EP2382081A2

EP2382081A2 - Method and system for reusing residual powder from an installation for the rapid prototyping of three-dimensional objects

Info

Publication number: EP2382081A2
Application number: EP10701468A
Authority: EP
Inventors: Martin Heugel; Michael Shellabear; Sven Pawliczek; Horst Maier
Original assignee: EOS GmbH
Current assignee: EOS GmbH
Priority date: 2009-01-23
Filing date: 2010-01-20
Publication date: 2011-11-02
Also published as: WO2010083997A2; JP2012515668A; US20100192806A1; WO2010083997A3; CN102164735A

Abstract

The invention relates to a method and a system for reusing residual powder from an installation for the rapid prototyping of three-dimensional objects (3), including the steps of sieving the residual powder (3a) or for mixing the residual powder (3a) with fresh powder. The method is characterized by adding the step of modifying a property of the resulting powder.

Description

Process and system for the reuse of residual powder from a plant for the generative production of three-dimensional objects

The present invention relates to a method and to a system for reusing residual powder from a plant for the additive production of three-dimensional objects.

DE 201 07 262 U1 describes a method and a system for reusing powder for producing three-dimensional objects. The system consists of a construction device which deposits a powder material layer-wise on a support or a previously applied layer and solidifies the powder material by energy-containing radiation at locations corresponding to the object. Non-solidified residual powder is conveyed from the building device via a delivery line directly into a separate from the building device provided screening device, which screens the residual powder supplied from the building device. The sieved residual powder is conveyed via a further delivery line into a storage container and can be reused. DE 103 42 883 A1 describes a construction device for producing three-dimensional objects with integrated suction device and integrated or external screening device.

Heretofore, in such building devices, integrated pipes and hoses have been used whose cleaning is complicated and which would therefore cause contamination when using different powder materials.

In particular, with metal-containing powder, the problem arises that the aging of the powder material by oxidation, etc. strongly depends on the grain size. However, a reuse of metal-containing powder is basically common. Any metal and its alloys as well as mixtures with metallic components or with non-metallic components are suitable as the metal-containing powder material. In addition, purely non-metallic powders such as plastic powder can be used.

The powder is exposed to different conditions in the plant. In the vicinity of the object to be built, higher temperatures prevail than at the edge of the installation space. In addition, the powder in the lower area of the installation space is exposed for longer than the powder in the upper area of the installation space of the warm temperature in the installation space. Furthermore, agglomerates form in the installation space, but not in the storage container and overflow container. Condensation in the construction space also creates a fine fraction which can be deposited in or on the powder. Furthermore, abrasion can occur from a coater blade.

Now, when new powder and already used residual powder are fed successively into a storage container, a ne layering with different properties in the reservoir. This creates a negative impact on the construction process.

It is the object of the present invention to provide a method and a system for reusing residual powder from a plant for the generative production of three-dimensional objects, which allow an increased quality of the building process and the objects as well as an increased economic efficiency.

This object is achieved by the method having the features of claim 1 and by the system having the features of claim 12. Advantageous developments are the subject of the dependent claims.

Further features and advantages of the invention will become apparent from the description of an embodiment with reference to the accompanying drawings.

From the figures show:

Fig. 1 is a schematic view of a building apparatus for producing a three-dimensional object;

Fig. 2 is a separately provided from the building device suction device according to the invention;

Fig. 3 is provided separately from the building device screening device according to the invention;

Fig. 4 is a separately provided from the building device feeding device according to the invention; 5 shows a transport device according to the invention when transporting a swap body. and

Fig. 6 shows the transport device according to the invention with an adapter plate for substrate plates and clamping systems.

A method and system for reusing residual powder from a plant for the generative production of three-dimensional objects are described below by the figures.

FIG. 1 shows a schematic view of a construction device for producing a three-dimensional object 3 according to the present invention, which in the embodiment is designed as a laser sintering device.

The laser sintering device has an upwardly open frame 1 with a vertically movable therein platform 2, which carries the manufactured three-dimensional object 3. The frame 1 and the platform 2 define a space inside. The platform 2 is in connection with a lifting mechanism 12, which moves it in the vertical direction so that the respective layer of the object 3 to be consolidated lies in a working plane 4.

Although not shown in FIG. 1, a metallic substrate plate may be manually placed on the platform and, if necessary, fastened or tightened. Such substrate plates are still relatively heavy with sintered objects 3. Preferably, a zero-point clamping system is used, wherein the substrate plate usually on the bottom at least one Mandrel or a pin, which must be lifted before unloading from the clamping system.

Furthermore, a coater 5 is provided for applying a layer of a powder 3a. As powder 3a, all laser-sinterable powders can be used. Any metal and its alloys as well as mixtures with metallic components or with non-metallic components are suitable as the metal-containing powder material. In addition, purely non-metallic powders such as plastic powder can be used. First, the powder 3a is supplied from a reservoir 6. The coater 5 is then moved at a predetermined height in the working plane 4, so that the layer of the powder 3a lies with a defined height above the last solidified layer. The construction device further comprises a laser 7, which generates a laser beam 7a, which is focused by a deflector 8 at any position in the working plane 4. Thereby, the laser beam 7a can selectively solidify the powder 3a at the cross section of the object 3 to be manufactured in the positions corresponding to the respective layer.

Reference numeral 10 denotes a process chamber in which the frame 1, the. Platform 2, the lifting mechanism 12 and the coater 5 can be arranged. The interior of the process chamber 10 is accessible by opening a door (not shown). Reference numeral 9 denotes an opening in the process chamber 10 for introducing the laser beam 7a. It is further a control unit 11, through which the jig is controlled in coordi ^¬ ned manner for performing the building process.

In the operation of the building device, the platform 2 is moved by the lifting mechanism 12 in a first step, until their upper side lies a layer thickness below the working plane 4. Then, by means of the storage container 6 and the coater 5, a first layer of the powder 3a is applied to the platform 2 and smoothed. Thereafter, the control unit 11 controls the deflector 8 such that the deflected laser beam 7a selectively impinges on the locations of the layer of powder 3a which are to be solidified. As a result, the powder 3a is solidified or sintered at these locations.

In a next step, the platform 2 is lowered by the lifting mechanism 12 by the thickness of the next layer. Through the reservoir 6 and the coater 5, a second layer of material is applied, smoothed and selectively solidified by means of the laser beam 7a. These steps are performed until the desired object 3 is made.

FIG. 2 shows a suction device 13 provided separately from the building device. The suction device 13 is arranged in a mobile trolley and has a receiving area for a first swap body 14. The first swap body 14 is arranged exchangeably in the suction device 13. The suction device 13 sucks in a non-solidified residual powder 3a from the building device into the first interchangeable container 14 via a flexible suction hose 15. The flexible suction hose 15 can be equipped with different nozzles, which are adapted to the geometry of the object 3 or to the material of the residual powder 3a to be absorbed. The illustrated suction device 13 further has a compressed air connection (not shown) via which it is supplied with compressed air. A compressed air source is usually present in the building devices. The suction device 13 has for this purpose a Venturi nozzle 16, which generates a suction pressure in the suction hose 15 by the compressed air, a pre-filter and a After-filter to purify exhaust gas. In addition, the suction device 13 may have an integrated balance for weighing the first interchangeable container 14. This makes it possible to detect the momentum present in the swap body 14 powder mass.

The sucked by the suction residual powder 3a is discharged via a first tube 17 into the first removable container 14. The first tube 17 is connectable at its lower end by a quick coupling 18 to an upper opening of the first replaceable container 14 and provides a dust-tight or airtight connection of the suction device 13 and the first replaceable container 14. Such quick couplings 18 can Kamlock- Clutches or other Hebelarmkupplungen be.

The upper end of the first tube 17 is secured to an outlet of the venturi 16 by a hose clamp (not shown).

FIG. 3 shows a screening device 19 provided separately from the building device. Like the suction device 13, the screening device 19 is arranged in a mobile trolley and has a receiving area for a second swap body 20. The second swap body 20 is exchangeable in the receiving area of the swap body Screening device 19 is arranged. Preferably, the second interchangeable container 20 is identical in construction to the first interchangeable container 14. The screening device 19 further has a screen 21, such as a vibrating wire screen. The sieve 21 is inserted into the sieve device 19 like a sieve insert in a sieve housing 22. The screen housing 22 consists of two housing shells, which are separable from each other to open the screen housing 22. The screening device 19 preferably further has an additional ultrasonic generator (not shown) for prevention a blockage of the sieve 21, a Überkornaustrag (not shown) for discharging coarse powder components and a metering device for controlling the amount of powder that is fed to the screen.

The strainer 21 has at its inlet a connection 23 for a second hose (not shown). The second hose is dust or airtight connected at one end by means of a hose clamp to the terminal 23 of the wire 21. The other end of the second tube is connected by a quick coupling to the upper opening of the first interchangeable container 14. The quick coupling is equal to the quick coupling 18 used in the suction device 13. In addition, the screening device 19 may have an integrated balance for weighing the second interchangeable container 14. This makes it possible to detect the momentum present in the swap body 14 powder mass.

A third hose 24 is connected at one end by means of a hose clamp (not shown) at the outlet of the wire 21. The other end of the third tube 24 can be connected by a quick coupling 25 to an upper opening of the second interchangeable container 20.

The screening device 19 screens the residual powder 3a supplied from the first swap body 14 and supplies it to the second swap body 20 provided separately from the building device.

FIG. 4 shows a feeding device 26 provided separately from the building device for feeding the sieved residual powder 3a into the building device. The feed device 26 has receptacles for at least one interchangeable container 14, 20 in the upper area, the second interchangeable containers 20 shown here being arranged upside down. are ordered so that their openings 27 are directed downwards. The powder 3a contained in the second exchangeable containers 20 can escape through the openings 27 by gravity. The second interchangeable container 20 in turn has a closure (not shown) so that the powder 3a therein can not escape unintentionally. Such a closure may be formed as a rotatable flap. Preferably, the closure is controlled by the building device. Preferably, a metering device is also provided on the supply device 26 or on the swap bodies 14, 20, which can preferably be controlled by the building device. In addition, the feeder 26 may include a replaceable nozzle that connects to the opening of the second interchangeable container 20. In addition, the feed device 26 may have an integrated balance for weighing the second interchangeable container 20. This makes it possible to detect the momentum present in the swap body 20 powder mass.

The hoses 15, 17, 24 described are interchangeable, since they are connected by hose clamps dust or air-tight with the suction device 13, the screening device 19 or the feeder 26. Instead of the hose clamps quick couplings can be used. The dust-tight or air-tight connection of the tubes 17, 24 with the swap bodies 14, 20 also takes place by means of quick-release couplings 18, 25.

The feeder 26 is preferably designed to be movable over the screening device 19. In this way, the first interchangeable container 14 can be placed upside down in the feeder 26 by a transport device described later, so that the first interchangeable container 14 is located directly above the screen 21 of the screening device 19. 5 shows the transport device 28 for transporting the first and / or second interchangeable container 14, 20. The transport device 28 is designed as a lift truck, which has a height-adjustable fork with two support arms 29. For example, the fork is moved up and down by a hand crank (not shown) via a chain drive. On the two support arms 29, two adapter pieces with coaxially arranged recesses 30 are placed. Alternatively, the recesses can also be incorporated directly into the support arms 29. The recesses 30 correspond to axes 31 which are laterally attached to the first and the second swap bodies 14, 20. If the first interchangeable container 14 and the second interchangeable container 20 are arranged in the receiving areas of the suction device 13 and the screening device 19, the recesses 30 of the support arms 29 can be moved under the corresponding axes 31 of the swap bodies 14, 20. By the hand crank, the support arms 29 can be raised so that the recesses 30 of the support arms 29 with the corresponding axes 31 of the swap bodies 14, 20 engage and the swap bodies 14, 20 are raised. After the swap bodies 14, 20 have been released from the tubes 17, 24 by releasing the quick-release couplings 18, 25, the interchangeable containers 14, 20 can be transported by the transport device 28 to the next station.

The same transport device 28 can also be used for transporting the substrate plate or a clamping system, as shown in FIG. For this purpose, an adapter in the form of an adapter plate 32 is placed on the support arms 29. The adapter plate 32 can be placed in various orientations on the support arms 29 so that the recording of various substrate plates and clamping systems allows becomes. The left side of Fig. 6 shows a first position of the adapter plate 32 for receiving a standard substrate plate, and the right side of Fig. 6 shows a second position of the adapter plate 32 for receiving a clamping system, wherein it is rotated 180 ° about the vertical axis has been.

It is obvious that the support arms 29 of the transport device 28 may have additional adapters or coaxially arranged recesses adapted to any swap bodies and substrate plates of different sizes and shapes.

The system for reusing residual powder 3a from a plant for the additive production of three-dimensional objects 3 may further comprise a device for mixing the screened or non-screened residual powder 3a with another powder. The other powder may in particular be new powder that has not yet been used. The device for mixing may moreover comprise a device for homogenizing the powder mixture or for homogenizing residual powder or new powder.

The system for reusing residual powder 3a from a plant for the generative production of three-dimensional objects 3 has, in addition to the sieving device or the mixing device, a further device for changing a property of the resulting powder.

The further device may be a device for removing particles below a defined particle size. Preferably, the removal then takes place by sight. The further device may be a device for selectively changing the chemical composition of the residual powder 3a or the resulting powder. Preferably then the targeted changing of the chemical composition by a reduction of oxides.

The further device may be a device for selectively changing the composition or a property of the atmosphere around the particles of the residual powder 3a or the resulting powder. Preferably, then, the targeted modification is effected by changing a main gas in the atmosphere and / or by changing a moisture content in the atmosphere and / or a pressure of the atmosphere.

The other device may be a device for removing impurities from the residual powder 3a or the resulting powder other than the sieving device. Preferably, the removal of impurities is accomplished by using a physical or chemical property of the residual powder 3a or the resulting powder to separate it from the impurities. More preferably, the physical or chemical property of the residual powder 3a or the resulting powder includes the geometric shape, the density and / or the relative weight, the electrical conductivity, the magnetizability or the solubility in a defined fluid medium.

Preferably, the property of the resulting powder to be changed by the processing step is measured before or after the processing step. More preferably, the measured property is documented. More preferably, the measured property is stored electronically as a data record. Preferably, the measured property is assigned to the resulting powder. More preferably, the measured property is stored on or in connection with a powder container, or the measured property is transferred to a control of the plant when reusing the resulting powder for the production of three-dimensional objects.

Preferably, the measured property is assigned to an object 3 which is produced generatively using the resulting powder.

The further device may accordingly be a device for measuring a property of the residual powder 3a, the resulting powder, the prepared powder or the new powder. Such a property of the residual powder 3a, the resulting powder, the processed powder or the new powder may be, in particular, a grain size distribution, a chemical composition, a flowability or a moisture content. The measured property of the residual powder 3a, the resulting powder, the processed powder or the new powder can be stored and documented on a memory.

Accordingly, the further device may also be a device which identifies the first or second interchangeable container 14, 20 with the property of the residual powder 3a, the resulting powder, the processed powder or the new powder. This can be realized in particular by attaching a barcode or an RFID chip (Radio Frequency Identification) to the first or second swap bodies 14, 20. In the bar code and in the RFID chip, the property of the residual powder 3a, the resulting powder, recycled powder or new powder.

Accordingly, the further device may also be a device for removing fines from the residual powder 3a, the resulting powder, the processed powder or the new powder by means of sifting or sieving. Preferably, this can be done by air classification, d. H. pneumatically or by means of a cyclone.

The further device can accordingly also be a device for processing the residual powder 3a, the resulting powder, the prepared powder or the new powder. The chemical treatment can be carried out in particular by exposing the powder to a reducing gas.

The further device may therefore also be a device for drying or moistening the residual powder 3a, the resulting powder, the prepared powder or the new powder to change its moisture content.

Accordingly, the further device may also be a device for removing impurities from the residual powder 3a, the resulting powder, the processed powder or the new powder. Such impurities may be abrasion of a coater blade of the coater 5 or abrasion of a brush (not shown).

The further device can therefore also be a device for transferring the property, stored, for example, in the barcode or the RFID chip, of the residual powder 3a, the resulting powder, the prepared powder or the new powder to the Be a construction device. The building apparatus, in turn, can have a device for changing a parameter of the production of the three-dimensional object 3 as a function of the measured property of the residual powder 3a, the resulting powder, the prepared powder or the new powder. The construction device may issue a corresponding message or warning to users. The device for changing the parameter may alternatively be realized by the control unit 11 and the associated software. Such a parameter may include a laser power, a laser scanning speed, a process temperature, a

Process gas composition or a pulsed or non-pulsed operation of the laser. Such properties are associated with the object 3 after being transferred to the building apparatus.

The operation of the system for reusing residual powder from a plant for the additive production of three-dimensional objects 3 is as follows:

After the construction device has completed the three-dimensional object 3 in the installation space, the door of the process chamber is opened. The first interchangeable container 14 was placed in the receptacle of the suction device 13, and its upper opening was dust-tight or airtight connected to the suction device 13 by the quick coupling 18. Due to the flexible suction hose 15 of the suction device 13, the non-solidified residual powder 3a is sucked out of the building device into the first interchangeable container 14 placed in the suction device 13. Subsequently, the transport device 28 is moved to the suction device 13 or vice versa that the recesses 30 of the support arms 29 are below the corresponding axes 31 of the first interchangeable container 14. By turning the hand crank, the support arms 29 are attached. lifted, so that the recesses 30 of the support arms 29 engage with the corresponding axes 31 of the first interchangeable container 14 and the first interchangeable container 14 is raised. After the upper opening of the first interchangeable container 14 has been separated from the first tube 17 by releasing the quick coupling 18, the first interchangeable container 14 is transported by the transport device 28 to the screening device 19.

At the screening device 19, the upper opening of the first interchangeable container 14 is dust-tight or airtightly connected to the second tube (not shown) by the quick-action coupling (not shown). The second swap body 20 has been dustproof or airtight with the third tube 24 already connected by the quick coupling 25.

The residual powder 3a is supplied via the second tube of the screening device 19, which sieves through the sieve 21. The dosing device prevents too much powder from landing on the sieve. The additionally provided ultrasonic generator prevents clogging of the screen 21. After the residual powder 3a has passed through the screen 21, it falls through the third tube 24 into the second interchangeable container 20.

Subsequently, the upper opening of the second interchangeable container 20 by releasing the quick coupling 25 of the third tube

24, and the second swap body 20 is transported by the transporting device 28 to the feeder 26 in a similar manner as described in the first swap body 14. It is now preferable to mix the powder with another powder and / or the processing step to change a property of the resulting powder. The second swap body 20 is lying on the support arms 29 for Example, by a tilting device (not shown) turned upside down and moved upwards so that it can be placed in the upper part of the feeder 26. The closure of the second interchangeable container 20 is closed so that no powder escapes unintentionally. The opening of the second interchangeable container 20 can now be connected to a further hose, so that the residual powder 3a located therein can be returned to the building device. The supply of the residual powder 3a from the second swap body 20 into the building apparatus can be effected by the gravity of the powder or pneumatically. Preferably, the further hose has at its end a slider or a closure which can separate the hose dust-free or airtight from the powder in the building device.

In addition to sifting the residual powder 3a or mixing the residual powder 3a with other powder, another processing step for changing a property of the resulting powder is performed.

The further treatment step may be a step for removing particles below a defined grain size. Preferably, the removal then takes place by sight.

The further processing step may be a step of selectively changing the chemical composition of the residual powder 3a or the resulting powder. Preferably then the targeted changing of the chemical composition by a reduction of oxides.

The further processing step may be a step for selectively changing the composition of the atmosphere around the particles of the residual powder 3a or the resulting powder. Vorzugswei- Then, the targeted modification is done by changing a main gas in the atmosphere and / or by changing a moisture content in the atmosphere.

The further processing step may be a step for removing impurities from the residual powder 3a or the resulting powder other than the sieving. Preferably, the removal of impurities is accomplished by using a physical or chemical property of the residual powder 3a or the resulting powder to separate it from the impurities. More preferably, the physical or chemical property of the residual powder 3a or the resulting powder includes the geometric shape, the density and / or the relative weight, the electrical conductivity, the magnetizability or the solubility in a defined fluid medium.

Preferably, the property is measured before or after the conditioning step. More preferably, the measured property is documented. More preferably, the measured property is stored electronically as a data record.

Preferably, the measured property is assigned to the resulting powder. More preferably, the measured property is stored on or in connection with a powder container, or the measured property is transferred to a control of the plant when reusing the resulting powder for the production of three-dimensional objects.

Preferably, the measured property is assigned to an object 3 which is produced generatively using the resulting powder. At any time, especially before transporting the second swap body 20 to the feeder 26 and after introducing the residual powder 3a into the second swap body 20, these quality management steps may be performed. Accordingly, such steps include, in particular, a step of measuring a property of the residual powder 3a, the resulting powder, the processed powder or the new powder, the characteristic being in particular a grain shape, a grain size distribution, a chemical composition, a flowability or a moisture content of the sieved residual powder 3a is; a step of identifying a swap body 14, 20 having the property of the residual powder 3a, the resulting powder, the processed powder or the new powder, in particular, by attaching a bar code or an RFID chip in which the property is stored

Swap bodies 14, 20; a step of removing fines from the residual powder 3a, the resulting powder, the processed powder or the new powder by sighting; a step of processing the residual powder 3a, the resulting powder, the processed powder or the new powder, in particular by chemical treatment by reduction of oxides; a step for removing impurities from the residual powder 3a, the resulting powder, the processed powder or the new powder, which may be magnetic, electrostatic or otherwise; a step to mixing the

Residual powder 3a, the resulting powder, the processed powder or the new powder with another powder; and a step of homogenizing the resulting mixed powder. The process or individual steps of the method kön- NEN be carried out in a protective gas atmosphere, which is particularly highly reactive powder _{materials, are} of advantage. Preferably, the suction device 13, the Siebvorrich- tion 19 and / or the feeder 26 has a connection for supplying or discharging the protective gas.

The property of the residual powder 3a, the resulting powder, the processed powder or the new powder stored in, for example, the bar code or the RFID chip may be transmitted to the device. In addition, the property transmitted to the construction device can be assigned to the object 3. The control unit 11 may change a parameter of manufacturing the three-dimensional object 3 depending on the measured property of the residual powder 3a, the resulting powder, the processed powder or the new powder.

The following invention offers the following advantages:

The suction and screening devices 13, 19 with the swap bodies 14, 20 provided separately from the building device make it possible to manage the quality of the residual powder 3a, of the resulting powder, of the prepared powder or of the new powder, which can be inexpensively and flexibly adapted to the customer's requirements.

The replaceable hoses 15, 17, 24 can be easily replaced or cleaned. It is thus possible that the same screening device 19 and the same suction device 13 after replacement or cleaning of the tubes 15, 17, 24 are used for various construction devices, which in turn use different powder materials.

The replaceable nozzle of the feeder 26 allows various functions, such as emptying a Ü overflow container, a powder removal of components, a delivery from separate powder containers, etc.

The swap bodies allow classification and documentation of the powders for quality management. In addition, the transport and mixing and homogenization of various powders is simplified.

The scope of protection is not limited to the illustrated embodiment, but it includes other changes and modifications, provided that they fall within the scope defined by the appended claims.

Preferably, the first swap body 14 is identical to the second swap body 20. However, this is not essential to the invention, so that the swap bodies 14, 20 may also differ.

Instead of the laser 7, an energy-containing particle radiation such as an electron beam can be used. The powder 3a does not necessarily have to be laser-sintered, but may be laser-melted.

The components described in the system can be combined as desired; For example, the suction device may be integrated with the screening device. The screening device may also be integrated with the delivery device.

The removal of the powder from the building device takes place in the exemplary embodiment by the suction device. Alternatively, the powder removal may be carried out by blowing out and collecting the powder or by discharging the powder by its gravity. The suction device can be operated by negative pressure or electrically instead of compressed air.

The preparation of the powder can be done not only for the sieved residual powder 3a, but also for fresh powder or for the non-sieved powder.

The removal of fines from the sieved residual powder 3a can be done by a twin-wire; Coarse particles remain above the twin wire, and fines are deposited below the twin wire. In between, the screened residual powder 3a is removed.

The individual steps may optionally be carried out in an inert gas atmosphere, i. H. be carried out under inert gas.

The jig is not limited to the laser sintering machine, but may be any jig using a layer-building method such as 3D printing.

Disclosed is a method for reusing residual powder 3a from a plant for the generative production of three-dimensional objects 3, wherein in addition to sifting the residual powder 3a or mixing the residual powder 3a with another powder, a further processing step for changing a property of the resulting powder is carried out. The further processing step may include removing impurities from the residual powder 3a or the resulting powder by a step other than sifting out, wherein the removal of impurities may be effected by causing a physical or chemical chemical property of the residual powder 3a or the resulting powder is used to separate it from the impurities. The physical or chemical property may include geometric shape, density, and / or relative weight, electrical conductivity, magnetizability, or solubility in a defined fluid medium.

Disclosed is a system for reusing residual powder from a plant for the additive production of three-dimensional objects 3, which performs one of the methods described above. The system may include a building apparatus that deposits a powder material layer-wise on a support or previously applied layer and solidifies the powder material by energy-containing radiation at locations corresponding to the object 3; and a separately provided from the building device suction device 13 having a first interchangeable container 14, in which the suction device 13 is sucked non-solidified residual powder 3a from the building device. The system may further comprise a separate from the building device provided screening device 19, which screens the supplied from the first swap body 14 residual powder 3a and a separately provided from the building device second swap body 20 supplies. The suction device 13 may comprise a compressed air suction with venturi 16 and a pre-filter. The screening device 19 may include a vibrating screen 21 and an additional ultrasonic generator to prevent clogging of the screen. The system may further include a feeder 26 separate from the jig for feeding the residual powder 3a, the resulting powder, the processed powder or virgin powder into the jig. The feeder 26 may have a replaceable nozzle. The suction device 13, the screening device 19 and / or the feeding device 26 can have an integrated scale. The system may further include at least one interchangeable hose 17, 24 connecting at least one swap body 14, 20 to the suction device 13, the screening device 19 or the delivery device 26; a quick coupling 18, 25 for dust or airtight connection of the at least one interchangeable container 20 with the hose 17, 24; and a hose clamp or quick coupling for dust or airtight connection of the at least one tube 17, 24 with the suction device 13, the screening device 19 or the feeding device 26 have. The system may further include a

Transport device 28 for transporting the first and / or second interchangeable container 20 have. The transport device 28 may comprise at least one adapter 30, 32, which is suitable for transporting both the first and / or second swap bodies 14, 20 and a substrate plate to be mounted in the building apparatus or a clamping system to be mounted in the building apparatus, onto which the three-dimensional object 3 is to build. The system may further include means for removing fines from the residual powder 3a, the resulting powder, the processed powder or the new powder by means of

Have views. The system may further comprise an apparatus for processing the residual powder 3a, the resulting powder, the processed powder or the new powder, in particular by chemical treatment by reduction of oxides. The system may further comprise an apparatus for removing impurities from the residual powder 3a, the resulting powder, the processed powder or the new powder. The system may further comprise means for mixing the residual powder 3a, the resulting powder, the processed powder or the new powder with another powder.

Claims

1. A method for reusing residual powder (3a) from a plant for the generative production of three-dimensional objects (3), wherein in addition to the screening of the residual powder (3a) or to mix the residual powder (3a) with another powder another Processing step for changing a property of the resulting powder is performed.

The method of claim 1, wherein the further processing step comprises removing, preferably by sifting, particles below a defined grain size.

3. The method according to any one of claims 1-2, wherein the further processing step comprises a targeted changing the chemical composition of the residual powder (3a) or the resulting powder.

The method of claim 3, wherein the targeted altering of the chemical composition comprises reduction of oxides.

5. The method according to any one of claims 1-4, wherein the further processing step comprises selectively altering the composition of the atmosphere around the particles of the residual powder (3a) or the resulting powder, preferably by changing a main gas or a moisture content in the atmosphere.

6. The method according to any one of claims 1-5, wherein the further processing step, a removal of impurities from the

Residual powder (3a) or the resulting powder by a step other than sieving.

A method according to any one of claims 1-6, wherein the property is measured before and / or after the conditioning step.

8. The method according to claim 7, wherein the measured property is documented, preferably by electronic storage as a record.

9. A method according to any one of claims 7-8, wherein the measured property is assigned to the resulting powder, preferably by storage on or in connection with a powder container.

A method according to claim 9, wherein the measured property in reusing the resulting powder to produce three-dimensional objects (3) is transferred to a plant control.

11. A method according to any one of claims 9-10, wherein the measured property is assigned to an object (3) which under

Use of the resulting powder is produced generatively.

12. A system for reusing residual powder from a plant for the generative production of three-dimensional objects (3), which carries out the method according to one of the preceding claims.

The system of claim 12, further comprising a device for measuring a property of the residual powder

(3a), the resulting powder, the treated powder or new powder, in particular a particle size distribution, a chemical composition, flowability or moisture content of the sieved residual powder (3a), the residual powder (3a), the resulting powder, the treated powder or the new powder.

14. System according to the previous claim, further with a

Device for marking a powder container (14, 20) with the property of the residual powder (3a), the resulting powder, the prepared powder or the new powder, in particular by attaching a barcode or an RFID chip in which the property is stored on the powder container (14, 20).

The system according to one of the preceding claims 13 and 14, further comprising means for transferring the property of the residual powder (3a), the resulting powder, the processed powder or the new powder contained in the tag to the building apparatus, and an apparatus for changing a parameter of manufacturing the three-dimensional object (3) depending on the measured property of the residual powder (3a), the resulting powder, the processed powder or the new powder.

16. System according to one of the preceding claims 12-15, further comprising a

Apparatus for homogenizing the resulting powder mixture.