Method and device for generating control data for a device for additively manufacturing a component

Abstract

The invention relates to a method for generating control data (PS) for a device (1) for additively manufacturing a component (2) in a manufacturing process, in which method build-up material (13), preferably comprising a metal powder, is built up in layers in a build-up field (8) by selectively solidifying the build-up material (13) by irradiating the build-up material (13) with at least one energy beam (22), the method comprising the steps of: - recording a process chamber sensor data set (SD) with spatially resolved thermal data of a component layer (B) currently being solidified; - providing a process chamber control data set (KD) with a target shape (F) of the component layer (B) currently being solidified; - determining a number of special regions (S) in the target shape (F); - assigning the number of special regions (S) to corresponding regions in the process chamber sensor data set (SD); - generating a correction factor module (KK), wherein correction factors (KF) are generated in the special regions (S) according to different rules than in other regions of the target shape (F) outside the special regions (S); - correcting control data (PS) for the additive manufacture of a subsequent component layer (B1) based on the correction factor module (KK); - outputting the corrected control data (PS) to a device (1) for additively manufacturing a component (2). The invention also relates to corresponding control data, a method for additive manufacturing, a control data generation device, a control device, and a manufacturing device.

Description

[0001] Method and device for generating control data for a device for the additive manufacturing of a component

[0002] The invention relates to a method and a device ("control data generation device") for generating control data for a device for the additive manufacturing of a component in a manufacturing process in which the component is built up in a build field in the form of component layers by selectively solidifying build material by irradiating the build material with at least one energy beam. The invention further relates to corresponding control data, a method for the additive manufacturing of a component with such control data, a device for additive manufacturing, and a control device for such a device.

[0003] Additive manufacturing processes are becoming increasingly relevant in the production of prototypes and, more recently, in series production. In general, "additive manufacturing processes" refers to manufacturing processes in which a finished product ("component") is built up by depositing material (the "build material"), usually based on digital 3D design data. The build-up is usually, but not necessarily, layered. The term "3D printing" is often used as a synonym for additive manufacturing. The production of models, samples, and prototypes using additive manufacturing processes is often referred to as "rapid prototyping," the production of tools as "rapid tooling," and the flexible production of series components as "rapid manufacturing."As mentioned at the beginning, a key aspect is the selective solidification of the build-up material. In many manufacturing processes, this solidification can be achieved by irradiation with radiant energy, e.g., electromagnetic radiation, in particular light and / or thermal radiation, but possibly also with particle radiation such as electron beams. Examples of processes that use irradiation are "selective laser sintering" or "selective laser melting." In this process, thin layers of a build-up material, usually in powder form, are repeatedly applied one on top of the other. In each layer, the build-up material is selectively solidified by spatially limited irradiation of the areas that will become part of the component after production in a "welding process." The powder grains of the build-up material are partially or completely melted using the energy locally introduced by the radiation at that location.During cooling, these powder grains then solidify into a solid. Typically, the energy beam is guided along solidification paths across the build area, and the remelting or solidification of the build material in the respective layer occurs accordingly in the form of "weld paths" or "weld beads," so that ultimately the component contains a multitude of such layers formed from weld paths. In this way, components with very high quality and fracture strength can now be manufactured.

[0004] During production, it can happen that the energy applied by the energy beam is absorbed inhomogeneously by the component. This manifests itself in areas of a component layer with inhomogeneous heat distribution. Sometimes it may be desirable to harden selected areas with a different energy input, but this is generally undesirable, especially with uniform surfaces or regular contours.

[0005] It is an object of the present invention to provide a method and a device for generating control data for a device for the additive manufacturing of a component, which overcomes the disadvantages of the prior art and, in particular, allows an improvement in the quality of a component. A preferred object of the invention is to increase the stability of the manufacturing process and, in particular, to prevent interruption of production or to prevent problems occurring during the application of the build material at locations with increased heat generation or radiation. A further preferred object is to reduce the support volume (and thus the part costs) and thus increase the process speed, which has a beneficial effect on component costs.

[0006] This object is achieved by a method according to patent claim 1, control data according to patent claim 10, a manufacturing method for additive manufacturing according to patent claim 11, a control data generating device according to patent claim 12, a control device according to patent claim 13 and a device according to patent claim 14.

[0007] A method according to the invention serves to generate control data for a device for the additive manufacturing of a component in a manufacturing process in which the component is built up in a build field in the form of component layers by selectively solidifying build material by irradiating the build material with at least one energy beam. Although the control data do not yet represent a finished component, they do represent a component because a component consists of layers of solidification paths that have been solidified according to the control data.

[0008] The method according to the invention comprises the following steps:

[0009] - Recording a process space sensor data set of a currently solidified component layer of the component by means of a sensor arrangement, wherein the process space sensor data set comprises at least spatially resolved thermal data of a number of areas of this component layer,

[0010] - Providing a process space control data set comprising information on a target shape of the currently solidified component layer,

[0011] - Defining a number of special areas in the target shape, each special area being an area with predetermined, systematic shape features and / or manufacturing features in the component layer,

[0012] - Assigning the number of special areas to corresponding areas of the number of areas in the process space sensor data set,

[0013] - generating a correction factor module which assigns correction factors or corrected irradiation values ​​to at least one partial area of ​​a subsequent component layer, wherein the correction factors or the corrected irradiation values ​​are generated from the process space sensor data set and are generated in the special areas according to different rules than in other areas of the target shape outside the special areas,

[0014] - Correcting control data for the additive manufacturing of a subsequent component layer based on the correction factor module,

[0015] - Output of the corrected control data to a device for the additive manufacturing of a component.

[0016] As already indicated, in a manufacturing process, build-up material is built up layer by layer in a build area, i.e., successively in several material application levels or material layers. The build-up material is preferably a metal powder or at least a metal-based powder. Such a powder preferably contains more than 50% by weight of metal, in particular more than 60% by weight, 70% by weight, 80% by weight, or even more than 90% by weight of metal. However, the invention is not limited to this, but can also be used with other, preferably powdered, build-up materials, such as plastics or ceramics or mixtures of the various materials.In this process, build-up material is solidified (particularly selectively), particularly between the application of two material layers, by irradiating the build-up material with at least one energy beam generated by an irradiation unit of the production device (this refers to an energetic beam of photons or particles, e.g., a light beam or an electron beam). Not only is the build-up material in the uppermost, freshly applied material layer captured and melted or remelted by the energy beam, but the energy beam typically penetrates a little deeper into the material bed and also reaches underlying, already remelted material from previously applied material layers.

[0017] The process space sensor data set with the thermal data can be recorded using a thermal imaging camera, e.g. a CMOS camera with a spectral filter in the near-infrared range, but this is not mandatory. A scanning measurement method can also be used in which spatial resolution is given - solely or additionally - by a respective scan position, and / or a measurement method in which the sensor is arranged in the beam path of the processing machine (on axis) and the spatial resolution is given - solely or additionally - by a current processing position. Spatially resolved "thermal data" refers to information on the heat distribution in at least one area of ​​the component layer or an entire component layer. Information on various points of the component layer along with the position of these points must be available.For example, an infrared image of the component layer could represent the thermal data, since thermal information is assigned to points in the component layer in this image. However, the thermal data does not necessarily have to be a thermal image from a thermal camera; it can be obtained in other ways. For example, the process space sensor dataset shows a component layer, or at least a component region within that component layer, as a thermal image.

[0018] The absolute temperature does not necessarily have to be measured directly for the thermal data; the pixel values ​​of a temperature-sensitive camera (essentially the "gray values") are sufficient. From their evaluation alone, the temperature can be accurately estimated. The thermal data can represent a temperature in both absolute and relative values. Typically, a baseline for the temperature values ​​(gray values) is measured for a machine or a build process (even on different machines), and the temperature is estimated based on a change relative to the baseline. This change can be "small" (e.g., for very high baselines) or "large" (e.g., for very low baselines). The process space control dataset contains data on the geometric shape of the respective component layer under consideration and / or on irradiation paths for the production of this component layer (target shape).The term "provision" in relation to the process-space control dataset means that it can be easily obtained, e.g., if the data is already available from another source, or can be generated, e.g., from CAD data of a component or from control data. In short, the target shape should enable reconstruction of the relevant component layer. For example, the process-space control dataset with respect to the target shape can include parallel sections of a CAD-generated component (at least one section) or scan vectors for the production of a component layer (or many component layers) of a component.

[0019] In principle, this information alone would be sufficient to minimize inhomogeneities in energy input. Therefore, the input energy is measured during the manufacturing process using a sensor array, e.g., by measuring the heat radiation of a component layer with a radiation sensor. These measurements can then be used to detect areas with excessive heat radiation, and the corresponding areas in the subsequent component layer can be strengthened with a lower energy input. The same applies to areas that radiate too little heat. In this way, inhomogeneities can be compensated iteratively.

[0020] However, this compensation cannot be optimally applied in some areas of a component because the data from the sensor array does not necessarily reflect correct values ​​for the actual thermal radiation, or these areas "function" thermally differently than other areas. These include, for example, areas with corners or sharp curves in the component, edge areas of the component, or very small structures within a component. In general, it can be said that wherever there is a risk that the resolution of the sensor array does not allow for precise separation of areas with different energy inputs, or where an energy input that differs from the ambient temperature is specifically desired, this general method cannot offer optimal compensation for inhomogeneities.These areas are particularly peripheral areas, i.e., areas where there is a large energy input for solidification on one side and no energy input on the other, since solidification is not intended to occur. However, these areas can also be areas where stripes of a hatch overlap and appear conspicuous in a layer-by-layer integrating sensor system, although they may not be so in reality.

[0021] Such an area is referred to as a “special area” in the context of the invention, as it requires special attention so that the compensation of inhomogeneities can be carried out as well as possible. Each special area is an area with predetermined, systematic shape and / or manufacturing features in the component layer. Shape features are features relating to the geometric shape or position, e.g., that the area lies at the edge of a cross-section of a component to be hardened, the area is smaller than the resolution of the sensor arrangement or is not imaged with sufficient precision by the sensor arrangement, or that special thermal conditions prevail in the area due to the shape or due to a position on or near a surface of the subsequent component, e.g., in the case of tight curves or tapers. Manufacturing features would be, for example,an overlap of hardening paths in a component layer, a local increase in the spacing of hardening paths in a component layer, a local change in the thickness or depth of hardening paths, or local changes in irradiation (e.g., due to pulses or the selection of a different process window, such as local hardening by conduction welding when the deep penetration welding process is generally selected). Special shape features and manufacturing features can also exist in combination, as a particular shape may lead to the selection of a particular local manufacturing mode. The term "predetermined systematically" means that the process space control dataset (and, if applicable, experience in component manufacturing) already indicates that special thermal conditions prevail in these areas during production. For example, the edge of a component represents a thermally problematic area.A special area could also be referred to as a (systematically special) "overheating area," "defective heating area," "deviation area," or "special correction area." In particular, a special area can be an area that requires or would require post-treatment if it were not exposed to elevated temperatures during production.

[0022] With regard to a particular aspect of the invention, a special region can be an area that is to be thermally post-treated or that is solidified with different parameters (e.g. laser parameters: beam profile, laser intensity) during the manufacture of the component in order to change / improve its properties or the properties of the component (e.g. hardness, mechanical strength, density, etc.). The definition of these special regions to corresponding regions of the target shape is preferably carried out automatically, e.g. by automatically classifying every edge region of a component layer of the target shape with a predetermined width, every overlap region or every clearly delimited region below a predetermined volume or a predetermined area in the build plane as a special region. What exactly is to be classified as a special region can, for example, be taken from a predetermined list, but could also be specified manually by user input.It is particularly preferred if a user can enter or change the parameters for an automatic classification of special areas by means of changeable presets.

[0023] These special areas are therefore initially defined in a non-physical environment (target shape). Since this target shape corresponds to the (real) component layer represented by the process space sensor data set, it is now necessary to determine which parts of the respective component layer are to be considered special areas. This is achieved through subsequent assignment. The process space sensor data set contains spatially resolved thermal data from a number of areas of the component layer. For clarity, this will be referred to below as the "thermal image of the component layer," although this term does not exclude other ways in which spatially resolved thermal data from a number of areas of the component layer could be present.

[0024] This assignment of special areas to corresponding areas of the "thermal image of the component layer" is preferably done automatically, e.g., by automatically classifying each area of ​​the thermal image whose corresponding area in the target shape has been classified as a special area in the thermal image as a special area in the thermal image. This assignment can be done purely using information technology, by adding a marker to an area of ​​the thermal image of the component layer, indicating that this is a special area, or by adding a marking to this area in an image (e.g., a special color). A mask can also be created that indicates which areas in the thermal image of the component layer are to be regarded as special areas. How exactly the information on the special area is assigned to the target shape (e.g.,The method of determining the thermal image (e.g., by means of a data link or by mapping) is essentially irrelevant as long as it is subsequently determined which areas of the thermal image of the component layer are to be regarded as special areas and which are not. This makes it clear which thermal data of the spatially resolved thermal data lie in a special area and which are not. The subsequently generated correction factor module assigns correction factors or corrected irradiation values, which are generated from the process space sensor data set, to at least one sub-area of ​​a (directly) subsequent component layer (i.e., the one lying directly on the other component layer after its production).The correction factor module preferably comprises a program and / or a database, wherein the program preferably comprises automated access to a database, wherein the access comprises using and / or modifying and / or saving and / or overwriting data based at least on the process space sensor data set and / or the process space control data set. The correction factors act in particular on a power and / or a focus diameter of the energy beam and / or its beam profile or intensity distribution and / or a scanning speed and / or a hatch distance. If the energy beam is a laser beam, the term "laser correction factor" (or LCF for "laser correction factor") or "laser power correction factor" can also be used. However, a restriction to a laser power is not necessary, since the energy input is essentially to be adjusted.Therefore, the correction factor module could also be called an “energy input parameter module” or “volume energy module,” e.g., with a volume energy as a reference value.

[0025] A "module" in the sense of the correction factor module is an element that is intended to apply or collect a plurality or multiplicity of correction factors. It can contain only data that are the correction factors or from which the correction factors can be determined, but it can also contain a functionality with which correction factors can be determined or even applied to control commands. The module itself can be software-implemented, e.g. in the form of a table, function, list or data set, or hardware-implemented, e.g. in the form of an FPGA or a processor or controller with a memory unit. The correction factor module is therefore preferably a software-based or hardware-based element that comprises data in the form of correction factors or data and / or functions by means of which the correction factors can be determined.

[0026] The correction factor module can be in the form of a correction factor map which contains the correction factors in the form of a matrix. If, for example, there is a digital thermal image of the component layer, the correction factor map can certainly comprise pixels or raster cells which correspond in particular to the pixels in the thermal image and, instead of color values ​​or gray values, comprise scalar quantities which specify correction factors. The correction factor module can alternatively or additionally be in the form of a correction factor function KF, which is preferably a two-dimensional function. The correction factors at a two-dimensional spatial position (x, y) in the component layer can then simply be the function values ​​of the correction factor function KF (x, y) at the corresponding locations. The correction factor function can, for example, be generated from a correction factor map by fitting a two-dimensional polynomial function.Although creating a function is more complicated than creating a map, it has the advantage of requiring less memory, since only the function coefficients need to be stored, and it also offers better scalability. Using such a correction factor function can also be advantageous for corrections without considering the special areas. A corresponding procedure then comprises the following steps:

[0027] - Optional: Assign the number of special areas to corresponding areas of the number of areas in the process room sensor data set,

[0028] - generating a correction factor function which assigns correction factors or corrected irradiation values ​​to at least one partial area of ​​a subsequent component layer, wherein the correction factors or the corrected irradiation values ​​are generated from the process space sensor data set and are preferably generated in the special areas according to different rules than in other areas of the target shape outside the special areas,

[0029] - Correcting control data for the additive manufacturing of a subsequent component layer based on the correction factor function.

[0030] What is important for the method according to the invention here is that the correction factors or corrected irradiation values ​​in the special areas are generated according to different rules than in other areas of the target shape outside the special areas. This is because “different rules” also apply in the special areas. For example, the data from pixels of a thermal imaging camera reflects the heat radiated from a surface area on the build plane. A first pixel that has recorded an unconsolidated area shows less heat than a second pixel that has recorded a recently consolidated area. A third pixel, however, which has recorded an edge area with consolidated and unconsolidated areas, will show less heat than the second pixel and more heat than the first pixel, even if the consolidated area should be the same temperature everywhere.This is because the pixels show an integral of the thermal radiation of the area they record. In a case where the second pixel (not a special area) would indicate that the area it recorded was too hot, a corresponding correction factor would indicate that less energy should be applied there in the next layer. However, for the third pixel (special area, here adjacent to the second pixel), which is considered colder even though there is too much heat in the solidified area because some unsolidified area was also recorded, no correction factor would be applied without special treatment (or a correction factor of 1) because no overheating was detected. However, the correct approach here would be to apply the same correction factor that is applied to the second pixel.This is precisely what the method according to the invention takes into account by generating the correction factors or corrected irradiation values ​​in the special areas according to different rules than in other areas of the target shape outside the special areas.

[0031] The exact nature of these other rules can depend on the component, the build material used, the type of irradiation, and the nature of the special area. Some preferred embodiments are listed below. In a very simple embodiment, for example, the correction factors of neighboring areas of the target shape can be used for the special areas.

[0032] The correction factor module (or KF module for short) does not have to refer to the entire build field. Different areas of the build field can be corrected by different KF modules. For example, an overall correction map can be created from a combination of correction factor maps (KF maps). Control of a build process is preferably carried out pixel-by-pixel according to points on these KF maps, with the control being better the higher the resolution of a KF map. Accordingly, a group of correction factor functions can also be used, with each correction factor function being applied to an area of ​​the build field. Preferably, specified irradiance values ​​are corrected during production using the correction factor and / or the correction factor directly provides the irradiance values.The correction factor is preferably a relative correction factor that is multiplied by a given laser power or by which a given laser power is divided.

[0033] The same applies to the corrected irradiation values ​​as to the correction factors, since they are simply irradiation values ​​that have already been corrected using (these) correction factors. The KF module can therefore include correction factors that are then used to correct irradiation values, or already corrected irradiation values. It is clear that the correction factors are chosen such that if the energy input is too high at one point in the subsequent layer, a lower energy input occurs at that point, which is calculated in particular to achieve a desired energy input.

[0034] To compensate for inhomogeneities, a subsequent component layer must be irradiated. If the subsequent component layer still exhibits inhomogeneities after its production, the process can be repeated for the next component layer based on the currently produced component layer. After a few iterations, with a reasonable choice of correction factors, the energy input can be homogenized.

[0035] Control data for the additive manufacturing of a subsequent component layer is corrected based on the correction factor module (e.g., a correction factor map or function), and the corrected control data is output to a device for additive manufacturing of a component so that a new component layer can be produced. This new component layer, or a process space sensor data set for this new component layer, should now serve as the basis for a new process run for the next component layer.

[0036] The KF module can be saved last, especially after the component has been manufactured, and used to manufacture further components. If the KF module does not contain correction methods but rather corrected irradiation data (and particularly preferably corrected control data), it could be considered control data according to the invention.

[0037] The method described above can be used to generate control data according to the invention that serves to control a device for additive manufacturing. As mentioned, this control data is characterized by being corrected so that inhomogeneities in the temperature distribution during production are compensated. It should be noted that this does not compensate for the temperature distribution itself; rather, an inhomogeneous temperature distribution of a current layer is taken into account for compensating irradiation in the subsequent layer. Strictly speaking, it is not just the heat balance of a single layer that is regulated, but, with a correspondingly lesser effect, the heat balance of many already solidified layers, up to the overall heat balance of a component, or even the simultaneous production of several components.The reason for this is that already solidified layers generally continue to emit heat, as the heat input into the build container during the production process usually exceeds the heat outflow from the build container, at least temporarily. With many solidified layers, the effect accumulates, significantly influencing the heat radiation of a measured surface. In practice, the correction factors of the correction factor module are usually only combined with the original control data (vectorized) in the machine controller and passed on to an exposure controller as "microsteps" (control signals in the scan cycle of the production device). However, directly corrected control data can also be used.

[0038] The control data preferably also includes further design instructions, such as a quantity of build material that may be locally selectively allocated for a layer application, and in particular, the lowering of the build platform between the production of the component layers. This is implicit in an arrangement of two component layers, since a new component layer can only be applied to an already solidified area by applying new build material. This application usually requires the lowering of the build platform.

[0039] In a manufacturing method according to the invention for the additive manufacturing of a component, the component is built up layer by layer in a build field by selectively solidifying build material, preferably comprising a metal-based powder, by irradiating the build material with at least one energy beam according to the control data according to the invention. To create component layers of the component, the energy beam is moved across the build field according to the control data, i.e., with corrected irradiation parameters.

[0040] A control data generation device according to the invention serves to generate control data according to the invention (according to the method according to the invention) for a device for the additive manufacturing of a component in a manufacturing process in which the component is built up in a construction field in the form of component layers by selective solidification of build material, preferably comprising a metal-based powder, by irradiating the build material with at least one energy beam.

[0041] The control data generating device comprises the following components:

[0042] - A data interface designed to receive a process space control data set comprising information on a target shape of the currently solidified component layer, and a process space sensor data set of a currently solidified component layer of the component recorded by means of a sensor arrangement, wherein the process space sensor data set comprises at least spatially resolved thermal data of a number of regions of this component layer,

[0043] - a registration unit designed to define a number of special areas in the target shape, each special area being an area with predetermined, systematic shape features and / or manufacturing features in the component layer, and to assign the number of special areas to corresponding areas of the number of areas in the process space sensor data set,

[0044] - a module unit designed to generate a correction factor module, which assigns correction factors or corrected irradiation values ​​to at least one sub-area of ​​a subsequent component layer, wherein the correction factors or corrected irradiation values ​​are generated from the process space sensor data set and are generated in the special areas according to different rules than outside the special areas,

[0045] - a correction unit designed to correct control data for the additive manufacturing of a subsequent component layer based on the correction factor module,

[0046] - a data interface (if applicable, the one mentioned above or another) designed to output the corrected control data to a device for the additive manufacturing of a component.

[0047] The function of the components has already been explained in detail above using the procedure.

[0048] A control device according to the invention serves a device for the additive manufacturing of a component in a manufacturing process in which the component is built up in a build field in the form of component layers layer by layer by selectively solidifying build material, preferably comprising a metal-based powder, by irradiating the build material with at least one energy beam using an irradiation device. The control device is designed to control the device for the additive manufacturing of the component layers of the component according to control data according to the invention. The control device according to the invention preferably comprises a control data generation device according to the invention.

[0049] A device according to the invention (“manufacturing device”) serves for the additive manufacturing of at least one component in an additive manufacturing process. It comprises at least

[0050] - a feeding device for applying layers of build material to a build area in a process chamber,

[0051] - an irradiation device for selectively solidifying build-up material by irradiation with at least one energy beam, in particular between the application of two material layers, and

[0052] - a control device according to the invention.

[0053] It should be noted at this point that the device according to the invention can also comprise multiple irradiation devices, which are then controlled in a coordinated manner using the control data, as mentioned above. It should also be mentioned again that the energy beam can also consist of multiple superimposed energy beams, or that the energy beam can be either particle radiation or electromagnetic radiation, such as light or, preferably, laser radiation.

[0054] The invention can be implemented in particular in the form of a computer unit, in particular in a control device, with suitable software. This refers in particular to the creation of the control data, since the production of a component takes place using additional components. For this purpose, the computer unit can, for example, have one or more cooperating microprocessors or the like. In particular, it can be implemented in the form of suitable software program components in the computer unit. A largely software-based implementation has the advantage that even computer units already used previously, in particular in control devices of production apparatus, can be easily retrofitted by means of a software or firmware update in order to operate in the manner according to the invention.In this respect, the object is also achieved by a corresponding computer program product with a computer program that can be loaded directly into a memory device of a computer unit, with program sections for executing all steps of the method according to the invention (at least those related to the generation of control data, but possibly also those that serve to transmit the control data for a production process) when the program is executed in the computer unit. Such a computer program product can, in addition to the computer program, optionally comprise additional components such as documentation and / or additional components, including hardware components such as hardware keys (dongles, etc.) for using the software.A computer-readable medium, for example a memory stick, a hard disk or another portable or permanently installed data storage device, on which the program sections of the computer program that can be read and executed by a computer unit are stored, can be used for transport to the computer unit and / or for storage on or in the computer unit.

[0055] Further, particularly advantageous embodiments and developments of the invention emerge from the dependent claims and the following description, wherein the independent claims of one claim category can also be developed analogously to the dependent claims and embodiments of another claim category and, in particular, individual features of different embodiments or variants can be combined to form new embodiments or variants.

[0056] According to a preferred method, before assigning the number of special areas to the corresponding areas in the process space sensor data set, the process space sensor data set is adapted according to existing (previously determined) calibration data or according to an adaptation function (e.g., a fit algorithm). It is preferred that the sensor arrangement is first calibrated and the process space sensor data set is recorded using the calibrated sensor arrangement. Alternatively, it is preferred that prefabricated calibration data is available and the process space sensor data set is adapted after it has been recorded by the sensor arrangement. It is preferred that the special areas are registered or otherwise mapped to corresponding areas in the process space sensor data set using an adaptation algorithm. The latter has the advantage that the sensor data can be calibrated directly depending on whether or not it originates from a special area.

[0057] Which area is specifically considered a special area depends on the type of component, the manufacturing method, or the user. It can be specified, e.g., through default settings or user specifications, what is considered a special area. The following areas of a component are preferred special areas. Individual alternatives or groups of the following alternatives can be selected as defaults for special areas. - A component edge area of ​​the component layer,

[0058] - an area of ​​the component layer in which hardening paths overlap, in particular their initial and / or final areas,

[0059] - an area in which a hatching strip (possibly consisting of parallel, adjacent consolidation strips) tapers (i.e. in which the consolidation strips have a length shorter than a standard or maximum length),

[0060] - an area that is smaller than the optical resolution of the sensor arrangement (ie a smallest possible area of ​​the component layer that can be individually measured by the spatially resolving sensor arrangement), an area with support structures, preferably wherein a wall thickness or a strut thickness or a diameter of the support structures is smaller than can be fully resolved with the sensor (e.g. < 5x pixel resolution, e.g. approx. 500pm).

[0061] According to a preferred method, the number of special areas is assigned to the corresponding positions in the process space sensor data set using image registration. A method based on enhanced correlation coefficients (common in image processing) is preferred (see, for example, Georgios D. Evangelidis and Emmanouil Z. Psarakis, "Parametric Image Alignment Using Enhanced Correlation Coefficient Maximization," IEEE Transactions on Pattern Analysis and Machine Intelligence, Vol. 30, No. 10, October 2008).

[0062] According to a preferred method, the correction factors of the correction factor module for a special area are interpolated or extrapolated from the correction factors for a number of component areas of the target shape adjacent to the special area. This is done, in particular, by interpolating correction factors from opposing component areas or by interpolating correction factors from a component area and specified values ​​outside the component, or from correction factors from a component area. This is particularly advantageous if the special area is an area where thermal post-treatment is to be performed.

[0063] Alternatively, it is preferred that the correction factors of the correction factor module for a special area are formed from predetermined, constant correction factors. Alternatively, it is preferred that the correction factors of the correction factor module for a special area are determined by interpolating methods from image processing that are based on a continuous continuation of the gray values, in particular based on colorization algorithms or inpainting algorithms.

[0064] Alternatively, it is preferred that the correction factors of the correction factor module for a special area be calculated based on a model of a theoretical temperature change or the local heat conduction properties. This is particularly advantageous if the special area is an area where thermal post-treatment is to be performed.

[0065] According to a preferred method, predetermined maximum and / or minimum values ​​are available for a correction factor, in particular a limit value module, in particular a limit value function or a limit value map with spatially resolved maximum and / or minimum values. The correction factors are then preferably generated such that they do not exceed the maximum values ​​and / or do not fall below the minimum values.

[0066] According to a preferred method, to generate a correction factor map, the correction factors are generated from the process space sensor data set outside the number of special areas using a controller, in particular a PD controller, a PI controller, or a PID controller. It is preferred that the correction factors within a special area, i.e., where they are generated according to different rules than in other areas:

[0067] - be generated without the controller, or

[0068] - are first generated using the controller and then corrected or

[0069] - first, the corresponding values ​​of the process space sensor data set are corrected and then the correction factors are generated using the controller.

[0070] For correction in non-special areas, the controller is preferably used in a conventional manner, using parameterizable proportional, derivative, and / or integral components. Completely software-based control is particularly preferred. The controller parameters can be adjusted specifically for the component.

[0071] As already indicated above, the method is preferably applied to several consecutive component layers. Control data is preferably stored together with a number of corresponding correction factor modules and / or with corrected control data. It should be noted that the correction factor modules may already contain corrected irradiation values, but the corrected control data may contain additional data than the corrected irradiation values. It is particularly preferred to store all correction factor modules or corrected control data obtained by the method, as these are interrelated. Finally, a process space sensor data set results from a component layer manufactured with corrected control data after prior application of the method.

[0072] It is preferred that, for the correction of control data for a component, only data from the correction factor module is used that was generated from a component layer of this specific component, in particular from the immediately preceding component layer. Thus, each component is considered individually. Alternatively, data from a correction factor module that was generated from a uniform component layer of another component is preferably used. This allows, for example, when manufacturing several similar components, the correction factor module of one of the components to be applied to the other components.

[0073] It should be noted here that the method according to the invention can also be applied to already corrected control data, provided that it is known that it has already been corrected and how. Essentially, only the correction factors then need to be configured accordingly. For example, corrected control data obtained from one component can undergo additional correction when applied to another component. Alternatively, corrected control data obtained from a component that, for example, has the same shape, is to be manufactured from the same material, and has the same requirements regarding its component properties, can undergo additional correction when applied to another example of this component. However, control data that was corrected without taking special areas into account can now be optimized using the method, e.g.by making specific corrections only to the special areas and retaining the other correction factors.

[0074] According to a preferred method, to define a number of special areas in the currently solidified component layer, information on the shape and / or position of the subsequent component layer is provided in addition to a process space control data set. Correction factors, in particular for downskin areas—i.e., surface areas or near-surface areas of a component that lie above and border on unsolidified powder in the manufacturing process in the manufacturing device—are then preferably derived from the process space control data sets of both component layers. Thus, when selecting the special areas, the subsequent component layer is also considered—essentially, the target shapes of these component layers.

[0075] The invention has the additional advantage that, at least during component production, reduced cooling times can be expected. Furthermore, production can also be carried out with higher packing densities, since temperature-related distances between components can be reduced.

[0076] To date, particular emphasis has been placed on designs that correct control data in such a way that inhomogeneities in temperature distribution during production are compensated. However, a correction can also be deliberately made to set a different temperature in a specific area than in another (adjacent) area.

[0077] Unwanted internal stresses often arise in a component, which can lead to adverse component properties such as cracks or deformation. To relieve or reduce such stresses, the component can be heat treated, e.g., in the case of metallic components, post-annealing with optional subsequent quenching. Depending on the desired quality, subsequent heat treatment may even be mandatory. For this purpose, the components are heated to a predetermined temperature in a furnace after production and then cooled in a liquid bath if necessary. For heat treatment, the temperature in the chamber is usually between 300°C and 350°C. A typical temperature for the production of metal parts is between 250 and 300°C.

[0078] A further preferred embodiment addresses this problem and solves the problem of adjusting a desired component property in the component by varying the heat distribution of regions of the layers. Such a component property is preferably a particular structure of the internal microstructure and / or an internal stress structure or another mechanical property. A mechanical property can, in particular, be a predetermined hardness, mechanical strength, density, and / or porosity of the component. A particular problem is to produce a component with regions of different microstructures, which determine the mechanical properties of the component.

[0079] A particular problem that could be solved by the invention would be the production of a component in which a heat treatment is intended to create a special area with a smaller porosity, which has better hardness and / or mechanical strength due to its greater density.

[0080] Another special task would be the production of a component in which the mechanical strength is also to be influenced by the (different) microstructure of the component areas. Regarding the term "microstructure," it should be noted that this can refer to both adherent grains and a crystal structure. A grain does not necessarily have to be a crystal, but can certainly be part of a crystal structure (e.g., the grain size of metals). A microstructure can be determined by a (relative or absolute) arrangement and / or by a (relative or absolute) size and / or by a shape of the crystals or grains.

[0081] Another special task would be the production of a component in which internal stresses need to be relieved. This usually involves stresses that develop during the component's cooling process. However, internal stresses can also be deliberately created.

[0082] With the following preferred embodiments, the step of subsequent heat treatment, e.g., post-annealing, can be avoided or simplified. This requires that the component be at a (possibly much) higher temperature during its production than is normally intended, at least in some areas.

[0083] As mentioned above, a special area can preferably be used to achieve a particularly homogeneous temperature distribution during production. This special area could also be referred to as a "homogeneity special area." A special area intended for heat treatment could also be referred to as a "heat treatment special area."

[0084] When determining the number of special areas, this number of special areas can include a number of homogeneity special areas and / or a number of heat treatment special areas (or both types of special areas, if necessary). A predetermined, systematic manufacturing feature of a heat treatment special area can be the creation or release of internal stress or the creation of a specified microstructure. In practice, the heat treatment special areas, in particular, are usually fixed.

[0085] Both types of special zones can certainly be present in a component layer. Preferably, a special heat treatment zone also has a special homogeneity zone, which corresponds to a sub-area, particularly the edge, of the special heat treatment zone. This special homogeneity zone has the advantage that the special heat treatment zone can be treated very homogeneously at a (specified) temperature.

[0086] Regardless of the type of special area, the assignment to the process room sensor data set is always the same.

[0087] As far as a correction factor module is concerned, it can be referred to as a "homogeneity correction factor module" or a "heat treatment correction factor module" depending on the specific special area. A homogeneity correction factor module is used to make the temperature as homogeneous as possible across a region of the component layer, while a heat treatment correction factor module is used to modify the specified temperature so that heat treatment is carried out in a specific area during production by applying a specified power before, during, and / or after solidification, and the specific area is heated more or less than the surrounding areas, or is heated a number of additional times. A heat treatment correction factor module can certainly lead to a correction in which a special area is irradiated two or more times instead of just once (at a higher or lower temperature) (e.g.B. once for solidification and then and / or before for heat treatment).

[0088] If a homogeneity correction factor module is used to ensure that the assigned correction factors or corrected irradiation values ​​lead to homogeneous production, the heat treatment correction factor module is used to assign correction factors or corrected irradiation values ​​with which a special area in question is manufactured or treated at a different temperature than the surrounding areas. In a preferred case, the control data that is corrected is already designed so that the heat treatment (for metal components, for example, post-annealing) takes place during production. The correction then ensures that this heat treatment is carried out homogeneously in the component and / or guarantees that the desired temperature or the temperature necessary for the heat treatment is reached during production. The areas in which heat treatment is to take place are preferably larger than the special areas orThe special areas are part of the areas where heat treatment is to take place. The special areas here are essentially homogeneity special areas.

[0089] For heat treatment, a laser power greater than 400 W, in particular greater than 600 W, or even greater than 800 W is preferred. However, the laser power is preferably less than 1200 W, in particular less than 1100 W, or even less than 1000 W. A preferred focus diameter is greater than 60 pm, in particular greater than 80 pm, or even greater than 100 pm. However, the focus diameter is preferably less than 10 mm, in particular less than 1 mm. Particularly preferred focus diameters are less than 260 pm, in particular less than 220 pm, or even less than 180 pm.

[0090] In the case where conventional control data is used, the correction factor module is essentially the aforementioned heat treatment correction factor module. This module assigns a correction factor or a corrected irradiation value that includes a predetermined radiation power. It is preferred that, in addition to the heat treatment correction factor module, a homogeneity correction factor module be used during the correction of the control data.

[0091] A heat treatment correction factor module therefore assigns correction factors or corrected irradiation values ​​for a heat treatment of the special area in question, which raise or lower the temperature before and / or during and / or after the solidification of the special area in such a way that the special area in question is manufactured at a higher or lower temperature than neighboring areas, so that a heat treatment takes place there during production.

[0092] It should be noted that if both a homogeneity correction factor module and a heat treatment correction factor module assign corrected irradiation values, these two modules should be taken into account when correcting the control data. In particular, values ​​could be added together, e.g., by adding the time periods specified for beam guidance, so that the beam takes longer to travel a path, thus introducing more heat there. The heat treatment correction factor module can also ensure that irradiation is performed a second time. The homogeneity correction factor module can ensure that a special homogeneity region within a special heat treatment region is heat-treated differently than its surroundings in order to achieve a particularly homogeneous heat treatment.

[0093] This embodiment makes it possible to perform a special heat treatment to adapt further component properties. In this process, selected special areas of the component are specifically heat-treated at a different temperature than others. For example, an interior area can be heated more or less than an exterior area, or areas in which different forces prevail during the component's subsequent use are heat-treated differently than other component areas. This makes it possible to deliberately make some areas of the component softer or harder, or more brittle or more elastic, than other areas of the component. In particular, different areas can be thermally treated differently, resulting in a different microstructure.

[0094] This can also be achieved using pre-defined control data. However, when correcting the control data, care must be taken to ensure that the correction factors generated by the correction factor module are such that a temperature distribution is achieved in the relevant sub-area of ​​a subsequent component layer that is specified by the pre-defined control data. This should not only be done for special temperature treatments, but also during "normal" production when different production temperatures are desired. Instead of correction factors, corrected irradiation values ​​could also be assigned directly. However, these must then be based on the pre-defined control data and should be designed to achieve the desired temperature profile.

[0095] During heat treatment (in a furnace) according to the prior art, a compromise must be found for parameters depending on the properties the resulting component is to have: some areas may require more intense heat treatment, while others should receive less intense heat treatment. However, only an average temperature can be achieved across the component in the furnace. Heat treatment according to the invention enables parts of the component to be heat treated at different temperatures. These parts can, for example, be areas that are intended to have better mechanical properties and / or a different microstructure than other areas. Specific areas can also be excluded from heat treatment or reheated. It is preferable for areas that have already hardened to be reheated after hardening (if necessary several times). In this case, the heat treatment is therefore carried out by this additional heating.

[0096] According to a preferred embodiment, "normal" control data is used for the additive manufacturing of a subsequent component layer, which is then corrected based on the heat treatment correction factor module (e.g., a heat treatment map or function). The heat treatment correction factor module particularly preferably specifies inhomogeneous irradiation (for the inhomogeneous heat treatment).

[0097] The control data corrected in this way is then output to a device for additive manufacturing of a component so that a new component layer can be produced. This new component layer, or a process space sensor data set for this new component layer, preferably serves as the basis for a new process run for the next component layer.

[0098] Preferably, the cooling of regions of a component layer is controlled by adjusting the laser parameters so that internal stresses are reduced or avoided through a desired controlled cooling behavior. However, depending on the component, it may also be preferable to control the cooling behavior by adjusting the laser parameters in such a way that stresses are deliberately created. It can also be advantageous to intentionally induce internal stresses so that the resulting component exhibits specific properties (similar to tempered glass).

[0099] Preferably, an increased temperature is achieved by adjusting the laser power and / or the beam profile.

[0100] A specific region that experiences a higher effective temperature during production due to beam deformation or intensity changes (i.e., a region that is to undergo heat treatment) could be referred to here as an "overheating region," with the overheating being intentionally induced by a change in the radiation. Within the scope of the invention, it is also preferred that the laser intensity be gradually reduced in some specific regions so that the component or a portion of the component is cooled in a controlled manner.

[0101] The (heat treatment) correction factor module can be saved last, especially after the component has been manufactured, and used to manufacture further components.

[0102] Considering the method according to the invention, a preferred embodiment in which the heat treatment is carried out in the course of a correction of “normal” control data could look like this:

[0103] - generating a heat treatment correction factor module which assigns correction factors or corrected irradiation values ​​for a heat treatment to at least one partial area of ​​a subsequent component layer, wherein the correction factors or the corrected irradiation values ​​for the heat treatment are generated from predetermined conditions and are generated in at least some of the special areas according to different rules than in other areas of the target shape outside the special areas,

[0104] - (preferably additionally:) generating a homogeneity correction factor module which assigns correction factors or corrected irradiation values ​​to at least one partial area of ​​a subsequent component layer, wherein the correction factors or the corrected irradiation values ​​are generated from the process space sensor data set and are generated in the special areas according to different rules than in other areas of the target shape outside the special areas,

[0105] - Correcting control data for the additive manufacturing of a subsequent component layer based on the homogeneity correction factor module and the heat treatment correction factor module,

[0106] - Output of the corrected control data to a device for the additive manufacturing of a component.

[0107] In short, these special designs allow a specific high temperature level to be maintained globally or locally across the component for the duration of the build process. Local differentiation allows specific areas to be created that have different local properties than the entire component. In principle, a big-spot or beam-shaping process, for example, is better suited for this than a standard process, as significantly more power is available to build a part significantly "hotter" than necessary. This can eliminate the need for subsequent heat treatment or can be used to adapt the component properties in another special way, for example, by further hardening the wall area of ​​the component.

[0108] The invention will be explained in more detail below with reference to exemplary embodiments in the accompanying figures. In the various figures, identical components are provided with identical reference numerals. They show:

[0109] Figure 1 is a schematic, partially sectioned view of an embodiment of an apparatus for additive manufacturing,

[0110] Figure 2 shows a sketch of an energy input and correction factors at the edge of a component layer,

[0111] Figure 3 shows a possible process space sensor data set for a component layer and its target shape,

[0112] Figure 4 is a block diagram of a possible process sequence of an embodiment of a method according to the invention,

[0113] Figure 5 Components for the production of a component,

[0114] Figure 6 shows a normal correction of control data according to the state of the art,

[0115] Figure 7 shows an optimized correction of control data.

[0116] The following exemplary embodiments are described with reference to a device 1 for the additive manufacturing of components in the form of a selective laser sintering or laser melting device. It should be explicitly noted that the invention is not limited to selective laser sintering or laser melting devices. The device will therefore be referred to below—without limiting its generality—as "manufacturing device" 1.

[0117] Such a manufacturing device 1 is shown schematically in Figure 1. The device has a process chamber 3 or a process space 3 with a chamber wall 4, in which the manufacturing process essentially takes place. Located within the process chamber 3 is an upwardly open container 5 with a container wall 6. The upper opening of the container 5 forms the current working plane 7. The area of ​​this working plane 7 lying within the opening of the container 5 can be used to build the object 2 and is therefore referred to as the construction field 8.

[0118] The container 5 has a base plate 11 which is movable in a vertical direction V and is arranged on a carrier 10. This base plate 11 closes off the container 5 at the bottom and thus forms its base. The base plate 11 can be formed integrally with the carrier 10, but it can also be a plate formed separately from the carrier 10 and fastened to the carrier 10 or simply mounted thereon. Depending on the type of specific build material, for example the powder used, and the manufacturing process, a build platform 12 can be attached to the base plate 11 as a build base, on which the object 2 is built. In principle, however, the object 2 can also be built on the base plate 11 itself, which then forms the build base.

[0119] The basic construction of the object 2 occurs by first applying a layer of build material 13 to the build platform 12. Then, as explained later, the build material 13 is selectively solidified using a laser beam 22 as an energy beam at the points that are to form parts of the object 2 to be manufactured. Then, with the aid of the carrier 10, the base plate 11, thus the build platform 12, is lowered, and a new layer of build material 13 is applied and selectively solidified, etc. In Figure 1, the object 2 built in the container on the build platform 12 is shown below the work plane 7 in an intermediate state. It already has several solidified layers, surrounded by unsolidified build material 13.Various materials can be used as the building material 13, preferably powder, in particular metal powder, plastic powder, ceramic powder, sand, filled or mixed powders or also pasty materials and optionally a mixture of several materials.

[0120] Fresh build material 15 is located in a storage container 14 of the production device 1. With the aid of a coater 16 movable in a horizontal direction H, the build material can be applied in the form of a thin layer in the working plane 7 or within the build area 8.

[0121] Optionally, an additional radiant heater 17 is located in the process chamber 3. This can be used to heat the applied build material 13, so that the irradiation device used for selective solidification does not have to introduce too much energy. This means, for example, that with the help of the radiant heater 17, a certain amount of basic energy can be introduced into the build material 13, which is naturally still below the energy required for the build material 13 to melt or sinter. An infrared radiator or VCSEL radiator, for example, can be used as the radiant heater 17.

[0122] For selective solidification, the production device 1 has an irradiation device 20, or more specifically, an exposure device 20 with a laser 21. This laser 21 generates a laser beam 22, which is deflected by a deflection device 23 in order to traverse the exposure paths or tracks (hatch lines) provided according to the exposure strategy in the respective layer to be selectively solidified and to selectively introduce the energy. Furthermore, this laser beam 22 is appropriately focused onto the working plane 7 by a focusing device 24. The irradiation device 20 is preferably located outside the process chamber 3, and the laser beam 22 is guided into the process chamber 3 via a coupling window 25 mounted on the top side of the process chamber 3 in the chamber wall 4.

[0123] The irradiation device 20 can, for example, comprise not just one but several lasers. These can preferably be gas or solid-state lasers or any other type of laser, such as laser diodes, in particular VCSELs (Vertical Cavity Surface Emitting Lasers) or VECSELs (Vertical External Cavity Surface Emitting Lasers), or a row of these lasers. Very particularly preferably, one or more unpolarized single-mode lasers, e.g., a 3 kW fiber laser with a wavelength of 1070 nm, can be used within the scope of the invention.

[0124] Production is monitored with the sensor arrangement 18. This can include, for example, a radiation sensor, e.g., a thermal imaging camera, and measures spatially resolved thermal data of a number of regions of a component layer B.

[0125] A control device 30 comprising a control unit 29 is used to control the units of the production device 1. The control device 30 controls the components of the irradiation device 20, namely the laser 21, the deflection device 23, and the focusing device 24, and transmits corresponding control data PS to them. The control unit 29 also controls the radiant heater 17 using suitable heating control data HS, the coater 16 using coating control data ST, and the movement of the carrier 10 using carrier control data TS, thus controlling the layer thickness.

[0126] The control device 30 is coupled, here, for example, via a bus 60 or another data connection, to a terminal 40 with a display or the like. Via this terminal 40, an operator can control the control device 30 and thus the entire laser sintering device 1, for example, by transmitting process control data PS.

[0127] In order to optimize the production process, the control data PS are generated or modified by means of a control data generation device 34 in the manner according to the invention in such a way that the control of the device 1 takes place at least temporarily in a mode according to the invention.

[0128] The control data generation device 34 here comprises a data interface 35, designed to receive a process chamber control data set KD comprising information on a target shape F of the currently solidified component layer B, and the process chamber sensor data set SD of the currently solidified component layer B of the component 2 (see, for example, Figure 3). The process chamber sensor data set SD comprises the spatially resolved thermal data recorded by the sensor arrangement 18.

[0129] Furthermore, the control data generation device 34 comprises a registration unit 36 ​​designed to define a number of special regions S in the target shape F, wherein each special region S is a region with predetermined, systematic shape features and / or manufacturing features in the component layer B. Furthermore, the registration unit 36 ​​is designed to assign the number of special regions S to corresponding regions of the number of regions in the process space sensor data set SD.

[0130] In addition, the control data generation device 34 comprises a module unit 37, designed to generate a correction factor map KK as a correction factor module KK. This correction factor map KK assigns correction factors KF or the corrected irradiation values ​​to at least a partial area of ​​a subsequent component layer B1. The correction factors KF or corrected irradiation values ​​are generated from the process space sensor data set SD and are generated in the special areas S according to different rules than outside the special areas S. Furthermore, the control data generation device 34 comprises a correction unit 38, designed to correct control data PS for the additive manufacturing of a subsequent component layer B1 based on the correction factor map KK.

[0131] In this example, the corrected control data PS can then be output to the device 1 for the additive manufacturing of a component 2 again via the data interface 35, although another data interface can also be used for this purpose.

[0132] It should also be noted again at this point that the present invention is not limited to such a manufacturing device 1. It can be applied to other methods for the generative or additive production of a three-dimensional object by layer-by-layer application and selective solidification of a building material, wherein an energy beam is emitted onto the building material to be solidified. Accordingly, the irradiation device can be not only a laser, as described here, but any device could be used with which energy can be selectively applied to or into the building material as wave or particle radiation. For example, another light source, an electron beam, etc., could be used instead of a laser.

[0133] Even though only a single object 2 or component 2 is shown in Figure 1, it is possible and generally common practice to produce multiple objects in parallel in the process chamber 3 or container 5. For this purpose, the build material is scanned layer by layer by the energy beam 22 at locations that correspond to the cross-sections of the objects in the respective layer.

[0134] Figure 2 shows a sketch of an energy input and correction factors KF at the edge of a component layer B. The arrow below indicates a spatial component, the arrow on the left a strength value. The solid vertical line symbolizes the edge of component layer B, and the adjacent dashed line represents the boundary of a special area S located between these two lines. The area between the dashed and the dash-dotted vertical line can be considered an adjacent, normal area.

[0135] The solid lines show two possible temperature curves in a process space sensor data set SD, with the upper line showing a temperature curve of an overheated component edge area, and the lower line showing a temperature curve in a non-overheated component edge area.

[0136] The dashed lines show two possible correction factors KF for the respective solid lines if a special area (component edge area) were not treated separately, but analogously to the component interior area (no special area). The dotted lines in the middle show the modified correction factors for the component edge area (special area S) for the two cases mentioned above.

[0137] Figure 3 shows a possible process space sensor data set SD (left) for a component layer B and its target shape F in a process space control data set KD (right). At the ends of the process space sensor data set SD for component layer B, one can see locations where overheating has occurred (darker hatched). These inhomogeneities in the temperature distribution can be compensated for in subsequent layers, particularly if a special area S is identified in the target shape F (see Figures 6 and 7). The two arrows indicate that the target shape can be segmented into a "normal area" (shown below, without a border) and a special area S (border only).

[0138] Please note that the overheated areas are not considered special areas S, since overheating in the "interior" can be counteracted during the production of the next component layer using an easily determined correction factor KF (see, for example, the method in Figure 4). However, the situation is different at the edge R. Here, the correction factor KF must be determined by another method, e.g., by interpolation or by using correction factors KF from neighboring interior areas. Therefore, the edge R is considered a special area S here.

[0139] Figure 4 shows a block diagram of a possible method sequence of an embodiment of a method according to the invention for generating control data PS for a device 1 for the additive manufacturing of a component 2 in a manufacturing process (see Figure 1), in which the component 2 is built up in a build field 8 in the form of component layers B by selectively solidifying build material 13, e.g. comprising a metal-based powder, by irradiating the build material 13 with at least one energy beam 22. In step I, a process space sensor data set SD of a currently solidified component layer B of the component 2 is recorded by means of a sensor arrangement 18, the process space sensor data set SD comprising at least spatially resolved thermal radiation data of a number of regions of this component layer B.

[0140] In step II, a process space control data set KD is provided with information on a target shape F of the currently solidified component layer B. This can be done, for example, based on CAD data of component 2 or from specified control data PS.

[0141] In step III, a number of special areas S are defined in the target shape F, whereby each special area S is an area with predetermined, systematic shape features and / or manufacturing features in the component layer B. Here, the component edge area of ​​the component layer B is marked with a dashed line as a special area.

[0142] In step IV, the number of special areas S is assigned to corresponding areas of the number of areas in the process space sensor data set SD. This can be done, for example, using image registration. In the process space sensor data set SD, different hatchings can be seen in the component layer. These are intended to symbolize different measured temperatures or radiated heat quantities.

[0143] In step V, a correction factor card KK is generated as a correction factor module KK, which assigns correction factors KF or corrected irradiation values ​​to at least one partial area of ​​a subsequent component layer B1 (see, for example, Figures 6 and 7). Here, for example, correction factors KF are generated by selecting a value for “normal” areas that is lower the warmer the corresponding area of ​​component layer B was in step IV. A different procedure is followed for the special area S. Here, the correction factors KF of neighboring “normal” areas could be used for the correction factors KF, or the correction factors KF could be formed from predetermined, constant correction factors KF. However, they could also be determined using interpolation methods or based on a model of a theoretical temperature change.

[0144] In this step V, the (original) control data PS for the additive manufacturing of a subsequent component layer B1 are corrected based on the correction factor map KK. As a result of the process, the corrected control data PS are output again to the device 1 for the additive manufacturing of the component 2 for the production of the next component layer.

[0145] Figure 5 shows components for manufacturing a component 2 that can be arranged in the manufacturing device 1 or linked thereto. In contrast to Figure 1, a simplified representation was chosen here, showing only the components most important for the process. The bold box on the left again shows the irradiation control interface 31 and the control data generation device 34 with data interface 35, registration unit 36, module unit 37, and correction unit 38. These receive control data PS from the left, which is corrected by correction factor cards KK as correction factor modules KK and sent in corrected form to the irradiation control interface 31. The sensor arrangement 18 supplies the necessary process space sensor data set SD. The deflection device 23 and the laser 21 are then controlled according to the corrected control data PS to manufacture the next component layer B with the energy beam 22.The correction factor cards KK are still stored in the memory unit 39.

[0146] Figures 6 and 7 outline a correction of control data PS. The bottom row shows the spatially resolved thermal data from several component layers B, B1, B2 directly above one another. These are recorded by the sensor arrangement 18 as a process space sensor data set SD, and correction factor maps KK are created as correction factor modules KK according to the method outlined in Figure 4 (top row). It can be seen that the correction factor maps KK look like a negative image of the heat distributions. This is because if the local heat is too high at this point, less energy should be introduced in the next production step.

[0147] In Figure 6, a normal correction is applied without taking special areas S into account. It can be seen that a homogeneous temperature distribution is finally established within the inner surface of the component layer (component layer B2, bottom right), but the edge experiences excessive energy input (indicated by a thick edge line). This is not detected by the sensor arrangement 18, however, since it also "sees" unsolidified areas at the edge and mixes their temperature with the temperature of the edge area due to the limited resolution. Figure 7 shows an optimized correction with consideration of special areas S. Here, the edge area is regarded as a special area S and the correction factors there are determined differently, e.g. by using correction factors from neighboring interior areas. This results in good homogeneity of the temperature distribution even in the edge area (component layer B2, bottom right).

[0148] Finally, it should be noted once again that the devices described in detail above are merely exemplary embodiments that can be modified in a variety of ways by those skilled in the art without departing from the scope of the invention. For example, solidification could be carried out using other energy beams instead of laser light. Furthermore, the use of the indefinite articles "a" or "an" does not exclude the possibility that the respective features may be present in multiple instances. Likewise, the term "unit" does not exclude the possibility that it consists of several interacting subcomponents, which may also be spatially distributed. The expression "a number" is to be understood as "at least one."

[0149] List of reference symbols

[0150] 1 device for additive manufacturing / laser sintering device

[0151] 2 Component / Object

[0152] 3 Process room / process chamber

[0153] 4 chamber wall

[0154] 5 containers

[0155] 6 Container wall

[0156] 7 Working level

[0157] 8 Construction site

[0158] 10 carriers

[0159] 11 Base plate

[0160] 12 Construction platform

[0161] 13 Construction material (in container 5)

[0162] 14 storage containers

[0163] 15 assembly material (in storage container 14)

[0164] 16 coaters

[0165] 17 Radiant heating

[0166] 18 Sensor arrangement

[0167] 20 Irradiation device / exposure device

[0168] 21 lasers

[0169] 22 Laser beam / energy beam

[0170] 23 Deflection device / scanner

[0171] 24 Focusing device

[0172] 25 coupling windows

[0173] 29 Control unit

[0174] 30 Control device

[0175] 31 Irradiation control interface

[0176] 34 Control data generating device

[0177] 35 Data interface

[0178] 36 Registration Unit

[0179] 37 module unit

[0180] 38 Correction unit

[0181] 39 storage unit

[0182] 40 Terminal

[0183] 60 Bus B, B1, B2 component layer

[0184] F Target form

[0185] H horizontal direction

[0186] HS heating control data KD process room control data set

[0187] KF correction factor

[0188] KK correction factor card / correction factor module

[0189] PS process control data

[0190] S Special area SD Process room sensor data set

[0191] ST coating control data

[0192] TS carrier tax data

[0193] V vertical direction

Claims

Patent claims 1. Method for generating control data (PS) for a device (1) for the additive manufacturing of a component (2) in a manufacturing process in which build material (13), preferably comprising a metal powder, is built up layer by layer in a build field (8) by selective solidification of build material (13) by means of irradiation of the build material (13) with at least one energy beam (22), the method comprising the steps: - Acquisition of a process space sensor data set (SD) of a currently solidified component layer (B) of the component (2) by means of a sensor arrangement (18), wherein the process space sensor data set (SD) includes at least spatially resolved thermal data of a number of areas of this component layer (B), - Providing a process space control data set (KD) containing comprehensive information on a target shape (F) of the currently solidified component layer (B), - Defining a number of special areas (S) in the target shape (F), where each special area (S) is an area with predetermined, systematic shape features and / or manufacturing features in the component layer (B), - Assigning the number of special areas (S) to corresponding areas of the number of areas in the process space sensor data set (SD), - Generating a correction factor module (CC) which assigns correction factors (CF) or corrected irradiance values ​​to at least one sub-area of ​​a subsequent component layer (B1), wherein the correction factors (CF) or the corrected irradiance values ​​are generated from the process space sensor data set (SD) and are generated in the special areas (S) according to different rules than in other areas of the target shape (F) outside the special areas (S). - Correcting control data (PS) for the additive manufacturing of a subsequent component layer (B1) based on the correction factor module (KK), - Output of the corrected control data (PS) to a device (1) for additive manufacturing of a component (2).

2. Method according to claim 1, wherein, prior to assigning the number of special areas (S) to the corresponding areas in the process space sensor data set (SD), the process space sensor data set (SD) is adapted according to existing calibration data or according to an adaptation function, preferably wherein - first, the sensor arrangement is calibrated and the process room sensor data set is recorded with the calibrated sensor arrangement or - pre-made calibration data are available and the process room sensor data set is adapted after its acquisition by the sensor arrangement, preferably whereby the special areas are registered to corresponding areas in the process room sensor data set or otherwise mapped there by means of an adaptation algorithm.

3. Method according to any one of the preceding claims, wherein at least one special area (S) - a component edge area of ​​the component layer, and / or - an area of ​​the component layer where hardening layers overlap, especially their initial or final areas, and / or - an area where a hatching strip tapers, and / or - is an area that is smaller than the optical resolution of the sensor arrangement (18), and / or - an area with support structures.

4. Method according to one of the preceding claims, wherein the assignment of the number of special areas (S) to the corresponding positions in the process space sensor data set (SD) is carried out by means of image registration, in particular by means of a method based on Enhanced Correlation Coefficients.

5. Method according to one of the preceding claims, wherein the correction factors (KF) of the correction factor module (KK) for a special range (S) - from the correction factors (KF) for a number of component areas adjacent to the special area (S) of the target shape (F) are interpolated or extrapolated, in particular by interpolating correction factors (KF) of opposing component areas or of a component area and specified values ​​outside the component, or correction factors (KF) of a component area are used, - are formed from predefined, constant correction factors (CF), - determined by interpolating image processing methods based on a continuous continuation of the gray values, in particular based on coloring algorithms or inpainting algorithms, - are formed based on a model of a theoretical temperature change.

6. A method according to any of the preceding claims, wherein predetermined maximum and / or minimum values ​​for a correction factor (CF) are provided, in particular a Limit value module with spatially resolved maximum and / or minimum values, and the correction factors (CF) are generated in such a way that they do not exceed the maximum values ​​and / or fall below the minimum values.

7. Method according to one of the preceding claims, wherein, for generating the correction factor module (KK), the correction factors (KF) are generated from the process space sensor data set (SD) outside the number of special areas (S) by means of a controller, in particular a PD controller, a PI controller or a PID controller, and preferably within the number of special areas (S). - without the controller being generated, or - first generated using the controller and then corrected or - first, the corresponding values ​​of the process space sensor data set (SD) are corrected, and then the correction factors (KF) are generated using the controller.

8. Method according to one of the preceding claims, wherein the method is applied for several successive component layers (B, B1, B2), preferably wherein control data (PS) are stored together with a number of corresponding correction factor modules (KK) and / or corrected control data (PS), preferably wherein for the correction of control data (PS) for a component (2) - only data of the correction factor module (CC) generated from a component layer (B) of this component (2) are used or - Data from a correction factor module (CC) are used, which were generated from a uniform component layer (B) of another component (2).

9. Method according to one of the preceding claims, wherein, in order to determine a number of special areas (S) in the currently solidified component layer (B), information on a shape and / or position of the subsequent component layer (B1) is provided in addition to a process space control data set (KD), and correction factors (KF), in particular for downskin areas, are derived from the process space control data sets (KD) of both component layers (B, B1).

10. Control data (PS) for controlling a device (1) for additive manufacturing, which have been corrected according to a method according to one of the preceding claims.

11. Manufacturing process for the additive manufacturing of a component (2), wherein in a build area (8) build material (13), preferably comprising a metal powder, is built up layer by layer by selective solidification of build material (13) by irradiating the build material (13) with at least one energy beam (22) according to the control data (PS) according to claim 10, wherein to create component layers (B, B1 , B2) of the component (2) the energy beam (22) is moved over the build area (8) within defined areas according to these control data (PS).

12. Control data generation device (34) for generating control data (PS) according to claim 10 for a device (1) for the additive manufacturing of a component (2) in a manufacturing process in which build material (13), preferably comprising a metal powder, is built up layer by layer in a build field (8) by selective solidification of build material (13) by means of irradiation of the build material (13) with at least one energy beam (22), the control data generation device (34) comprising: - a data interface (35) designed to receive a process space control data set (KD) comprising information on a target shape (F) of the currently solidified component layer (B), and a process space sensor data set (SD) of a currently solidified component layer (B) of the component (2) recorded by means of a sensor arrangement (18), wherein the process space sensor data set (SD) comprises at least spatially resolved thermal data of a number of areas of this component layer (B), - a registration unit (36) designed to define a number of special areas (S) in the target shape (F), wherein each special area (S) is an area with predetermined, systematic shape features and / or manufacturing features in the component layer (B), and to assign the number of special areas (S) to corresponding areas of the number of areas in the process space sensor data set (SD), - a module unit (37) designed to generate a correction factor module (CC) which assigns correction factors (CF) or corrected irradiance values ​​to at least a sub-area of ​​a subsequent component layer (B1), wherein the correction factors (CF) or corrected irradiance values ​​are generated from the process space sensor data set (SD) and are generated in the special areas (S) according to different rules than outside the special areas (S), - a correction unit (38) designed to correct control data (PS) for the additive manufacturing of a subsequent component layer (B1) based on the correction factor module (KK), a data interface (35) designed to output the corrected control data (PS) to a device (1) for additive manufacturing of a component (2).

13. Control device (30) for a device (1) for the additive manufacturing of a component (2) in a manufacturing process in which build material (13), preferably comprising a metal powder, is built up layer by layer in a build field (8) by selective solidification of build material (13) by means of irradiation of the build material (13) with at least one energy beam (22) by means of an irradiation device (20), wherein the control device (30) is configured to control the device (1) for the additive manufacturing of the component layers (B, B1, B2) of the component (2) according to control data (PS) according to claim 10, wherein the control device (30) preferably comprises a control data generation device (34) according to claim 12.

14. Device (1) for the additive manufacturing of at least one component (2) in an additive manufacturing process with at least - a feeding device for applying layers of build material (13) to a build area in a process chamber (3), - an irradiation device (20) to selectively solidify build-up material (13) by irradiation with at least one energy beam (22), in particular between the application of two material layers, and - a control device (30) according to claim 13.

15. Computer program product comprising instructions which, when the program is executed by a computer, cause it to perform the steps of the method according to claim 1 to 9 and / or 11.

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