharge device (36a, 36b) for discharging powdery build-up material and at least one fluidization zone (40, 41a) , 41 b) for fluidizing the powdery building material using a gas in the powder container (30), and

at least one first flow-reducing element (50a, 50b) provided in the powder container (30).

2. Powder discharge module according to claim 1, wherein the powder container (30) has the first flow reducing element (50a, 50b) on at least one upper container area (32), wherein it extends substantially from the at least one upper container area (32) in the direction of the output area (31) extends and / or

wherein the first flow reducing element extends at least over 50%, preferably over at least 70%, more preferably over at least 90% of a distance (H) of an upper container region (32) from the output region (31) and / or

wherein the first flow reducing element (50a, 50b) is provided in the powder container (30) at a distance from the discharge region (31).

3. Powder discharge module according to claim 1 or 2, wherein the first flow reducing element (50a, 50b) extends essentially in a longitudinal direction transversely, preferably perpendicularly, to the intended direction of movement (B) of the coating device (16) and preferably in the longitudinal direction Extends substantially over an entire dimension (L) of an interior of the Pulverbehäl age (30).

4. Powder discharge module according to one of claims 1 to 3, wherein the first flow reducing element (50a, 50b) has at least one, preferably a plurality of structures, the structure (s) preferably one or a plurality of the flow reducing element (50a, 50b) ) has penetrating powder opening (s) (52a, 52b).

5. Powder discharge module according to one of claims 1 to 4, wherein in the powder container (30) at least one second flow reducing element (50a, 50b) is seen, which is preferably an alignment corresponding to the first flow reducing element (50a, 50b) in the powder container (30 ), is further preferably arranged parallel to this first flow reducing element (50a, 50b).

6. Powder discharge module according to claim 5, wherein the first and the second flow reducing element (50a, 50b) designed and / or in the powder container (30) are arranged that in a projection of the first flow reducing element (50a, 50b) on the second flow reduction element (50a, 50b) the powder openings (52a, 52b) of the first and second flow reduction elements (50a, 50b) are at least partially offset from one another.

7. Powder discharge module according to one of claims 1 to 6, wherein in a first area of the output area (31), which is an area of the output area (31) adjoining the first discharge device (36a, 36b), a first discharge fluidization zone (41a, 41 b) is provided for fluidizing the powdery building material using a gas in the powder container (30) and / or in a second area of the dispensing area (31), which is an area of the dispensing area (31) spaced apart from the first dispensing device (36a, 36b), a central fluidization zone (40) for fluidizing the powdery build-up material using a gas in the powder container (30) is provided.

8. Powder discharge module according to claim 7, wherein the powder container (30) has at least one upper container area (32) on which the feed opening (33) is seen, and wherein the feed opening (33) in a projection of the at least one upper container area ( 32) is provided on the output area (31) preferably essentially in an area of the central fluidization zone (40).

9. Powder discharge module according to claim 7 or 8, wherein the output area (31) further has a second discharge device (36a, 36b) and wherein in a third area of the output area (31) which is an area adjacent to the second discharge device (36a, 36b) of the output area (31), a second discharge fluidization zone (41 a, 41 b) is provided for fluidizing the powdery build-up material using a gas in the powder container (30).

10. Powder discharge module according to one of claims 7 to 9, wherein at least one of the fluidization zones (40, 41 a, 41 b) comprises a control device for setting a volume flow through the at least one fluidization zone.

1 1. Device for the additive Fierstellen a three-dimensional object (2) by applying powdery building material layer by layer and selective solidification of the applied layer at points that correspond to the respective cross-section of the three-dimensional object (2) in the respective layer, comprising a coating device (16), which is used for Layer-by-layer application of the build-up material is provided as movable in the device (1) in at least one direction of movement (8) over a working plane (7) of the device (1), the coating device (16) having a powder discharge module (18) according to one of the claims 1 to 10 includes.

12. A method for applying at least one layer of a powdery building material, feasible in a device (1) for the additive production of a three-dimensional object (2) by applying powdery building material layer by layer and selectively solidifying the applied layers at points corresponding to the respective cross-section of the three-dimensional Object (2) in the respective layer, where

a coating device (16) for applying a layer of the powdery building material is moved in at least one direction of movement (B) over a working plane (7) of the device (1), the coating device (16) comprising a powder discharge module (18) and

wherein the powder discharge module (18) has a powder container (30) which receives powdery building material, wherein the powder container (30) comprises: a supply opening (33) for supplying the powdery building material to the powder container (30),

13. The method according to claim 12, wherein the powder discharge module (18) in a first area of the output area (31), which is an area of the output area (31) adjoining the first discharge device (36a, 36b), a discharge fluidization zone (41a , 41 b) for fluidizing the powdery building material using a gas in the powder container (30) and in a second area of the output area (31), which is an area of the output area (31) spaced from the first discharge device (36a, 36b) , a central fluidization zone (40) for fluidizing the powdery build-up material using a gas in the powder container (30) and wherein gas at least is temporarily introduced into the powder container (30) through the discharge fluidization zone (41 a, 41 b) and / or the central fluidization zone (40).

14. The method according to claim 13, wherein while moving (S3) the coating device (16) over the working plane (7) gas is introduced into the powder container (30) at least through the tragsfluidisierungszone (41 a, 41 b) and where in the case of gas with a lower volume flow through the central fluidization zone (40) than through the discharge fluidization zone (41 a, 41 b) and / or essentially no gas through the central fluidization zone (40) into the powder container (30).

15. Fierierungsverfahren for the additive Fierstellung of a three-dimensional object (2) in a device (1) by applying powdery build-up material in layers and selective solidification of the applied layer at points that correspond to the respective cross-section of the three-dimensional object (2) in the respective layer, in which

a method according to one of claims 12 to 14 is carried out to apply at least one layer of the building material.