METHOD AND DEVICE FOR ADDITIVE PRODUCTION OF AT LEAST ONE COMPONENT LAYER OF A COMPONENT, AND STORAGE MEDIUM

Abstract

The invention relates to a method for additive production of a component layer of a component including the steps of: generating at least one layer from a powdery component material in the region of a structuring and joining zone; subdividing model data of the layer into virtual sub-regions by a control device; selecting at least one of the virtual sub-regions by the control device; localized heating of at least one heating region in a real sub-region of the layer corresponding with the selected virtual sub-region by a heating device; verifying whether a temperature of the layer has, in a predetermined inspection region, a predetermined minimum temperature; and localized solidifying of the layer in a predetermined solidifying region by selective irradiation by at least one energy beam of an energy source, if the layer has the predetermined minimum temperature in the inspection region.

Claims

1. A method for additive production of at least one component layer of a component comprising the steps of: a) generating at least one layer from a powdery component material in the region of a structuring and joining zone; b) subdividing model data of the layer into virtual sub-regions by a control device; c) selecting at least one of the virtual sub-regions by the control device; d) locally heating at least one heating region in a real sub-region of the layer corresponding to the selected virtual sub-region by a heating device; e) verifying if a temperature of the layer has a predetermined minimum temperature at least in a predetermined inspection region; and f) locally solidifying the layer at least in a predetermined solidifying region by selectively irradiating by at least one energy beam of an energy source if the layer has at least the predetermined minimum temperature in the inspection region.

2. The method according to claim 1, wherein the heating device selectively heats a partial volume of an overall volume of the powdery component material in a construction container to the predetermined minimum temperature at a point of time, wherein the partial volume includes at least 0.01%, and/or at most 50% of a surface area of a work plane in the structuring and joining zone.

3. The method according to claim 1, wherein at least two regions of the group of real sub-region, heating region, inspection region and solidifying region are at least substantially identically selected and/or that at least one region of the group of real sub-region, heating region, inspection region and solidifying region is a subset and/or an intersecting set of another region of this group and/or that at least two procedurally consecutive regions of the group of real sub-region, heating region, inspection region and solidifying region overlap with each other.

4. The method according to claim 1, wherein at least the steps c) to f) are performed for two or more sub-regions of the layer to be solidified.

5. The method according to claim 1, wherein at least one of the steps c) to e) is performed during step f) for at least one further sub-region.

6. The method according to claim 5, wherein the layer is heated in the heating region of the further sub-region such that the heating region of the further sub-region has at least the predetermined minimum temperature as soon as the irradiation of the preceding sub-region is completed.

7. The method according to claim 1, wherein step f) is only performed for the first time for the layer if at least a predetermined minimum number of sub-regions has been selected and the associated heating regions have been heated to their respectively predetermined minimum temperature.

8. The method according to claim 1, wherein at least one further sub-region is selected by the control device and the heating region associated with the further sub-region is heated by the heating device if a predetermined maximum number of solidified sub-regions and/or sub-regions heated to their respectively predetermined minimum temperature has been reached or exceeded.

9. The method according to claim 1, wherein the control device controls and/or regulates the heating device and the energy source depending on each other.

10. The method according to claim 1, wherein the solidifying region is heated during and/or after step f) by the heating device and/or that the heating of the solidifying region by the heating device before, during or after step f) is aborted or reduced with respect to heating in step d).

11. The method according to claim 1, wherein a predetermined minimum temperature and/or a predetermined maximum temperature or a predetermined temperature progression is selected for a number of inspection regions and/or solidifying regions respectively depending on an area and/or a geometry and/or a sought microstructure of a component cross-section or section of the component cross-section to be solidified or being solidified, wherein the minimum temperature and/or the maximum temperature and/or the temperature progression is preferably separately set for each inspection region and/or solidifying region.

12. The method according to claim 1, wherein the control device controls and/or regulates the heating device such that an already locally solidified sub-region has at least a predetermined minimum temperature and/or has at most a predetermined maximum temperature.

13. The method according to claim 1, wherein a relative movement of the heating region of the heating device and of the solidified sub-region is effected by a distance and/or in a direction, by which the sub-region leaves a maximum effective range of the heating device, which allows heating the sub-region to a temperature value of at least 1000 C. and/or of at least 70% of the melting temperature in C. of the currently used component material, depending on a positive verification to the effect if the temperature of at least a predetermined section of the solidified sub-region corresponds to the preset temperature progression and/or at most to the predetermined maximum temperature.

14. A device for additive production of at least one component layer of a component, comprising: at least one coater for generating at least one layer from a powdery component material in the region of a structuring and joining zone; at least one energy source for generating at least one energy beam, by which the layer can be solidified locally to the component layer in the region of the structuring and joining zone; at least one heating device), which the layer can be locally heated; and at least one inspection device, by which a temperature of the layer can be verified; a control device, which is configured to subdivide model data of the structuring and joining zone into virtual sub-regions, to select at least one of the virtual sub-regions, to locally heat at least one heating region in a real sub-region of the layer corresponding to the selected virtual sub-region by the heating device, to verify by the inspection device if a temperature of the layer has a predetermined minimum temperature at least in a predetermined inspection region, and to locally solidify the layer at least in a predetermined solidifying region by selectively irradiating by the at least one energy beam if the layer has at least the predetermined minimum temperature in the inspection region.

15. The device of claim 14, further comprising a storage medium with program code, which is configured and arranged to control the device upon execution by the control device.

Description

[0037] Further features of the invention are apparent from the claims, the figures and the description of figures. The features and feature combinations mentioned above in the description as well as the features and feature combinations mentioned below in the description of figures and/or shown in the figures alone are usable not only in the respectively specified combination, but also in other combinations without departing from the scope of the invention. Thus, implementations are also to be considered as encompassed and disclosed by the invention, which are not explicitly shown in the figures and explained, but arise from and can be generated by separated feature combinations from the explained implementations. Implementations and feature combinations are also to be considered as disclosed, which thus do not comprise all of the features of an originally formulated independent claim. Moreover, implementations and feature combinations are to be considered as disclosed, in particular by the implementations set out above, which extend beyond or deviate from the feature combinations set out in the relations of the claims. There shows:

[0038] FIG. 1 a schematic view of a component layer, which is generatively produced by locally solidifying a layer;

[0039] FIG. 2 a schematic view of a further component layer, which is generatively produced by locally solidifying a layer;

[0040] FIG. 3 a schematic top view of a local heating device with two induction coils, which are arranged parallel to a solidification progress direction in their longitudinal extension;

[0041] FIG. 4 a diagram of a resulting temperature progression in a powder and component layer, respectively, located below the heating device shown in FIG. 3;

[0042] FIG. 5 a schematic top view of the local heating device, wherein an induction coil is arranged obliquely to a solidification progress direction in its longitudinal extension;

[0043] FIG. 6 a schematic top view of the local heating device with multiple associated heating regions;

[0044] FIG. 7 a diagram of a heating control of the heating device shown in FIG. 6 and a resulting temperature progression in the powder and component layer, respectively;

[0045] FIG. 8 a schematic top view of the local heating device, wherein an induction coil is arranged perpendicularly to strip-shaped arranged sub-regions in its longitudinal extension;

[0046] FIG. 9 a schematic top view of the local heating device, wherein an induction coil is oriented with respect to the sub-regions based on a reference location;

[0047] FIG. 10 a schematic top view of the local heating device, wherein procedurally consecutive inspection regions overlap with each other; and

[0048] FIG. 11 a schematic diagram of an embodiment of a device according to the invention.

[0049] FIG. 1 shows a schematic view of a component layer 10, which is generatively produced by locally solidifying a layer 12. A schematic diagram of an embodiment of a device 28 according to the invention, by means of which a so-called additive and generative manufacturing method, respectively, can be performed, is illustrated in FIG. 11. FIG. 1 will be explained in synopsis with FIG. 11 in the following.

[0050] Therein, a component 40, which can for example be a component 40 of a fluid kinetic machine or an aircraft engine, is structured in layers. Predominantly metallic components 40 can for example be produced by laser and electron beam melting or sintering methods, respectively. Therein, at least one powdery component material 48 is first applied in layers in the region of a construction field or a structuring and joining zone 42 to form the layer 12. Subsequently, the component material 48 is locally solidified by supplying energy to the component material 48 by means of at least one energy beam in the region of the structuring and joining zone 42, whereby the component material 48 melts or sinters and forms the component layer 10. Therein, the energy beam is controlled depending on layer information of the component layer 10 respectively to be produced. The layer information is usually generated from a 3D CAD body of the component 40 and subdivided into individual component layers 10. After solidifying the molten component material, a component platform 46 is lowered by a predefined layer thickness. Thereafter, the mentioned steps are repeated until final completion of the desired component region or the entire component 40. Therein, the component region or the component 40 can basically be produced on the component platform 46 or for example on an already generated part of the component 40, on a support structure or directly on a base plate 44 of the device 28. The advantages of this additive manufacture are in particular in the possibility of being able to produce very complex component geometries with cavities, undercuts and the like within the scope of a single method.

[0051] In order to be able to locally heat the component material 48, a heating device 90 is used, by means of which the layer 12 can be heated to a desired minimum temperature in individual heating regions. Therein, the local heating device 90 serves for improving e.g. the mechanical characteristics of a component 40 and for example comprises one or more induction coil(s) 92a, 92b (see FIG. 3) or inductor(s) movable relative to the layer 12. By the local inductive heating for example individually adaptable to the geometry of the component layer 10 to be produced, it is possible that hot crack formations are reliably prevented in the production of the component in particular in using high-temperature alloys as the component material. Since eddy currents cannot be induced in powders, already solidified component layers 10 located below the layer 12 are heated in this case. Initially and in the region of the first component layers 10, respectively, the prefabricated base plate 44 can be captured by the induction field. The heat is then transferred into the layer(s) 12 located above via thermal conduction/thermal radiation.

[0052] Therein, an area of the powder bed 12 heatable at least to a minimum or set temperature at an identical point of time, however, only occupies a small portion of a construction field 42 and the component layer 10, respectively. Thus, the heating region of the local heating device 90 usually has to be moved across the construction field 42 in order that the entire component layer 10 can be heated and irradiated. At the same time, however, a scan speed of the energy beam, for example a laser beam 60 or an electron beam, is usually relatively high. An action field of the energy beam can include jumps or large distances on the layer 12, which are traveled in very short time (e.g. in contour exposure, island irradiation strategy). Displacing the heating region (coil assembly) is effected substantially slower in contrast thereto for mechanical and thermal reasons. The interaction of heating and irradiatingwith energy sources 58 such as for instance lasers, one speaks of exposureshould therefore be coordinated such that a component layer 10 can be solidified in a time as short as possible and as continuously as possible despite of the limiting factor speed of the displacement of a heating region, wherein the process reliability and the maximally achievable component quality always have priority.

[0053] Therefore, for high component quality, it should be ensured that only solidifying regions of the layer 12 are irradiated, which reach or have reached at least a predefined minimum or set temperature (approved inspection region) during the irradiation. Due to the possible irradiation speed, the solidifying regions, which reach or exceed the minimum or set temperature at the same time, have to be multiple times larger than a laser spot and a location of impingement of a focused solidification beam, respectively, on the surface of the layer 12 in practice, since an irradiation procedure otherwise either would proceed severely slowed or would have to be interrupted each time a solidifying region 16 is completely solidified. Thereby, the maximum area of a solidifying region 16 is substantially determined by the area, in which a minimum or set temperature is achievable at the same time anyway.

[0054] In a heating device 90 with a cross-coil arrangement or an arrangement, in which a small induction coil 92b is positioned in a larger induction coil 92a (see FIG. 3), the heating region 102 for example corresponds approximately to the area between the coil arms, in which the effective ranges of the induction coils 92a, 92b superimpose on each other. Since an approved inspection region 104 indicates approval of a subsequent irradiation, a section often has to be subtracted from the mentioned heating region 102 in practice, which is covered by a coil arm arranged above.

[0055] A corresponding production method can be differently configured.

EXAMPLE 1

Sequential Irradiation

[0056] The additive production of the component layer 10 can generally be effected in sequential, stepped and/or successive manner. First, the layer 12 is subdivided into multiple virtual sub-regions 14 based on model data, which are consecutively selected in a preset or dynamically determined order. For example, this can be effected with the aid of the control device 80. Each real sub-region 14 of the layer 12 to be solidified, which corresponds to a corresponding virtual sub-region 14, is then locally heated in a heating region by means of the heating device 90. Subsequently, it is verified in an inspection region 104 by means of an inspection device 70 including a temperature measuring device, if a predetermined minimum temperature has been reached. After reaching the preset minimum temperature, the layer 12 is solidified in a solidifying region 16. The real sub-regions 14, the heating regions 102, the inspection regions 104 and the solidifying regions 16 can, but do not compulsorily have to correspond to identical regions of the layer 12. For example, a heating region 102 can overlap with a virtual/real sub-region 14, for instance if the heating by means of the heating device 90 is not restricted to a clearly limited (real) sub-region 14. However, a heating region 102 can also be a subset of a sub-region 14, for example if the heating occurs exclusively within the (real) sub-region 14. Similarly, an inspection region 104 and/or a solidifying region 16 can also be identical to a (virtual/real) sub-region 14 or overlap with it or represent a subset of the respective sub-region 14. The individual virtual/real sub-regions 14 do not compulsorily have to be geometrically contiguous and either not compulsorily be a constituent of an individual component 40.

[0057] After exposure of a sub-region 14, the heating region 102 or the heating device 90 is displaced to another location of the layer 12 and directly or indirectly heats a procedurally following heating region 102 in the procedurally following sub-region 14 to the respectively desired minimum temperature. After reaching the minimum temperature (approved inspection region 104), the further sub-region 14 is solidified in the solidifying region 16 etc. until the component layer 10 is finished.

EXAMPLE 2

Continuous Feed of the Energy Beam

[0058] In this embodiment, the steps of heating and exposing or irradiating are effected coordinated in time such that irradiation breaks as low as possible occur. In other words, the period of time, in which it is not irradiated, is minimized, e.g. because the heating device 90 first has to move to a target position to heat there a heating region 102 in a subsequent sub-region 14 or because the solidifying region 16 is not (yet) irradiated, because the required minimum temperature has not (yet) been reached in the inspection region 104. Preferably, the irradiation of the entire component layer 10 is effected continuously and without irradiation interruption, respectively. Therein, short irradiation breaks are not understood as irradiation interruption, which e.g. are taken in the typical irradiation pattern of hatching between sweeping or scanning individual lines substantially parallel to each other when a beam deflection unit performs a reversal operation without the beam being activated therein. Hereto, the individual sub-regions 14 can for example be arranged along one or more strip-shaped solidifying regions 16 as it is shown in FIG. 1. In this manner, continuously or largely or quasi-continuously consecutive solidifying regions 16 arise since the layer 12 is locally heated in temporally and locally consecutive heating regions of corresponding sub-regions 14 and is at least largely continuously solidified after reaching the respective minimum temperature.

[0059] In FIG. 2, a schematic view of a further component layer 10 is illustrated, which is generatively produced by locally solidifying a layer 12. In contrast to the embodiment shown in FIG. 1, the layer 12 is subdivided in rectangular or square virtual and thereby also real sub-regions 14 in grid-shaped manner. One recognizes that some sub-regions 14 include edge regions of the component layer 10 to be solidified as well as powder regions not to be solidified. Alternatively, the sub-regions 14 can also be defined such that they exclusively include solidifying regions of the layer 12. Similarly, it can generally be provided that some sub-regions 14 do not include solidifying regions, but still are directly or indirectly heated, and/or that some sub-regions 14 comprise solidifying regions, but are not or at least not directly pre-heated by means of the local heating device 90.

[0060] Via reaching the minimum or set temperature, sub-regions 14 can be defined, which are not necessarily locally contiguous. The order of the processing of the sub-regions 14 is for example determined by the point of time of reaching the minimum temperature or also the vicinity of the actual temperature to a respective set or minimum temperature and is effected preferably temporally to the approval of the respective sub-region 14 (triggering of the approval by reaching the minimum temperature). Therein, the geometrically continuous irradiation can also be interrupted if it allows a more advantageous irradiation and solidification, respectively, or if the geometric data of the component layer 10 to be produced makes this required. It should always be the goal to achieve a solidification as continuous as possible, that is a break portion as low as possible of the overall duration of the exposure of the layer 12 per component layer 10 to be produced.

[0061] For heating the layer 12 preferably low in interruptions or without interruption, therefore, the movement of the heating spot of the heating device 90 is preferably coupled to the direction and speed, respectively, of the irradiation progress to achieve travel paths of the heating device 90 as efficient as possible with regard to the overall area of the component layer 10 to be irradiated depending on the used heating method and induction coil arrangement, respectively. Due to the relative inertia of the heating device 90, long paths without heating activity are generally to be avoided as possible.

[0062] In terms of control, these goals are achieved by the already described segmentation or subdivision of the layer 12 into virtual and real sub-regions 14 and the mechanism of heating, verifying the temperature and the approval of the individual sub-regions 14 for the solidification upon reaching the respective minimum temperature. A sub-region 14 or a solidifying region 16 can for example be locally defined via [0063] a defined irradiation region; and/or [0064] a cross-sectional area of the component 40 to be produced; and/or [0065] a geometry of the component layer 10 to be produced; and/or [0066] a geometry of the entire construction field 42.

[0067] Alternatively or additionally, a sub-region 14 or a solidifying region 16 can for example be temporally defined: [0068] dynamically during the construction process; and/or [0069] as a pre-calculation or predetermined.

[0070] Other criteria, which can be incorporated individually and in any combination into the determination of the number and configuration of the individual regions (virtual/real sub-region 14, heating region, inspection region, solidifying region), for example include the ascertainment of suitable minimum values with respect to the surface area of a sub-region 14 and/or the simulated irradiation duration of a sub-region 14 and/or the length of an irradiation path located in a sub-region 14 or in a solidifying region 16. Furthermore, segmentation or subdivision of the component layer 10 can be effected in multiple stages such that multiple segments or sub-regions 14 are for example combined to clusters. Each cluster can then be irradiated e.g. with different irradiation types. For example, a sub-region 14 or cluster of sub-regions 14 or solidifying regions can be irradiated with the alternative irradiation type checkerboard pattern or another suitable pattern instead of the irradiation type strip pattern, to for example avoid local overheatings in particularly sensitive regions like tapered regions or contour regions.

[0071] As further variants of implementation, regions (sub-regions 14, heating regions 102, inspection regions 104, solidifying regions 16) arranged overlapping with each other can be provided. Similarly, it can be provided that individual, multiple or all regions (sub-regions 14, heating regions 102, inspection regions 104, solidifying regions 16) are differently determined depending on the method state, thus for example with smaller area before the solidification and with larger area after the solidification or vice versa. Thus, an unilateral or mutual dependency between the movement path of the heating device 90 and the movement path of the energy path is basically taken into account for the control and/or regulation of the device 28.

[0072] In the following embodiments, the real sub-regions 14 and the solidifying regions 16 are usually identically selected. The heating regions 102 are selected such that each sub-region 14 is overall heated at least to its respectively requested minimum temperature, wherein it is not excluded that adjoining sub-regions 14 are optionally co-heated, but without therein having to reach the minimum temperature requested for them. In the following embodiments, the inspection regions 104 are subsets of the respective sub-regions 14 such that the momentary temperature and reaching the minimum temperature, respectively, are respectively not verified in the entire sub-region 14. Instead, the temperature in the section of the associated sub-region 14 located outside of the inspection region 104 is inferred with the aid of empirical values, extrapolation or the like based on the temperature in the inspection region 104. This principle can basically be applied within the scope of the present disclosure without being restricted to the following embodiments.

[0073] In an embodiment, the heating, verifying and solidifying step of n sub-regions 14 (X.sub.1 . . . X.sub.n) of a component layer 10 can be statically effected and include the following steps of: [0074] subdividing model data of the layer 12 or the construction field 42 into virtual sub-regions; [0075] selecting a first virtual sub-region and associating a real sub-region 14 (segment X.sub.1); [0076] control: heating the first sub-region 14 (segment X.sub.1) (variable or optionally max. heating power HL) in a corresponding heating region 102; [0077] inspection: set or minimum temperature reached in the inspection region 104 for sub-region 14 (X.sub.1)? [0078] If yes: signal approval for irradiation; if no: signal: continue heating, optionally with changed heating rate and heating power HL, respectively; [0079] control: with active approval, continuous heating (optionally with changed heating rate and heating power HL, respectively) or aborting heating of the sub-region 14; [0080] control: exposure of the sub-region 14 (X.sub.1); [0081] optionally signal: approval for deactivation of the heating of the heating region 102 of the associated sub-region 14 (X.sub.1) (immediately or with temporal offset, e.g. due to an advantageous thermal post-treatment); [0082] optionally signal: final approval of the sub-region 14 (X.sub.1) after deactivation of heating; [0083] control: displacing the heating region (optionally max. heating level) for heating the procedurally following sub-region 14 (X.sub.2) and performing the process in analogous manner for all of the remaining sub-regions 14 (X.sub.2 . . . X.sub.n) of the component layer 10.

[0084] In alternative embodiments, the heating, verifying and solidifying step of the sub-regions 14 (X.sub.1 . . . X.sub.n) of a component layer 10 can be dynamically effected and include the following steps and embodiments individually or in any combination: [0085] setting a required minimum number or a minimum pre-run and/or a maximum number or a minimum post-run of heating relative to the location of impingement of the energy beam; the definition of minimum number/minimum pre-run and maximum number/minimum post-run, respectively, can be effected e.g. according to the following criteria: [0086] based on time (heating/irradiation); [0087] length of an irradiation path in an approved sub-region 14 with reached minimum temperature; [0088] number of sub-regions 14 (included in pre-heating; approved for exposure; already exposed, etc.).

[0089] From a minimum pre-run of approved heated sub-regions 14, the irradiation and solidification of the component layer 10 starts, respectively. After effected approval of a sub-region 14 (heating terminated and optionally solidification terminated), the heating region is displaced to the next sub-region 14 to be solidified. With sufficiently large buffer, a permanent movement of the energy beam, optionally with acceleration and deceleration phases, can thereby be achieved. Successively heated sub-regions 14 can be displayed as segments approved for irradiation in a display device to provide the corresponding information to a user. An irradiation of the respective component layer 10 is effected continuously and largely uninterrupted as possible, respectively. The buffer of heated and approved sub-regions 14 is preferably adjusted such that it is not consumed until the irradiation of the entire component layer 10 is terminated. Hereto, it can be required that procedurally later sub-regions 14 are differently heated than procedurally earlier sub-regions 14 to provide a heat buffer for compensation for the cooling to be expected up to the beginning of the respective irradiation. Therein, it has generally proven advantageous if a maximum temperature, which can be identically or differently predetermined or dynamically ascertained for different sub-regions 14, is not exceeded to prevent burning of the component material or new fusing of already solidified component layers 10.

[0090] The movement of the comparatively narrow effective range of the heating device 90 (coverage of the small induction coil 92b) can be adjusted corresponding to an averaged movement direction of an energy beam, wherein the movement of the energy beam is usually effected perpendicularly or at an angle of at least 45, that is of 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89 or 90 to the movement direction of the heating device 90 on the layer 12. Therein, irradiation jumps are to be reduced or to be avoided as far as possible, which overstrain a displacement speed of the heating device 90 to prevent that a buffer of tempered sub-regions 14 is consumed in the meantime and a continuous irradiation of the entire layer 12 is interrupted.

EXAMPLE 3

[0091] According to a further embodiment, a ratio of minimum pre-run:minimum post-run is set between 1.5:1 and 3:1, thus for example 1:5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, 2.0:1, 2.1:1, 2.2:1, 2.3:1, 2.4:1, 2.5:1, 2.6:1, 2.7:1, 2.8:1 2.9:1 or 3:1.

EXAMPLE 4

[0092] A minimum number of sub-regions 14 to be approved for irradiation is set before irradiation of the concerned component layer 10 starts. This offers the advantage that a buffer is provided with the purpose that an irradiation does not have to be terminated after approval of a segment or sub-region 14, but can be immediately continued in a next approved sub-region 14.

EXAMPLE 5

[0093] A maximum number of irradiated and approved sub-regions 14 or segments, respectively, is defined before a heating region of the heating device 90 is displaced. This offers the advantage that a buffer is provided with the purpose that a heating region of the heating device 90 is displaced in time such that a minimum number of approved (i.e. sufficiently heated according to verification) sub-regions 14 is always available.

EXAMPLE 6

[0094] After effected approval (see above) for a segment or a sub-region 14 due to the reached minimum temperature, the heating region of the heating device 90 is displaced, for example by moving an induction coil assembly, namely by a certain distance or segment, such that at least one further sub-region 14 to be irradiated is in a distance and orientation to the heating device 90, respectively, which allow heating to the respectively desired minimum temperature value.

EXAMPLE 7

[0095] An x/y control coordinate is calculated, for example via reference locations of a (e.g. regularly shaped) heating region and a (e.g. regularly shaped) solidifying region, respectively. Therein, various parameters can be taken into account, such as for example the capturing frequency (60 Hz) of an IR camera (inspection device 70), which can be used for temperature measurement of the layer 12, a hatch distance, a width of an irradiation strip or a scan speed of the energy beam. Before the beginning of the irradiation, a buffer of sub-regions 14 approved for irradiation is preferably generated here too.

[0096] FIG. 3 shows a schematic top view of a local heating device 90 with a large and a small induction coil 92a, 92b, which are presently arranged parallel to a solidification progress direction VR in their longitudinal extension, that is in an ideal orientation to strip- or band-shaped arranged sub-regions 14. The sub-regions 14 are selected one after the other in solidification progress direction or feed direction VR, heated, inspected and solidified after reaching the predetermined minimum temperature. In the following, FIG. 3 will be discussed in synopsis with FIG. 4, which shows a diagram of a resulting temperature progression in a layer 12 located below the heating device 90 shown in FIG. 3. One recognizes that the solidifying region 16 is presently selected congruent or identical with one of the sub-regions 14, while the heating regions 102 are not congruent with the sub-regions 14. As one recognizes in FIG. 4, a multi-step temperature progression arises along the extension of the heating device 90 from left to right, that is viewed in the direction of the feed direction VR. The initial temperature is a base temperature T1, which prevails in the process chamber 30 and can for example be generated by the radiation heating 54 shown in FIG. 11 or also only by the ambient temperature. It is basically variable and can increase e.g. over a construction or production operation. Starting from the base temperature T1, the temperature increases first to a temperature T2 by the induction effect of the large coil 92a. By the superposition with the eddy currents induced by the small induction coil 92b, the temperature increases in a component platform 46 and an already selectively solidified layer below the layer 12, respectively, and thereby per thermal transfer also the temperature of the layer 12 itself over a ramp to the temperature T3 located slightly below the melting temperature of the component material, which presently represents the desired minimum temperature (Tmin) for the solidification at the same time. By the exposure paths of the laser beam 60 symbolized by arrows, the temperature of the layer 12 in the currently processed solidifying region 16 is increased to a temperature T4 located above the melting temperature of the component material such that the component material 48 is locally and selectively molten and solidified, respectively, in the concerned sub-region 14 and solidifying region 16, respectively. Subsequently, the temperature falls again back to the value T3 over a ramp in a solidified post-heating region within the effective range of the small induction coil 92b and to the value T2 outside of the small induction coil 92b. After an effective range of the large induction coil 92a has departed from a solidified sub-region 14 by moving the coil 92a, the temperature finally again falls to the ambient temperature T1.

[0097] Furthermore, one recognizes in FIG. 3 projection regions 104 identified with circles in the region of the large and the small induction coil 92a, 92b, in which a direct measurement of the temperature of the layer 12, for example with the aid of a thermal imaging camera or thermography device of the inspection device 70, respectively, is not possible due to the shading by the induction coils 92a, 92b. In FIG. 4, the projection regions 104 are also identified with circles. In these projection regions 104, a projection or an estimation based on empirical values replaces the direct ascertainment or measurement of the current temperature.

[0098] FIG. 5 shows a schematic top view of the local heating device 90, wherein the induction coils 92a, 92b are arranged obliquely to a solidification progress direction VR according to their longitudinal extension, in which the strip- or band-shaped arranged sub-regions 14 are to be solidified one after the other. For reasons of clarity, only the small induction coil 92b is illustrated. One recognizes that the rectangularly selected sub-regions 14 of the layer 12 are differently severely shaded due to the oblique arrangement of the induction coil 92b related to the progress direction of the solidification process indicated by the arrow VR. Therefore, the inspection regions 104 are presently selected such that they only correspond to a partial area of the respective sub-region 14. For example, each inspection region 104 can be selected or predetermined such that it has only less than 50%, 51%, 52, %, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% of the area of the respective sub-region 14. It is understood that all of the inspection regions 104 can basically have identical areas or area portions or individually selected or predetermined areas or area portions. Generally, the inspection regions 104 are of course to be selected such that a meaningful result can be ascertained. Those sections of a sub-region 14, which are not located within an inspection region 104, either cannot be considered for the temperature verification or for example considered by extrapolation or estimation based on empirical values (projection regions 104).

[0099] FIG. 6 shows a schematic top view of the local heating device 90 with multiple associated heating regions 102, wherein only the smaller induction coil 92b is illustrated for reasons or clarity. In the following, FIG. 6 will be explained in synopsis with FIG. 7, in which a diagram of a heating control of the heating device 90 shown in FIG. 6 and a resulting temperature progression in the layer 12 is shown. The control of the heating power HL of the heating device 90 can for example be effected by the control device 80. The heating control is exemplarily shown for four procedurally consecutive sub-regions 14, which are identified by Roman numerals (I-IV) in FIG. 6 and FIG. 7. Therein, the sub-regions 14 identified by I and II can also be referred to as pre-run, while the sub-region 14 identified by IV and further sub-regions 14 within the vision window of the induction coil 92b can be referred to as post-run, whereby a ratio of pre-run to post-run of about 2:3 presently results.

[0100] Viewed from right to left, that is opposite to the solidification progress direction VR, pre-heating of the layer 12 is first effected in the region I by means of the small induction coil 92b from a temperature T2, to which the layer 12 was already heated by the large induction coil 92a, to a higher temperature T3, which prevails in the region II. Therein, the temperature curve of the layer 12 ascertained with the aid of the inspection device 70 (actual temperature) is presently identified by the reference character T. In the region III, that is in the approved sub-region 14 and in the solidifying region 16 presently congruent with it, respectively, solidification of the layer 12 is effected by irradiation with an energy beam, whereby the temperature increases from T3 to T4. In the region IV, a post-heating phase is then effected, whereby the temperature decreases to the value T5. As one sees in FIG. 7, the heating power HL, which is immediately coupled to the temperature progression T in the regions I, II and IV, is therein reduced in the region III, that is in the solidifying region 16 to account for the additional energy input by the energy beam. Hereby, it is ensured that the actual temperature T of the layer 12 always ranges in a predetermined temperature band, which can be defined by a predetermined minimum temperature Tmin and a predetermined maximum temperature Tmax. This represents a particularly process-reliable solidification of the layer 12 and a correspondingly high-quality component layer 10, since sufficient pre-heating of the component material 48 is ensured on the one hand and an inadmissible heating of the component material 48 is prevented on the other hand. Since the solidifying region 16 possibly cannot be monitored by thermography depending on the respectively used inspection device 70, the control and regulation of the heating power HL, respectively, are for example effected by extrapolation, calculation and/or based on empirical values.

[0101] FIG. 8 shows a schematic top view of the local heating device 90, wherein the small induction coil 92b is oriented perpendicularly to a solidification progress direction VR of the strip- or band-shaped arranged sub-regions 14 according to its longitudinal extension. The strip- or band-shaped arranged sub-regions 14 thereby formally form a segmented exposure strip. In FIG. 8 too, the large induction coil 92a is not illustrated for reasons of clarity. One recognizes that related to the solidification progress direction VR, a ratio of pre-run:post-run is presently 3:2. It is understood that other ratios can basically also be adjusted by corresponding dimensioning of the induction coils 92a, 92b and/or the sub-regions 14. For example, a ratio of pre-run:post-run can be 4:3.

[0102] FIG. 9 shows a schematic top view of the local heating device 90, wherein the small induction coil 92b is oriented with respect to the sub-regions 14 based on a reference location RP. Hereto, a central point of the vision region of the induction coil 92b is first ascertained, for example via the point of intersection of the diagonals D1, D2 and correlated with a global coordinate system of the process chamber 30 with the aid of the control device 80. Furthermore, a central line ML of the sub-regions 14 arranged along an exposure strip is ascertained in the vision region of the induction coil 92b. Therein, the sub-regions 14 are rectangularly formed in the present example and each have the same distance d and the same dimensions, respectively. By referencing the central line ML and the central point to each other, the reference location RP is ascertained, with the aid of which the respective solidifying region 16, the respective pre-run and post-run of sub-regions 14 and/or the respective inspection regions 104 can be determined. For example, a perpendicular can be formally dropped by the reference location RP, which is then perpendicular to a given orientation of strip-shaped arranged sub-regions 14. Parallels to the perpendicular then define boundaries of the associated inspection regions 104 or sub-regions 14.

[0103] FIG. 10 shows a schematic top view of the local heating device 90, only the small induction coil 92b of which is again illustrated. Furthermore, multiple sub-regions 14 are illustrated, which are again strip- or band-shaped arranged in the solidification direction X. One recognizes that the two exemplarily shown inspection regions 104 procedurally evaluated one after the other or at the same time are selected not identically with their respective sub-regions 14 on the one hand and overlap with each other in an overlap region 106 on the other hand. The overlap is presently 50%, wherein deviating values above or below 50% can basically also be provided. Furthermore, more than two inspection regions 104 can basically also overlap with each other. An overlap of inspection regions 104 is generally reasonable if the inspection regions 104 represent a relatively large area of the layer 12 and a relatively large portion of the vision region of the small induction coil 92b, respectively.

[0104] FIG. 11 shows a schematic diagram of an embodiment of a device 28 according to the invention. The preceding embodiments can be performed with the aid of such a correspondingly configured device 28, wherein the device 28 is presently formed as a laser sintering or laser melting device for additive manufacture of components 40. It is explicitly pointed out that the invention is not restricted to laser sintering or laser melting devices such that the device 28 can for example also be formed as an electron beam sintering or melting device. In the following, the device 28 is therefore also referred to as laser sintering devicewithout restriction of generality.

[0105] The device 28 comprises a process chamber 30 or a process space 30 with a chamber wall 32, in which the manufacturing process substantially proceeds. A container 34 open to the top with a container wall 36 is located in the process chamber 30. The upper opening of the container 34 forms the respectively current work plane 38. The region of this work plane 38 located within the opening of the container 34 can be used for structuring the component 40 and is therefore referred to as construction field 42 or as structuring and joining zone. Usually, it is sufficient if the process space sensor data SDS and the model data used within the scope of the invention respectively relate to the region of the process space 30 defined by the construction field 42 (i.e. in the work plane), optionally also a part thereof.

[0106] The container 34 comprises a base plate 44 movable in a vertical direction XI, which is arranged on a support 47. This base plate 44 terminates the container 34 to the bottom and thereby forms its bottom. The base plate 44 can be formed integrally with the support 47, but it can also be a plate formed separately from the support 47 and attached to the support 47 or simply supported on it. According to the type of the component material 48 used as a structuring material and the manufacturing process, a component platform 46 can be mounted on the base plate 44 as a construction base, on which the component 40 is structured. However, the component 40 can basically also be structured on the base plate 44 itself, which then forms the component platform 46.

[0107] The basic construction of the component 40 is effected such that a layer of the powdery component material 48 or structuring material is first applied to the component platform 46, thenas explained laterthe component material 48 is selectively solidified with a laser beam 60 at the locations, which are to form parts of the component 40 to be manufactured, then the base plate 44 and thus the component platform 46 is lowered with the aid of the support 47 and a new layer of the component material 48 is applied and then selectively solidified. These steps are repeated until completion of the component segment or a complete component 40. The component 40 structured in the container 34 on the component platform 46 is presently illustrated below the work plane 38 in an intermediate state. It already comprises multiple solidified layers, surrounded by component material 48 left non-solidified. Various materials can be used as the component material 48, preferably powders, in particular metal-based powders with a metal or metal alloy content of at least 50% by vol. or also filled or mixed powders.

[0108] Fresh component material 48 is located in a storage container 50 of the laser sintering device 28. With the aid of a coater 52 movable in a horizontal direction H, the component material 48 can be applied in the form of a thin layer 12 in the work plane 38 and within the construction field 42, respectively.

[0109] A basically optional radiation heating 54 is located in the process chamber 30. It can serve for globally heating the applied component material 48 such that an additionally used locally acting heating device 90 can input a lower amount of energy. That is, an amount of basic energy can already be input into the component material 48 for example with the aid of the radiation heating 54, which is of course still below the required energy, at which the component material 48 sinters or even melts. For example, an infrared radiator can be used as the radiation heating 54.

[0110] For selectively solidifying, the laser sintering device 28 comprises an irradiation device 56 or an exposure device 56 in the example described here with an energy source 58 formed as a laser. This laser 58 generates the laser beam 60, which is deflected via a deflection device 62 to thus sweep the exposure paths or tracks provided according to the exposure strategy in the layer respectively selectively to be solidified and to selectively input the energy. Further, this laser beam 60 is focused to the work plane 38 in suitable manner by a focusing device 64. Here, the irradiation device 56 is preferably located outside of the process chamber 30 and the laser beam 60 is directed into the process chamber 30 via a coupling window 66 attached to the top side of the process chamber 30 in the chamber wall 32.

[0111] The irradiation device 56 can for example include not only one, but multiple lasers 58 and laser beams 60, respectively. Preferably, they can be gas or solid state lasers. Alternatively or additionally, one or more electron beam sources are basically also conceivable as the irradiation device 56.

[0112] The laser sintering device 28 furthermore contains a sensor assembly or inspection device 70, which is suitable to capture a process radiation emitted during impingement of the laser beam 60 on the component material 48 in the work plane 38 and to determine a measurement value characterizing the temperature in the work plane 38. Therein, this inspection device 70 works locally resolved, i.e. it is presently capable of capturing a type of emission image of the respective layer. Preferably, the inspection device 70 includes a camera, for example a thermography camera, which is sufficiently sensitive in the range of the emitted radiation. Alternatively or additionally, one or more sensors for capturing an optical and/or thermal process radiation could also be used, e.g. photodiodes, which capture the electromagnetic radiation emitted by the impinging laser beam 60, or temperature sensors for capturing an emitted thermal radiation. An association of the signal of a sensor not locally resolving itself with the coordinates would be possible in that the coordinates used for controlling the laser beam 60 are respectively temporally associated with the sensor signal. Presently, the inspection device 70 is arranged within the process chamber 30. However, it could also be located outside of the process chamber 30 and then capture the process radiation through a further window in the process chamber 30 or chamber wall 32.

[0113] Here, the signals captured by the inspection device 70 are passed to a control device 80 of the device 28 as process space sensor dataset SDS, which also serves to control the various components of the device 28 for overall control of the additive manufacturing process and which is configured to execute at least one embodiment of the method according to the invention. Hereto, the control device 80 comprises a processor device 82, which usually controls the components of the irradiation device 56, namely here the laser 58, the deflection device 62 and the focusing device 64, and hereto correspondingly passes irradiation control data BS to them.

[0114] The control device 80 also controls and regulates, respectively, the radiation heating 54 by means of suitable warming control data HS, the coater 52 by means of coating control data SD and the movement of the component platform 46 in the direction XI by means of support control data TD. Furthermore, the control device 80 controls and regulates, respectively, the heating device 90 by means of heating data HD, by means of which heating regions 102 in the structuring and joining zone 42 can be locally heated. For example, the heating device 90 can be formed as an induction heating as shown in FIG. 3 and comprise an assembly of a large induction coil 92a as well as a small induction coil 92b movable across the construction field 42, wherein the small induction coil 92b is additionally movable within the large induction coil 92a, such that the two induction fields can be selectively superimposed. However, other configurations of the local heating device 90 are also conceivable.

[0115] Here, the control device 80 is coupled to a computer device 86 with a display or another human-machine interface e.g. via a bus system 84 or another wired and/or wireless data link for data exchange. An operator can control and/or regulate the control device 80 and thus the entire device 28 via this computer device 86. In particular, the process space sensor dataset SDS can also be suitably visualized on the display of the computer device 86.

[0116] At this place, it is again pointed out that the present invention is not restricted to a device 28 formed as a laser melting and/or laser sintering equipment and a device 28 for performing a laser melting and/or sintering method, respectively. It can be applied to any other methods for generative and additive production of a three-dimensional component, respectively, by applying and selectively solidifying a component material 48 in particular in layers, wherein an energy beam is emitted to the component material 48 to be solidified for solidification. Accordingly, the irradiation device 56 either cannot only be a laser 58 as described here, but each device could be used, by which energy can be selectively brought on and into the component material 48, respectively, as wave and/or particle radiation. For example, another light source, an electron beam etc. could be used instead of a laser.

[0117] Even if only a single component 40 is illustrated in FIG. 10, it is possible and normally also usual to produce multiple components 40 in the process chamber 30 and in the container 34, respectively, during a construction operation, i.e. within a similar period of time.

[0118] In summary, various additive production variants can be performed and corresponding advantages with regard to process reliability and component quality of a correspondingly produced component layer 10 and of a complete component 40, respectively, can be achieved with the aid of the method according to the invention and with the aid of the device 28 according to the invention, respectively, which is configured for performing such a method. Thereby, the invention provides a simple and effective solution of the problem of matching of continuous heating and continuous irradiation of potentially irregular areas, which combines the goals of a reliable and fast performance of the process and allows the additive production of component layers 10 with maximum layer quality.

[0119] The parameter values indicated in the documents for the definition of process and measurement conditions for the characterization of specific characteristics of the inventive subject matter are to be considered as encompassed by the scope of the invention also within the scope of deviationsfor example due to measurement errors, system errors, DIN tolerances and the like.

LIST OF REFERENCE CHARACTERS

[0120] 10 component layer

[0121] 12 layer

[0122] 14 sub-region

[0123] 16 solidifying region

[0124] 28 device

[0125] 30 process chamber

[0126] 32 chamber wall

[0127] 34 container

[0128] 36 container wall

[0129] 38 work plane

[0130] 40 component

[0131] 42 structuring and joining zone

[0132] 44 base plate

[0133] 46 component platform

[0134] 47 support

[0135] 48 component material

[0136] 50 storage container

[0137] 52 coater

[0138] 54 radiation heating

[0139] 56 irradiation device

[0140] 58 energy source

[0141] 60 laser beam

[0142] 62 deflection device

[0143] 64 focusing device

[0144] 66 coupling window

[0145] 70 inspection device

[0146] 80 control device

[0147] 82 processor device

[0148] 84 bus system

[0149] 86 computer device

[0150] 90 heating device

[0151] 92a induction coil

[0152] 92b induction coil

[0153] 102 heating region

[0154] 104 inspection region

[0155] 104 projection region

[0156] 106 overlap region

[0157] HL heating power

[0158] SDS sensor dataset

[0159] SD coating control data

[0160] HD heating control data

[0161] BS irradiation control data

[0162] HS warming control data

[0163] TD support control data

[0164] RP reference location

[0165] VR solidification progress direction

[0166] d distance and dimension of the sub-region 14, respectively

[0167] D1, D2 diagonal

[0168] H movement direction of the coater 52

[0169] ML central line

[0170] T1, T2, T3, T4, T5 temperature

[0171] Tmin minimum temperature

[0172] Tmax maximum temperature

[0173] T temperature progression

[0174] I, II, III, IV region

[0175] XI movement direction of the base plate 44