METHOD FOR THE ADDITIVE PROCESSING OF THREE-DIMENSIONAL OBJECTS

Description

[0001] The invention relates to a device for the additive production of three-dimensional objects by successive layer-by-layer selective irradiation and the concomitant successive layer-by-layer selective solidification of building material layers made of a building material that can be solidified by means of an energy beam. The device comprises a plurality of irradiation devices, each configured to generate at least one energy beam, and a control device configured to generate control information controlling the operation of the irradiation devices and to control the operation of the irradiation devices based on the generated control information. Devices for the additive production of three-dimensional objects are known in principle.Using appropriate devices, three-dimensional objects to be manufactured are additively constructed from a building material that can be solidified by means of an energy beam by successive layer-by-layer selective irradiation and the associated successive layer-by-layer selective solidification of building material layers in the areas corresponding to the layer-related cross-section of the object to be manufactured. US2015 / 064048A1 discloses a method according to the preamble of claim 1.

[0002] Furthermore, it is known that, in order to achieve the best possible properties for additively manufactured objects, it is advisable to temper layers of building material that are to be selectively solidified or that have been selectively solidified. Such tempering can, for example, contribute to reducing gas porosity, particularly hydrogen porosity, in typically pre-dried, hygroscopic building materials such as aluminum.

[0003] To date, the temperature control of layers of build material to be selectively solidified or selectively solidified has typically been achieved using heating elements, such as resistance heating elements, integrated into a build module defining a build chamber. The heating elements can, for example, be integrated into a base plate of the build module that defines the bottom of the build chamber. The thermal energy introduced into the build chamber via the heating elements ensures a certain temperature control of the possibly pre-dried build material in the build chamber.

[0004] This tempering principle requires further development in several respects, particularly because it does not allow for pre-drying of the building material or local tempering of the building material. Furthermore, tempering of the building material with corresponding heating elements is limited to a temperature threshold, which may be too low for processing new, particularly high-melting, materials.

[0005] The invention is therefore based on the object of providing an improved device for the additive production of three-dimensional objects.

[0006] The object is achieved by a device for the additive production of three-dimensional objects according to claim 1. The dependent claims relate to possible embodiments of the device.

[0007] The device described herein ("device") is designed for the additive manufacturing of three-dimensional objects, i.e., for example, technical components or groups of technical components, by successive layer-by-layer selective irradiation and the associated successive layer-by-layer selective solidification of construction material layers made of a solidifiable construction material in the construction material layer regions corresponding to the layer-related cross-section of the respective object to be manufactured. The construction material can be a particulate or powdered metal, plastic, and / or ceramic material. The selective solidification of the respective construction material layers to be selectively solidified is carried out based on object-related construction data. Corresponding construction data describe the geometric-structural shape of the respective object to be additively manufactured and can, for example, contain "sliced" data of the object to be additively manufactured.

[0008] The device can be designed, for example, as a device for performing selective laser melting processes (abbreviated to SLM processes) or as a device for performing selective laser sintering processes (abbreviated to SLS processes). It is also conceivable that the device is designed as a device for performing selective electron beam melting processes (abbreviated to SEBS processes).

[0009] The device comprises the functional components typically required for carrying out additive construction processes. These include, in particular, at least one coating device and at least one irradiation device. A corresponding coating device is configured to form build material layers to be selectively solidified in a build plane of the device, in which the successive layer-by-layer selective irradiation and the associated successive layer-by-layer selective solidification of build material layers takes place. For this purpose, it typically comprises a coating element, in particular a blade-like or blade-shaped element, that is movably mounted relative to the build plane.A corresponding irradiation device is designed for the selective irradiation of building material layers to be selectively solidified in the building plane of the device and for this purpose typically comprises an energy beam generating device which is designed to generate an energy beam, and optionally an energy beam deflection device which can also be referred to or considered as a scanner device and which is designed to deflect an energy beam onto respective building material layers.

[0010] The device described herein comprises a plurality of irradiation devices. Each irradiation device comprises an energy beam generating device configured to generate an energy beam, i.e. in particular a laser beam, with definable energy beam properties. Each irradiation device can further comprise an energy beam deflection device configured to deflect the energy beam generated by its own energy beam generating device onto respective regions of respective building material layers that are to be selectively irradiated or selectively solidified. It is also conceivable for a (single) energy beam deflection device to be assigned to the respective energy beam generating devices of different irradiation devices, wherein the energy beam deflection device is configured to deflect the energy beams generated by the energy beam generating devices assigned to it onto respective regions that are to be selectively irradiated orto selectively deflect areas of the respective building material layers that are to be solidified.

[0011] The device comprises a control device implemented in hardware and / or software. The control device can be or is assigned to the irradiation devices in terms of control technology and is designed to generate control information controlling the operation of the irradiation devices and to control the operation of the irradiation devices on the basis of correspondingly generated control information. The control of the operation of respective irradiation devices includes in particular the control of the energy beam properties of a generated energy beam, i.e. e.g. the energy beam intensity and / or the energy beam focus diameter, and the control of the movement properties of a generated energy beam, i.e. e.g. a movement path along which an energy beam moves over a building material layer to be selectively solidified, or certain movement parameters related to a movement of the energy beam, such as e.g.B. the speed of movement with which an energy beam is moved over a layer of building material to be selectively solidified.

[0012] As will become apparent below, the control device is configured to generate different control information for different irradiation devices, so that the energy beams generated by different irradiation devices differ, for example, in one or more energy beam properties and / or in one or more movement properties.

[0013] Specifically, the control device is configured to generate first control information for controlling the operation of at least one first irradiation device, on the basis of which control information the first irradiation device generates a first energy beam for the successive, layer-by-layer selective solidification of a building material layer. An irradiation device defined by the control device as a first irradiation device is controlled or operated by the control device on the basis of control based on first control information to generate an energy beam for the successive, layer-by-layer selective solidification of a building material layer. Of course, the control device can define or operate a plurality of irradiation devices as first irradiation devices, which are thus each controlled or operated by the control device on the basis of control based on first control information.operated to generate an energy beam for the successive, layer-by-layer selective solidification of a layer of building material.

[0014] The control device is further configured to generate second control information for controlling the operation of at least one second irradiation device, on the basis of which second irradiation device generates a second energy beam for the thermal pretreatment of a building material layer to be selectively consolidated, in particular in a region of the building material layer to be selectively consolidated, and / or a second energy beam for the thermal aftertreatment of a selectively consolidated building material layer, in particular in a selectively consolidated region of the building material layer. An irradiation device defined by the control device as a second irradiation device is controlled oroperated to generate an energy beam for the thermal pretreatment of a building material layer to be selectively consolidated, in particular in a region of the building material layer to be selectively consolidated, and / or an energy beam for the thermal aftertreatment of a selectively consolidated building material layer, in particular in a selectively consolidated region of the building material layer. Of course, the control device can define or operate a plurality of irradiation devices as second irradiation devices, which are thus each controlled by the control device on the basis of a control based on second control information to generate an energy beam for the thermal pretreatment of a building material layer to be selectively consolidated and / or for the thermal aftertreatment of a selectively consolidated building material layer.

[0015] Based on corresponding control information generated by the control device, the device thus makes it possible to specifically "assign" different irradiation devices with different functions. At least one irradiation device can be defined or operated as the first irradiation device, so that it generates an energy beam for the selective solidification of a building material layer. At least one other irradiation device can be defined or operated as the second irradiation device, so that it generates an energy beam for the thermal pre- or post-treatment of a building material layer. Thermal pre- or post-treatment of a building material layer is also referred to below as tempering of a building material layer.

[0016] The possibility of using irradiation devices in the device for tempering building material layers thus opened up allows for targeted and localized tempering of building material layers, as well as targeted control of the heating and cooling conditions, or rather, targeted control of the melting and solidification conditions of the building material, which was not possible with conventional heating elements. Through targeted control of the heating and cooling conditions, or rather, the melting and solidification conditions, one can actively influence the structural properties of an object to be manufactured – since, for example, a specific microstructure can be adjusted in this way. Pre-drying of the building material is also possible.

[0017] The possibility of using irradiation devices for tempering layers of building material also allows for considerably less energy to be applied to temper a layer of building material, since permanent and lengthy tempering of the entire building material in the building chamber is not necessary.

[0018] Through targeted local temperature control of a build material layer, the previously common thermal load on the build chamber, on functional components of the device thermally coupled to the build chamber, and on already additively constructed object sections located within the build chamber is reduced to a minimum, as the input of thermal energy for temperature control of the build material can be limited to the build material areas to be temperature controlled. The thermal load on the unconsolidated build material, which may be reused or recycled, is also reduced to a minimum. The build material is therefore not exposed to permanent temperature control, which, as studies have shown, can lead to an undesirable increase in the oxygen content in the build material.Furthermore, the formation of temperature gradients within or between different functional components of the device is reduced to a minimum, so that "migration" of individual functional components due to different thermal expansions of functional components is not or hardly possible.

[0019] Overall, this represents an improved device compared to the state of the art described at the beginning.

[0020] Before discussing further embodiments of the device or the method that can be implemented with it, it should be noted that a respective definition of the irradiation devices as first or second irradiation device is typically variable, i.e., by no means fixed. The control device can thus be configured to define at least one specific irradiation device as the first irradiation device within the scope of the selective solidification of a first building material layer and to operate it accordingly, and to define the same irradiation device as the second irradiation device within the scope of the selective solidification of a further building material layer that is different from the first building material layer and to operate it accordingly.The control device can also be configured to define at least one specific irradiation device as the first irradiation device within the scope of the selective solidification of a first region of a building material layer and to operate it accordingly, and to define the same irradiation device as the second irradiation device within the scope of the selective solidification of a further region of the building material layer that is different from the first region of the building material layer and to operate it accordingly. An irradiation device can therefore be used once or more than once as the first irradiation device, i.e., for the selective solidification of a building material layer, and once or more than once as the second irradiation device, i.e., for tempering a building material layer, within the scope of one and the same construction process.

[0021] When reference is made to a "first irradiation device" below, this is to be understood as an irradiation device of the device that is controlled or operated by the control device at least temporarily as the first irradiation device. Similarly, when reference is made to a "second irradiation device" below, this is to be understood as an irradiation device of the device that is controlled or operated by the control device at least temporarily as the second irradiation device.

[0022] As will become apparent below, the control device can be configured to generate second control information, on the basis of which the second energy beam generated by a second irradiation device can be guided or directed along the same or a different trajectory path over a building material layer to be selectively consolidated or solidified as the first energy beam generated by a first irradiation device. A second irradiation device can thus be configured to generate a second energy beam that can be guided or directed along the same or a different trajectory path over a building material layer to be selectively consolidated or solidified as the first energy beam generated by a first irradiation device.

[0023] The control device can in particular be configured to generate second control information on the basis of which a second energy beam generated by a second irradiation device can be guided or guided ahead or behind a first energy beam generated by a first irradiation device with a definable or defined, in particular synchronized, local and / or temporal lead or lag along the same movement path over a building material layer to be selectively solidified or solidified as the first energy beam generated by the first irradiation device.A second irradiation device can thus be configured to generate a second energy beam which is guided ahead of or behind a first energy beam generated by a first irradiation device along the same movement path over a building material layer to be selectively solidified or solidified as the first energy beam generated by the first irradiation device.

[0024] Thus, at least a second energy beam can be guided ahead of a first energy beam with a specific spatial and / or temporal advance along the same trajectory over a layer of building material, thereby resulting in a specifically controllable pre-tempering of the building material to be solidified by means of the first energy beam, particularly through the specific spatial and / or temporal advance of the second energy beam. Such pre-tempering generally enables (local) preheating of the building material, which, for example, allows processing, particularly of high-melting building materials, or drying of the building material.

[0025] Alternatively or additionally, at least a second energy beam can be guided along the same trajectory over a layer of building material, following a first energy beam with a specific spatial and / or temporal lag, thereby resulting in a specifically controllable post-temperature adjustment of the building material solidified by the first energy beam, particularly through the specific spatial and / or temporal lag of the second energy beam. Such post-temperature adjustment generally enables a reduction in mechanical stresses that may lead to crack formation, as well as in the gas or hydrogen porosity in the object, particularly through the diffusion of gas pores.

[0026] The same applies analogously to the case in which the device comprises a plurality of irradiation devices operable or operated as second irradiation devices. In this case, the control device can be configured to generate second control information, on the basis of which the second energy beams generated by respective second irradiation devices can be guided or are guided ahead or behind a first energy beam generated by a first irradiation device, each with a definable or defined, in particular synchronized, local and / or temporal lead or lag, along the same movement path over a building material layer to be selectively solidified or solidified as the first energy beam generated by the first irradiation device.The device can thus comprise a plurality of second irradiation devices which are configured to generate a plurality of second energy beams which can be guided or are guided ahead of or behind a first energy beam generated by a first irradiation device along the same movement path over a building material layer to be selectively solidified or solidified as the first energy beam generated by the first irradiation device.

[0027] The control device can be configured to control the energy input to be introduced or introduced into a building material layer by respective second energy beams generated by respective second irradiation devices depending on the spatial and / or temporal lead or lag of the respective second energy beams relative to the first energy beam generated by the first irradiation device. The energy input to be introduced or introduced into the building material layer via respective second energy beams can thus be varied (almost) as desired, so that (almost) as desired or (almost) as desired variable temperature profiles, i.e., for example, uniformly or unevenly rising or falling temperature ramps, can be realized by controlling the respective energy input of respective second energy beams.

[0028] For example, the energy input of a second energy beam to be introduced or introduced into a building material layer, which has a greater spatial and / or temporal lead or lag compared to a first energy beam generated by a first irradiation device, can be lower than the energy input of a further second energy beam to be introduced or introduced into the building material layer, which has a smaller spatial and / or temporal lead or lag compared to the energy beam generated by the first irradiation device. This provides an exemplary possibility for realizing a specific temperature profile with which the heating or cooling properties of the building material can be influenced locally and specifically.

[0029] A variant has been described above, according to which a movement of first and second energy beams takes place in one and the same movement path, wherein at least one second energy beam is guided ahead or behind a first energy beam with a specific local and / or temporal lead or lag.

[0030] A variant which is equally conceivable and which can be combined in particular with the one described above is described below, according to which a movement of first and second energy beams takes place in different movement paths, wherein at least one second energy beam is guided laterally, in particular parallel, offset to a first energy beam with a specific spatial and / or temporal offset.

[0031] The control device can thus (alternatively or additionally) be configured to generate second control information, on the basis of which the second energy beam generated by a second irradiation device can be guided or guided over the building material layer to be selectively solidified or solidified, with a definable or defined spatial and / or temporal offset laterally, in particular parallel, offset to a movement path along which the first energy beam generated by a first irradiation device can be guided or guided over a building material layer to be selectively solidified. A second irradiation device can thus be configured to generate a second energy beam which is laterally offset to the first energy beam generated by a first irradiation device, ienot in the same trajectory as the first energy beam generated by the first irradiation device, over a layer of building material to be selectively solidified or solidified.

[0032] At least a second energy beam can therefore be guided over a layer of building material with a specific local and / or temporal offset laterally offset to the path of movement of a first energy beam, whereby, for example for the purpose of controlled influencing or controlling the heating or melting behavior or the cooling or solidification behavior of the building material, a specifically controllable pre- or post-tempering of the building material to be solidified or solidified by means of the first energy beam is achieved, in particular by the specific local and / or temporal lateral offset of the second energy beam.

[0033] The same applies analogously to the case in which the device comprises a plurality of irradiation devices operable or operated as second irradiation devices. In this case, the control device can be configured to generate second control information, on the basis of which the second energy beams generated by respective second irradiation devices are guided or guided over the selectively solidified or solidified building material layer with a definable or defined spatial and / or temporal offset laterally, in particular parallel, offset to a movement path along which a first energy beam generated by a first irradiation device can be guided or guided over a building material layer to be selectively solidified.The device can thus comprise a plurality of second irradiation devices which are configured to generate a plurality of second energy beams which can be guided or are guided in a separate movement path offset laterally to the first energy beam generated by a first irradiation device over a building material layer which is to be selectively solidified or has been solidified.

[0034] Here, too, the control device can be configured to control the energy input to be introduced or introduced into a building material layer by respective second energy beams generated by respective second irradiation devices as a function of the spatial and / or temporal offset of the respective second energy beams relative to the trajectory of the first energy beam generated by the first irradiation device. In this way, too, the energy input to be introduced or introduced into the building material layer via respective second energy beams can be varied (almost) arbitrarily, so that (almost) arbitrary or (almost) arbitrarily variable temperature profiles, i.e., for example, uniformly or unevenly rising or falling temperature ramps, can be realized by appropriately controlling the respective energy input of respective second energy beams.

[0035] For example, the energy input of a second energy beam to be introduced or introduced into a building material layer, which has a greater spatial and / or temporal offset compared to the trajectory of the first energy beam generated by the first irradiation device, can be lower than the energy input of a further second energy beam to be introduced or introduced into the building material layer, which has a smaller spatial and / or temporal offset compared to the trajectory of the energy beam generated by the first irradiation device. This again provides an example of a possibility for realizing a specific temperature profile with which the heating or cooling properties of the building material can be locally and specifically influenced.

[0036] Regardless of whether a second energy beam is guided ahead of or behind a first energy beam or with a lateral offset relative to it, the following applies: a second energy beam can differ from a first energy beam in at least one energy beam parameter that influences the energy input of the energy beam into a building material layer. A second energy beam can differ from a first energy beam, for example, in the energy beam intensity and / or the energy beam focus diameter and / or the energy beam speed with which the energy beam is guided over a building material layer. The differentiation in the energy input is typically made with the proviso that the energy input of a second energy beam is so low that melting of building material with the second energy beam is not possible.Thus, a second energy beam typically has a lower energy beam intensity and / or a larger energy beam focus diameter than a first energy beam.

[0037] The device can comprise a detection device configured to detect at least one property of a building material layer to be selectively solidified or a selectively solidified region of a building material layer to be selectively solidified or a selectively solidified region, and to generate detection information describing the at least one detected property of the building material layer to be selectively solidified or a selectively solidified region. A corresponding property can be, for example, the temperature or the state of aggregation, in particular the molten state, of a region to be selectively solidified or a selectively solidified region, so that a local melt pool can be detected via the detection device. The detection device can be, for example, an optical detection device, i.e.in particular a camera device, or the detection device can comprise at least one such device.

[0038] The control device can be configured to control at least one energy beam parameter of a second energy beam influencing the energy input of a respective energy beam into a building material layer as a function of a property of a building material layer to be selectively solidified or solidified, as described by detection information. By means of respective properties of a building material layer described by corresponding detection information, an even more precisely controlled influencing or control of the heating or melting behavior, or the cooling or solidification behavior, of the building material layer can be realized, particularly in real time, by means of one or more second energy beams.

[0039] In addition to the device, the invention relates to a method for the additive production of three-dimensional objects by successive layer-by-layer selective irradiation and concomitant successive layer-by-layer selective solidification of building material layers from a building material that can be solidified by means of an energy beam, in particular a laser beam, wherein a plurality of irradiation devices are used, each of which is configured to generate at least one energy beam with definable energy beam properties.The method is characterized in that at least one first irradiation device is operated on the basis of first control information generated by a control device to generate a first energy beam for the successive layer-by-layer selective solidification of a building material layer, and at least one second irradiation device is operated on the basis of second control information generated by a control device to generate a second energy beam for the thermal pretreatment of a building material layer to be selectively solidified, in particular in a region of the building material layer to be selectively solidified, and / or a second energy beam for the thermal aftertreatment of a selectively solidified building material layer, in particular in a selectively solidified region of the building material layer. The method, which is e.g.The melting process, which can be a selective laser melting process (abbreviated to SLM), a selective laser sintering process (abbreviated to SLS), or a selective electron beam melting process (abbreviated to SEBS), can be carried out using a device as described. All statements relating to the device apply analogously to the process, and vice versa.

[0040] The invention is explained in more detail using exemplary embodiments in the drawings. In the drawings: Fig. 1 shows a schematic diagram of a device according to an embodiment; and Figs. 2 - 5 each show a schematic diagram of several energy beams guided over a layer of building material.

[0041] Fig. 1 shows a schematic diagram of a device 1 according to an embodiment. The device 1 serves for the additive production of three-dimensional objects 2, i.e. in particular technical components or technical component groups, by successive layer-by-layer selective irradiation and the associated successive layer-by-layer selective solidification of building material layers made of a solidifiable building material 3, i.e., e.g., a metal powder, by means of an energy beam, i.e., in particular, a laser beam. The selective solidification of the respective building material layers to be solidified is carried out on the basis of object-related construction data. Corresponding construction data describe the geometric or geometric-constructive shape of the respective object 2 to be additively manufactured and can, for example, contain "sliced" data of the object 2 to be manufactured. The device 1 can, for example, be designed as a laser CUSINGO device, i.e.as a device for carrying out selective laser melting processes (abbreviated SLM processes).

[0042] The device 1 comprises a coating device 5 as a functional component for carrying out additive construction processes. The coating device 5 is designed to form layers of building material that are to be selectively irradiated or selectively solidified in a construction plane E of the device 1 and for this purpose comprises a coating element (not further designated) that is movably mounted relative to a construction plane E of the device 1, in particular a blade-like or blade-shaped element.

[0043] The device 1 comprises several functional components for carrying out additive construction processes, ie in the Fig. 1 The exemplary embodiment shown comprises, by way of example, two irradiation devices 6, 7. Each irradiation device 6, 7 comprises an energy beam generating device 8, 9 configured to generate an energy beam 4a, 4b, ie in particular a laser beam, with definable energy beam properties, and an energy beam deflection device 10, 11 optically coupled thereto and configured to deflect an energy beam 4a, 4b onto respective building material layers. It would also be conceivable for a (single) energy beam deflection device to be assigned to the respective energy beam generating devices 8, 9 of different irradiation devices 6, 7.

[0044] In the Fig. 1 The embodiment shown also shows a dosing module 12, a construction module 13, and an overflow module 14, which are docked to a lower region of an inertizable process chamber 15 of the device 1. These modules can also form a lower region of the process chamber 15 of the device 1.

[0045] The device 1 comprises a control device 16 which is implemented in hardware and / or software and is assigned to the irradiation devices 6, 7. The control device 16 is configured to generate control information controlling the operation of the irradiation devices 6, 7 and to control the operation of the irradiation devices 6, 7 on the basis of correspondingly generated control information. The control of the operation of respective irradiation devices 6, 7 includes, in particular, the control of the energy beam and the movement properties of an energy beam 4a, 4b generated via a respective irradiation device 6, 7. The control device 16 is configured to generate different control information for different irradiation devices 6, 7, so that the energy beams 4a, 4b generated by different irradiation devices 6, 7, for example,differ in single or multiple energy beam properties and / or in single or multiple movement properties.

[0046] The control device 16 is configured to generate first control information for controlling the operation of a first irradiation device, i.e., for example, the left-hand irradiation device 6 in the figure, on the basis of which the first irradiation device generates a first energy beam 4a for the successive, layer-by-layer selective solidification of a building material layer. The irradiation device 6, defined by the control device 16 as the first irradiation device, is controlled or operated by the control device 16 based on the first control information to generate an energy beam 4a for the successive, layer-by-layer selective solidification of a building material layer.

[0047] The control device 16 is further configured to generate second control information for controlling the operation of at least one second irradiation device, i.e., for example, the irradiation device 7 on the right in the figure, on the basis of which second control information the second irradiation device generates a second energy beam 4b for the thermal pretreatment of a building material layer to be selectively consolidated, in particular in a region of the building material layer to be selectively consolidated, and / or a second energy beam 4b for the thermal aftertreatment of a selectively consolidated building material layer, in particular in a selectively consolidated region of the building material layer. The irradiation device 7, defined by the control device 16 as the second irradiation device, is controlled oroperated to generate an energy beam 4b for the thermal pretreatment of a building material layer to be selectively solidified, in particular in a region of the building material layer to be selectively solidified, and / or an energy beam 4b for the thermal aftertreatment of a selectively solidified building material layer, in particular in a selectively solidified region of the building material layer.

[0048] The device 1 thus makes it possible, based on corresponding control information generated by the control device 16, to specifically "assign" different functions to different irradiation devices 6, 7. One (or more) irradiation devices 6 can be defined or operated as the first irradiation device, so that it generates an energy beam 4a for the selective solidification of a building material layer. One (or more) other irradiation devices 7 can be defined or operated as the second irradiation device, so that it generates an energy beam 4b for the thermal pre- or post-treatment ("tempering") of a building material layer.

[0049] The possibility thus opened up of using an irradiation device, i.e. for example the irradiation device 7, for tempering building material layers allows a targeted and local tempering of building material layers as well as a targeted control of the heating and cooling conditions or a targeted control of the melting and solidification conditions of the building material 3. By means of the targeted control of the heating and cooling conditions or the melting and solidification conditions, it is possible to actively influence the structural properties of an object 2 to be produced - since in this way, for example, a specific microstructure can be set.

[0050] The respective definition of the irradiation devices 6, 7 as first or second irradiation devices is variable, i.e., by no means fixed. The control device 16 is thus configured to define a specific irradiation device 6, 7 as the first irradiation device within the scope of the selective solidification of a first building material layer and to operate it accordingly, and to define the same irradiation device 6, 7 as the second irradiation device within the scope of the selective solidification of a further building material layer different from the first building material layer and to operate it accordingly.The control device 16 is also configured to define a specific irradiation device 6, 7 as the first irradiation device within the scope of the selective solidification of a first region of a building material layer and to operate it accordingly, and to define the same irradiation device 6, 7 as the second irradiation device within the scope of the selective solidification of a further region of the building material layer that is different from the first region of the building material layer and to operate it accordingly. An irradiation device 6, 7 can therefore be used once or more than once as the first irradiation device, i.e., for the selective solidification of a building material layer, and once or more than once as the second irradiation device, i.e., for tempering a building material layer, within the scope of one and the same construction process.

[0051] When reference is made to a "first irradiation device" below, this is to be understood as an irradiation device 6, 7 that is controlled or operated by the control device 16 at least temporarily as a first irradiation device. Similarly, when reference is made to a "second irradiation device" below, this is to be understood as an irradiation device 6, 7 that is controlled or operated by the control device 16 at least temporarily as a second irradiation device.

[0052] As can be seen from the schematic diagram of several energy beams 4a, 4b guided over a layer of building material, Fig. 2 ff, the control device 16 is configured to generate second control information, on the basis of which a second energy beam 4b generated by a second irradiation device is positioned at a first energy beam 4a with a defined, in particular synchronized, local and / or temporal lead time (cf. Fig. 2 ) or caster (cf. Fig. 3 ) is guided along the same path of movement (see the movement vectors indicated by the arrows) over the building material layer as the first energy beam 4a. A second energy beam 4b can thus follow a first energy beam 4a with a certain spatial and / or temporal lead (in Fig. 2 by the symbols "+Δx" for the local advance and "+Δt" ​​for the time advance) are guided along the same movement path over a layer of building material, whereby, for example for the purpose of controlled influencing or controlling the heating or melting behavior of the building material 3, a specifically controllable pre-tempering of the building material 3 to be solidified by means of the first energy beam 4a results, in particular through the specific local and / or time advance of the second energy beam 4b. A corresponding advance is in Fig. 2 shown.

[0053] Alternatively or additionally, a second energy beam 4b can be coupled to a first energy beam 4a with a specific spatial and / or temporal lag (in Fig. 3 by the symbols "-Δx" for the local advance and "-Δt" for the temporal lag) are guided along the same movement path over a layer of building material, whereby, for example for the purpose of controlled influencing or controlling the cooling or solidification behavior of the building material 3, a specifically controllable subsequent tempering of the building material 3 solidified by means of the first energy beam 4a results, in particular through the specific local and / or temporal lag of the second energy beam 4b. A corresponding lag is in Fig. 3 shown, with the dashed line indicating that an additional corresponding lead time would also be possible here.

[0054] The same applies to the Fig. 5 illustrated case, in which the device 1 comprises a plurality of irradiation devices 6, 7 which are operable or operated as second irradiation devices. In this case, the control device 16 is configured to generate second control information, on the basis of which the second energy beams 4b generated by respective second irradiation devices are guided or guided ahead or behind a first energy beam 4a, each with a defined, in particular synchronized, local and / or temporal lead or lag, along the same movement path over a building material layer as the first energy beam 4a. Fig. 3 An optional caster is shown here in dashed lines.

[0055] The control device 16 can be configured to control the energy input introduced into a building material layer by respective second energy beams 4b generated by respective second irradiation devices as a function of the spatial and / or temporal lead or lag of the respective second energy beams 4b relative to the first energy beam 4a generated by the first irradiation device. The energy input introduced into the building material layer via respective second energy beams 4b can thus be varied (almost) as desired, so that (almost) any desired or (almost) any variable temperature profiles, i.e., for example, uniformly or unevenly rising or falling temperature ramps, can be realized by controlling the respective energy input of respective second energy beams.

[0056] In Fig. 4 an equally conceivable variant is described, according to which a movement of first and second energy beams 4a, 4b takes place in different movement paths, wherein at least one second energy beam 4b follows a first energy beam 4a with a certain spatial and / or temporal offset (in Fig. 4 by the symbols "+Δx" for the local offset and "+Δt" ​​for the temporal offset to the right of the movement path of the first energy beam 4a and by the symbols "-Δx" for the local offset and "-Δt" for the temporal offset to the left of the movement path of the first energy beam 4a) is / is guided laterally, in particular parallel, offset to a first energy beam 4a.

[0057] The control device 16 can thus be configured to generate second control information, on the basis of which a second energy beam 4b generated by a second irradiation device is guided over the building material layer with a defined spatial and / or temporal offset laterally, in particular parallel, offset to a movement path along which a first energy beam 4a is guided over a building material layer. A second energy beam 4b can therefore be guided over a building material layer with a specific spatial and / or temporal offset laterally offset to the movement path of a first energy beam 4a, whereby equally, for example for the purpose of controlled influencing or controlling the heating or melting behavior or the cooling orSolidification behavior of the building material 3, a specifically controllable pre- or post-tempering of the building material 3 to be solidified or solidified by means of the first energy beam 4a, in particular by the specific local and / or temporal lateral offset of the second energy beam 4b.

[0058] The same applies analogously to the case in which the device 1 comprises a plurality of irradiation devices 6, 7 that can be or are operated as second irradiation devices. In this case, the control device 16 is configured to generate second control information, on the basis of which the second energy beams 4b generated by respective second irradiation devices are guided over the building material layer with a defined spatial and / or temporal offset laterally, in particular parallel, offset to a movement path along which a first energy beam 4a is guided over a building material layer.

[0059] The control device 16 can also be configured here to control the energy input introduced into a building material layer by respective second energy beams 4b depending on the spatial and / or temporal offset of the respective second energy beams 4b relative to the movement path of the first energy beam 4a. In this way, too, the energy input introduced into the building material layer via respective second energy beams 4b can be varied (almost) arbitrarily, so that (almost) arbitrary or (almost) arbitrarily variable temperature profiles, i.e., for example, uniformly or unevenly rising or falling temperature ramps, can be realized by appropriately controlling the respective energy input of respective second energy beams 4b.

[0060] In general, a second energy beam 4b differs from a first energy beam 4a in at least one energy beam parameter influencing the energy input of the energy beam 4b into a building material layer. The second energy beam 4b can differ from the first energy beam 4a, for example, in the energy beam intensity and / or the energy beam focus diameter, and / or the energy beam speed at which the energy beam 4b is guided over a building material layer. The differentiation in the respective energy input is typically made with the proviso that the energy input of a second energy beam 4b is so low that melting of building material 3 with the second energy beam 4b is not possible.

[0061] Returning to Fig. 1 It can be seen that the device 1 can comprise a detection device 17, e.g. designed as a camera device, which is designed to detect at least one property of a building material layer, in particular of a region of a building material layer to be selectively solidified or of a selectively solidified region, and to generate detection information describing the at least one detected property of the building material layer. A corresponding property can be, for example, the temperature or the state of aggregation, in particular the molten state, of a region to be selectively solidified or of a selectively solidified region, so that a local melt pool 18 (cf. Fig. 2 ff).

[0062] The control device 16 can be configured to control at least one energy beam parameter of a second energy beam 4b, which influences the energy input of a respective energy beam into a building material layer, depending on a property of a building material layer described by detection information. By respective properties of a building material layer described by corresponding detection information, an even more precisely controlled influencing or control of the heating or melting behavior, or the cooling or solidification behavior, of the building material layer can be realized, particularly in real time, by means of one or more second energy beams 4b.

[0063] With the Fig. 1The device 1 shown can be used to implement a method for the additive production of three-dimensional objects 2 by successive layer-by-layer selective irradiation and the associated successive layer-by-layer selective solidification of building material layers from a building material 3 that can be solidified by means of an energy beam 4a, wherein a plurality of irradiation devices 6, 7 are used.The method is characterized in that a first irradiation device is operated on the basis of first control information generated by a control device 16 for generating a first energy beam 4a for successive layer-by-layer selective solidification of a building material layer, and a second irradiation device is operated on the basis of second control information generated by a control device 16 for generating a second energy beam 4b for thermal pretreatment of a building material layer to be selectively solidified, in particular in a region of the building material layer to be selectively solidified, and / or a second energy beam 4b for thermal aftertreatment of a selectively solidified building material layer, in particular in a selectively solidified region of the building material layer.

Claims

1. A method for additively manufacturing three-dimensional objects, the method comprising: emitting a first energy beam from a first irradiation device (6), which is set up for successive layer-by-layer selective solidification of layers of a building material; emitting a second energy beam from a second irradiation device (7), which is equipped for thermal pretreatment and / or for thermal posttreatment of the corresponding selectively to be solidified layer of a building material; characterized in that the first irradiation device and the second irradiation device are controlled by a control device based on control information, which are set up for controlling a local and / or time offset of the second energy beam relative to the first energy beam.

2. The method of claim 1, wherein the control device is set up to generate first control information, wherein the first control information is set up to control the first irradiation device; and / or wherein the control device is set up to generate second control information, wherein the second control information is set up to control the second irradiation device.

3. The method of claim 1 or 2, comprising: Leading the second energy beam, based on control information from the control device, wherein the second energy beam precedes or follows the first energy beam according to the local and / or time offset along the same trajectory as the first energy beam.

4. The method according to any one of claims 1 to 3, wherein the local and / or temporal offset includes a lateral offset relative to a trajectory of the first energy beam.

5. The method according to any one of claims 1 to 4, wherein the control device is set up to control the energy input of the thermal pretreatment and / or the thermal posttreatment on the basis of the local and / or temporal offset.

6. The method according to any one of claims 1 to 5, wherein the first energy beam and the second energy beam differ from each other in at least one energy beam parameter, which affects the energy input into a building material layer.

7. The method according to any one of claims 1 to 6, wherein the at least one energy beam parameter comprises: the energy beam intensity and / or the energy beam focus diameter and / or the energy beam velocity at which the energy beam is guided over a building material layer.

8. The method according to any one of claims 1 to 7, comprising: detecting, by means of a detection device, at least one property of a building material layer; and generating, by means of the detection device, one of the at least one detected property of the building material layer descriptive detection information.

9. The method of claim 8, wherein the control device is configured to control at least one energy beam parameter of the second energy beam based on the detection information.

10. The method according to any one of claims 1 to 9, comprising: emitting an additional second energy beam from an additional second irradiation device, wherein the additional second energy beam is set up for thermal pretreatment and / or thermal post-treatment of a layer of a building material; wherein the additional second energy beam is controlled by the control device on the basis of control information for controlling an additional local and / or time offset of the additional second energy beam relative to the first energy beam; and Leading the additional second energy beam based on control information from the control device, wherein the additional second energy beam precedes or precedes the first energy beam according to the additional local and / or time offset along the same path of motion as the first energy beam].

11. The method of claim 10, wherein it comprises several irradiation devices that can be operated or operated as second irradiation devices (6, 7), wherein the control device (16) is configured to generate second control information, on the basis of which the second energy rays (4b) generated by respective second irradiation devices with a defined local and / or temporal offset laterally to a trajectory along which the first energy beam (4b) generated by the first irradiation device can be guided or guided via a selectively solidified building material layer, via the selectively solidified or solidified building material layer.

12. The method according to any one of claims 1 to 12, wherein at least one first irradiation device is operated on the basis of first control information generated by a control device (16) for generating a first energy beam (4a) for successive layer-wise selective solidification of a building material layer, and at least one second irradiation device based on second control information generated by a control device (16) for generating a second energy beam (4b) for thermal pretreatment of a selectively solidified building material layer, in particular in a selectively solidified region of the building material layer, and / or a second energy beam (4b) for thermal post-treatment of a selectively solidified building material layer, in particular in a selectively solidified region of the building material layer is operated.

13. The method of claim 11, wherein the second energy beams (4b) generated by the respective second irradiation devices with a defined local and / or temporal offset parallel to the trajectory along which the first energy beam (4b) generated by the first irradiation device can be guided or guided via a selectively to be solidified building material layer, can be guided or guided via the selectively to be solidified or solidified building material layer.