DEVICE FOR THE ADDITIVE MANUFACTURING OF THREE-DIMENSIONAL OBJECTS

Abstract

Device (1) for the additive manufacturing of three-dimensional objects (2), comprising an application device (3) which is configured to apply, in particular, molten metallic building material (4) layer by layer in a build surface (5) for the layer-by-layer production of a three-dimensional object (2), wherein a melting device (6) is configured to melt metallic raw material supplied to the melting device (6) in a melting chamber (7) of the melting device (6) and to provide the application device (3) of the device (1) as, in particular, molten metallic building material (4).

Description

[0001] The invention relates to a device for the additive manufacturing of three-dimensional objects, comprising an application device which is designed to apply, in particular, molten metallic building material layer by layer to a build surface for the layer-by-layer production of a three-dimensional object.

[0002] Devices for the additive manufacturing of three-dimensional objects, in which the object is produced layer by layer by means of an application unit through the layer-by-layer application of molten metallic building material to the build surface, are generally known from the prior art. In such liquid metal printing, metallic building material is used as the raw material, which is molten and applied to the build surface in order to build up the object layer by layer according to its cross-sections.

[0003] It is also known that the operation of such additive manufacturing devices generates building material that has been used in a process, for example, unsolidified building material, or that has been incorporated into support structures or prototypes and cannot subsequently be reused. Typically, the building material is fed into the additive manufacturing device in the form of a metal wire, which is melted before application. It is therefore necessary to provide new building material for the additive manufacturing process and to dispose of previously used building material, such as manufactured objects, support structures, and the like, in a costly manner as waste.

[0004] The invention is based on the objective of providing an improved device for the additive manufacturing of three-dimensional objects, which is particularly more sustainable with regard to the use of the building material.

[0005] The problem is solved by a device according to claim 1. The dependent claims relate to possible embodiments.

[0006] As described, the invention relates to a device for the additive manufacturing of three-dimensional objects. The device comprises an application unit, which is fundamentally designed for applying building material. Specifically, the application unit is designed to apply metallic building material, in particular in a molten state, to the build surface. The object is manufactured layer by layer through the, in particular selective, application of the metallic building material. As is generally known in the operation of such devices, after completion of a layer, the distance between the application unit and the already manufactured object or the last manufactured layer can be increased, for example, by lowering a build platform on which the partially manufactured object is arranged and / or by raising the application unit.The first layer can therefore be produced on a building platform, with the building area subsequently being formed by the last layer of the object produced.

[0007] The invention is based on the understanding that a melting device is designed to melt metallic raw material supplied to the melting device in a melting chamber of the melting device and to provide it to the application unit of the device as, in particular, molten metallic building material. Advantageously, it is therefore not necessary to provide the device with a specific metallic building material, and in particular, it is not necessary for the metallic building material to be provided as processed wire. Instead, the device provides the melting device or is correspondingly connected to the melting device, so that virtually any metallic raw material can be used. The melting device is, in particular, designed as a separate assembly and / or separately from the application unit.

[0008] The metallic raw material can be melted in the melting chamber of the melting unit and then fed to the application unit of the device. This allows the application unit to deposit the metallic building material, obtained by melting the raw material in the melting chamber, onto the build surface. This means, in particular, that previously used building material, support structures, prototypes, objects, and the like can also be remelted in the melting chamber, thus yielding metallic building material for further construction or manufacturing processes on the device. This creates at least a partial cycle in which previously used building material can be reused and therefore does not have to be disposed of as waste. Advantageously, this increases the sustainability of the device's operation.

[0009] The melting device can, for example, provide a melting chamber, such as a crucible, in which metallic raw material placed in the melting chamber can be melted by applying appropriate temperature. In other words, the melting device in this configuration is designed to melt metallic raw material, especially granules, in the melting chamber by applying temperature, particularly by means of a heating device. As described, the melting chamber can be designed as a crucible. The metallic raw material, which is introduced into the melting chamber in solid form, can be melted by applying the temperature.

[0010] The metallic raw material can be, for example, granules. It is also possible to feed other forms of metallic raw material into the melting chamber, such as previously used support structures, prototypes, objects, metal powder, and the like. To ensure the most efficient melting process, the melting chamber can be appropriately insulated. The molten metallic material can then be fed to the dispensing unit. The dispensing unit can have a suitable, controllable nozzle. The metallic material can be dispensed, for example, as drops or as a jet.

[0011] According to a further embodiment, the melting device can have, or be connectable to, a feeding device configured to feed metallic raw material, in particular recycled material, into the melting chamber. The feeding device can, for example, be used to meter the quantity of metallic raw material into the melting chamber. Specifically, the feeding device can feed metallic recycled material into the melting chamber. The recycled material can, for example, consist of components previously manufactured with the device or a device, metallic components, previously used building materials, in particular powders, metallic granules, and the like, or comprise such materials individually or in combination.

[0012] For example, previously used building material can be clumped or material that no longer meets other requirements, such as grain size or grain size distribution ("out-of-spec" material). In this description, "recycled material" refers specifically to metallic material that consists of or comprises previously used or reprocessed metallic building material. For example, previously manufactured objects, components of previously manufactured objects, partially solidified, unsolidified, or solidified metallic building material, support structures, and the like can be reintroduced into the melting process as recycled material.

[0013] The device can be further configured to feed metallic raw material to the melting unit in pure form or as a mixture of at least two materials. For example, in a closed loop where the device is used to manufacture objects, particularly prototypes, from a specific metallic building material, these objects can be returned to the melting unit when no longer needed. This creates at least a partially closed material cycle, ensuring the use of pure metallic raw material. Alternatively, it is also possible to supply the melting unit with mixtures as raw material, which may contain at least two materials. These mixtures are obtained, for example, by melting objects of different origins or...Materials of varying composition can be fed into the melting unit, for example, from different alloys. Mixtures of virgin material and recycled material are also possible.

[0014] In a further development of the device, the melting unit may include a detection device configured to detect at least one material parameter, in particular a material composition, of the raw material being and / or to be supplied to the melting chamber. The detection device makes it possible to detect the material parameter of the metallic raw material, especially when it is supplied to the melting chamber or before it is supplied to the melting chamber. The material parameter can, in principle, describe any property of the raw material, for example, its temperature, mass, volume, composition, in particular its constituents, such as the alloy, impurities, and the like. In other words, the detection device can determine which material, in which state, is to be introduced into the melting chamber.This allows, for example, the determination of whether the raw material in the melting chamber corresponds to a specific material composition, such as a particular alloy.

[0015] In a further development of the device, the melting unit may include a cleaning device designed to remove foreign substances from the metallic raw material, particularly the molten material. Such foreign substances may, for example, be impurities in the metallic raw material, such as unwanted plastic components or metal components that should not be present in the desired alloy. The cleaning device may, for example, be designed to remove such foreign substances before the metallic raw material is introduced into the melting chamber.

[0016] It is also possible for the cleaning system to remove these foreign substances from the raw metallic material in its molten state. For example, impurities can be burned off or selectively skimmed off by heating the metallic raw material. Such impurities might, for instance, float on the surface of the metallic raw material and then be skimmed off by the cleaning system or removed with a doctor blade. This ensures that impurities are removed from the metallic raw material before it is fed to the application system as a finished building material.

[0017] According to a further embodiment, the melting unit of the device can be configured to modify the composition of the raw material melted in the melting chamber. For example, the composition of the metallic raw material in the melting chamber can be determined using the previously described detection device. This actual composition, which can be detected by the detection device, for example by sampling or optical methods, can be compared with a target composition.

[0018] Subsequently, the melting device can selectively change the composition of the molten raw material if a deviation between the target composition and the actual composition is detected.

[0019] Thus, depending on the specific deviation, at least one additive can be added to the molten raw material in the melting chamber to achieve the desired composition, i.e., a specific alloy of the molten raw material. The melting unit can therefore be specifically designed for re-alloying the metallic raw material. By way of example, any materials or additives can be added to the molten raw material, such as silicon, magnesium, and the like. In principle, the melting unit can be designed for melting any metal, especially aluminum or aluminum alloys. Here, low-melting-point metals, i.e., metals with a melting point below 800 °C, may be preferred. Furthermore, metals exhibiting low oxidation tendency may be preferred. Alternatively or additionally, the melting unit can be equipped with a protective gas supply.

[0020] In a further embodiment of the device, a comminution unit can be provided, which is designed to produce metallic raw material from metallic starting materials, in particular components or assemblies, by comminution. The comminution unit can therefore also be referred to or considered as a "shredder". If, for example, the melting chamber is too small to accommodate an entire assembly or component, the comminution unit can be used to selectively comminute the metallic starting material.

[0021] For example, the metallic starting material can be reduced to granules by the comminution unit, for instance by chopping, cutting, separating, or rolling. Any combination of these processes or other methods for comminuting the metallic starting material are possible. This allows, for example, the recovery of metallic raw material from previously manufactured components or prototypes, from sprues or support structures—in other words, from any previously manufactured product. This raw material can then be reduced to the form of metal granules and subsequently fed into the melting unit for a further additive manufacturing process.

[0022] In addition to the apparatus, the invention relates to a system comprising at least one of the previously described devices. The system may, in particular, be designed to combine several devices for the production of three-dimensional objects. The individual devices can be supplied with metallic material, especially in molten form, from a central melting unit. For this purpose, it is possible, for example, that the central melting unit has a melting chamber that supplies subordinate melting chambers in the devices. Likewise, metallic material can be supplied directly from the central melting chamber to the application devices of the individual devices.

[0023] This allows for the creation of a self-contained system within the plant regarding the recycling of manufactured objects or used building materials. Products generated on-site, such as previously manufactured objects, prototypes, previously used building materials, support structures, sprues, and the like, can be recycled by feeding them into the central melting unit. This can be achieved either by providing a multitude of the previously described devices, each with its own melting unit, or by using a central melting unit that feeds the individual devices with metallic building material. Consequently, the complex disposal of used building materials or raw materials is unnecessary.

[0024] Furthermore, the invention relates to a method for the additive manufacturing of three-dimensional objects, wherein, for the production of at least one three-dimensional object, layer upon layer, in particular molten, metallic building material is applied to a build surface by means of an application unit of a device for the production of three-dimensional objects, wherein metallic raw material supplied to a melting unit is melted in a melting chamber of the melting unit and is provided to the application unit of the device as, in particular, molten, metallic building material. The method can be carried out in particular with a previously described device or system.

[0025] All advantages, details, designs and / or features described in relation to the device are fully transferable to the plant and the process.

[0026] The invention is explained with reference to exemplary embodiments and the figures. The figures are schematic representations and show: Fig. 1. A schematic representation of a device for the additive manufacturing of three-dimensional objects according to an exemplary embodiment; and Fig. 2 A schematic representation of a system comprising several devices for the additive manufacturing of three-dimensional objects according to an exemplary embodiment.

[0027] Fig. Figure 1 schematically shows a device 1 for the additive manufacturing of three-dimensional objects 2. The device 1 comprises an application unit 3, which is configured to apply metallic building material 4 layer by layer to a build platform 5. The object 2 is manufactured layer by layer, meaning that the building material 4 is applied, for example, selectively, in a layer to form a cross-section of the object 2 in that layer. Subsequently, a build platform can be lowered and / or the application unit 3 can be positioned accordingly to apply the next layer of the object 2. The build platform 5 can be understood as the area on which the application unit 3 applies the building material 4, for example, initially a surface of a build platform and subsequently the most recently completed layer of the object 2.

[0028] The device 1 is connected to a melting unit 6 in which metallic raw material can be melted in a melting chamber 7. The molten raw material can then be fed to the application unit 3 as building material for application, as previously described. Alternatively, the metallic raw material can be cooled again after melting in the melting chamber 7 and fed to the application unit 3 as wire. In other words, metallic building material 4 is produced from the metallic raw material fed to the melting unit 6 and is then used by the application unit 3 in the production of three-dimensional objects 2.

[0029] The melting unit 6 can, for example, include a heating device (not shown in detail) to melt raw material, i.e., metal, that is fed into the melting chamber 7. The melting chamber 7 can be suitably insulated to ensure efficient melting of the metallic raw material. Optionally, a feeding device 8 can be provided to supply the metallic raw material to the melting unit 6. This feeding device can, for example, be designed to meter the quantity of metallic raw material into the melting chamber 7. For instance, only the amount of raw material required for a specific process step can be supplied.

[0030] Specifically, the feeding device 8 can feed recycled material into the melting chamber 7. This means raw material that has already been used previously, for example in a preceding additive manufacturing process or any other subsequent manufacturing process. The recycled material can then be melted by the melting device 6. The recycled material can include, for example, old metallic building materials, support structures, sprues, prototypes, objects 2, and the like.

[0031] For example, the recyclate can be produced in a comminution unit 9, such as a shredder, from the previously described input materials. For this purpose, the comminution unit 9 can be fed with, for example, old components, prototypes, assemblies, building materials, and the like. The comminution unit 9 comminutes these metallic input materials and produces the raw material, which can then be conveyed via the feed unit 8 into the melting unit 6, for example, metered into the melting chamber 7.

[0032] The raw material can, for example, be comminuted into granules by the comminution device 9, which can then be supplied to the device 1 or melted in the melting chamber 7. Particularly advantageous dosing of the granules is possible via the feed device 8. The raw material can also be supplied in mixed form, for example as powder, granules, components, assemblies, and the like. The selection of which starting material can be used depends, for example, on the size of the melting chamber 7. If the melting chamber 7 is large enough to directly accommodate all components and assemblies, the comminution device 9 may be omitted. Otherwise, the comminution device 9 can at least comminute the starting material sufficiently so that it can be accommodated in the melting chamber 7.The smaller the comminution unit 9 reduces the raw materials to, the finer the raw material can be dosed into the melting chamber 7. Furthermore, the comminution simplifies the melting of the raw material.

[0033] Fig. Figure 1 further shows that the device 1 has a detection device 10. The detection device 10 is configured, for example, to detect at least one material parameter of the raw material that is or has been fed into the melting chamber 7. For example, the detection device 10 can take samples from the melting chamber 7 or samples from the raw material. The detection device 10 can, for example, check the composition of the raw material based on optical methods. For example, the actual composition of the raw material melted in the melting chamber 7 can be detected. Other material parameters include, for example, the temperature, mass, or volume of the raw material. The actual composition, which can be detected or determined by means of the detection device 10, can then be compared with a target composition.

[0034] If a deviation occurs between the target composition and the actual composition, material can be selectively fed in using the feeder 8, or material can be selectively melted in the melting chamber 7 using the melting unit, in order to achieve the target composition. For example, additives can be introduced into the melting chamber 7 using the feeder 8 or the melting unit 6, allowing for the re-alloying of the raw material. Once the target composition is achieved, the raw material can be supplied to the application unit 3 as building material 4, as described previously.

[0035] Furthermore, a cleaning device 11 is shown, by means of which the raw material in the melting chamber 7 can be cleaned. For example, the cleaning device 11 can remove foreign substances before the raw material is fed into the melting chamber 7. Alternatively, it is also possible for the cleaning device 11 to remove foreign substances from the molten raw material in the melting chamber 7, for example by burning or by skimming off foreign substances floating on the surface of the molten raw material.

[0036] Fig. Figure 2 schematically shows a system 12 designed for the production of three-dimensional objects 2 and comprising several devices 1. The devices 1 can be, for example, according to Fig. 1. Alternatively, the devices 1 of Annex 12 of Fig.1. The design may differ. A central melting unit 13 may be provided in system 12, which can also be considered a melting unit 6 within the scope of the preceding description. Therefore, the description of the melting unit 6 is, in principle, completely transferable to the central melting unit 13.

[0037] It is therefore possible that the central melting unit 13 supplies metallic building material 4 to the individual devices 1. The individual devices 1 may have their own melting units 6, which, for example, are smaller in size than the central melting unit 13. It is also possible that the devices 1 do not have their own independent melting units 6, but rather that the central melting unit 13 is designed to melt raw material for all devices 1 and to supply the building material 4 directly, in particular in its molten state, to the application units 3 of the devices 1.

[0038] This allows a closed loop to be achieved in system 12 with regard to the building material 4, in particular the building material 4 that is processed, for example into objects 2. For example, as also described above, this can be fed to the central melting unit 13 by means of a feeding device 8. All details described with regard to the collection device 10 and the cleaning device 11 are also transferable to the central melting unit 13.

[0039] For example, it is possible to collect potential raw materials from starting materials, such as prototypes, objects 2, solidified building materials, support structures, sprue material, and the like, via system 12, for example, a production facility. These materials can either be fed directly to the melting chamber 7 of the central melting unit 13, for example, by means of the feeding device 8 of system 12, or a comminution device 9, as described above, can be provided to first comminute such starting materials, for example, into granules. The granules can then be fed into the melting chamber 7 of the central melting unit 13 via the feeding device 8 and melted there. Likewise, all previously described details regarding the re-alloying of the raw material from the melting unit 6 to the central melting unit 13 are transferable.

[0040] The advantages, details, and features described in relation to the individual embodiments can be combined, interchanged, and transferred to one another as desired. The description of device 1 is fully transferable to system 12 and vice versa. The method described herein can be carried out using device 1 or system 12. Therefore, the description is also transferable to the method. REFERENCE MARK LIST 1 Device 2 objects 3. Order setup 4 Building materials 5 Building area 6 Melting device 7 Melting chamber 8 Feeding device 9 Shredding device Collection device 10 11 Cleaning facility 12 13 Plant central melting facility

Claims

[1] Device (1) for the additive manufacturing of three-dimensional objects (2), comprising an application device (3) which is configured to apply, in particular, molten metallic building material (4) layer by layer in a build surface (5) for the layer-by-layer manufacturing of a three-dimensional object (2), characterized by a melting device (6) which is designed to melt metallic raw material supplied to the melting device (6) in a melting chamber (7) of the melting device (6) and to provide it to the application device (3) of the device (1) as, in particular, melted, metallic building material (4). [2] Device (1) according to claim 1, characterized by , that the melting device (6) is designed to melt metallic raw material, in particular granules, in the melting chamber (7) by means of temperature action, in particular by means of a heating device. [3] Device (1) according to claim 1 or 2, characterized bythat the melting device (6) has a feed device (8) or is connectable or connected to a feed device (8) designed to feed metallic raw material, in particular recycled material, into the melting chamber (7). [4] Device (1) according to any one of the preceding claims, characterized by , that the device (1) is designed to supply metallic raw material in a pure form or as a mixture of at least two materials to the melting device (6). [5] Device (1) according to any one of the preceding claims, characterized by , that the melting device (6) has a detection device (10) which is designed to detect at least one material parameter, in particular a material composition, of the raw material supplied and / or to be supplied to the melting chamber (7). [6] Device (1) according to any one of the preceding claims, characterized by, that the melting device (6) has a cleaning device (11) which is designed to remove foreign substances from the, in particular melted, metallic raw material. [7] Device (1) according to any one of the preceding claims, characterized by , that the melting device (6) is designed to change the composition of the raw material melted in the melting chamber (7). [8] Device (1) according to any one of the preceding claims, characterized by a comminution device (9) designed to produce metallic raw material from metallic starting materials, in particular components or assemblies, by comminution. [9] System (12) comprising at least one device (1) according to any one of the preceding claims. [10] Method for the additive manufacturing of three-dimensional objects (2), wherein, for the production of at least one three-dimensional object (2), a device (1) for the production of three-dimensional objects (2) is applied layer by layer, in particular molten, metallic building material (4) in a build surface (5) by means of an application device (3), characterized by , that metallic raw material supplied to a melting device (6) is melted in a melting chamber (7) of the melting device (6) and is provided to the application device (3) of the device (1) as, in particular, melted, metallic building material (4).

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