Method and device for separating build material from objects produced using 3D printing.

Abstract

Method for separating unsolidified build material remaining from at least one object (3, 3') created by layer-by-layer application and selective solidification of the build material within a generative construction process by means of a flow of pressurized fluid, wherein a) the at least one object (3, 3') with the build material adhering to it and / or in it is arranged inside a chamber (2, 2') which is sealed pressure-tight, and then b) the interior of the chamber (2, 2') is subjected to a second pressure (p2) from a pressure source (6) that is higher than a first pressure (p1) prevailing or generated outside the chamber (2, 2') and in a space (22') or in a pressure sink (5), by flooding the interior of the chamber (2, 2') with pressurized fluid from the pressure source (6) until the second pressure (p2) is present inside the chamber (2, 2'), and then c) a connection between the interior of the chamber (2,2') is formed with the space (22') or with the pressure sink (5) in order to establish at least partial pressure equalization between the first pressure (p1) and the second pressure (p2), wherein d) steps a) to c) are carried out in such a way that the flow of pressure fluid resulting from the at least partial pressure equalization between the first pressure (p1) and the second pressure (p2) can encompass the at least one object (3, 3'), and wherein e) as a result of the flow of pressure fluid, any unconsolidated structural material remaining is separated from the at least one object (3, 3') and transported along with the flow of pressure fluid, and wherein f) the interior of the chamber (2') is formed between a bell (14') and at least one support or bearing element (23') for the at least one object (3'), wherein the bell (14') and the at least one support or bearing element (23') are formed and controlled to be movable relative to each other,that (g) to seal the interior of the chamber (2') in a pressure-tight manner, the bell (14') and the support or bearing element (23') are brought into pressure-tight contact with each other, and (h) to establish the connection between the interior of the chamber (2) and the space (22') or the pressure sink, the bell (14') and the support or bearing element (23') are brought out of contact.

Description

The present invention relates to a method and an apparatus for separating unsolidified build material from at least one object produced by layer application and selective solidification of the build material in the context of a generative construction process, according to claims 1 and 14.A method for separating unsolidified remaining build material from at least one object produced by layer application and selective solidification of the build material in the context of a generative construction process is known from WO 2015 / 071184 A1. There, the object is clamped in a working chamber by means of a clamping device. An air jet nozzle is provided in the working chamber, which generates an air flow directed onto the component, by means of which air flow unsolidified remaining build material is removed from the object. However, the direction of the air flow must be varied for large objects in order to detect the entire outer surface of such an object. Furthermore, it is difficult to align the nozzle inside the working chamber such that channels formed in the interior of the object and also containing loose build-up material are captured by the air flow. Not least, an operator is necessary for a targeted flow of the air flow onto the object, which is disadvantageous in an industrially carried out cleaning process. WO 2020 / 056355 A1 describes a method for depowdering additively manufactured parts in which the powder is separated from the parts by generating a pressure difference between the powder and the parts. WO 2019,027 404 A1 describes a method of cleaning parts which comprises placing the parts in a variable compression chamber, filling the chamber with a liquid and dissolving pressurized gas in the liquid to form a gas-liquid solution. US 2002 / 0074022A1 describes a method for cleaning objects in a pressure vessel using a compressed liquid containing a gas which is compressed and expanded one or more times. US 20040072706A1 describes a method for cleaning a surface of an object, in which the object is placed on a support region within a pressure chamber and the pressure chamber is subsequently pressurized.The object of the invention is to provide a method and a device for separating unsolidified build-up material from at least one object produced by layer application and selective solidification of the build-up material in the context of a generative construction process, which provides a good cleaning result in a simple and efficient manner.This object is achieved according to the invention by the features of claims 1 and 14.Disclosure of the InventionThe production of the at least one three-dimensional object, such as a component or model, which is then separated from unsolidified building material remaining with the method according to the invention, takes place in a layer building method with the aid of computer data by repeatedly applying thin layers of loose powdered building material to a building platform and / or in a building container and selectively solidifying each individual layer to form a component or model cross section. The solidification takes place, for example, chemically by applying droplets of adhesive selectively to defined regions of the layers of loose powdered building material using printing technology. Alternatively, it is possible to selectively fuse or sinter loose powdered building material with high-energy (laser) radiation.An object is therefore to be understood in the sense of the invention as a workpiece or component produced together with the construction platform, or else the workpiece or component alone without a construction platform and also an object. which has been generatively generated in a construction container.After the additive construction process, powder construction material still remaining unsolidified adheres to the object. This powdery building material which remains unsolidified is intended to be separated from the object by the method according to the invention. The separation of the at least one object from loose, non-consolidated powdery building material can comprise the complete unpacking of the object from the cake of loose building material or powder or else merely a cleaning of residues of loose powder or building material from the at least one object and optionally also from the building platform and optionally also from supporting structures which are still present on the at least one object after the unpacking.The invention therefore relates to a method for separating unsolidified build material from at least one object produced by layer application and selective solidification of the build material in the context of a generative construction process by means of a flow of pressurized fluid.The method according to the invention comprises the steps of a) placing the at least one object with the building material adhering to it and / or in it inside a chamber which is sealed pressure-tightly, and then b) placing the inside of the chamber under a second pressure from a pressure source which is higher than a first pressure prevailing or generated outside the chamber and in a space or in a pressure sink, in particular by completely flooding the inside of the chamber with pressure fluid from the pressure source, so that the second pressure prevails in particular everywhere inside the chamber, and then c) establishing a connection between the inside of the chamber with the space or with the pressure sink, in order to establish an at least partial pressure equalization between the first pressure and the second pressure, wherein d) the steps a) to c) are carried out in such a way that, the flow of pressurized fluid arising as a result of the at least partial pressure equalization between the first pressure and the second pressure can detect the at least one object, and wherein e) build-up material remaining unsolidified as a result of the flow of pressurized fluid is separated from the at least one object and carried along with the flow, and wherein f) the interior of the chamber is formed between a bell and at least one supporting or bearing element for the at least one object, wherein the bell and the at least one supporting or bearing element are formed and controlled so as to be movable relative to one another in such a way that, for the pressure-tight closing of the interior of the chamber, the bell and the supporting or bearing element are brought into a pressure-tight contact with one another, and h) for establishing the communication between the interior of the chamber and the space or the pressure sink, the bell and the supporting element are brought out of contact.In step g), the chamber is then separated from the space or the pressure sink, so that no pressure equalization can take place, while in step h) the pressure equalization can take place. Since a bell opening of a bell can provide a relatively large opening cross section, the pressure equalization takes place advantageously quickly or abruptly.The bell may be any bell-shaped, box-shaped or cup-shaped structure enclosing an interior.Most preferably, the connection between the interior of the chamber and the space or the pressure sink is established abruptly or abruptly. This is achieved in the method by bringing the bell from the lowered position into a raised position. Since such a bell, which encloses the at least one object in the lowered position, provides a relatively large flow cross section through its bell opening in the lifted position, the pressure equalization can take place very quickly.In addition, a venting valve with a flow cross section can be provided, which is then brought from its blocking position into its open position for pressure compensation.The support or bearing element can represent any element or any structural unit on or on which the at least one object can be mounted or transported, in particular on a planar surface. In this respect, a surface of the support or bearing element facing the at least one object is preferably planar, so that this planar surface can form a pressure-tight connection with the circumferential edge of the bell surrounding the bell opening in the event of contact. The bell cooperating with the support or bearing element preferably formed as a flat surface then forms a plate valve as a venting valve and a second valve, wherein the bell rim then represents a valve sealing surface of the plate valve.In contrast to the prior art mentioned at the beginning, therefore, a directed air jet is not generated by means of a nozzle, but a flow of pressurized fluid is generated by pressure equalization between the second higher pressure in the chamber and the first, in contrast lower pressure in the pressure sink or in the space. The chamber space is in particular completely flooded with the pressurized fluid under the second pressure until the second pressure acts or is present everywhere in the chamber before the pressure equalization is established. In contrast, in the case of a compressed air jet flowing from a nozzle and directed onto the object according to the prior art mentioned at the beginning, the higher pressure acts only in the local region of the compressed air jet, while zones of the working chamber deviating therefrom have a lower pressure.A sufficient flow velocity of the flow of pressurized fluid arises in particular when the pressure equalization takes place explosively, abruptly or abruptly, which can be achieved, for example, by a large flow cross section and / or a high opening velocity of a valve, for example in the form of a bell cooperating with an in particular planar valve sealing surface, by means of which the pressure equalization is produced. The pressure equalization which then takes place in particular explosively therefore generates a strong flow of pressurized fluid in which then unsolidified build-up material is detached from the at least one object and "entrained".The invention therefore has the advantage that it delivers a good cleaning result of the at least one object with little effort, because a pressurized fluid jet to be aligned multiple times with respect to the object can then be dispensed with.The dependent claims contain further embodiments of the method.Preferably, unsolidified remaining build material carried along with the flow is separated from the flow and collected in a filter device. For this purpose, the flow is conducted through the filter device.The interior of the chamber can also be connectable to the pressure source via at least one first opening in a chamber wall of the chamber, wherein the setting of the interior of the chamber under the second pressure of the pressure source takes place by a coordinated control of at least one first valve arranged in the first opening.Therefore, according to a development of the method, the first connection can additionally comprise a first valve which can be controlled in a coordinated manner by a controller. Furthermore, the second connection can additionally comprise a second valve which can be controlled in a coordinated manner by the controller.The pressure source can comprise, for example, a pressurized fluid supply such as a compressed air supply and / or a compressor and / or a pressurized fluid pump. The space can be any space in which the lower first pressure is then present or is present. This first pressure can be generated in particular by evacuating the space and then represents in particular the pressure in a vacuum. Likewise, the pressure sink can represent a vacuum. The space and / or the pressure sink can therefore also be realized in a container which has been evacuated.In particular, the support or bearing element can comprise a construction platform of the at least one object. In some objects, the at least one object is produced integrally with the construction platform in a 3D printing method. Consequently, the construction platform then has an advantageous dual function in that it constitutes, on the one hand, the "construction plate" during the production of the at least one object during the construction process and, on the other hand, the sealing surface of the support or bearing element which interacts with the bell edge of the bell with its upwardly pointing surface.The bell can also comprise a construction container in which the at least one object has been additively constructed and the upper construction container opening which is open per se after the construction process is firmly closed by a lid, wherein the at least one object is left in the construction container. The chamber is then formed by the interior of the construction container which is firmly closed by the cover and is closed at the top by the cover and at the bottom by the construction platform. The construction container then seals pressure-tightly with its construction container edge, which surrounds the lower construction container opening, viewed in the vertical direction, against the construction platform. For pressure compensation, the construction container, which stands on the construction platform, for example, but does not have a fixed connection to it, is lifted off the construction platform, in particular abruptly or abruptly, together with the cover.The bell can also be formed by a cover which, after the construction process, is placed onto the upper construction container opening of the construction container in a sealing manner with the upper construction container edge, wherein the at least one object is left in the construction container. For pressure compensation, the cover is then lifted off the upper rim of the construction container in particular abruptly or abruptly, whereby the pressure compensation is produced. In this case, the construction container is used together with the construction platform as a support or bearing element.The support or bearing element can also comprise a conveyor belt of a conveying direction, on which the at least one object is conveyed. The bell can then be controlled in a coordinated manner between a position lowered onto the conveyor belt, in which position an edge of the bell sealingly contacts the conveyor belt, and a position lifted from the conveyor belt, in which position the edge of the bell is out of contact with the conveyor belt.In this case, a) the bell can form a chamber wall of the chamber and the space or the pressure sink can be formed outside the bell and, in the position of the bell lowered onto the conveyor belt, can be bounded by the bell, a housing and the conveyor belt, wherein the bell is guided on the housing such that it can be moved relative to the conveyor belt, and b) the at least one object can be transported by transport by means of the conveyor belt through a closable feed opening of the housing into the interior of the housing and through a closable discharge opening of the housing out of the interior of the housing, wherein in the method the at least one object can be transportedα) in the position of the bell lifted off the conveyor belt, the at least one object is transported by the transport by means of the conveyor belt through the opened feed opening of the housing into the interior of the housing, and thenβ) bringing the bell into the lowered position onto the conveyor belt and closing the supply opening and the discharge opening of the housing, and thenγ) placing the interior of the chamber under the second pressure from the pressure source by fully flooding the interior of the chamber with pressurized fluid from the pressure source, and thenσ) the bell is brought in particular abruptly or abruptly into the position lifted off the conveyor belt, whereby the interior of the chamber is connected to the interior of the space or the pressure sink and, as a result of the pressure compensation between the second pressure in the chamber and the first pressure in the space or the pressure sink, the flow of pressurized fluid detecting the at least one object is generated, and thenε) opening the discharge opening of the housing, and thenξ) the at least one object is transported by transport by means of the conveyor belt in the conveying direction through the opened discharge opening out of the interior of the housing.Preferably, the conveyor belt is stopped when performing the above steps β), γ) and σ).Also, between the above steps δ) and ε), as a result of the flow, build-up material which is separated from the at least one object and which remains unsolidified and entrained together with the flow can be discharged from the space or the pressure sink. This can be accomplished, for example, by collecting the remaining unsolidified building material in a collecting container.A particularly good suitability of the above-described embodiment of the method for industrial use results if it is applied successively to a plurality of objects transported one behind the other in the conveying direction by the conveyor belt.Compressed air and / or a protective gas can be used as the pressure fluid, for example.Most preferably, the flow of pressurized fluid is generated and directed in the direction of the lower level, viewed in the vertical direction, starting from a higher level than a lower level. Then, the action of gravity assists in the detachment and removal of unsolidified remaining build material from the at least one object.The invention also relates to a device for separating unsolidified building material from at least one object produced by layer application and selective solidification of the building material in the course of a generative construction process, which device comprises at least: a) a pressure-sealable chamber which is designed for arranging the at least one object in its interior, b) a space or a pressure sink which is or is under the first pressure, c) a pressure source which is under the second pressure or which is under the second pressure, d) a controller, e) at least one first connection between the interior of the chamber and the pressure source which can be produced or blocked by the controller, f) at least one second connection between the interior of the chamber and the space or the pressure sink, which can be produced or locked by the controller, wherein g) the interior of the chamber is formed between a bell and at least one support or bearing element for the at least one object, wherein the bell and the at least one support or bearing element are formed and controlled by the controller such that they can be moved and coordinated relative to one another such that h) for the pressure-tight closing of the interior of the chamber, the bell and the support or bearing element are brought into a pressure-tight contact with one another, and i) for the at least partial production of the second connection between the interior of the chamber and the space or the pressure sink, the bell and the support or bearing element are brought out of contact.According to a development of the device, the first connection can additionally comprise a first valve which can be controlled in a coordinated manner by the controller. Furthermore, the second connection can comprise a second valve that can be controlled in a coordinated manner by the controller.In particular, the support or bearing element can comprise a conveyor belt of a conveying direction, on which the at least one object can be conveyed.Furthermore, the bell can be controlled in a coordinated manner between a position lowered onto the support or bearing element, in particular onto the conveyor belt, in which position an edge of the bell makes sealing contact with the support or bearing element, in particular the conveyor belt, and a position lifted from the support or bearing element, in particular from the conveyor belt, in which position the edge of the bell is out of contact with the support or bearing element, in particular with the conveyor belt.The lowered position and the lifted position and also intermediate positions of the bell in relation to the support or bearing element can be brought about in particular by a coordinated controllable lifting device which is operatively connected to the bell and sets the bell in particular in the vertical direction.A) the bell can also form a chamber wall of the chamber and the space or the pressure sink can be formed outside the bell and, in the position of the bell lowered onto the conveyor belt, can be bounded by the bell, a housing and the conveyor belt, wherein the bell is guided on the housing such that it can be moved relative to the conveyor belt, wherein b) the at least one object can be transported by transport by means of the conveyor belt through a closable feed opening of the housing into the interior of the housing and through a closable discharge opening of the housing out of the interior of the housing.Advantageous further developments of the invention are evident from the patent claims, the description and the drawings. The advantages of features and combinations of a plurality of features mentioned in the introduction to the description are merely exemplary and can be applied alternatively or cumulatively without the advantages necessarily having to be achieved by embodiments according to the invention. Further features can be seen from the drawings-in particular the geometries illustrated and the relative dimensions of a plurality of components with respect to one another and their relative arrangement and operative connection. The combination of features of different embodiments of the invention or of features of different patent claims is likewise possible deviating from the selected relations of the patent claims and is hereby excited. This also relates to features which are illustrated in separate drawings or are mentioned in the description thereof. These features can also be combined with features of different patent claims. Features listed in the patent claims can likewise be omitted for further embodiments of the invention.DRAWINGAn exemplary embodiment of the invention is illustrated in the drawing and explained in more detail in the following description. The drawing shows FIG. 1 shows a schematic perspective cross-sectional illustration of a device for separating real, additively manufactured objects from unsolidified remaining build material; FIG. 2 shows a schematic perspective cross-sectional representation of a preferred embodiment of a device for separating real, additively manufactured objects from unsolidified remaining building material according to the invention, with which a preferred embodiment of the method according to the invention is carried out; FIGS. 2A-2C show the apparatus of FIG. 2 in various states corresponding to steps of the method.DESCRIPTION OF THE EMBODIMENTFIG. 1 shows a schematic perspective view of a part of an apparatus 1 for separating additively manufactured 3D objects from unsolidified remaining build material from unsolidified remaining (loose) build material.The device 1 comprises a chamber 2 which can be placed in a pressure-tight manner and which is designed, for example, for clamping here an object 3, for example, in a clamping device 4, wherein building material which remains unsolidified (loose) adheres to the object 3. For the supply and discharge of the object 3, the chamber 2 can have, for example, a door which is closable in a pressure-tight manner and is not shown here. Furthermore, the device comprises a pressure sink 5, which is at the first pressure p 1 and is formed, for example, by an evacuated container, and a pressure source 6, which is at the second pressure p 2 and is formed here, for example, by a compressed-air reservoir, which is filled, for example, with compressed air by a compressor, wherein, for example, a pressure control ensures that the second pressure p 2 in the compressed-air reservoir is kept within certain tolerance limits. The chamber 2 is formed here, for example, by a cleaning chamber which is surrounded by a housing wall of a housing 7 and which can be connected to the pressure source 6 by means of a first opening 8 which is formed, for example, in the use position of the device 1 and viewed in the vertical direction in a ceiling of the housing wall. In the region of the first opening 8, a first valve 9 is arranged, with which the first opening 8 can be opened or blocked. The upper arrow in FIG. 1 represents the compressed air flow when the first valve 9 is open. This is because the chamber 2 is, for example, under atmospheric pressure, which is lower than the second pressure p 2. before the first valve 9 is opened.In addition, the housing 7 also comprises a second opening 10, here preferably in a base of the housing wall, in which a second valve 11 is arranged, with which a second connection between the interior of the chamber 2 and the pressure sink 5 connected to the second opening 10 can be opened or blocked. The middle arrow in FIG. 1 represents the compressed air flow when the second valve 11 is opened. Between the second opening 10 or the second valve 11 and the pressure sink 5, a filter device 12 is preferably arranged, by means of which loose construction material, which has separated the compressed air originating from the pressure source 6 from the object 3 in the chamber 2 as a compressed air flow and then carries it with it, is separated from the compressed air flow, so that substantially purified compressed air is discharged into the pressure sink 5, as symbolized by the lower arrow in FIG. 1.Instead of being embodied by an evacuated container, the pressure sink 5 can also be embodied in any desired space, for example also by the atmosphere or environment, if only the first pressure p 1, which prevails there, is lower than the second pressure p 2.The pressure source 6 or its pressure generator, for example in the form of a compressor, the first valve 9, the second valve 11, for example in the form of solenoid valves, and the pressure sink 5 or its vacuum generator are controlled in a coordinated manner, for example, by a superordinate electronic controller, in order to carry out the method.With respect to the apparatus of Fig. 1, the method then proceeds in at least the following steps:First, the object 3 is arranged in the interior of the chamber 2, for example together with the construction platform 13 integrally formed thereon and with the loose construction material adhering thereto and / or therein, and is tensioned in the tensioning device 4, for example. The chamber 2 is then sealed pressure-tightly. The chamber 2 is then, for example, under atmospheric pressure. The first valve 9 as well as the second valve 11 are initially closed.The interior of the chamber 2 is then completely placed under the second pressure p 2 of the pressure source 6, which second pressure p 2 is in particular substantially higher than atmospheric pressure, by opening the first valve 9 until the second pressure p prevails everywhere in the interior of the chamber 2. A pressure sensor which is arranged in the chamber 2 and is not shown here and which reports the respective actual pressure p ist in the chamber 2 to a higher-order electronic controller can be used to check when the actual pressure p ist in the chamber 2 has reached the second pressure p 2. In this respect, a pressure regulation is preferably implemented here, which adjusts the actual pressure p ist in the chamber 2 to the second pressure as the setpoint pressure p soll.When the actual pressure p ist has reached the second pressure p 2 the first valve 9 is preferably closed and the second valve 11 is opened, in particular abruptly or abruptly. This leads to an immediate pressure equalization between the relatively high second pressure p 2 prevailing in the chamber 2 and the first pressure p 1 in the pressure sink 5 which is substantially lower than this. The low first pressure p 1 in the pressure sink 5 can likewise be maintained, for example, by means of a pressure regulation. The pressure equalization produces a compressed air flow which grasps the object 3 and separates or removes loose construction material from the object 3. At the same time, the compressed air flow transports this loose building material with it and into the filter device 12, in which the building material is then separated from the compressed air flow, so that finally cleaned compressed air reaches the pressure sink 5. The building material separated from the object 3 can then be guided from the filter device 12 into a collecting container and then used, for example, for the construction of a further object.After cleaning, the object 3 can then be removed from the chamber 2.FIG. 2 shows a schematic perspective view of a part of a preferred embodiment of an apparatus 1' for separating additively manufactured 3D objects from unsolidified remaining construction material from unsolidified remaining (loose) construction material according to the invention.As in the embodiment of FIG. 1, there is also a chamber 2' which is chambered by a bell 14' with a bell opening 15'. The bell opening 15' is bordered by a circumferential bell edge 16', which is arranged, for example, in a plane. On the circumferential bell rim 15' a circumferential seal, not shown here, can be arranged.The bell 14' is guided on a housing 7', for example, so as to be vertically movable, and can be moved vertically between a raised position and a lowered position by a lifting device 17' which is also mounted, in particular, on the housing 7'. In addition, a feed bulkhead 18' and a discharge bulkhead 19' are mounted so as to be vertically movable relative to the housing 7', wherein the feed bulkhead 18' opens up a feed opening 20' of the housing 7' in an open position and closes the feed opening 20' in a closed position. Analogously, the discharge partition 19' opens a discharge opening 21' of the housing 7' in an opening position and closes it in a closing position.In this case, the bell 14' forms a chamber wall of the chamber 2' and a pressure sink 5' is formed in a space 22' which is formed outside the bell 14' and, in the position of the bell 14' lowered onto a conveyor belt 23' of a conveying device 24', is delimited by an outer surface of the bell 14', an inner surface of the housing 7' and the conveyor belt 23'. The higher second pressure p 2 is generated in the chamber 2' for example by supplying the interior of the bell 14' in its position lowered onto the conveyor belt 23' by a first valve, not shown here, as in the embodiment of FIG. 1, by pressure from a pressure source, not shown here. Likewise, the lower first pressure p 1 in the space 22' can be generated by connecting the space 22' in an analogous manner via a second valve to a pressure sink.In the lowered position, the bell rim 16' or the seal arranged on it and a lower rim of the feed bulkhead 18' and of the discharge bulkhead 19' respectively contact the conveyor belt 23' of the conveying device 24', which likewise forms a component of the second embodiment of the apparatus 1'. In this respect, in the respectively lowered position, the bell rim 16' or the seal arranged on it as well as a lower rim of the feed bulkhead 18' and of the discharge bulkhead 19' lie in the plane of the conveyor belt 23' and seal it, for example pressure-tightly, with respect to the latter. As is easily conceivable with reference to FIG. 2, in the position of the bell 14' lifted off the conveyor belt 23' a pressure equalization takes place between the higher second pressure p 2 in the chamber 2 and the pressure in the space 22' which is lower in comparison therewith, whereby a compressed air flow is produced which is directed out of the chamber 2' into the space 22' and by means of which loose building material is released from the object 3 arranged on the conveyor belt 23' and is transported away from the latter. To collect the loose building material transported by the compressed air flow, a collecting container 25' is arranged here below the conveyor belt.The conveyor belt 23' is designed to transport objects additively produced on it in a conveying direction which is symbolized by the arrow in FIG. 2A.The conveying device 24' or a drive of the conveyor belt 23', the lifting device 17', the feed bulkhead 18' and the discharge bulkhead 19' or their drives as well as the first valve and the second valve, for example designed as solenoid valves, are controlled in a coordinated manner by a higher-order electronic control in order to carry out the method.With respect to the second embodiment of the apparatus 1' of Fig. 2, the method then proceeds in at least the following steps:First, a plurality of objects 3' are preferably positioned one behind the other in series on the conveyor belt, wherein the objects 3' are again connected to their construction platforms 13', for example. In this case, the bell 14' is in the lifted position and the feed bulkhead 18' and the discharge bulkhead 19' are each in the open position. The discharge bulkhead 19' can, however, also be in the closed position. The first valve and the second valve are closed, for example.At the same time, thereafter or before, according to FIG. 2A, the conveyor belt 23' is started and conveys a first object 3' via the opened feed bulkhead 18' into the housing 7', until it is located below the bell 14'. Then, the drive of the conveyor 23' is turned off, so that the position of the first object 3' with respect to the bell 14' is maintained. The bell 14' is then controlled into the lowered position, the feed bulkhead 18' and the discharge bulkhead 19', if the latter is not already in the closed position, are each controlled into the closed position by the controller. This situation is shown in FIG. 2B.The now pressure-tight chamber 2', which has now formed between the bell 14' and the conveyor belt 23', is then flooded with compressed air from the compressed air source by opening the first valve until the entire interior of the chamber 2' is under the higher second pressure p 2 which can be detected, for example, by a pressure sensor. Then, the first valve is closed. Simultaneously, subsequently or before, the space 22', which has now formed pressure-tightly between the outer surface of the bell 14', the conveyor belt 23' and the inner surface of the housing 7', is connected to the pressure sink by opening the second valve and in particular evacuated, so that a relatively large pressure drop is produced between the chamber 2' and the space 22'. The second valve, for example, arranged in an opening of the wall of the housing 7', is then closed.Then, the lifting device 17' is controlled by the controller so that the bell 14' is abruptly lifted off the conveyor belt 23', as shown in FIG. 2C. As a result, a pressure equalization takes place between the higher second pressure p 2 in the chamber 2' and the lower first pressure p 1 in the space 22', as a result of which a compressed air flow directed from the chamber 2' into the space 22' is produced, which releases loose construction material from the first object 3' and carries along or carries along with it. Due to gravity, the loose building material then passes the conveyor belt 23' for example laterally in order to reach the collecting container 25' in which it is collected.Then, the feeding gate 18' and the discharging gate 19' are controlled to the opening position and the conveyor belt 23' is restarted so that the cleaned first object 3' moves out of the housing 7', and a second object 3' arranged in series behind the first object 3' on the conveyor belt 23' moves into the housing 7', to apply the method again to the second object 3'. It is obvious that the method can be applied successively to a plurality or plurality of objects 3' arranged on the conveyor belt 23'.List of Reference Numbers1, 1' Device 2, 2' Chamber 3, 3' Object 4 Clamping device 5 Pressure sink 6 Pressure source 7, 7' Housing 8 First opening 9 First valve 10 Second opening 11 Second valve 12 Filter device 13, 13' Construction platform 14' Bell 15' Bell opening 16' Bell rim 17' Lifting device 18' Feed bulkhead 19' Discharge bulkhead 20' Feed opening 21' Discharge opening 22' Space 23' Conveyor belt 24' Conveying device 25' Collecting containers

Claims

Method for separating unsolidified remaining building material from at least one object (3, 3') produced by layer application and selective solidification of the building material in the context of a generative construction process by means of a flow of pressurized fluid, wherein a) the at least one object (3, 3') with the building material adhering to it and / or in it is arranged in the interior of a chamber (2, 2'), which is sealed pressure-tightly, and then b) the interior of the chamber (2, 2') is placed from a pressure source (6) under a second pressure (p 1) higher than a first pressure (p 2) prevailing or generated outside the chamber (2, 2') and in a space (22') or in a pressure sink (5), by the interior of the chamber (2, 2'), 2') is flooded with pressurized fluid from the pressure source (6) until the second pressure (p 2) is present in the interior of the chamber (2, 2'), and then c) a connection is established between the interior of the chamber (2, 2') with the space (22') or with the pressure sink (5) in order to establish an at least partial pressure equalization between the first pressure (p 1) and the second pressure (p 2) wherein d) steps a) to c) are carried out in such a way that the flow of pressurized fluid arising due to the at least partial pressure equalization between the first pressure (p 1) and the second pressure (p 2) can detect the at least one object (3, 3'), and wherein e) structural material which remains unsolidified as a result of the flow of pressurized fluid is separated from the at least one object (3, 3') and transported along with the flow of pressurized fluid, and wherein f) the interior of the chamber (2') is formed between a bell (14') and at least one supporting or bearing element (23') for the at least one object (3'), wherein the bell (14') and the at least one supporting or bearing element (23') are formed and controlled so as to be movable relative to one another in such a way that g) for the pressure-tight closing of the interior of the chamber (2'), the bell (14') and the supporting or bearing element (23') are brought into pressure-tight contact with one another, and h) for establishing the communication between the interior of the chamber (2) and the space (22') or the pressure sink, the bell (14') and the supporting or bearing element (23') are brought out of contact.Method according to Claim 1, characterized in that unsolidified remaining build-up material which is carried along with the flow of pressurized fluid is separated from the flow and collected in a filter device (12).Method according to Claim 1 or 2, characterized in that the connection between the interior of the chamber (2, 2') and the space (22') or the pressure sink (5) is produced abruptly or abruptly.Method according to one of the preceding claims, characterized in that the supporting or bearing element (23') comprises a conveyor belt of a conveying direction, on which the at least one object (3') is conveyed, and in that the bell (14') is controlled in a coordinated manner between a position lowered onto the conveyor belt, in which a bell edge (16') of the bell (14') contacts the conveyor belt in a sealing manner, and a position lifted off the conveyor belt, in which the bell edge (16') of the bell (14') is out of contact with the conveyor belt.Method according to claim 4, characterised in that a) the bell (14') forms a chamber wall of the chamber (2') and the space (22') or the pressure sink is or is formed outside the bell (14') and, in the position of the bell (14') lowered onto the conveyor belt, is delimited by the bell (14'), a housing (7') and the conveyor belt, wherein the bell (14') is guided movably on the housing (7') relative to the conveyor belt, and that b) the at least one object (3') can be transported by transport by means of the conveyor belt through a closable feed opening (20') of the housing (7') into the interior of the housing (7') and through a closable discharge opening (21') of the housing (7') out of the interior of the housing (7'), wherein in the method α) in the position of the bell (14') lifted off the conveyor belt, first the at least one object (3') is transported by transport by means of the conveyor belt through the opened feed opening (20') of the housing (7') into the interior of the housing (7') into a position below the bell (14'), β) the bell (14') is then brought into the position lowered onto the conveyor belt and the feed opening (20') and the discharge opening (21') of the housing are closed or the feed opening (20') is closed and the discharge opening (21') is kept closed, and then γ) the interior of the chamber (2') is placed under the second pressure (p 2) by flooding the interior of the chamber (2') with pressurized fluid from the pressure source (6), and then δ) the bell (14') is brought in particular abruptly or abruptly into the position lifted off the conveyor belt, whereby the interior of the chamber (2') is connected to the interior of the space (22') or the pressure sink and, as a result of the pressure compensation between the second pressure (p 2) in the chamber (2') and the first pressure (p 1) in the space (22') or the pressure sink, the flow of pressurized fluid detecting the at least one object (3') is generated, and then ε) the discharge opening (21') of the housing (7') is opened, and then ξ) the at least one object (3') is transported through the opened discharge opening (21') from the interior of the housing (7') by transport by means of the conveyor belt.Method according to claim 5, characterised in that the conveyor belt is stopped when steps β), γ) and σ) are carried out.Method according to claim 5 or 6, characterised in that between steps δ) and ε), build-up material which is separated from the at least one object (3') as a result of the flow and remains unsolidified together with the flow is discharged from the space (22').Method according to one of Claims 5 to 7, characterized in that it is applied successively to a plurality of objects (3') which are transported one behind the other in the conveying direction by the conveyor belt.Method according to one of the preceding claims, characterized in that a construction platform (13') is used as the support or bearing element, on which platform the at least one object (3') has been additively produced.Method according to one of the preceding claims, characterized in that the bell (14') used is a construction container in which the at least one object (3') has been additively produced.Method according to one of the preceding claims, characterized in that compressed air and / or a protective gas is used as the pressure fluid.Method according to one of the preceding claims, characterized in that the first pressure (p 1) is generated by evacuating the space (22') or the pressure sink.Method according to one of the preceding claims, characterized in that the flow of pressurized fluid is generated and directed in the direction of the lower level, as seen in the vertical direction starting from a level which is higher than a lower level.Device for separating unsolidified remaining building material from at least one object (3, 3') produced by layer application and selective solidification of the building material in the context of a generative construction process by means of a flow of pressurized fluid, comprising at least the following: a) a pressure-sealable chamber (2, 2') which is designed for arranging the at least one object (3, 3') in the interior thereof, b) a space (22') or a pressure sink (5) which is or is under the first pressure (p 1) or which is placed under the first pressure (p 1) c) a pressure source (6) which is under the second pressure (p 2) or which is placed under the second pressure (p 2) d) a controller, e) at least one first connection (8) between the interior of the chamber (2, 2') and the pressure source (6), which connection can be established or blocked by the controller, f) at least one second connection (10, 16') between the interior of the chamber (2) and the space (22') or the pressure sink (5), which connection can be established or blocked by the controller, wherein g) the interior of the chamber (2') is formed between a bell (14') and at least one support or bearing element (23') for the at least one object (3'), wherein the bell (14') and the at least one support or bearing element (23') are formed in such a way and are controlled by the controller so as to be movable relative to one another and coordinated, h) bringing the bell (14') and the supporting or bearing element (23') into pressure-tight contact with one another for pressure-tight closing of the interior of the chamber (2'), and i) bringing the bell (14') and the supporting or bearing element (23') out of contact for at least partially establishing the second connection between the interior of the chamber (2') and the space (23') or the pressure sink.Device according to claim 14, characterised in that the support or bearing element (23') comprises a conveyor belt of a conveying direction, on which the at least one object (3') can be conveyed, and in that the bell (14') can be controlled in a coordinated manner by the controller between a position lowered onto the conveyor belt, in which a bell edge (16') of the bell (14') contacts the conveyor belt in a sealing manner, and a position lifted off the conveyor belt, in which the bell edge (16') of the bell (14') is out of contact with the conveyor belt.Device according to claim 15, characterised in that a) the bell (14') forms a chamber wall of the chamber (2'), and the space (22') or the pressure sink is formed outside the bell (14') and, in the position of the bell (14') lowered onto the conveyor belt, is delimited by the bell (14'), a housing (7') and the conveyor belt, wherein the bell (14') is guided on the housing (7') so as to be movable and coordinated relative to the conveyor belt by the controller, and in that b) the at least one object (3') can be transported by transport by means of the conveyor belt through a closable feed opening (18') of the housing (7') into the interior of the housing and through a closable discharge opening (21') of the housing (7') out of the interior of the housing (7').Device according to one of Claims 14 to 16, characterized in that the supporting or bearing element comprises a construction platform (13'), on which the at least one object (3') has been additively produced.Device according to one of Claims 14 to 17, characterized in that the bell (14') comprises a construction container in which the at least one object (3') has been additively produced.

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