DE102015010390B4 - Plant for additive manufacturing of three-dimensional structures - Google Patents

Abstract

System for the additive manufacturing of three-dimensional components by micro-laser deposition melting or sintering, which, within a housing (1), has a lifting table (3) that can be gradually lowered into a powder chamber (2) and is provided with a construction platform (4), a powder application tool (8) for layer-by-layer Application of a powder material to the lifting table (4) and a laser device for layer-by-layer melting or sintering of the powder layers according to the respective component contour on the construction platform (4) and outside of the housing (1) a powder storage container (6 ) and a sieving device (16) for the processing of powder material removed from the powder chamber (2) and to be returned in a cleaned state to the powder storage container (6), furthermore having at least one interchangeably and sealingly coupled to the housing (1) and having an associated powder storage container (6) connected spoke Module (13) with a powder supply channel (36) leading from the powder storage container (6) to the powder application tool (8) and closable discharge channels (25) connected to the powder chamber (2) for complete emptying of the powder contained therein into the storage module (13), which open out at a metering valve (24) formed in the storage module (13), to which an associated screening device (16) can be connected, to which a powder transfer valve (21) is assigned on the relevant powder storage container (6), with several storage modules (13) each having a powder storage containers (6) provided for a different powder material are arranged on/in a magazine frame (11) assigned to the housing (1), on which the separate screening device (16) belonging to each storage module (13) can be moved vertically and horizontally and about a horizontal axis is rotatably mounted and to a metering valve (24) connected to the outlet valve (29) or on the magazine rack (11). Powder reservoir (6) associated powder transfer valve (21) or in a position rotated by 180 ° to a waste transfer valve (22) can be coupled.

Description

The invention relates to a system for the generative manufacture of three-dimensional components by means of micro-laser deposition melting or sintering, which contains, within a housing, a lifting table which can be lowered step by step into a powder chamber and is provided with a construction platform, a powder application tool for applying a powder material in layers to the lifting table and a laser device for layer-by-layer comprises melting or sintering of the powder layers according to the respective component contour on the construction platform and, outside the housing, has a powder reservoir connected to the powder application tool and a sieve device for processing powder material removed from the powder chamber and to be returned to the powder reservoir in a cleaned state,

Selective laser sintering or melting is a generative layer construction process - also known as laser deposition welding or laser deposition melting - for the layer-by-layer production of three-dimensional structures from a powdery starting material, which is applied in a large number of thin layers to a lifting table that can be lowered into a powder chamber and is equipped with a construction platform. On the construction platform, under the effect of laser beams, an area corresponding to the contour of the three-dimensional component to be produced is melted or sintered in each powder layer and the desired component is built up layer by layer while the lifting table is lowered in layers. The powder material remaining in the powder chamber after the completion of the component, not irradiated with the laser light but still contaminated by dirt particles from the previous manufacturing process, is removed manually from the powder chamber, cleaned in a sieve device and then returned to the powder storage container. The removal of the residual powder, the sieving process and the refilling of the powder container are associated with a considerable amount of time, so that an economical series production of three-dimensional objects is not possible. When converting production to a component to be manufactured from a different powder material, there is also a great deal of effort involved in cleaning the powder storage container, the powder chamber and the screening device, as well as the connecting lines and valves. Due to the non-productive times associated with the high cleaning effort, there are also limits to the economical manufacture of three-dimensional components by laser deposition melting in this case.

One from the DE 10 2009 029 765 A1 known device for producing a three-dimensional object by successive solidification of powder layers comprises at least one receiving container, assigned to an overflow container, for the excess, contaminated powder material, which can be transported with a shifting device to a screening system or, after the cleaned powder has been received, to a powder storage container.

the DE 10 2009 005 769 A1 describes a system for reusing residual powder in the additive manufacturing of three-dimensional objects with a first and second interchangeable container for receiving residual powder sucked off using a suction device and with a separately arranged sieve device and a transport device for transporting the interchangeable container.

The invention is based on the object of designing a system for laser deposition melting in such a way that the non-productive times occurring in the manufacturing process are minimized and economic production with little expenditure of time is also ensured when manufacturing components made from different powder materials.

According to the invention, the object is achieved with a laser deposition melting system designed according to the features of patent claim 1 .

Further features and advantageous developments of the invention are the subject matter of the dependent claims.

In a system of the type mentioned at the beginning for the additive manufacturing of three-dimensional structures, in particular made of metal powder, by means of micro-laser deposition melting or sintering, the basic idea of the invention consists in the formation of a separate powder circuit for the powder material used in each case, namely by arranging at least one on the Housing that can be coupled in a precise position and connected to an associated powder reservoir Storage module trained dosing valve for portioned transfer of the powder material to a - the respective storage module and the associated, via its own powder transfer valve BES chickten associated powder reservoir - open sieve device.

With the inventive integration of the storage module, which is detachably coupled to the housing, into the powder feed to the powder application tool and the powder discharge from the powder chamber, as well as the metered transfer of the contaminated powder material from the storage module to the sieve device and from this to the powder storage container connected to the storage module, an uninterrupted powder cycle is guaranteed created from the same powder material that enables continuous series production and thus economical manufacture of three-dimensional components by laser deposition melting without the need for intermediate cleaning. With the provision of several powder circuits, each formed by a powder reservoir, a storage module, a sieve device and a powder transfer valve, intended for different powder materials, production can be immediately switched to a different powder material with the powder chamber automatically emptied via the discharge channels and without complex cleaning work. The storage module is able to fully absorb the powder material remaining in the powder chamber at the end of a manufacturing process, so that it can be immediately replaced by another storage module connected to a powder storage container. The next manufacturing process can be carried out without delay while the powder material from the previous process is being cleaned.

Several storage modules, each with a powder reservoir intended for a different powder material, are attached to a rotatable and horizontally movable magazine frame assigned to the housing, to which the separate sieve device belonging to each storage module is attached so that it can be moved vertically and horizontally and can be rotated about a horizontal axis, and to a an outlet valve connected to the dosing valve or a waste transfer valve or a powder transfer valve assigned to the respective powder storage container on the magazine frame can be coupled. This makes it possible to quickly exchange the elements forming the respective powder circuit with little effort when changing the material.

In a further embodiment of the invention, the powder feed channel in the storage module is connected via a powder transfer area in the storage module and in the housing to the powder application tool and, for emptying the powder reservoir, to an emptying channel leading to the dosing valve, into which the discharge channels open.

In an advantageous development of the invention, at the level of the powder transfer area of the storage module, further channel openings penetrating the housing in the powder transfer area are provided for drainage channels running in the storage module for removing dirt particles removed from the respective upper powder layer with the air supply unit.

In an embodiment of the invention, a closing valve that closes automatically when the powder storage container is removed is arranged in the powder feed channel.

In a further embodiment of the invention, the storage modules are attached to the magazine frame in a floating manner and can be coupled to the housing with the aid of centering domes provided on the storage modules in the powder transfer area and in the area of the channel openings of the powder discharge channels.

According to a further feature of the invention, the dosing valve in the storage module is designed as a hollow body that is open to the emptying and discharge channels and holds a specific volume of powder, which can be rotated about a horizontal axis to deliver the powder material into the sieve device connected to the outlet valve.

In a further embodiment of the invention, the discharge channels of the storage module, which are connected to the interior of the powder chamber, can be closed by a locking ring that is adjustably arranged in the powder chamber.

In an expedient embodiment of the invention, the waste transfer valves, to which an associated screening device for emptying screened powder waste into a waste container can be connected, are each fastened to the back of the storage module facing away from the housing.

In an advantageous further development of the invention, the powder reservoir has in its cover a filling opening that can be connected to the powder transfer valve for refilling with powder material processed in the screening device.

In a base plate held on the storage module, the powder reservoir has outlet openings adjoining the powder feed channel, which are held in a closed position by valve rods held on the cover under the action of a compression spring, the compression spring acting on an adjusting plate attached to the valve rod, on which a counter the compression spring acts against the eccentric shaft acting to keep the outlet openings open against the spring action.

• 1 eine Vorderansicht einer Anlage zur additiven Fertigung dreidimensionaler metallischer Bauteile durch Laserauftragsschmelzen;
• 2 eine Schnittansicht der in 1 gezeigten Anlage;
• 3 eine separate Darstellung eines mit einem Pulvervorratsbehälter verbundenen Speichermoduls mit einer Vertikalführung für eine vertikal und horizontal verfahrbare Siebvorrichtung in der Übergabeposition zu einem Einfüllventil;
• 4 das in 3 gezeigte Speichermodul in der Übergabeposition der Siebvorrichtung an ein Abfallentleerungsventil;
• 5 eine vergrößerte Darstellung des Arbeitsbereichs der Anlage zum Laserauftragsschmelzen und dem an diesen gekoppelten Pulvervorratsbehälter mit Speichermodul;
• 6 eine Detailansicht der Pulverkammer der Laseraufschmelzvorrichtung und des an diese gekoppelten Speichermoduls mit angeschlossener Siebvorrichtung bei der Pulverabführung aus der Pulverkammer über einen Ablaufkanal;
• 7 die in 6 gezeigte Detailansicht, jedoch mit geschlossenem Ablaufkanal;
• 8 eine Schnittansicht des Pulvervorratsbehälters in einer für die Zuführung von Pulvermaterial in das Speichermodul geöffneten Stellung des Ablaufventils; und
• 9 eine perspektivische Darstellung des Pulvervorratsbehälters.

An embodiment of the invention is explained in more detail with reference to the drawing. Show it:

• 1 a front view of a system for the additive manufacturing of three-dimensional metallic components by laser deposition melting;
• 2 a sectional view of the 1 plant shown;
• 3 a separate representation of a connected to a powder reservoir storage module with a vertical guide for a vertically and horizontally movable screening device in the transfer position to a filling valve;
• 4 this in 3 storage module shown in the transfer position of the screening device to a waste discharge valve;
• 5 an enlarged view of the work area of the system for laser deposition melting and the powder storage container coupled to it with storage module;
• 6 a detailed view of the powder chamber of the laser melting device and the storage module coupled to it with a connected sieve device during the powder discharge from the powder chamber via a discharge channel;
• 7 in the 6 detailed view shown, but with the drain channel closed;
• 8th a sectional view of the powder reservoir in an open position for the supply of powder material in the storage module of the drain valve; and
• 9 a perspective view of the powder reservoir.

the 1 and 2 show the entire system for producing three-dimensional metallic structures by laser deposition melting, which includes a laser deposition melting device and a device associated with it for providing the powder material required in each case and consisting of different metals.

The device for laser deposition melting, which is 5 is shown in detail, has within a housing 1 in a powder chamber 2 vertically movable lifting table 3 with a construction platform 4 mounted on it, on which the component in question is built up in layers by laser deposition melting. Via a powder feed channel 36 provided in a storage module 13 explained in more detail below and a slot opening 5 ( 5 ) The powder material provided in a powder storage container 6 reaches a powder application tool 8, which can be moved back and forth by a pendulum drive 7, with which a thin powder layer is applied to the lifting table 3 and the construction platform 4 formed on it. The reference numeral 9 designates the working area of laser beams (not shown), in which the part of the applied powder layer located on the construction platform 4 is melted in a contour corresponding to the three-dimensional structure to be produced in order to build up the desired component layer by layer by laser deposition melting. An air supply unit 10 arranged above the powder chamber 2 ensures that dirt particles occurring during the respective melting process are removed from the previously melted component area and the non-melted powder area. With the construction of the component and the simultaneous lowering of the lifting table 3 in layers, the powder chamber 2 in the area surrounding the component gradually fills with reusable powder that still has to be processed.

The laser deposition melting device described above is assigned a device for providing, preparing and feeding the powder material to the above-mentioned powder application tool 8, which essentially consists of a magazine frame 11 arranged on the powder feed side of the housing 1 and having longitudinal bars on its outer sides (four in the present exemplary embodiment). 12 at the same height floating fixed storage modules 13 and connected to these powder storage containers 6 consists. The magazine rack 11 is arranged on a rotary carriage 14 that can be moved horizontally in the direction of the housing 1 . In the interior of the magazine frame 11, each storage module 13 is assigned a screening device 16 that can be moved in a vertical guide rail 15 of each vertical longitudinal beam 12 of the magazine frame 11. The screening device 16 attached to a holding frame 17 can also be moved on a horizontal guide rail 18 and rotated about a horizontal axis. Above a filling opening 20 formed in a cover 19 of the powder storage container 6, a powder transfer valve 21 is held vertically adjustable on each longitudinal beam 12 in order to be able to return cleaned powder material from the screening device 16 via the filling opening 20 back into the powder storage container 6. A waste transfer valve 22 for emptying the waste remaining in the screening device 16 after a screening process into a waste container (not shown) is attached to the inner surface of each of the storage modules 13 .

On the side of the respective storage module 13 that faces the housing 1 during operation, there are channel openings 23 sealingly adjoining the powder chamber 2 of the laser deposition melting device, from drain channels 25 leading in the storage module 13 to a metering valve 24 provided at its lower end (see Fig 6 and 7 ) educated. Contaminated powder material that is discharged from the powder layer with the air supply unit 10 and flows out of the filled powder chamber 2 when the closing ring 26 is open, but which can be reused after a sieving process, reaches the storage module 13 via openings formed in the powder chamber 2 and can be closed with a closing ring 26. With the Reference numeral 27 designates the powder transfer area, which is connected in a sealing manner (to the powder transfer area 34 of the housing 1), from the storage module 13, which is connected to the powder storage container 6, to the powder application tool 8. Further channel openings 23 of discharge channels for dirt particles removed with the air supply unit 10 are located at the height of the powder transfer area 27. The exact coupling of the respective storage module 13 with the powder transfer area 27 to the powder transfer area 34 in the housing 1 or the channel openings 23 of the discharge channels 25 to the powder chamber 2 is carried out with the aid of centering domes 28 provided on the side of the memory module 13 facing towards the housing 1.

the 6 and 7 detail the connection between the storage module 13 and the powder chamber 2, specifically in an operating situation in which the outflow channel 25 in the storage module 13 is closed by the locking ring 26 ( 7 ) and once in the position releasing the channel opening 23 in the storage module 13 through the locking ring 26 ( 6 ). In this position of the locking ring 26, the reusable powder material that accumulates in the powder chamber during the manufacturing process and is not in the working area of the laser can automatically flow into the storage module 13 and the metering valve 24 that is arranged at its lower end and is open at the top and can be rotated about a horizontal axis . Below the metering valve 24 is an outlet valve 29 to which the screening device 16 - as in 6 and 7 shown - can be coupled in order to receive a precisely metered quantity of powder from the metering valve 24 after each rotation of the metering valve 24 by 180° and to prepare it for return to the powder storage container 6 and reuse in the laser deposition welding process.

the 1 and 3 FIG 4 the screening device 16 is shown in a position rotated by 180° about a horizontal axis and connected to the waste transfer valve 22, in which the dirt particles and non-recyclable powder components remaining in the screening device 16 are emptied into a waste container for disposal.

In this way, the powder chamber 2 can be gradually and automatically emptied via the discharge channels 25 and the metering valve 24 and the powder material can be processed using the screening device assigned to each storage module and powder storage container and reintroduced into the production process. The manufacturing process does not have to be interrupted. Even if the powder material is finally used up and the same material is to be used for further production, another powder storage container 6 held in the magazine frame 11 and filled with this material and connected to a storage module 13 can be connected immediately to the laser deposition melting device, so that there is no time-consuming additional work such as emptying the powder chamber or filling the powder reservoir can be continued immediately. This applies in particular to the conversion of production to a product made of a different material. The other material can be kept ready in a further storage module 13 connected to the magazine frame and filled with the new powder material and is immediately available for the continuation of the production process after the previously used storage module has been uncoupled and the new storage module has been coupled on without manual and time expenditure for the emptying of the powder chamber and the powder storage container and their cleaning and refilling as well as the cleaning of connecting lines and valves.

In a base plate 37 held on the storage module 13 , the powder storage container 6 has outlet openings 38 that can be closed in a sealing manner by valve rods 35 guided in the cover 19 . It can be emptied via an emptying channel 31 running in the storage module 13 up to the metering valve 24 without having to be removed from the storage module 13 . The powder storage container 6 can also be removed from the storage module 13, but is connected to it via closing valves 30, which automatically close the storage module 13 when the powder storage container 6 is removed, so that no protective gas can escape from the housing 1 via the storage module 13, and thus a Component possibly damaging refilling with protective gas is avoided. After the remaining powder material is in the position ( 8th and 9 ) of the valve rods 35 from the powder reservoir 6 ab has flowed, the storage container 6 can be removed from the storage module 13 with simultaneous actuation of the closing valves 30 , the powder storage container 6 being closed by the compression springs 33 acting on the adjusting plates 39 and thus on the valve rods 35 .

Reference List

1

housing

2

powder chamber

3

lifting table

4

build platform

5

Slot opening in 1

6

powder storage container

7

Pendulum drive from 8

8th

powder applicator

9

Working range of the laser

10

air supply unit

11

magazine rack

12

Longitudinal spars from 11

13

memory modules

14

turntable

15

vertical guide rail from 16

16

screening device

17

Holding frame of 16

18

horizontal guide rail from 17

19

cover of 6

20

Filling opening of 6

21

Powder transfer valve from 12

22

waste transfer valve

23

Channel openings from 13

24

Dosing valve from 13

25

drainage channels in 13

26

locking ring of 2

27

Powder transfer area from 13

28

centering dome

29

exhaust valve from 13

30

Closing valve from 13

31

Drainage channel from 13

32

eccentric shaft

33

compression springs

34

Powder transfer area from 1

35

valve rods

36

Powder feed channel in 13

37

bottom plate of 6

38

outlet openings of 6

39

Setting plate of 35

Claims (12)

System for the additive manufacturing of three-dimensional components by micro-laser deposition melting or sintering, which, within a housing (1), has a lifting table (3) that can be gradually lowered into a powder chamber (2) and is provided with a construction platform (4), a powder application tool (8) for layer-by-layer Application of a powder material to the lifting table (4) and a laser device for layer-by-layer melting or sintering of the powder layers according to the respective component contour on the construction platform (4) and outside of the housing (1) a powder storage container (6 ) and a sieving device (16) for the processing of powder material removed from the powder chamber (2) and to be returned in a cleaned state to the powder storage container (6), furthermore having at least one interchangeably and sealingly coupled to the housing (1) and having an associated powder storage container (6) connected spoke Module (13) with a powder supply channel (36) leading from the powder storage container (6) to the powder application tool (8) and closable discharge channels (25) connected to the powder chamber (2) for complete emptying of the powder contained therein into the storage module (13), which open out at a metering valve (24) formed in the storage module (13), to which an associated screening device (16) can be connected, to which a powder transfer valve (21) is assigned on the relevant powder storage container (6), with several storage modules (13) each having a powder storage containers (6) provided for a different powder material are arranged on/in a magazine frame (11) assigned to the housing (1), on which the separate screening device (16) belonging to each storage module (13) can be moved vertically and horizontally and about a horizontal axis is rotatably mounted and to a metering valve (24) connected to the outlet valve (29) or on the magazine rack (11). Powder reservoir (6) associated powder transfer valve (21) or in a position rotated by 180 ° to a waste transfer valve (22) can be coupled. plant after claim 1 , characterized in that the magazine frame (11) for fastening the storage modules (13) provided longitudinal bars (12) with vertical guide rails (15) for moving the screening devices (16) and is arranged on a horizontally movable rotary carriage (14). plant after claim 1 , characterized in that the powder feed channel (36) in the storage module (13) via a powder transfer area (27, 34) in the storage module (13) and in the housing (1) with the powder application tool (8) and for emptying the powder storage container (6) with a to the metering valve (24) leading discharge channel (31) into which the discharge channels (25) open. plant after claim 3 , characterized in that at the level of the powder transfer area (27) of the storage module (13), further channel openings (23) of drainage channels running in the storage module (13) are provided for discharging dirt particles removed by an air supply unit (10) from the respective upper layer of powder. plant after claim 1 , characterized in that in the powder feed channel (36) of the storage module (13) is arranged a closing valve (30) which closes automatically when the powder storage container (6) is removed. Plant after one of claims 3 until 4 , characterized in that the storage modules (13) are fixed floating on the magazine frame (11) and with the help of centering domes (28) provided on the storage modules (13) in the powder transfer area (27, 34) and in the area of the channel openings (23) of the powder discharge channels (25) can be coupled to the housing (1) in a precise position. plant after claim 1 , characterized in that the dosing valve (24) is designed as a hollow body which is open towards the emptying and discharge channels (25, 31) and accommodates a specific volume of powder, which is used to discharge the powder material into the sieve device (16 ) can be rotated around a horizontal axis. plant after claim 1 , characterized in that the outlet channels (25) of the storage module (13) connected to the interior of the powder chamber (2) can be closed by a locking ring (26) adjustably arranged in the powder chamber (2). plant after claim 1 , characterized in that the waste transfer valves (22), to which a respectively associated screening device (16) for emptying screened powder waste into a waste container can be connected, are each fastened to the rear of the storage module (13) facing away from the housing (1). plant after claim 1 , characterized in that the powder storage container has in its cover (19) a filling opening (20) that can be connected to the powder transfer valve (21) for refilling with powder material processed in the screening device. plant after claim 1 , characterized in that the powder reservoir (6) in a base plate (37) held on the storage module (13) has outlet openings (38) adjoining the powder feed channel (36), which are held by valve rods (35) on the cover (19) under the be held in a closed position by the action of a compression spring (33), the compression spring (33) acting on an adjusting plate (39) fastened to the valve rod, on which an eccentric shaft (32) acting counter to the compression spring (33) for keeping the outlet openings (38 ) attacks. plant after claim 1 , characterized in that a vibrator is assigned to the powder chamber for its complete emptying into the storage module (13).

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