Method and device for generating control data for a device for additive manufacturing components

Abstract

The invention relates to a method for generating control data (PS) for a device (1) for additive manufacturing of a component (2) in a manufacturing process in which a construction material (13), preferably comprising a metal powder, is constructed layer by layer in a construction field (8) in such a way that the construction material (13) is selectively solidified by irradiating the construction material (13) with at least one energy beam (22), the method comprises the following steps:-recording a process chamber sensor data set (SD) having spatially resolved thermal data of the currently cured component layer (B),-providing a process chamber control data set (KD) having a target shape (F) of the currently cured component layer (B),-defining a number of special regions (S) in the target shape (F), -assigning the number of special regions (S) to corresponding regions in the processing chamber sensor data set (SD),-generating a correction factor module (KK), in which special regions (S) a correction factor (KF) is generated in accordance with a rule different from other regions in the target shape (F) that are not the special regions (S), correcting the control data (PS) for the additive manufacturing of the subsequent component layer (B1) on the basis of the correction factor module (KK), and outputting the corrected control data (PS) to the device (1) for the additive manufacturing of the 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

Technical Field

[0001] The invention relates to a method and a device for generating control data for a device for additively manufacturing a component in a manufacturing process ("control data generating device"), in which the component is built in the form of component layers in a building field by irradiating the building material with at least one energy beam to selectively solidify the building material. The invention also relates to corresponding control data, a method for additively manufacturing a component using such control data, a device for additive manufacturing and a control device for such a device. Background Art

[0002] Additive manufacturing processes are becoming more and more important in the production of prototypes and at the same time in mass production. In general, an "additive manufacturing process" can be understood as a manufacturing process in which a manufactured product ("component") is constructed by accumulating materials ("construction materials"), usually based on digital 3D design data. Here, this construction is usually carried out layer by layer, but it is not mandatory. As a synonym for additive manufacturing, the term "3D printing" is often used, and the production of models, samples and prototypes with additive manufacturing processes is often called "rapid prototyping", mold production is called "rapid molds", and the flexible production of series components is called "rapid manufacturing". As mentioned at the beginning, the key point is the selective solidification of the construction material, where in a variety of manufacturing processes, this solidification can be irradiated with radiation energy (such as electromagnetic radiation, especially light and / or thermal radiation), but if necessary, it can also be irradiated with particle radiation (such as electron radiation). Examples of methods that work by irradiation are "selective laser sintering" or "selective laser melting". Here, thin layers of a usually powdered construction material are repeatedly applied in a superimposed manner, and in each layer, the construction material is selectively solidified by spatially limited irradiation of the location that should belong to the component to be produced after the production is completed in the "welding process", in which the powder particles of the construction material are partially or completely melted by means of the energy introduced locally at this location by radiation. During cooling, these powder particles then bond to each other and solidify into a solid. In most cases, the energy beam is guided along a solidification path above the construction field, and the remelting or solidification of the construction material in the corresponding layer is correspondingly carried out in the form of a "welding path" or "weld bead", so that in the end there are a plurality of such layers formed by welding paths in the component. In this way, components with very high quality and breaking strength can now be produced.

[0003] During the manufacturing process, it may happen that the energy input by the energy beam is absorbed unevenly by the component. This manifests itself as the presence of areas of the component layer with uneven heat distribution. Sometimes, it may be desirable to cure selected areas with different energy inputs, but this is usually undesirable, especially in the case of uniform surfaces or regular contours. Summary of the invention

[0004] The object of the present invention is to provide a method and a device for generating control data for an apparatus for additive manufacturing of a component, which overcome the disadvantages of the prior art and in particular allow the quality of the component to be improved. Preferably, the object of the present invention is to increase the stability of the manufacturing process and in particular to prevent interruptions in the manufacturing process or to prevent the occurrence of thermal effects. Areas of enhanced reinforcement or heat radiation increase cause problems in applying the construction material.Another preferred object is to reduce the support structure volume (and thus the part costs) and thus increase the process speed, which has an advantage in terms of component costs.

[0005] This object is achieved by a method according to claim 1 , control data according to claim 10 , a production method for additive manufacturing according to claim 11 , a control data generating device according to claim 12 , a control device according to claim 13 and an apparatus according to claim 14 .

[0006] The method according to the invention is used to generate control data for an apparatus for additively manufacturing a component in a manufacturing process in which the component is constructed in the form of component layers in a construction field by irradiating the construction material with at least one energy beam to selectively solidify the construction material. The control data do not yet represent the finished component, but rather a component, because the component is composed of curing path layers that have been cured according to the control data.

[0007] The method according to the invention comprises the following steps:

[0008] - recording a process chamber sensor data set of a currently solidified component layer of the component by means of the sensor arrangement, wherein the process chamber sensor data set comprises at least spatially resolved thermal data of a plurality of regions of the component layer,

[0009] - providing a process chamber control data set including information about the target shape of the currently solidified component layer,

[0010] - defining a plurality of special regions in the target shape, wherein each special region is a region in the component layer having predetermined system shape characteristics and / or manufacturing characteristics,

[0011] - assigning a plurality of special regions to corresponding regions of a plurality of regions in the processing chamber sensor data set,

[0012] a correction factor generation module, which assigns a correction factor or a corrected illumination value to at least one sub-region of a subsequent component layer, wherein the correction factor or the corrected illumination value is generated based on a process chamber sensor data set and is generated in the special region according to a different rule than in other regions of the target shape that are not the special region,

[0013] - correcting the control data for additively manufacturing subsequent component layers based on the correction factor module,

[0014] - Outputting the corrected control data to a device for additive manufacturing of a component.

[0015] As described above, during the manufacturing process, the building material is built up layer by layer (i.e., in succession with a plurality of material stacks or material layers) in the building field. The building 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%, 70%, 80% by weight or even more than 90% by weight of metal. However, the present invention is not limited thereto, but other, preferably powdered building materials, such as plastics or ceramics or mixtures of various materials can also be applied. Here, in particular, between the corresponding application of two material layers, the building material is (in particular selectively solidified) irradiated with at least one energy beam (herein an energy beam of photons or particles, such as a light beam or an electron beam) generated by an irradiation unit of the manufacturing device. Here, not only is the building material in the newly applied material layer of the top layer impacted by the energy beam and melted or remelted, but the energy beam also usually penetrates slightly deeper into the material bed and also reaches the previously applied material layer located below and already remelted material.

[0016] For example, the processing room sensor data set and the thermal data can be recorded with a thermal imaging camera, for example with a CMOS camera with a spectral filter in the near infrared range, but this is not mandatory. It is also possible to use a scanning measurement method, in which the spatial resolution is (only or additionally) given by the corresponding scanning position, and / or to use the following measurement method, in which the sensor is (coaxially) arranged in the beam path of the processing machine and the spatial resolution is (only or additionally) given by the current processing position. Spatially resolved "thermal data" refers to information about the heat distribution in at least one area of ​​the component layer or the entire component layer. Here, there must be information about the individual points of the component layer together with the positions of these points. For example, an infrared image of a component layer can represent thermal data, because the points in the component layer are assigned thermal information in this image. However, the thermal data does not necessarily have to be a thermal image of a thermal camera, but can be obtained in other ways. Therefore, the processing room sensor data set, for example, displays a certain component layer or at least one component area in the component layer as a thermal image.

[0017] For thermal data, it is not necessary to measure the absolute temperature directly, it is sufficient to use only the pixel values ​​(basically "gray values") of a temperature-sensitive camera. The temperature can be well estimated based on the evaluation of the pixel values ​​alone. Here, the thermal data can reflect the temperature both in absolute and relative values. Typically, for a machine or a construction process (the same applies to different machines), a baseline of temperature values ​​(gray values) is measured and the temperature is estimated based on the change relative to the baseline. This change can be "small" (e.g. at a very high baseline) or "large" (e.g. at a very low baseline).

[0018] The process room control data set contains data on the geometry of the component layer under consideration and / or data on the irradiation path (target shape) for producing the component layer. With respect to the process room control data set, the term "provided" means that it can be easily obtained, for example these data are already available from the other end, or can be generated, for example, based on the CAD data of the component or based on control data. In short, the target shape should enable reconstruction of the relevant component layer. For example, the process room control data set with respect to the target shape can include parallel sections (at least one section) of the component generated by CAD or include scan vectors of a component layer (or multiple component layers) for producing the component.

[0019] Basically, this information is sufficient to keep the inhomogeneities of the energy input as low as possible. Therefore, during the manufacturing process, the energy input is measured with the aid of a sensor assembly, for example by measuring the thermal radiation of the component layer with a radiation sensor. In these measurements, areas with excessively high thermal radiation can then be detected, and the corresponding areas in the subsequent component layer can be cured with a lower energy input. The same applies to areas that emit too little heat. In this way, inhomogeneities can be compensated iteratively.

[0020] However, this compensation cannot be optimally applied to certain areas of the component, because the data of the sensor assembly do not necessarily reflect the correct value of the actual thermal radiation, or these areas have a different "function" thermally compared to other areas. For example, these are areas with corners or sharp curves in the component, edge areas of the component or very small structures within the component. In general, it can be said that this general method cannot provide optimal compensation of inhomogeneities at any location where there is a risk that the resolution of the sensor assembly does not allow an accurate distinction between areas with different energy inputs, or in the case of energy inputs that are specifically desired to be different from the surroundings. These areas are especially edge areas, i.e., on one side there is a large amount of energy input for curing, while on the other side there is no energy input because curing should not take place. However, these areas can also be areas where the hatching bands overlap each other and are more obvious in a layer-by-layer integrated sensor system, although this is not necessarily the case in reality.

[0021] In the context of the present invention, such an area is referred to as a "special area" because it requires special attention in order to compensate for the inhomogeneities as well as possible. Each special area is an area in a component layer with a predetermined system shape feature and / or manufacturing feature. Shape features are features about geometry or position, for example: the area is located at the edge of the cross section of the component to be solidified; the area is smaller than the resolution of the sensor assembly or the sensor assembly is not accurately imaged; or due to the shape or due to the position on the surface or near the subsequent component, special thermal conditions prevail in this area, such as in narrow curves or tapered sections. Manufacturing features may, for example, be: overlapping of solidification paths in component layers; local increase in the distance of solidification paths in component layers; local changes in the thickness or depth of solidification paths; or local changes in irradiation (for example, by pulses or by selecting another process window, such as by means of heat conduction welding to achieve local solidification, where a deep welding process is generally selected). Special shape features and manufacturing features can also exist in combination, because a special local manufacturing mode may be selected due to a special shape. The term "predetermined, systematic" means that it has been determined based on the process room control data set (and if necessary based on experience with component production) that during the manufacturing process, special thermal conditions prevail in these areas. For example, the edges of the component are areas with thermal problems. Special areas can also be referred to as (system-specific) "overheating areas", "erroneous heating areas", "deviation areas" or "special correction areas". In particular, special areas can be areas that require or may require post-treatment if they do not experience a temperature increase during production.

[0022] With regard to specific aspects of the present invention, a special area may be an area that should be subjected to thermal post-treatment, or an area that is solidified during the production of a component with different parameters (e.g. laser parameters: beam profile, laser intensity) in order to change / improve its properties or component properties (e.g. hardness, mechanical strength, density, etc.).

[0023] Preferably, the definition of these special areas as corresponding areas of the target shape is preferably carried out in an automatic manner, for example, wherein each edge area of ​​a component layer of the target shape having a predetermined width, each overlapping area or each clearly defined area below a predetermined volume in the construction plane or a predetermined surface is automatically classified as a special area. For example, what exactly should be classified as a special area can be extracted from a predetermined list, but can also be manually specified by user input. It is particularly preferred that the user can input or change the parameters for the automatic classification of the special areas by means of changeable presets.

[0024] Therefore, these special areas are initially defined in an immaterial environment (target shape). Since this target shape corresponds to the (real) component layer represented by the process chamber sensor data set, it is now necessary to determine which parts of the relevant component layer are to be regarded as special areas. This is achieved by subsequent assignment. In the process chamber sensor data set there are spatially resolved thermal data of multiple areas of the component layer. For a better understanding, this is referred to as a "thermal image of the component layer" hereinafter, wherein this term does not exclude other possibilities, for example there may be spatially resolved thermal data from multiple areas of the component layer.

[0025] The assignment of special areas to corresponding areas of the "thermal image of the component layer" is preferably performed automatically, for example, in such a way that individual areas of the thermal image whose equivalents in the target shape have already been classified as special areas are also automatically classified as special areas in the thermal image. This assignment can be performed only in terms of information technology, in such a way that a mark is added to a certain area of ​​the thermal image of the component layer, which indicates that the area is a special area; or a mark is added to the area in the image (for example, a special color). A mask can also be created, which indicates which areas in the thermal image of the component layer should be regarded as special areas. It is basically irrelevant how the information about the special areas is assigned to the target shape (for example, by data technology linking or by imaging), as long as it determines which areas of the thermal image of the component layer are regarded as special areas and which are not regarded as special areas. It is therefore clear which thermal data of the spatially resolved thermal data are in the special area and which thermal data are not therein.

[0026] The correction factor module generated subsequently assigns a correction factor or a corrected irradiation value generated based on the process chamber sensor data set to at least one sub-area of ​​the subsequent (next) component layer (i.e., another component layer immediately following its manufacture). The correction factor module preferably comprises a program and / or a database, wherein the program preferably comprises an automatic access to the database, wherein the access comprises using and / or modifying and / or saving and / or overwriting data based at least on the process chamber sensor data set and / or the process chamber control data set. These correction factors affect, in particular, the power and / or focal diameter of the energy beam and / or its beam profile or intensity distribution and / or the scanning speed and / or the shadow distance. If the energy beam is a laser beam, the term "laser correction factor" (or LCF, in English: "Laser Correction Factor") or "laser power correction factor" may also be used. However, there is no need to limit the laser power, since the energy input should basically be adjusted. Therefore, the correction factor module may also be referred to as an "energy input parameter module" or a "volume energy module", for example with the volume energy as a reference variable.

[0027] " Module " in the sense of correction factor module is following element, and this element is used for applying or collecting multiple or several correction factors as expected.This element can only comprise the data as correction factor or can measure the data of correction factor based on it, and also comprise the function that can measure correction factor or even apply it to control instruction.The module itself can be realized with software, for example in the form of table, function, list or data set, or with hardware realization, for example in the form of FPGA or processor or controller with storage unit.Preferably, correction factor module is therefore software-based or hardware-based element, and this element comprises the data in the form of correction factor, or comprises the data and / or function that can measure correction factor.

[0028] The correction factor module may be in the form of a correction factor map having the correction factors in matrix form. For example, if there is a digital thermal image of the component layer, the correction factor map may simply include pixels or grid cells corresponding in particular to pixels in the thermal image and include scalars specifying the correction factors rather than color values ​​or grayscale values.

[0029] Alternatively or additionally, the correction factor module can also be in the form of a correction factor function KF, which is preferably a two-dimensional function. Then, the correction factor at the two-dimensional spatial position (x, y) in the component layer can simply be the function value KF (x, y) of the correction factor function at the corresponding position. The correction factor function can be generated from the correction factor graph, for example, by fitting a two-dimensional polynomial function. Even if the creation function is more complicated than mapping, the function has the advantage of less storage requirements, because only the function coefficients need to be stored, and it has better scalability. Using such a correction factor function can also have the advantage of not considering special areas for correction. So, the corresponding method alternatively comprises the following steps:

[0030] - optionally: assigning a plurality of special areas to corresponding areas of a plurality of areas in the process chamber sensor data set,

[0031] - generating a correction factor function which assigns a correction factor or a corrected illumination value to at least one sub-region of the subsequent component layer, wherein the correction factor or the corrected illumination value is generated based on the process chamber sensor data set and preferably in the special region according to a different rule than in other regions of the target shape which are not the special region,

[0032] - Correcting control data for additive manufacturing of subsequent component layers based on the correction factor function.

[0033] It is important for the method of the present invention that in the special area, the correction factor or the corrected irradiation value is generated according to a different rule than other areas of the target shape that are not special areas. This is because "other rules" also apply to special areas. For example, the data from the pixels of the thermal imaging camera reflects the heat radiated by a certain surface area on the construction plane. The first pixel that records the uncured area shows lower heat than the second pixel that records the area that has just been cured. However, the third pixel that records the edge area with cured and uncured areas shows lower heat than the second pixel and higher heat than the first pixel, even if the temperature of the cured area should be consistent everywhere. This is because these pixels show the integrated value of the thermal radiation of the area recorded by them. In the case where the second pixel (non-special area) indicates that the area recorded by it may be too hot, the corresponding correction factor will indicate that less energy is introduced in the next layer. However, for the third pixel (special area, here adjacent to the second pixel) that is considered to be cooler, although there is too much heat in the cured area, since part of the uncured area is also recorded in it, no correction factor is applied (or the correction factor is 1) without separate processing, because no overheating is detected. However, it is correct to apply the same correction factor as the second pixel. The method of the present invention takes this into account in that in the special area, the correction factor or the corrected illumination value is generated according to a different rule than in other areas of the target shape that are not the special area.

[0034] The exact definition of these additional rules may depend on the component, the construction material used, the type of radiation and the type of special area. Below, some preferred embodiments will be described in the following. In a very simple embodiment, for example, the correction factors of adjacent areas of the target shape can be used for the special area.

[0035] The correction factor module (KF module for short) does not have to be for the entire construction field. Different areas of the construction field can be corrected by different KF modules. For example, a total correction map can be formed by a combination of correction factor maps (KF maps). The adjustment of the construction process is preferably performed pixel by pixel according to these KF maps, wherein the higher the resolution of the KF map, the better the adjustment effect. Therefore, a set of correction factor functions can also be used, wherein each correction factor function is applied to a single area of ​​the construction field. Preferably, during manufacturing, the defined irradiation value is corrected with the correction factor, and / or the correction factor directly provides the irradiation value. Here, the correction factor is preferably a relative correction factor, which is multiplied by a predetermined laser power or divided by a predetermined laser power.

[0036] For the corrected irradiation values, the same principle applies as for the correction factors, since they are only irradiation values ​​that have been corrected with the aid of the correction factors. The KF module can therefore include correction factors with which the irradiation values ​​or already corrected irradiation values ​​are subsequently corrected. It is clear that these correction factors are selected such that, in the event of an excessively high energy input at a certain location, a lower energy input is carried out at this location in a subsequent layer, the lower energy input being calculated in particular in such a way that the desired energy input is adjusted.

[0037] At this point, in order to compensate for the inhomogeneity, the subsequent component layer must be irradiated. If the subsequent component layer still has inhomogeneities after it is manufactured, the method can be performed on the corresponding next component layer based on the corresponding component layer just manufactured. After several iterations, the energy input can be homogenized by properly selecting the correction factor.

[0038] Therefore, the control data for additive manufacturing of a subsequent component layer is corrected based on the correction factor module (e.g., correction factor map or function), and the corrected control data is output to the device for additive manufacturing of components so that a new component layer can be manufactured. This new component layer or the processing chamber sensor data set of this new component layer will now serve as the basis for the updated method operation of the next component layer.

[0039] The KF module can be stored eventually, in particular after the component has been manufactured, and used to manufacture other components. If the KF module does not include a correction method, but includes corrected irradiation data (and particularly preferably corrected control data), it can be regarded as control data according to the invention.

[0040] By the above method, control data according to the present invention can be generated, which are used to control the additive manufacturing device. As mentioned above, these control data are characterized in that they are corrected, so that the inhomogeneity of the temperature distribution during the manufacturing process is compensated. Here, it should be noted that the temperature distribution itself is not compensated, but the inhomogeneous temperature distribution of the current layer is considered for the compensating radiation in the subsequent layer. Strictly speaking, not only the thermal balance of a single layer is adjusted, but also the thermal balance of multiple layers that have been cured, even the overall thermal balance of a component or the simultaneous manufacture of multiple components is adjusted, and the impact is correspondingly small. The reason is that the already cured layer usually continues to emit heat, because during the manufacturing process, the heat entering the construction container usually exceeds the heat flowing out of the construction container at least temporarily. For many cured layers, the effect is cumulative, which significantly affects the thermal radiation of the measuring surface. In practical applications, the correction factors of the correction factor module are usually combined with the original control data (vectorization) in the machine controller and transmitted to the irradiation controller as a "microstep" (control signal in the scanning cycle of the manufacturing device). However, the directly corrected control data can also be used.

[0041] In addition, the control data preferably include further building instructions, such as the amount of building material provided for the layer to be applied locally selectively if necessary, and in particular also the extent of the lowering of the building platform between the production of component layers. This is implicit in the arrangement of two component layers, since a new component layer can only be formed on an already solidified area by applying new building material. Due to this application scheme, it is usually necessary to lower the building platform.

[0042] In the production method according to the invention for additively manufacturing a component, the component is built layer by layer in a building field in the form of component layers by selectively solidifying the building material, which preferably comprises a metal-based powder, by irradiating the building material with at least one energy beam according to control data according to the invention. In order to produce the component layers of the component, the energy beam is moved over the building field according to the control data (i.e. with corrected irradiation parameters).

[0043] The control data generating device according to the present invention is used to generate control data according to the present invention for a device for additive manufacturing of a component in a manufacturing process (according to the method according to the present invention), in which the component is constructed in the form of component layers in a construction field by irradiating the construction material with at least one energy beam to selectively solidify the construction material, which preferably includes a metal-based powder.

[0044] The control data generating device comprises the following components:

[0045] a data interface, which is designed to receive a process chamber control data set including information about a target shape of a currently solidified component layer, and to receive a process chamber sensor data set of the component, which is recorded by means of a sensor arrangement, of the currently solidified component layer, wherein the process chamber sensor data set includes at least spatially resolved thermal data of a plurality of regions of the component layer,

[0046] a registration unit, which is designed to define a plurality of special regions in the target shape, wherein each special region is a region in the component layer having a predetermined system shape characteristic and / or a manufacturing characteristic, and to assign the plurality of special regions to corresponding regions of the plurality of regions in the process chamber sensor data set,

[0047] a modulation unit, which is designed to: generate a correction factor module, which assigns a correction factor or a corrected irradiance value to at least one subregion of a subsequent component layer, wherein the correction factor or the corrected irradiance value is generated based on a process chamber sensor data set and, in a special region, is generated according to further rules outside the special region,

[0048] a correction unit, which is designed to correct control data for additive manufacturing of subsequent component layers based on the correction factor module,

[0049] A data interface (if necessary the abovementioned data interface or a further data interface) which is designed to output the corrected control data to a device for additive manufacturing of a component.

[0050] The functions of these components have been explained in detail above in conjunction with the method.

[0051] The control device according to the invention is used for an apparatus for additively manufacturing a component in a manufacturing process in which the component is built layer by layer in a building field in the form of component layers by selectively solidifying a building material, preferably comprising a metal-based powder, by irradiating the building material with at least one energy beam by means of an irradiation device. The control device is designed to control an apparatus for additively manufacturing component layers of a component according to control data according to the invention. Preferably, the control device according to the invention comprises a control data generation device according to the invention.

[0052] The device according to the invention ("manufacturing device") is used for additive manufacturing of at least one component in an additive manufacturing process. The device comprises at least:

[0053] - a supply device for applying a material layer of building material into a building field in the process chamber,

[0054] - an irradiation device for selectively curing the building material by irradiation with at least one energy beam, in particular between the application of two material layers, and

[0055] - A control device according to the invention.

[0056] At this point it should be pointed out that the device according to the invention can also have a plurality of irradiation devices, which are then controlled in a correspondingly coordinated manner with the control data in the manner described above. It should also be mentioned again that the energy beam can also consist of a plurality of superimposed energy beams or the energy beam can be both particle radiation and electromagnetic radiation, such as light radiation or preferably laser radiation.

[0057] The invention can be realized in particular in the form of a computer unit, in particular a control device, with suitable software. This refers in particular to the creation of control data, since the manufacture of the component is performed with the aid of other components. For this purpose, the computer unit can, for example, have one or more microprocessors or the like that work in cooperation. In particular, it can be realized in the form of suitable software program components in the computer unit. The advantage of a mainly software-based implementation is that previously used computer units, in particular control devices of manufacturing devices, can also be transformed in a simple manner by software or firmware updates in order to work in the manner according to the invention. In this respect, the object is also achieved by a corresponding computer program product, which has a computer program that can be directly loaded into a storage device of a computer unit, and which has program segments so that when the program is executed in the computer unit, all steps of the method of the invention are executed (at least those steps related to the generation of control data, and, if necessary, those steps for transmitting control data for the manufacturing process). In addition to the computer program, such a computer program product can also include other components, such as documents and / or other components, and hardware components, such as hardware keys (software dongles, etc.) for using the software. For transmission to a computer unit and / or storage on or in a computer unit, a computer-readable medium can be used, such as a memory stick, a hard disk or another removable or fixed data carrier, on which program segments of a computer program that can be read and executed by the computer unit are stored.

[0058] Other particularly advantageous designs and improvements of the present invention are derived from the dependent claims and the following description, wherein an independent claim of one claim category may also be improved similarly to the dependent claims and embodiments of another claim category, and in particular individual features of different embodiments or variants may also be combined into new embodiments or variants.

[0059] According to a preferred method, before the number of special regions is assigned to the corresponding regions in the process chamber sensor data set, the process chamber sensor data set is adjusted according to existing (previously determined) calibration data or according to an adjustment function (e.g. a fitting algorithm). In this case, it is preferred that the sensor assembly is first calibrated and the process chamber sensor data set is recorded with the calibrated sensor assembly. Alternatively, it is preferred that prefabricated calibration data are present and that the process chamber sensor data set is adjusted after the recording with the sensor assembly. In this case, the special regions are preferably registered to the corresponding regions in the process chamber sensor data set by means of an adjustment algorithm or are mapped thereto in another way. The latter has the advantage that the sensor data can be calibrated directly depending on whether they come from special regions or not.

[0060] Specifically, which area is considered a special area depends on the type of component, the type of production or the user. It can be provided that what is considered a special area is defined, for example, by presetting or by user default values. The following areas of the component are preferred special areas. Individual alternatives or groups of alternatives from the following alternatives can be selected as default values ​​for special areas.

[0061] - is the component edge area of ​​the component layer,

[0062] - is a region of the component layer in which the solidification paths overlap one another, in particular their starting and / or ending regions overlap one another,

[0063] - a region in which the shadow band (if necessary consisting of curing paths arranged parallel to one another, adjacent to one another) tapers (ie in which the length of the curing paths is shorter than the standard length or maximum length),

[0064] - an area smaller than the optical resolution of the sensor assembly (ie the smallest possible area of ​​the component layer that can be measured individually by the spatially resolving sensor assembly),

[0065] - an area with a support structure, preferably where the wall thickness or strut thickness or diameter of the support structure is so small that it cannot be fully resolved by the sensor (eg less than 5 times the pixel resolution, eg about 500 μm).

[0066] According to a preferred method, the assignment of the plurality of special regions to corresponding positions in the process chamber sensor data set is achieved by means of image registration. Here, methods based on the Enhanced Correlation Coefficient (common in image processing) are 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).

[0067] According to a preferred method, the correction factor of the correction factor module for the special area is obtained by interpolation or extrapolation based on the correction factors for a certain number of component areas adjacent to the special area for the target shape. This is achieved in particular by: interpolating the correction factors of the relative component areas; or interpolating between the correction factors of a certain component area and a predetermined value outside the component; or interpolating the correction factors of a certain component area. In addition, this is particularly advantageous if the special area is an area that should be subjected to thermal post-treatment.

[0068] Alternatively, it is preferred that the correction factors of the correction factor module for a special area are formed by predetermined constant correction factors.

[0069] Alternatively, it is preferred that the correction factors of the correction factor module for a specific area are determined by an interpolation method in image processing which is based on a continuous progression of gray values, in particular on a coloring algorithm or an inpainting algorithm.

[0070] Alternatively, it is preferred that the correction factors of the correction factor module for the special region are formed based on a theoretical temperature change model or a local thermal conductivity characteristic. Furthermore, this is particularly advantageous if the special region is a region that should be subjected to thermal post-treatment.

[0071] According to a preferred method, there are predetermined maximum and / or minimum values ​​for the correction factor, in particular there is 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 factor is then preferably generated in such a way that it does not exceed these maximum values ​​and / or does not fall below these minimum values.

[0072] According to a preferred method, in order to generate the correction factor map, correction factors are generated based on the process chamber sensor data set outside a certain number of special areas by means of a controller, in particular a PD controller, a PI controller or a PID controller. Preferably, the correction factors are generated in the special area, i.e. the correction factors are generated there according to a different rule than in other areas:

[0073] - can be spawned without a controller, or

[0074] - first generated with the aid of a controller and then corrected, or

[0075] Firstly the corresponding values ​​of the process chamber sensor data set are corrected and subsequently the correction factors are generated by means of the controller.

[0076] For correction in non-special areas, a controller is preferably used in a classical manner, wherein parameterizable proportional, differential and / or integral components are used. A completely SW-based control system is particularly preferred. The parameters of the controller can be set, in particular, for the component.

[0077] As described above, the method is preferably used for a plurality of consecutive component layers. In this case, the control data are preferably stored together with a certain number of corresponding correction factor modules and / or with corrected control data. It should be noted here that the correction factor modules can contain corrected irradiation values, but the corrected control data can contain other data in addition to corrected irradiation values. It is particularly preferred that all correction factor modules or corrected control data obtained by the method are stored, since they are related to one another. Finally, after the previous application of the method, a process chamber sensor data set is obtained based on the component layer produced with the corrected control data.

[0078] Preferably, for correcting the control data of a component, only the data of the correction factor module generated by the component layer of the determined component, in particular by the previously manufactured component layer, are used. Thus, each component is considered independent. Alternatively, preferably, the data of the correction factor module generated by the component layer of the same shape of another component are used. This allows, for example, when manufacturing several components of the same type, to apply the correction factor module of one component to other components.

[0079] At this point, it should be noted that the method according to the invention can also be applied to control data that have already been corrected, provided that it is known that these data have been corrected and in what manner. Basically, it is only necessary to design the correction factors accordingly. For example, corrected control data obtained from one component can be additionally corrected when applied to another component. Alternatively, corrected control data obtained from a component (for example, of the same design, which should be made of the same material and to which the same requirements are made in terms of its component properties) can be additionally corrected when applied to another sample of the component. However, the control data that have been corrected without taking into account special areas can now also be optimized by this method, for example in such a way that only the special areas are specifically corrected and the remaining correction factors are retained.

[0080] According to a preferred method, in order to define a certain number of special areas in the currently solidified component layer, information about the shape and / or position of the subsequent component layers is provided in addition to the process room control data set. Then, preferably from the process room control data sets of the two component layers, correction factors are derived, in particular for the downskin areas (downskin-Bereiche), i.e. the surface areas of the component or areas close to the surface, which are located above and adjacent to the unsolidified powder during the manufacturing process in the manufacturing device. Therefore, when selecting the special areas, the subsequent component layers are also taken into account, i.e. the target shape of these component layers is essentially taken into account.

[0081] The invention has the additional advantage that the cooling time can be shortened at least during the manufacture of the components. In addition, since the temperature-dependent distances between the components can be shortened, the manufacture can also be carried out at a higher packing density.

[0082] So far, particular attention has been paid to those embodiments in which the control data are corrected in such a way that inhomogeneities in the temperature distribution are compensated during the production process. However, it is also possible to intentionally set a different temperature in a specific area than in another (adjacent) area by means of the correction.

[0083] Undesirable internal stresses often occur in components, which can lead to unfavorable component properties, such as cracks or deformations. In order to eliminate or reduce such stresses, the components can be subjected to a heat treatment, for example, in the case of metal components, reannealing with optional subsequent quenching. Depending on the required quality, a subsequent heat treatment may even be mandatory. For this purpose, the components are heated to a predetermined temperature in an oven after their manufacture and then cooled in a liquid bath if necessary. For the heat treatment, the temperature in the chamber is usually between 300°C and 350°C. The usual temperatures for the manufacture of metal parts are between 250°C and 300°C.

[0084] Another preferred embodiment solves this problem and achieves the following object, namely to set the desired component properties in the component by different thermal distributions in the regions of the layer. Such component properties are preferably a special structure of the internal microstructure and / or an internal stress structure or another mechanical property. The mechanical property can be in particular a predetermined hardness, mechanical strength, density and / or porosity of the component. A special purpose is to produce a component with regions of different microstructures, which determine the mechanical properties of the component.

[0085] A particular object achieved by the invention is to produce a component in which a specific region with a lower porosity is intended to be created by heat treatment, which region has a better hardness and / or mechanical strength due to its greater density.

[0086] Another special object is to produce a component in which the mechanical strength is also to be influenced by the (different) microstructure of the component region. With regard to the term "microstructure", it should be noted that it can refer to both particles bonded together and to a crystal structure. In this case, a particle does not necessarily have to be a crystal, but it can be completely part of a crystal structure (e.g., granulation of a metal). The microstructure can be determined by the (relative or absolute) arrangement and / or the (relative or absolute) size and / or shape of the crystals or particles.

[0087] Another special purpose is to produce components in which the internal stresses are to be relieved. These are usually stresses that develop during the cooling of the component. However, internal stresses can also be generated in a targeted manner.

[0088] By the following preferred embodiments, subsequent heat treatment steps, such as reannealing, can be avoided or simplified. For this purpose, the component must have a higher (if necessary much higher) temperature than is usually set during its production, at least in some sub-regions.

[0089] As mentioned above, the special area can be preferably used to produce a particularly uniform temperature distribution during the manufacturing process. This special area can also be called a "special area for uniformity". The special area for heat treatment can also be called a "special area for heat treatment".

[0090] When defining a certain number of special areas, the certain number of special areas may include a certain number of uniformity special areas and / or a certain number of heat treatment special areas (or both types of special areas if necessary). The predetermined, systematic manufacturing characteristics of the heat treatment special areas may be the generation or release of internal stresses or the generation of a predetermined microstructure. In practical applications, the heat treatment special areas are usually fixed.

[0091] Both types of special regions can exist in one component layer. Preferably, the special region for heat treatment also has an additional special region for uniformity, which corresponds to a sub-region, especially an edge, of the special region for heat treatment. The advantage of this special region for uniformity is that the special region for heat treatment can be treated very uniformly with a (predetermined) temperature.

[0092] Regardless of the type of special area, the assignment of the process chamber sensor data sets is accordingly the same.

[0093] As for the correction factor module, it can be called a "uniformity correction factor module" or a "heat treatment correction factor module" depending on the corresponding special area. The uniformity correction factor module is used to design the temperature on a certain area of ​​the component layer to be as uniform as possible, and the heat treatment correction factor module is used to modify the predetermined temperature so that in the special area, the heat treatment is carried out during the manufacturing process in the form of: a predetermined power is introduced there before and / or during and / or after curing; and the part of the special area is heated more or less than the surrounding area or is heated multiple times. The heat treatment correction factor module can fully realize the following correction, that is, the special area is irradiated (with a higher or lower temperature) twice or more instead of once (for example, once for curing and afterwards and / or before for heat treatment).

[0094] Thus, if a uniformity correction factor module is used to ensure that assigned correction factors or corrected illumination values ​​achieve uniform manufacturing, then a thermal treatment correction factor module is used to assign correction factors or corrected illumination values ​​that are used to manufacture or process specific areas at temperatures that are different from the surrounding areas.

[0095] In the preferred case, the corrected control data are designed so that the heat treatment (for the metal component, for example, reannealing) is carried out during the manufacturing process. This correction then ensures that the heat treatment is carried out uniformly in the component and / or that the desired temperature or the temperature required for the heat treatment is reached during the production process. The area to be heat treated is preferably larger than the special area, or the special area is part of the area to be heat treated. The special area is essentially a homogeneity special area.

[0096] For the heat treatment, laser powers of more than 400 W, in particular more than 600 W or even more than 800 W are preferred. However, the laser power is preferably less than 1200 W, in particular less than 1100 W or even less than 1000 W. Preferred focal diameters are greater than 60 μm, in particular greater than 80 μm or even greater than 100 μm. However, the focal diameter is preferably less than 10 mm, in particular less than 1 mm. Particularly preferred focal diameters are less than 260 μm, in particular less than 220 μm or even less than 180 μm.

[0097] In the case of using conventional control data, the correction factor module is essentially the above-mentioned thermal treatment correction factor module. This module assigns correction factors or assigns corrected irradiation values ​​including predetermined radiation powers. Preferably, in the process of correcting the control data, in addition to the thermal treatment correction factor module, a uniformity correction factor module is also used.

[0098] Therefore, the heat treatment correction factor module assigns correction factors or corrected irradiation values ​​to the heat treatment of the relevant special area, which correction factors or corrected irradiation values ​​increase or decrease the temperature before and / or during and / or after the curing of the special area, so that the relevant special area is produced at a higher or lower temperature than the adjacent areas, and thus heat treatment is performed there during manufacturing.

[0099] It should be noted that in the case that both the uniformity correction factor module and the heat treatment correction factor module assign corrected irradiation values, both modules should take the irradiation values ​​into account when correcting the control data. In particular, values ​​can be superimposed here, for example by superimposing a predetermined duration for the beam guidance, so that the beam takes longer to travel on the path, i.e. more heat is introduced there. However, the heat treatment correction factor module can also ensure a second irradiation. The uniformity correction factor module can ensure that the uniformity special area within the heat treatment special area is heat treated differently from its surroundings, so as to achieve a particularly uniform heat treatment.

[0100] This embodiment allows for a special heat treatment to be carried out in order to adjust other component properties. In this case, selected specific areas of the component are heat treated in a targeted manner at a temperature different from that of other areas. For example, inner areas can be heated more or less strongly than outer areas, or in the subsequent use of the component, areas where additional forces are expected to prevail are heat treated differently from other areas of the component. This makes it possible for some areas of the component to be designed in a targeted manner to be softer or harder or more brittle or more elastic than other areas of the component. In particular, different areas can be heat treated differently so that they have different microstructures.

[0101] This can also be achieved by means of prefabricated control data. However, for this purpose, care must be taken when correcting the control data to ensure that, when generating the correction factor module, the correction factors are generated in such a way that the temperature distribution predetermined by the prefabricated control data is achieved in the relevant sub-regions of the subsequent component layer. Furthermore, this should be done not only under special temperature treatments, but also in "normal" production if different production temperatures are desired. Instead of correction factors, it is also possible to directly assign corrected irradiation values. However, the corrected irradiation values ​​must then be based on prefabricated control data and should be designed to achieve the desired temperature profile.

[0102] In the case of heat treatment according to the prior art (in an oven), a compromise of parameters must be found, depending on the properties of the resulting component: some sub-areas may require a stronger heat treatment, while other sub-areas should receive a weaker heat treatment. However, in an oven, only an average temperature on the component can be achieved. The heat treatment according to the invention makes it possible that sub-areas of the component can receive a heat treatment at different temperatures. These sub-areas can, for example, be areas that should have better mechanical properties and / or a different microstructure than other areas. Some areas can also be excluded from the heat treatment or reheated in a targeted manner. Preferably, the already cured areas are reheated after curing (multiple times if necessary). Therefore, in this case, the heat treatment is carried out by this additional heating.

[0103] According to a preferred embodiment, the "normal" control data are used for the additive manufacturing of the subsequent component layers, and the "normal" control data are then corrected based on a heat treatment correction factor module (e.g., a heat treatment map or function). Here, the heat treatment correction factor module particularly preferably specifies an inhomogeneous irradiation (for an inhomogeneous heat treatment).

[0104] The control data corrected in this way are then output to the device for additive manufacturing of components so that a new component layer can be produced. Preferably, this new component layer or the processing chamber sensor data set of this new component layer is then used again as the basis for the updated method operation of the next component layer.

[0105] Preferably, the cooling of a region of a component layer is controlled by setting the laser parameters in order to reduce or avoid internal stresses by means of a desired controlled cooling behavior. However, depending on the component, it is also preferred to control the cooling behavior by setting the laser parameters so that stresses are generated in a targeted manner. It may therefore also be advantageous to intentionally induce internal stresses so that the resulting component thus has certain properties (similar to tempered glass).

[0106] Preferably, higher temperatures are achieved by adjusting the laser power and / or beam profile.

[0107] Here, specific areas that are subject to higher effective temperatures due to beam deformation or intensity changes during the production process (i.e., areas that should be subjected to heat treatment) can be referred to as "overheating areas", where this overheating is intentionally caused by radiation changes.

[0108] It is also preferred within the scope of the invention if the laser intensity is reduced in specific areas so that the component or a sub-area of ​​the component is cooled in a controlled manner.

[0109] The (heat treatment) correction factor model can be stored eventually, in particular after the component has been manufactured, and used for manufacturing other components.

[0110] If the method according to the invention is considered, a preferred embodiment for the heat treatment during the correction of the "normal" control data may be:

[0111] - a module for generating a heat treatment correction factor, which assigns a correction factor for the heat treatment or a corrected illumination value to at least one sub-region of the subsequent component layer, wherein the correction factor for the heat treatment or the corrected illumination value is generated based on a predetermined condition and, in at least a portion of the special region, is generated according to a rule different from that of other regions of the target shape that are not special regions,

[0112] - (preferably additionally:) generating a uniformity correction factor module, which assigns a correction factor or a corrected illumination value to at least one sub-region of the subsequent component layer, wherein the correction factor or the corrected illumination value is generated based on the process chamber sensor data set and is generated in the special region according to a different rule than in other regions of the target shape that are not the special region,

[0113] - correcting the control data for additive manufacturing of subsequent component layers based on the uniformity correction factor module and the heat treatment correction factor module,

[0114] - Outputting the corrected control data to a device for additive manufacturing of a component.

[0115] In short, with these special embodiments, a specific high temperature level can be maintained globally or locally on the component for the duration of the construction process. In the case of local differentiation, it is possible to produce in a targeted manner areas that have properties that differ from the overall component. In principle, for example, large spot or beam shaping processes are more suitable than standard processes, because significantly more power can be provided, so that the workpiece can be heated to a temperature far higher than required. As a result, subsequent heat treatment can be omitted or can be used to adjust the component properties in another special way, for example by hardening the wall area of ​​the component again in a special way. BRIEF DESCRIPTION OF THE DRAWINGS

[0116] The present invention will be described in more detail below in conjunction with embodiments with reference to the accompanying drawings. In each of the accompanying drawings, the same reference numerals are used for the same components. The accompanying drawings show:

[0117] Figure 1 A partial cross-sectional schematic diagram showing an embodiment of an apparatus for additive manufacturing;

[0118] Figure 2 A schematic diagram showing the energy input and correction factors at the edge of a component layer,

[0119] Figure 3 shows possible process chamber sensor data sets for component layers and their target shapes,

[0120] Figure 4 A block diagram showing a possible method sequence according to an exemplary embodiment of the method of the present invention,

[0121] Figure 5 Shows the components used to make the component,

[0122] Figure 6 shows the normal correction of control data according to the prior art,

[0123] Figure 7 An optimized correction to the control data is shown. DETAILED DESCRIPTION

[0124] The following embodiments will be described with reference to a device 1 for additively manufacturing a component in the form of a selective laser sintering device or a laser melting device, wherein it is once again explicitly pointed out that the present invention is not limited to selective laser sintering devices or laser melting devices. Therefore, without limiting its generality, the device is referred to as a "manufacturing device" 1 in the following text.

[0125] Figure 1 Such a manufacturing device 1 is schematically shown. The device has a processing chamber 3 or processing chamber 3 with a chamber wall 4, in which the manufacturing process is essentially carried out. In the processing chamber 3, there is a container 5 open to the top with a container wall 6. The top opening of the container 5 forms a corresponding current working plane 7. The area of ​​this working plane 7 located within the opening of the container 5 can be used to construct the object 2 and is therefore called a construction field 8.

[0126] The container 5 has a base plate 11 which is movable in a vertical direction V and is arranged on a carrier 10. The base plate 11 closes the container 5 downwards and thus forms its bottom. 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 can be fastened to the carrier 10 or simply supported thereon. Depending on the specific building material (i.e., for example, the powder used) and the type of manufacturing process, a building platform 12 can be mounted on the base plate 11 as a building support, 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 constitutes the building support.

[0127] The basic construction principle of the object 2 is as follows: first, a layer of construction material 13 is applied to the construction platform 12; then, as explained below, a laser beam 22 is used as an energy beam to selectively cure the construction material 13 at points that should form parts of the object 2 to be manufactured; then, the substrate 11 and therefore the construction platform 12 are lowered with the aid of the carrier 10, and a new layer of construction material 13 is applied and selectively cured, and so on. Figure 1 An object 2 constructed in a container on a construction platform 12 is shown in an intermediate state, below a working plane 7. The object already has a plurality of cured layers, which are surrounded by a still uncured construction material 13. Various materials can be used as construction material 13, preferably powders, in particular metal powders, plastic powders, ceramic powders, sand, filled or mixed powders, or also pasty materials, and optionally mixtures of a plurality of materials.

[0128] Fresh building material 15 is located in a storage container 14 of the production device 1. By means of a coating machine 16 which is movable in a horizontal direction H, the building material can be applied in the form of a thin layer to the working plane 7 or the building field 8.

[0129] Optionally, an additional radiation heating device 17 is provided in the process chamber 3. For example, the radiation heating device can be used to heat the applied building material 13 so that the irradiation device for selective curing does not need to introduce too much energy. This means that, for example, with the aid of the radiation heating device 17, a certain amount of basic energy can already be introduced into the building material 13, which is of course still lower than the energy required to melt or sinter the building material 13. For example, infrared radiators or VCSEL radiators can be used as radiation heating devices 17.

[0130] In order to perform selective curing, the manufacturing device 1 has an irradiation device 20, or more precisely, an irradiation device 20 with a laser 21. The laser 21 generates a laser beam 22, which is deflected by a deflection device 23 so as to scan the corresponding layer to be selectively cured along an irradiation path or track (hatching) set according to the irradiation strategy and selectively introduce energy. Further, the laser beam 22 is focused on the working plane 7 in a suitable manner by a focusing device 24. Here, the irradiation device 20 is preferably located outside the processing chamber 3, and the laser beam 22 is guided into the processing chamber 3 via a coupling window 25 installed in the chamber wall 4 at the top of the processing chamber 3.

[0131] For example, the illumination device 20 may comprise not one but a plurality of lasers. Preferably, it may be a gas or solid-state laser or any other type of laser, such as a laser diode, in particular a VCSEL (Vertical Cavity Surface Emitting Laser) or a VECSEL (Vertical External Cavity Surface Emitting Laser) or a series of these lasers. Particularly preferably, within the scope of the invention, one or more unpolarized single-mode lasers are used, such as a 3 kW fiber laser with a wavelength of 1070 nm.

[0132] The manufacturing is monitored with a sensor assembly 18. The sensor assembly may, for example, comprise a radiation sensor such as a thermal imaging camera and measure spatially resolved thermal data of a number of areas of layer B of the component.

[0133] The control device 30 is used to control the units of the production device 1 and comprises a control unit 29 which actuates the components of the irradiation device 20 , namely here the laser 21 , the deflection device 23 and the focusing device 24 , and transmits corresponding control data PS to these components.

[0134] The control unit 29 also controls the radiation heating device 17 by means of suitable heating control data HS, controls the coater 16 by means of coating control data ST, and controls the movement of the carrier 10 by means of carrier control data TS, thereby controlling the layer thickness.

[0135] The control device 30 can be connected here, for example, via a bus 60 or another data connection to a terminal 40 having a display etc. Via the 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.

[0136] In order to optimize the production process, control data PS are generated or modified in the manner according to the invention by means of control data generation device 34 , so that device 1 is at least temporarily actuated in the mode according to the invention.

[0137] Here, the control data generating device 34 comprises a data interface 35, which is designed to receive a process room control data set KD including information about the target shape F of the currently solidified component layer B and to receive a process room sensor data set SD of the currently solidified component layer B of the component 2 (see, for example Figure 3 ). In this case, the process chamber sensor data set SD comprises spatially resolved thermal data recorded by means of the sensor arrangement 18 .

[0138] Furthermore, the control data generating device 34 comprises a registration unit 36, which is designed to define a certain number of special regions S in the target shape F, wherein each special region S is a region having a predetermined system shape feature and / or manufacturing feature in the component layer B. Furthermore, the registration unit 36 ​​is designed to assign the certain number of special regions S to corresponding regions of the certain number of regions in the process chamber sensor data set SD.

[0139] Furthermore, the control data generation device 34 comprises a modulation unit 37, which is designed to generate a correction factor map KK as a correction factor module KK. The correction factor map KK assigns a correction factor KF or a corrected irradiation value to at least one sub-region of the subsequent component layer B1. Here, the correction factor KF or the corrected irradiation value is generated based on the process chamber sensor data set SD and, in the special region S, is generated according to another rule outside the special region S.

[0140] Furthermore, the control data generating device 34 comprises a correction unit 38 which is designed to correct the control data PS for the additive production of the subsequent component layer B1 based on the correction factor map KK.

[0141] In this example, the corrected control data PS can then be output via the data interface 35 to the device 1 for additive manufacturing of a component 2 , but further data interfaces can also be used for this purpose.

[0142] At this point, it should also be noted that the present invention is not limited to such a manufacturing device 1. The present invention can be applied to other methods of generative or additive manufacturing of three-dimensional objects by layer-by-layer application and selective curing of construction materials, wherein the energy beam for curing is irradiated onto the construction material to be cured. In addition, correspondingly, the irradiation device can not only be a laser as described herein, but any device that can selectively apply energy as wave or particle radiation to or into the construction material can be used. For example, different light sources, electron beams, etc. can be used instead of lasers.

[0143] Even in Figure 1 Only a single object 2 or component 2 is shown, but it is also possible and common to produce multiple objects in parallel in time in the processing chamber 3 or container 5. For this purpose, the energy beam 22 is scanned layer by layer in the structure material at the location corresponding to the cross section of the object in each layer.

[0144] Figure 2 A sketch showing the energy input and the correction factor KF at the edge of the component layer B. The arrows below represent the spatial components and the arrows on the left represent the intensity values. The vertical solid line is intended to represent the edge of the component layer B, and the adjacent dotted line is intended to represent the boundary of the special area S located between these two lines. The area between the vertical dotted line and the dotted vertical line can be regarded as an adjacent normal area.

[0145] The solid lines show two possible temperature curves in the process chamber sensor data set SD, wherein the upper line shows the temperature curve of the edge region of the overheated component, and the lower line shows the temperature curve of the edge region of the non-overheated component.

[0146] If a special area (component edge area) is not processed separately, but is processed similarly to the internal area of ​​the component (non-special area), the dashed line shows two possible correction factors KF for the corresponding solid line. The dotted line in the middle shows the changed correction factors for the component edge area (special area S) in the above two cases.

[0147] Figure 3 A possible process chamber sensor data set SD for a component layer B (left) and its target shape F in the process chamber control data set KD (right) are shown. At the end of the component layer, in the process chamber sensor data set SD of the component layer B, locations where overheating occurs can be seen (darker shading). Such inhomogeneities in the temperature distribution can be compensated in subsequent layers, in particular if special areas S are shown in the target shape F (see Figure 6 and Figure 7 ). The two arrows indicate that the target shape can be split into a “normal region” (below, without border) and a special region S (with only border).

[0148] Please note that overheated areas are not considered as special areas S, since during the fabrication of the next component layer this “internal” overheating can be compensated by an easily determined correction factor KF (see for example Figure 4 ). However, it looks different at the edge R. Here, the correction factor KF must be determined in another way, for example by interpolation or by using the correction factor KF of the adjacent inner area. Therefore, the edge R is regarded as a special area S here.

[0149] Figure 4 The invention is shown for use in a manufacturing process (see Figure 1 ) is a block diagram of a possible method flow of an embodiment of a method for generating control data PS by an apparatus 1 for additively manufacturing a component 2, in which manufacturing process the component 2 is constructed in the form of component layers B in a construction field 8 by irradiating a construction material 13 with at least one energy beam 22 to selectively solidify the construction material 13, for example, comprising a metal-based powder.

[0150] In step I, a process room sensor data set SD of a currently solidified component layer B of the component 2 is recorded by means of the sensor arrangement 18 , wherein the process room sensor data set SD comprises at least spatially resolved thermal radiation data of a certain number of regions of the component layer B.

[0151] In step II, a process room control data set KD is provided which contains information about the target shape F of the currently solidified component layer B. This can be done, for example, on the basis of CAD data of the component 2 or in accordance with predetermined control data PS.

[0152] In step III, a certain number of special regions S are defined in the target shape F, wherein each special region S is a region having predetermined system shape features and / or manufacturing features in the component layer B. Here, the component edge region of the component layer B is marked as a special region with a dotted line.

[0153] In step IV, the certain number of special regions S are assigned to corresponding regions of the certain number of regions in the process chamber sensor data set SD. This can be achieved, for example, by means of image registration. In the process chamber sensor data set SD, different hatching lines can be identified in the component layer. These hatching lines are intended to represent different measured temperatures or radiated heat.

[0154] In step V, a correction factor map KK is generated as a correction factor module KK, which assigns a correction factor KF or a corrected irradiation value to at least one subregion of the subsequent component layer B1 (see, for example, Figure 6 and Figure 7 ). Here, the correction factor KF is generated, for example, in such a way that a corresponding value is selected for the "normal" area, the lower the value, the hotter the corresponding area of ​​the component layer B is in step IV. For the special area S, it is different. Here, the correction factor KF of the adjacent "normal" area can be used for the correction factor KF, or the correction factor KF can be formed by a predetermined constant correction factor KF. The correction factor can also be determined by an interpolation method or a model based on a theoretical temperature change.

[0155] In this step V, the (original) control data PS for the additive production of the subsequent component layer B1 are corrected based on the correction factor map KK.

[0156] As a result of the method, the corrected control data PS are output again to the device 1 for additive manufacturing of a component 2 in order to produce the next component layer.

[0157] Figure 5 Components for producing a component 2 are shown, which can be arranged in a production device 1 or connected to a production device. Figure 1, a simplified representation has been chosen here, which shows only the most important components for the method. In the left bold box, the irradiation control interface 31 and the control data generation device 34 with data interface 35, registration unit 36, modulation unit 37 and correction unit 38 can be seen again. They receive control data PS from the left, which are corrected by the correction factor map KK as correction factor module KK and sent to the irradiation control interface 31 in corrected form. The sensor assembly 18 provides the required process chamber sensor data set SD. The deflection device 23 and the laser 21 are then controlled based on the corrected control data PS to produce the next component layer B with the energy beam 22. Here, the correction factor map KK is still stored in the storage unit 39.

[0158] Figure 6 and Figure 7 The correction of the control data PS is shown. The lower row shows the spatially resolved thermal data of a plurality of component layers B, B1, B2 stacked directly on top of each other. These data are recorded by the sensor assembly 18 as a process chamber sensor data set SD, and the correction factor map KK is based on Figure 4 The method shown is created as a correction factor module KK (upper row). It can be seen that the correction factor map KK looks like a negative image of the heat distribution. This is because, if the local heat in this area is too high, less energy should be introduced in the next production step.

[0159] exist Figure 6 , a normal correction is applied without considering the special area S. It can be seen that the temperature distribution is uniform inside the inner surface of the final component layer (component layer B2 at the bottom right), but the edge experiences too strong energy input (indicated by the thick edge line). However, this will not be sensed by the sensor assembly 18, because the sensor assembly also "sees" the uncured area at the edge, and due to the limited resolution, the temperature of the uncured area is mixed with the temperature of the edge area.

[0160] Figure 7 The optimized correction taking into account the special area S is shown. Here, the edge area is regarded as a special area S and the correction factor there is determined in a different way, for example by using the correction factor of the adjacent inner area. This results in a good uniformity of the temperature distribution even in the edge area (component layer B2 at the bottom right).

[0161] Finally, it is pointed out again that the device described in detail above is only an embodiment and various modifications may be made to it by a person skilled in the art without departing from the scope of the invention. For example, curing can also be carried out with other energy beams instead of lasers. In addition, the use of the indefinite article "a" or "an" does not exclude that the relevant features may be present in plurality. Similarly, the term "unit" does not exclude that it is composed of a plurality of subcomponents that cooperate with each other and these subcomponents may also be spatially dispersed if necessary. The expression "a certain number" should be understood as "at least one".

[0162] Reference numerals list

[0163] 1Device for additive manufacturing / laser sintering device

[0164] 2Components / Objects

[0165] 3 Processing room / processing cavity

[0166] 4 Cavity wall

[0167] 5. Container

[0168] 6 container wall

[0169] 7 Work Plane

[0170] 8 Tectonic Field

[0171] 10 Carrier

[0172] 11 base plate

[0173] 12 Construction Platform

[0174] 13 Construction materials (in container 5)

[0175] 14 Storage Containers

[0176] 15 Construction materials (in storage container 14)

[0177] 16 Coating Machine

[0178] 17 Radiant heating device

[0179] 18 Sensor components

[0180] 20 Irradiation device / irradiation device

[0181] 21 Lasers

[0182] 22 Laser beam / energy beam

[0183] 23 Deflector / Scanner

[0184] 24 Focusing Equipment

[0185] 25 Coupling window

[0186] 29 Control Unit

[0187] 30 Control Equipment

[0188] 31 Irradiation control interface

[0189] 34 Control data generating device

[0190] 35 Data Interface

[0191] 36 Registration Unit

[0192] 37 Modulation Unit

[0193] 38 Calibration Unit

[0194] 39 Storage Units

[0195] 40 Terminal

[0196] 60 Bus

[0197] B, B1, B2 component layers

[0198] F Target shape

[0199] H Horizontal direction

[0200] HS Heating Control Data

[0201] KD Processing Room Control Dataset

[0202] KF Correction Factor

[0203] KK correction factor graph / correction factor module

[0204] PS Process Control Data

[0205] S Special Area

[0206] SD Processing Room Sensor Dataset

[0207] ST coating control data

[0208] TS Carrier Control Data

[0209] V Vertical direction.

Claims

1. A method for generating control data (PS) for a device (1) for additively manufacturing a component (2) in a manufacturing process in which a building material (13) preferably comprising metal powder is built up layer by layer in a building field (8) by selectively solidifying the building material (13) by irradiating the building material (13) with at least one energy beam (22), the method comprising the following steps: - recording a process room 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 room sensor data set (SD) comprises at least spatially resolved thermal data of a certain number of regions of the component layer (B), - providing a process room control data set (KD) comprising information about the target shape (F) of the component layer (B) which has currently been solidified, - defining a certain number of special regions (S) in the target shape (F), wherein each special region (S) is a region in the component layer (B) having predetermined system shape characteristics and / or manufacturing characteristics, - assigning the number of special areas (S) to corresponding areas of the number of areas in the process chamber sensor data set (SD), - a correction factor generation module (KK) which assigns a correction factor (KF) or a corrected illumination value to at least one sub-area of ​​a subsequent component layer (B1), wherein the correction factor (KF) or the corrected illumination value is generated based on the process chamber sensor data set (SD) and is generated in the special area (S) according to a different rule than in other areas of the target shape (F) which are not the special area (S), - correcting control data (PS) for additive manufacturing of a subsequent component layer (B1) based on the correction factor module (KK), - outputting the corrected control data (PS) to a device (1) for additive manufacturing of a component (2).

2. The method according to claim 1 , wherein before assigning the number of special regions (S) to corresponding regions in the process chamber sensor data set (SD), the process chamber sensor data set (SD) is adjusted according to existing calibration data or according to an adjustment function, preferably wherein - first calibrating the sensor assembly and recording the process chamber sensor data set with the calibrated sensor assembly, or - prefabricated calibration data exist and after recording the process chamber sensor data set with the sensor assembly, the latter is adjusted, Preferably, the special area is registered to a corresponding area in the process chamber sensor data set by means of an adjustment algorithm, or is mapped thereto in another way.

3. The method according to claim 1, wherein at least one special area (S) - is a component edge region of the component layer, and / or - is a region of the component layer in which the solidification paths overlap one another, in particular their starting or ending regions overlap one another, and / or - is an area where the shadow band tapers, and / or - is smaller than the optical resolution of the sensor assembly (18), and / or - is the area with supporting structure.

4. The method according to claim 1, wherein the assignment of the certain number of special areas (S) to corresponding positions in the process chamber sensor data set (SD) is achieved by means of image registration, in particular by means of a method based on enhanced correlation coefficients.

5. The method according to claim 1 , wherein the correction factor (KF) of the correction factor module (KK) for a specific zone (S) is - the correction factor (KF) for a certain number of component regions adjacent to the specific region (S) for the target shape (F) is obtained by interpolation or extrapolation, in particular by interpolating correction factors (KF) of opposite component regions, or by interpolating the correction factor (KF) of a component region with a predetermined value outside the component, or by interpolating the correction factor (KF) of a component region, - formed by a predetermined constant correction factor (KF), - determined by an interpolation method in image processing based on a continuous progression of grayscale values, in particular based on a colorization algorithm or an inpainting algorithm, - Based on theoretical temperature change model formation.

6. A method according to one of the preceding claims, wherein there is a predetermined maximum and / or minimum value for the correction factor (KF), in particular there is a limit value module with a spatially resolved maximum and / or minimum value, and the correction factor (KF) is generated in such a way that it does not exceed the maximum value and / or does not fall below the minimum value.

7. The method according to claim 1 , wherein for generating the correction factor module (KK), the correction factor (KF) is generated outside the certain number of special areas (S) based on the process chamber sensor data set (SD) by means of a controller, in particular a PD controller, a PI controller or a PID controller, and within the certain number of special areas (S), preferably, - can be generated without said controller, or - first generated by means of the controller and then corrected, or - Firstly the corresponding values ​​of the process chamber sensor data set (SD) are corrected and subsequently the correction factor (KF) is generated by means of the controller.

8. The method according to claim 1 , wherein the method is used for a plurality of consecutive component layers (B, B1, B2), preferably wherein the control data (PS) are stored together with a certain number of corresponding correction factor modules (KK) and / or corrected control data (PS), Preferably, wherein To correct the control data (PS) of the component (2) - using only the data of the correction factor module (KK) generated by the component layer (B) of the component (2), or - Data generated by a component layer (B) of the same shape of another component (2) using a correction factor module (KK).

9. A method according to one of the preceding claims, wherein, in order to define a certain number of special areas (S) in the currently solidified component layer (B), in addition to the process chamber control data set (KD), information about the shape and / or position of the subsequent component layer (B1) is also provided, and a correction factor (KF) in particular for the sub-layer area is derived from the process chamber control data set (KD) of the two component layers (B, B1).

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

11. A production method for additively manufacturing a component (2), wherein in a building field (8), a building material (13) preferably comprising metal powder is built up layer by layer according to control data (PS) according to claim 10, in that the building material (13) is selectively solidified by irradiating the building material (13) with at least one energy beam (22), wherein: In order to produce component layers (B, B1, B2) of the component (2), the energy beam (22) is moved over the construction field (8) in a region defined according to the control data (PS).

12. A control data generating device (34) for generating control data (PS) according to claim 10 for a device (1) for additively manufacturing a component (2) in a manufacturing process in which a building material (13) preferably comprising metal powder is built up layer by layer in a building field (8) by selectively solidifying the building material (13) by irradiating the building material (13) with at least one energy beam (22), the control data generating device (34) comprising: a data interface (35) designed to receive a process room control data set (KD) comprising information about a target shape (F) of a currently solidified component layer (B), and to receive a process room sensor data set (SD) of the currently solidified component layer (B) of the component (2) recorded by means of a sensor arrangement (18), wherein the process room sensor data set (SD) comprises at least spatially resolved thermal data of a certain number of regions of the component layer (B), - 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 in the component layer (B) having predetermined system shape characteristics and / or manufacturing characteristics; and assigning the certain number of special areas (S) to corresponding areas of the certain number of areas in the process chamber sensor data set (SD), a modulation unit (37) designed to generate a correction factor module (KK) which assigns a correction factor (KF) or a corrected irradiance value to at least one sub-region of the subsequent component layer (B1), wherein the correction factor (KF) or the corrected irradiance value is generated based on the process chamber sensor data set (SD) and in the special region (S) according to a further rule outside the special region (S), a correction unit (38) designed to correct control data (PS) for additive manufacturing of a subsequent component layer (B1) based on the correction factor module (KK), A data interface (35) is designed to output the corrected control data (PS) to a device (1) for additive manufacturing of a component (2).

13. A control device (30) for an apparatus (1) for additively manufacturing a component (2) in a manufacturing process in which a building material (13) which preferably comprises a metal powder is built up layer by layer in a building field (8) by selectively solidifying the building material (13) by irradiating the building material (13) with at least one energy beam (22) by means of an irradiation device (20). in, The control device (30) is designed to control the device (1) for additively manufacturing component layers (B, B1, B2) of the component (2) according to the control data (PS) according to claim 10, wherein the control device (30) preferably includes a control data generating device (34) according to claim 12.

14. A device (1) for additively manufacturing at least one component (2) in an additive manufacturing process, the device comprising at least: - a supply device for applying a material layer of a building material (13) into a building field in the process chamber (3), - an irradiation device (20) for selectively curing the building 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. A computer program product comprising instructions which, when a computer executes the program, cause the computer to perform the steps of the method according to claims 1 to 9 and / or 11.

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