METHOD FOR DETECTING A WORKING AREA OF A GENERATIVE MANUFACTURING DEVICE AND MANUFACTURING DEVICE FOR THE GENERATIVE MANUFACTURING OF COMPONENTS FROM A POWDER MATERIAL

Description

[0001] The invention relates to a method for detecting a working area of ​​an additive manufacturing device and to a manufacturing device for additively manufacturing components from a powder material.

[0002] Such a manufacturing device inherently requires monitoring the work area in which a component is additively built from a powder material. This particularly concerns the monitoring of newly applied powder layers, especially for potentially defective areas or edges, the analysis of molten areas within a powder layer, the recording of the emerging component, and other requirements. Increasingly, it is also becoming apparent that certain components are not entirely additively manufactured, particularly due to the resulting cost and speed advantages. Instead, specific sections of a component, where the advantages of this process are particularly evident, are additively built onto a conventionally manufactured base form, a so-called preform.This allows the preform, for example, a tool shank where additive manufacturing would offer no advantages, to be produced quickly and, in particular, cost-effectively using conventional methods. Subsequently, only the component geometry that would be impossible or significantly more difficult to produce using conventional methods is additively built onto the preform. Essential for the high quality of such hybrid components is precise knowledge of the preform's position within the work area. This ensures that the additively manufactured component area can be built onto the preform with high accuracy and without misalignment. Specifically, it is necessary to determine the preform's position with an accuracy of a few tens of micrometers.In principle, separate measuring devices or measuring devices specifically integrated into the additive manufacturing system can be used for this purpose. However, two factors influence the position determination: firstly, the accuracy of the measuring device itself, and secondly, the registration accuracy between the measuring device and a scanner used to move an optical work beam for additive manufacturing. The term "registration accuracy" refers specifically to the accuracy of the transformation from the coordinate system of the measuring device to the coordinate system of the scanner. This registration accuracy is directly affected by instabilities and / or drifts in both the measuring device and the scanner.Such errors, especially when cumulative, directly lead to a reduction in the quality and / or accuracy of the resulting component, particularly to a misalignment between the preform and the additively manufactured component section built upon it. This problem occurs regardless of the measuring device used for position determination, be it triangulation sensors, photogrammetric sensors, structured light projection sensors, optical cameras, photodiodes, or line sensors that capture the working area independently of the scanner.

[0003] US Patent 2018 / 0297117 A1 discloses a method and a system in which optical interferometry is used in the context of material modification processes, particularly for process monitoring and / or process control. If a material modification beam source is also used as an imaging light source, the material modification beam source is operated at the same output power used for the material modification process, so that the process carried out with the material modification beam can be monitored and / or controlled interferometrically.

[0004] DE 10 2016 222186 B3 discloses a method and a processing machine in which two scanner devices, each over which a laser beam is guided, are calibrated to each other by determining and correcting a deviation of an actual position from a target position of the retroreflector in the working area on the basis of a laser radiation reflected back from the retroreflector into the scanner device and detected.

[0005] WO 2017 / 085470 A1 shows the introduction of markings into the surface of a preform using the energy beam of an additive manufacturing device, the introduction of further features into the preform, wherein the position of the features depends on a position of the markings determined by means of image acquisition, and the preform is subsequently used for additive manufacturing in the additive manufacturing device.

[0006] The invention is based on the objective of creating a method for capturing a working area of ​​an additive manufacturing device and an additive manufacturing device for the additive manufacturing of components from a powder material, without the aforementioned disadvantages occurring.

[0007] The problem is solved by providing the present technical teaching, in particular the teaching of the independent claims and the embodiments disclosed in the dependent claims and the description.

[0008] The problem is solved in particular by providing a method according to claim 1 for detecting a working area of ​​an additive manufacturing device, comprising the following steps: An optical work beam of the additive manufacturing device is moved within the working area. Signal values ​​of light emitted along an optical axis of the optical work beam are detected as a function of location. A signal value is assigned to each location of displacement of the optical work beam within the working area. Finally, an image of the working area is obtained from the location-dependently detected signal values.By capturing reflected light from the optical beam in a location-dependent manner and obtaining an image of the work area from it, it is possible to use the optical beam itself for work area detection, thus eliminating the need for separate measuring devices or those specifically designed for this purpose. Capturing reflected light allows the work area to be observed with a comparatively low optical output power of the beam, as it avoids the need for process lighting and / or thermal emissions, which occur at power levels of the optical beam where changes to materials located in the work area, be it a preform or powder material, could occur.This allows for the detection of the work area, particularly without damage and / or without impacting a subsequent build process for the production of an additively manufactured component. Because the reflected light is detected along the optical axis of the optical work beam, the position-dependent acquisition of the signal values ​​occurs directly in the coordinate system of the scanner device, completely eliminating the otherwise necessary registration between a measuring device and the scanner. This also eliminates the aforementioned sources of error, resulting in highly accurate detection of the work area. In particular, the position of a preform can be determined very precisely. Furthermore, using the optical work beam for detecting the work area eliminates the need for additional sensor components in a simple and cost-effective manner. The process is therefore very simple and inexpensive to implement.In particular, existing components of the additive manufacturing device can be advantageously used, so that only the implementation of the process into the control software of the additive manufacturing device is required, which is quick, simple, cost-effective and also possible by way of retrofitting for existing additive manufacturing devices.

[0009] In this context, additive manufacturing refers specifically to the layer-by-layer construction of a component. Specifically, it involves building a component from powder material. In particular, an additive manufacturing device is used that is configured for the layer-by-layer construction of a component from a powder material, especially for carrying out a powder bed-based manufacturing process, preferably an additive manufacturing process selected from the group consisting of selective laser sintering, laser metal fusion (LMF), direct metal laser melting (DMLM), laser net shaping manufacturing (LNSM), and laser engineered net shaping (LENS).

[0010] An optical working beam is understood to be, in particular, directed electromagnetic radiation, continuous or pulsed, which, with regard to its wavelength or a wavelength range, is suitable for the additive manufacturing of a component from powder material, especially for sintering or melting the powder material. In particular, an optical working beam is understood to be a laser beam, which can be generated continuously or in pulses. The optical working beam preferably has a wavelength or a wavelength range in the visible electromagnetic spectrum or in the infrared electromagnetic spectrum, or in the overlap region between the infrared and visible regions of the electromagnetic spectrum.

[0011] The optical beam can be moved throughout the entire work area during the process to capture the whole area. However, it is equally possible to move the optical beam only within a specific section of the work area, i.e., a subsection of the work area to be captured. It is also possible to capture multiple separate sections within the work area individually with the optical beam.

[0012] The reflected light of the optical working beam is detected, in particular, along an optical axis of the optical working beam by arranging a detection device, which is designed to detect the reflected light, on the optical axis.

[0013] Preferably, a beam device configured to generate the optical working beam has a deflecting mirror over which the optical working beam is deflected, wherein the reflectivity of the deflecting mirror is less than 100%, so that a portion of the light remitted along the optical axis passes through the deflecting mirror and falls onto the detection device arranged behind the deflecting mirror.

[0014] Alternatively, it is also possible for the optical working beam to be sent through the deflecting mirror, which then has a transmissivity of less than 100%, in which case the detection device is arranged such that the remitted light is partially deflected by the deflecting mirror and directed to the detection device.

[0015] Furthermore, it is also preferably possible for the optical working beam to pass through an opening of a deflecting mirror, wherein remitted light is at least partially deflected by the surface of the deflecting mirror surrounding the opening and directed to the detection device. In particular, a so-called scraper mirror can be used.

[0016] If the deflecting mirror is configured to deflect the optical working beam and to transmit the reflected light, it preferably has a reflectivity of at least 99% to at most 99.98%. If the deflecting mirror is configured to transmit the optical working beam and to reflect the reflected light, it preferably has a transmissivity of at least 99% to at most 99.98%.

[0017] Alternatively, a polarization beam splitter can be used instead of a deflecting mirror, in which case the optical working beam is preferably linearly polarized. Due to remission, particularly scattering, the polarization is at least partially destroyed, with the polarization direction perpendicular to the incident working beam then containing only the remitted signal. The polarization beam splitter thus preferably reflects the incident light of the optical working beam, which is linearly polarized with a specific polarization direction, and transmits the polarization direction perpendicular to that specific polarization direction – or vice versa.

[0018] In this context, reflected light refers to light that is reflected and / or scattered, particularly from a surface within the work area. Here, "reflection" refers specifically to directional reflection, while "scattering" refers to diffuse reflection, especially as described by Lambert's law.

[0019] The signal values ​​are acquired point-by-point, particularly one-dimensionally, and are location-dependent. Thus, each point of displacement of the optical working beam is preferably assigned exactly one signal value. Such a signal value is, in particular, a brightness value.

[0020] In contrast, a mapping of the work area is understood to be, in particular, a two-dimensional mapping of the work area, especially at least one detection section of the work area. The mapping is obtained, in particular, by being composed of the location-dependent signal values, calculated, or otherwise generated.

[0021] According to a further development of the invention, it is provided that no interference signal is detected. In particular, no interference signals are detected as signal values. The method is therefore very easy to implement; moreover, a simple optical image of the working area is preferably obtained.

[0022] Alternatively or additionally, signal values ​​are preferably recorded that increase with increasing intensity of the reflected light. The signal values ​​are thus directly related to the intensity of the reflected light. This also provides a particularly simple optical representation of the working area, which can be easily evaluated.

[0023] Alternatively or additionally, brightness values, in particular the brightness values ​​of the reflected light, are preferably recorded as signal values. This also represents a particularly simple embodiment of the method, in which, in particular, an easily evaluated optical image of the working area is obtained.

[0024] According to a further development of the invention, the image of the work area is evaluated to detect geometric structures. Thus, a specific evaluation of the image is performed within the method to detect at least one geometric structure in the work area. Particularly preferably, the image is evaluated for edges; in particular, edge detection is preferably applied to the image.

[0025] The positioning accuracy of a typical scanner device of an additive manufacturing system allows the image of the work area to be obtained with a resolution of approximately 40,000 pixels per square millimeter, at a pixel pitch of approximately 5 µm.

[0026] Using suitable algorithms for evaluating the image, edge detection with sub-pixel accuracy can also be performed, so that the accuracy of capturing the work area, in particular the detection of the position of a preform in the work area, can be further increased.

[0027] According to a further development of the invention, the signal value of the reflected light is detected by a photodiode arranged on the optical axis of the optical working beam. This represents a simple and cost-effective way to detect the optical signal values. A silicon photodiode is preferably used. The photodiode can be sensitive in the visible and / or infrared spectral range. Preferably, the sensitivity of the photodiode is matched to the wavelength range of the optical working beam. An infrared photodiode or a pyrometer diode can preferably be used.

[0028] The signal value is preferably acquired with spatial resolution by assigning a photodiode output signal to a momentary state, particularly an internal state, of the scanner device in a time-dependent manner. The acquisition of the signal values, in this case the photodiode output signal, and the displacement of the optical working beam by corresponding control of the scanner device are thus performed synchronously, so that each signal value can be assigned a state of the scanner device and therefore simultaneously a location within the working area. The state of the scanner device is, in particular, the position of at least one movable mirror of the scanner device, especially a galvanometric mirror, which in turn is assigned to a location within the working area toward which the optical working beam is directed. The spatially resolved acquisition of the signal values ​​thus takes place directly within the coordinate system of the scanner device.

[0029] According to a further development of the invention, the resolution of the detection of the working area is set, preferably changed. In particular, the resolution is preferably selected as required. The resolution is most preferably set by shifting the optical working beam in appropriate steps. However, it is also possible to select the resolution by targeted time-dependent evaluation of the detection device, for example, by not continuously capturing the output signal, but rather only at predetermined intervals that are greater than the time interval between two successive output signal values. By adjusting the resolution, it is possible, on the one hand, to provide a high resolution when this is desirable or necessary, and on the other hand, to advantageously reduce the data volume when a lower resolution is sufficient.

[0030] Alternatively or additionally, a detection section of the work area is preferably set, or preferably changed. In particular, the detection section is preferably selected based on requirements. It is also possible to define several separate detection sections. This can again be achieved by shifting the optical beam only within a specific detection section, or by evaluating the output signal of the detection device only within the defined detection section.

[0031] The resolution and / or the detection area can be selected dynamically, preferably via software configuration. In particular, this makes it possible, for example, to perform a powder bed analysis with a higher spatial resolution than a positional analysis of a preform, especially to detect defects in the powder bed, particularly in a newly applied powder layer, more accurately.

[0032] According to a further development of the invention, the position of at least one preform within the working area is determined from the representation of the working area. Here, the position of the preform within the working area is understood to mean, in particular, its position in the coordinate system of the optical working beam, wherein the preform is arranged within the working area. The position of the preform within the working area—especially within the coordinate system of the optical working beam—can be determined with very high accuracy using the method proposed here, so that additively manufactured component sections can be built up on the preform with high accuracy and quality, in particular with extremely low or no offset.

[0033] According to a further development of the invention, the position of the preform is determined based on at least one edge of the preform visible in the illustration. An edge visible in the illustration is understood to be, in particular, a machine-detectable edge, especially using an edge detection algorithm. Such edge detection enables the position of the preform to be determined in a very precise and, at the same time, cost-effective manner. In particular, no additional processing steps or modifications to the preform are required.

[0034] Edge detection is possible, in particular, based on sharp discontinuities in the location-dependent signal values. Specifically, the remission behavior of the preform changes discontinuously at an edge. This also applies when the preform is surrounded by or embedded in powder material, namely the working powder of the additive manufacturing device, provided that a surface of the preform facing the scanner is not covered by powder material. If the optical beam crosses an edge of this surface, the remission behavior changes from strong scattering by the powder material to at least more directional reflection on the surface of the preform – or vice versa.The signal value typically exhibits a higher level, particularly a higher brightness, when the light of the optical working beam is diffusely backscattered, since at least a partially directed reflection is directed away from the optical axis of the optical working beam in a large majority of cases, so that little or no light returns to the detection device.

[0035] A working powder is understood to be a powder material which is used in or by the additive manufacturing device to produce a component from the powder material.

[0036] The process is particularly preferably carried out with a roughened surface of the preform, wherein the surface is particularly preferably sandblasted, corundum-blasted, or glass-bead blasted. In this way, the surface of the preform can be given matte, diffusely scattering optical properties, so that it does not simply appear dark—possibly with individual highlights—in the image of the working area, but rather is clearly visible. If the surface roughness is appropriately adjusted, excellent contrast is still achieved with any powder material that may be arranged in the vicinity of the surface. For example, it may also be possible to increase the signal value from the roughened surface above the level of the signal value of the scattering of the powder material.

[0037] Alternatively or additionally, the position of the preform is preferably determined using at least one marking provided on a surface of the preform. This method also allows for very high accuracy in determining the position of the preform.

[0038] The surface of the preform on which the marking is located faces the scanner device. Specifically, it is the top surface of the preform.

[0039] A marking on a surface of the preform introduces at least one edge, which can then be detected by means of edge detection, especially automatically.

[0040] According to a further development of the invention, at least one notch filled with the working powder is used as a marking on the surface of the preform. The rest of the preform's surface is not coated with working powder, so that – as previously described – a clear difference occurs in the location-dependent signal values, depending on whether the optical beam falls on working powder within the notch or on the essentially directionally reflective surface of the preform outside the notch.

[0041] The width of at least one notch is in particular much smaller than the extent of the notch along its longitudinal direction, i.e., its longest extent.

[0042] Preferably, at least two notches oriented obliquely to each other, preferably perpendicular to each other, in particular in the form of a cross, are used as a marking, with both notches preferably being filled with working powder.

[0043] The position of the preform can also be determined using at least one marking on its surface by observing process luminescence along the optical axis of the optical working beam. This luminescence is caused by the optical working beam on the surface of the preform—and, if applicable, in the notch filled with working powder. The process luminescence is significantly stronger in the area of ​​the powder material than on the powder-free surface of the preform, primarily due to the increased absorption and simultaneously reduced thermal conductivity compared to bare metal.

[0044] Preferably, the process illumination and the corresponding position of the optical working beam are recorded in a measurement map. Preferably, the position and / or intersection points of working powder-filled notches, and thus ultimately the position of the preform in the coordinate system of the working beam, particularly in the coordinate system of the scanner device, are then determined using analysis software.

[0045] The work area is preferably scanned point by point along parallel, offset lines using the optical work beam, in particular by rasterization.

[0046] To detect the position of the preform based on the at least one marking on the surface of the preform, an alternative or additional camera located away from the optical axis, i.e. outside the optical axis of the optical working beam, or a photodiode located outside the optical axis, in particular a pyrometer diode, can be used.

[0047] A preferred embodiment of the method is one in which the imaging of the working area is used for powder bed monitoring, in particular for detecting defects in a newly applied powder layer, for analyzing a molten powder layer, and / or for monitoring a developing, additively manufactured component. It is particularly possible to intercept working area acquisition steps between additive manufacturing steps. Specifically, the optical working beam can be generated with a first optical output power in the additive manufacturing steps, and with a second optical output power in the acquisition steps, which is lower than the first optical output power.

[0048] According to a further development of the invention, the optical beam used to capture the work area is operated with an optical output power that is lower than a lower power limit for the optical output power of the optical beam used in additive manufacturing. This prevents any alteration of the material located in the work area, whether powder material or a preform. The lower power limit is specifically chosen such that material changes, particularly sintering or melting, of the powder material of the additive manufacturing device only occur below or above this lower power limit, thus enabling additive manufacturing with the optical beam. Therefore, the optical output power of the optical beam is preferably chosen to be higher than the lower power limit for additive manufacturing.Thus, an operating mode for capturing the work area on the one hand and an operating mode for additive manufacturing on the other are clearly separated with respect to the selected optical output power of the optical work beam. In this way, simple and / or easy-to-interpret optical images of the unchanged work area, preferably unaffected by the work beam, can be obtained, especially before the actual work process, i.e., the additive manufacturing.

[0049] In particular, the same optical work beam - except, if necessary, for the reduction of the optical output power - is used for both additive manufacturing and for capturing the work area.

[0050] According to a preferred embodiment, the lower power limit is 100 W. For capturing the work area, the optical work beam is preferably operated with an optical output power of at least 1 W to a maximum of 99.9 W, in particular at least 2 W to a maximum of 50 W. For additive manufacturing, the optical work beam is preferably operated with an optical output power of at least 100 W, preferably more than 100 W, and preferably at least 100 W to a maximum of 500 W.

[0051] The problem is ultimately solved by creating a manufacturing device according to claim 10 for the additive manufacturing of a component from a powder material, which has a beam device configured to generate an optical working beam in order to additively manufacture a component from a powder material using the optical working beam. The manufacturing device also has a working area configured for the additive manufacturing of a component from the powder material within the working area. Furthermore, the manufacturing device has a scanner device configured for repositioning the optical working beam within the working area.Furthermore, the manufacturing device includes a detection device configured to detect light reflected along an optical axis of the optical work beam, the detection device being arranged on the optical axis of the optical work beam. Finally, the manufacturing device includes a control device configured to control the scanner device for repositioning the optical work beam within the work area, to acquire location-dependent signal values ​​from the detection device during the repositioning of the optical work beam, to assign a signal value from the detection device to each location of repositioning of the optical work beam within the work area, and to obtain an image of the work area from the location-dependently acquired signal values.In connection with the manufacturing device, the advantages already explained in connection with the process are particularly realized.

[0052] The manufacturing device is particularly designed to carry out a method according to the invention or a method according to one of the embodiments described above.

[0053] In particular, the control device is set up to operate the optical work beam for capturing the work area with an optical output power that is reduced compared to a lower power limit for the optical output power of the optical work beam for additive manufacturing.

[0054] In particular, the additive manufacturing device is set up for the layer-by-layer construction of a component from a powder material, in particular for carrying out a powder bed-based manufacturing process, in particular selected from the group disclosed above in this context.

[0055] In particular, the control device is preferably configured to compose, calculate or otherwise create the representation of the working area from the location-dependent signal values.

[0056] Furthermore, the control device is preferably configured to evaluate the mapping of the work area for the recognition of geometric structures, in particular to perform edge detection.

[0057] According to a further development of the invention, the beam device comprises a laser or is configured as a laser. Alternatively or additionally, the detection device comprises a photodiode or is configured as a photodiode.

[0058] The invention will be explained in more detail below with reference to the drawing. The drawing shows: Figure 1 is a schematic representation of an embodiment of a manufacturing device which is set up to carry out an embodiment of a method for detecting a working area of ​​the manufacturing device, and Figure 2 is a schematic representation of an embodiment of the method for detecting the working area of ​​the manufacturing device in the form of a flowchart.

[0059] Fig. 1 Figure 1 shows a schematic representation of an embodiment of a manufacturing device 1, which is configured for the generative, in particular additive, manufacturing of a component from a powder material. For this purpose, the manufacturing device 1 has a beam device 3, which is configured to generate an optical working beam 5. Using the optical working beam 5, a component can be manufactured generatively, in particular additively, in a working area 7 of the manufacturing device 1, in particular by partially melting or sintering a powder material arranged in the working area 7, which is also referred to as the working powder of the generative manufacturing device 1, by means of the optical working beam 5, in order to build up a component layer by layer generatively, in particular additively, in a manner otherwise known in itself.

[0060] The beam device 3 is in particular designed as a laser, and the optical working beam 5 is preferably a laser beam. This can be generated in pulses or continuously.

[0061] The manufacturing device 1 also includes a scanner device 9, which is configured to reposition the optical work beam 5 within the work area 7. For this purpose, the scanner device 9 preferably includes at least one movable mirror, preferably at least two movable mirrors, in particular galvanometer mirrors, wherein a momentary state of the scanner device 9, that is, in particular, a momentary position of the at least one movable mirror, is assigned to a location 11 in the work area 7 towards which the work beam 5 is momentarily directed. By changing the state of the scanner device 9, that is, by changing the position, in particular of the at least one mirror, the entire work area 7 can preferably be scanned by the optical work beam 5.

[0062] The manufacturing device 1 also includes a detection device 13, which is configured to detect light 15 reflected from the optical working beam 5 along an optical axis A of the optical working beam 5. The detection device 13 is arranged on the optical axis A. An optical axis A of the additive manufacturing device 1 is, in particular, an axis along which the optical working beam 5 extends, at least partially.

[0063] Furthermore, the additive manufacturing device 1 has a control unit 17, which is configured to control the scanner unit 9 for repositioning the optical work beam 5 within the work area 7. For this purpose, the control unit 17 is operatively connected to the scanner unit 9. The control unit 17 is also configured to acquire location-dependent signal values ​​from the detection unit 13 during the repositioning of the optical work beam 5 and to assign a signal value from the detection unit 13 to each location 11 of the repositioning of the optical work beam 5 within the work area 7. The control unit 17 is also configured to obtain a representation of the work area 7 from the location-dependently acquired signal values, in particular to assemble, calculate, or otherwise generate it.

[0064] In this way, it is possible to capture the working area 7 with high accuracy, simply and cost-effectively, and in particular to precisely determine the position of a preform within the working area 7, especially by measuring this position in the coordinate system of the scanner device 9. This eliminates the need to know the precise absolute position of location 11 within the working area 7.

[0065] The manufacturing device 1 here includes a focusing unit 19, in particular a dynamic focusing unit 19, to always focus the optical work beam 5 precisely on the working area 7, regardless of the current state of the scanner device 9. Dynamic focusing is necessary here, in particular, because the distance of the point 11 currently targeted by the optical work beam 5 from the scanner device 9 varies with the current position of this point 11 and thus also with the current state of the scanner device 9. This, in turn, results from the planar geometry of the working area 7 and the way in which the optical work beam 5 is displaced by the scanner device 9, whereby points at a constant distance from the scanner device 9 would be arranged on a hemisphere around the scanner device 9.

[0066] In the beam path of the optical working beam 5, a deflecting mirror 21 is arranged, by which the optical working beam 5 is deflected from the beam device 3 to the scanner device 9, in particular to the focusing unit 19. The deflecting mirror 21 has a reflectivity of less than 100%. Therefore, it is partially transparent to the light 15 reflected along the optical axis A, which at least partially transmits the deflecting mirror 21 along the optical axis A and thus reaches the detection device 13. A converging lens 23 is preferably arranged in the beam path of the reflected light 15 behind the deflecting mirror 21, which focuses the reflected light 15 onto the detection device 13, in particular imaging the location 11 onto the detection device 13.Instead of the deflecting mirror 21, a scraper mirror or a polarization beam splitter can also be used, in the latter case the optical working beam 5 is preferably linearly polarized.

[0067] The detection device 13 is preferably designed as a photodiode, in particular as a silicon photodiode.

[0068] The signal values ​​of the detection device 13 are preferably spatially resolved by the control device 17 by assigning an output signal of the detection device 13 to a synchronous state of the scanner device 9, and thus simultaneously to a momentary location 11 in the working area 7, depending on the time.

[0069] Preferably, no interference signals are recorded as signal values. Alternatively or additionally, signal values ​​that increase with increasing intensity of the reflected light are preferably recorded. Alternatively or additionally, brightness values, in particular brightness values ​​of the reflected light, are preferably recorded as signal values.

[0070] The control device 17 is preferably configured to evaluate the image of the work area 7 for the recognition of geometric structures, in particular by means of edge detection.

[0071] A resolution of the recording and / or a recording section within the working area 7 is / are preferably adjustable, in particular changeable.

[0072] Preferably, the control device 17 determines the position of at least one preform within the working area 7 from the illustration of the working area 7, particularly preferably based on at least one edge of the preform visible in the illustration, and / or based on at least one marking on a surface of the preform. Preferably, at least one notch in the preform filled with the working powder of the additive manufacturing device 1 is used as the marking.

[0073] Fig. 2Figure 1 shows a schematic representation of an embodiment of the method for detecting the working area 7 of the additive manufacturing device 1 in the form of a flowchart. In a first step S1, the optical work beam 5 is moved within the working area 7. In a second step S2, signal values ​​of the light 15 emitted along the optical axis A are detected as a function of location, in particular in the coordinate system of the scanner device 9. In a third step S3, a signal value is assigned to each location 11 of the displacement of the optical work beam 5 within the working area 7, and in a fourth step S4, a representation of the working area 7 is obtained from the location-dependently detected signal values, in particular by being composed, calculated, or otherwise generated.

[0074] In a fifth step S5, the image is preferably evaluated, in particular an automated evaluation using the control unit 17. The image is preferably evaluated for the recognition of geometric structures, especially using an edge detection algorithm. Particularly preferably, the position of at least one preform in the working area 7 is determined based on the image. However, it is also possible that the image is used for powder bed monitoring, for the analysis of a molten powder layer, and / or for monitoring a developing, additively manufactured component.

[0075] Preferably, during the acquisition of the optical working area 7, the optical output power of the optical working beam 5 is reduced compared to the optical output power of the working beam 5 during additive manufacturing.

Claims

1. A method for the detecting of a working area (7) of a generative manufacturing device (1), comprising the following steps: - scanning an optical working beam (5) of the generative manufacturing device (1) in the working area (7); - detecting, as a function of location, signal values of light (15) of the optical working beam (5), the light remitted along an optical axis (A) of the optical working beam (5), wherein a signal value is assigned to each location (11) of the scan of the optical working beam (5) in the working area (7), and - obtaining an image of the working area (7) from the signal values detected as a function of location, characterized in that - the optical working beam (5) for the detecting of the working area (7) is operated at an optical output power that is reduced compared to a lower power limit for the optical output power of the optical working beam (5) for the generative manufacturing.

2. The method according to claim 1, characterized in that the generative manufacturing device (1) is configured for the building up of a component layer-by-layer from a powder material, in particular for the carrying out of a powder bed-based manufacturing process.

3. The method according to any one of the preceding claims, characterized in that a) no interference signal is detected; and / or b) signal values are detected which increase with increasing intensity of the remitted light (15); and / or c) brightness values are detected as signal values.

4. The method according to any one of the preceding claims, characterized in that the image of the working area (7) is evaluated for purposes of recognizing geometric structures.

5. The method according to any one of the preceding claims, characterized in that the signal value of the remitted light (15) is detected by a photodiode arranged on the optical axis (A) of the optical working beam (5), wherein the signal value is detected in a spatially resolved manner in that an output signal of the photodiode is assigned as a function of time to a synchronous state of a scanner apparatus (9) for the scanning of the optical working beam (5).

6. The method according to any one of the preceding claims, characterized in that a resolution of the detection and / or a detection section of the working area (7) is / are adjusted.

7. The method according to any one of the preceding claims, characterized in that a position of at least one preform within the working area (7) is determined from the image of the working area (7).

8. The method according to any one of the preceding claims, characterized in that the position of the preform is determined based on a) at least one edge of the preform recognizable in the image, and / or b) at least one marking on a surface of the preform.

9. The method according to any one of the preceding claims, characterized in that at least one preform notch filled with a working powder of the generative manufacturing device (1) is used as a marking on the surface of the preform.

10. A manufacturing device for the generative manufacturing of a component from a powder material, comprising - a beam apparatus (3) configured for the generating of an optical working beam (5) in order to generatively manufacture a component from a powder material by means of the optical working beam (5), - a working area (7) configured for the generative manufacturing of a component from the powder material in the working area (7), - a scanner apparatus (9) configured for the scanning of the optical working beam (5) in the working area (7), - a detection apparatus (13) configured for the detecting of light (15) of the optical working beam (5) which is remitted along an optical axis (A) of the optical working beam (5), wherein - the detection apparatus (13) is arranged on an optical axis (A) of the optical working beam (5), and comprising - a control apparatus (17) configured in order to control the scanner apparatus (9) for the scanning of the optical working beam (5) in the working area (7) to detect, as a function of location, signal values of the detection apparatus (13) during the scanning of the optical working beam (5), to assign a signal value of the detection apparatus (13) to each scanning location (11) of the optical working beam (5) in the working area (7), and to obtain an image of the working area (7) from the signal values detected as a function of location, characterized in that - the control apparatus (17) is configured in order to operate the optical working beam (5) for the detecting of the working area (7) at an optical output power that is reduced compared to a lower power limit for the optical output power of the optical working beam (5) for the generative manufacturing.

11. The manufacturing device (1) according to claim 10, characterized in that the beam apparatus (3) has a laser or is designed as a laser, and / or that the detection apparatus (13) has a photodiode or is designed as a photodiode.