DE102022111558A1 - Method for calibrating a generative manufacturing device, manufacturing device for the generative manufacturing of a component from a powder material and computer program for carrying out such a method - Google Patents

Abstract

The invention relates to a method for calibrating a generative manufacturing device (1), with the following steps: - Displacing an optical working beam (5) of the generative manufacturing device (1) over at least two spaced-apart probing areas (27) of a working field (7), in which one a construction platform (9) adjustable with respect to at least one coordinate is arranged, the probing areas (27) being selected such that a contour section (29) of the building platform (9) is expected in each of the probing areas (27); - detecting signal values from the scanning areas (27) remitted light (15) of the optical working beam (5); - deriving a position of the building platform (9) with respect to the at least one coordinate from the recorded signal values, and - calibrating the manufacturing device (1) based on the derived position of the building platform (9).

Description

The invention relates to a method for calibrating a generative manufacturing device, a manufacturing device for the generative manufacturing of a component from a powder material and a computer program for carrying out such a method.

In order to equip a generative manufacturing device for the generative manufacturing of a component from a powder material, a construction platform is arranged in the generative manufacturing device. In order to ensure a good connection of the generatively manufactured components to a work surface of the construction platform and/or preforms possibly arranged on the work surface, it is essential that the construction platform is correctly oriented relative to a coordinate system of the generative manufacturing device, in particular with regard to a height coordinate and/or at least one angular coordinate. In particular, the working surface of the building platform should be aligned parallel and at a predetermined height relative to an imaginary building plane in which the powder material is exposed to an optical working beam in order to produce a component generatively. In particular, it is possible for the imaginary construction level to be arranged above a target level by a predetermined application layer thickness for the powder material - in particular 1 mm above a highest position of a chamber floor of the production device - with the working surface of the construction platform at least initially when setting up the production device in particular at the level of the chamber floor and parallel to it and should therefore be arranged in the target plane and aligned parallel to it.

After the construction platform has been installed, its position in the manufacturing device is initially undetermined. Manual measurement and alignment of the construction platform is very time-consuming and labor-intensive. An optical measurement using a 2D or even 3D camera requires high computing power.

The invention is therefore based on the object of creating a method for calibrating a generative manufacturing device, a manufacturing device for the generative manufacturing of a component from a powder material and a computer program for carrying out such a method, the disadvantages mentioned being at least reduced, preferably avoided.

The object is achieved 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.

The object is achieved in particular by creating a method for calibrating a generative manufacturing device with the following steps: an optical working beam of the generative manufacturing device is shifted over at least two spaced-apart probing areas of a working field in which a construction platform that is adjustable with respect to at least one coordinate is arranged, wherein the probing areas are selected such that a contour section of the building platform is expected in each of the probing areas. Signal values of light of the optical working beam remitted from the scanning areas are recorded. A position of the building platform with respect to the at least one coordinate is derived from the detected signal values, and the manufacturing device is calibrated based on the derived position of the building platform. Advantageously, using the method proposed here, a position of the construction platform in the manufacturing device can be derived automatically, that is, in particular without a lot of work and time, and at the same time with comparatively low computing power, and the manufacturing device can be calibrated based on the derived position. By recording the signal values of the light remitted from the scanning areas, comparatively small amounts of data are generated, and the information obtained in this way can be evaluated quickly and easily. In particular, the method does not rely on two- or even three-dimensional image data, and no image evaluation is required. In particular, the method proposed here can be implemented with elements already present in the manufacturing device, so that no additional components are required. Furthermore, a sufficiently high resolution would be necessary for the aforementioned two- or three-dimensional image data, which may not be able to be achieved with every camera, whereas the optical working beam can easily be adjusted with the appropriate precision using the elements that are already present. Furthermore, the calibration can advantageously be carried out during the setup of a process environment, that is to say in particular during the generation of a protective gas atmosphere and/or a defined flow of a gas intended for the removal of particles, smoke and smoke generated during production.

In particular, the signal values of the remitted light change - in particular discontinuously or abruptly - when the optical working beam hits a contour section of the build platform in a probing area. Therefore, the position of the contour sections can be determined from the recorded signal values This ultimately allows conclusions to be drawn about the position of the construction platform.

In the context of the present technical teaching, the working field is understood to mean, in particular, an area of the manufacturing device in which the construction platform is arranged as intended, the working field being at least slightly larger than the construction platform, so that contour sections of the construction platform, i.e. outer borders or boundaries of the construction platform, lie in the work area. The working field preferably extends beyond the building platform on all sides, so that all contour sections of the building platform lie within the working field.

The probing areas are chosen within the working field in particular so that a contour section of the building platform is expected in each of the probing areas, that is to say that a part of the outer border or boundary of the building platform is arranged in each of the probing areas if the building platform is not too large Deviation from its intended position is arranged in the manufacturing device. Typically, however, it can be assumed without limiting the generality that a deviation of the construction platform from its intended position is small, in particular a height deviation being at most a few millimeters, in particular at most 5 mm, or at most 4 mm, or at most 3 mm, or at most 2 mm , or at most 1 mm, whereby an angular deviation is at most a few degrees, in particular at most 5°, or at most 4°, or at most 3°, or at most 2°, or at most 1°. In particular, the probing areas are selected so that, under these conditions, a contour section is arranged in each of the probing areas when the building platform is arranged in the manufacturing device.

In particular, the probing areas are arranged on sides facing away from one another, in particular on - in particular diametrically - opposite ends of the construction platform. In this way, the position of the construction platform can be determined particularly precisely.

It is possible for the optical working beam to be displaced - in particular diametrically - from a first probing area of the probing areas across the entire construction platform to a second probing area of the probing areas. Alternatively, it is possible that the optical working beam is only shifted in the probing areas, whereby it jumps virtually discontinuously from one probing area to the next probing area. This means in particular that the construction platform between the probing areas is not subjected to the optical work bearing.

Additive or generative manufacturing or manufacturing of a component is understood to mean, in particular, a powder bed-based method for producing a component, in particular a manufacturing method that is selected from a group consisting of selective laser sintering, laser metal fusion - LMF), a direct metal laser melting (DMLM), a laser net shaping manufacturing (LNSM), and a laser engineered net shaping (LENS). The manufacturing device is therefore in particular set up to carry out at least one of the aforementioned additive or generative manufacturing processes.

In the context of the present technical teaching, an optical working beam is to be understood in particular as directed electromagnetic radiation, continuous or pulsed, which is suitable, in particular with regard to its wavelength or a wavelength range, for the generative manufacturing of a component from powder material, in particular for sintering or melting the powder material . The optical working beam is in particular a laser beam. In particular, the optical working beam is designed as a continuous or pulsed laser beam. 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 region and the visible region of the electromagnetic spectrum.

In the context of the present technical teaching, remitted light is understood to mean, in particular, light which is reflected and/or scattered - in particular by the work surface of the construction platform. Here, “reflection” in the narrower sense is understood to mean directed reflection, while “scattering” is understood to mean diffuse reflection, in particular according to Lambert's law. The construction platform typically has a milled surface that is sufficiently rough to cause, in particular, a diffuse reflection of the optical working beam. This does not require any special processing of the construction platform. However, it is possible for the construction platform to be roughened or roughly ground, particularly in the area of its working surface, in order to increase the diffuse reflectivity, in particular for a higher sensitivity of the method proposed here.

In particular, the working jet is not, or at least hardly, in the area of a gap between the chamber floor and the building platform reflected, so that the detected signal values increase suddenly when the working beam in a probing area, starting from the gap, hits a contour section of the build platform, or conversely, drop suddenly when the working beam enters the gap in a probing area starting from a contour section of the build platform. In particular, a contrast is recorded between the reflectivity of the construction platform and the reflectivity in the area of the gap.

Alternatively or additionally, the construction platform can have a reflectivity that is different from a reflectivity of the chamber floor of the manufacturing device. In particular, it is possible for the building platform to have a higher roughness than the chamber floor, so that more light is remitted in the area of the building platform than in the area of the chamber floor. In particular, it is possible for the chamber floor to be ground smooth, while the construction platform is comparatively rough, or roughly polished, or otherwise specially roughened due to the production by milling.

According to a further development of the invention, it is provided that the signal values are recorded depending on the location. In this way, very precise information about the position of the construction platform can be derived directly from the measured signal values.

In particular, in one embodiment, the signal values are recorded depending on a functional position of a scanner device set up to shift the optical working beam. The respective functional position of the scanner device is clearly assigned to a respective position in the working field - in particular via calibration. In particular, the functional position of the scanner device can be an angular position of a deflection element, in particular a pivotable mirror, provided for displacing the optical working beam in the working field.

Alternatively or additionally, the signal values are recorded as a function of time. This represents a particularly simple and less computationally intensive embodiment of the method. In particular, with this embodiment there is no mandatory need to resort to calibrating the scanner device.

The signal values are recorded in particular point by point, in particular one-dimensionally, depending on location and/or time. Each location and/or each point in time of the displacement of the optical working beam is therefore preferably assigned exactly one signal value. Such a signal value is in particular a brightness value.

The signal values of the remitted light are detected in particular by a detection device, in particular a photodiode. This represents a simple and cost-effective way to record the optical signal values. In particular, a silicon photodiode is used as the photodiode. It is possible that the photodiode is sensitive in the visible and/or infrared spectral range. In particular, the sensitivity of the photodiode is tailored to the wavelength range of the optical working beam. In one embodiment, an infrared photodiode or a pyrometer diode may be used.

The signal values are in particular recorded in a spatially resolved manner by assigning an output signal of the photodiode to a current functional position of the scanner device as a function of time. The detection of the signal values, here the output signal of the photodiode, and the displacement of the optical working beam by appropriate control of the scanner device are carried out in particular synchronously, so that each signal value can be assigned a functional position of the scanner device and thus at the same time a location in the working field. The functional position of the scanner device is - as already stated - in particular a position of at least one deflection element, in particular a movable mirror of the scanner device, in particular a galvanometric mirror, which in turn is assigned to a location in the working field to which the optical working beam is directed. The spatially resolved detection of the signal values thus takes place directly in the coordinate system of the scanner device.

According to a further development of the invention, it is provided that - as the signal values - signal values of light remitted from the scanning areas along an optical axis of the optical working beam are detected. The remitted light of the optical working beam is detected in particular along the optical axis of the optical working beam by arranging the detection device, which is set up to detect the remitted light, on the optical axis.

For this purpose, a beam device which is set up to generate the optical working beam preferably has a deflecting mirror via which the optical working beam is deflected, the reflectivity of the deflecting mirror being less than 100%, so that a proportion of the light remitted along the optical axis is reflected by the Deflecting mirror passes through and falls onto the detection device arranged behind the deflecting mirror. Alternatively, it is also possible for the optical working beam to be sent through the deflection 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 deflection mirror and directed to the detection device.

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

If the deflection mirror is set up to deflect the optical working beam and to transmit the remitted light, it preferably has a reflectivity of at least 99% to at most 99.98%. If the deflection mirror is set up to transmit the optical working beam and to reflect the remitted light, it preferably has a transmissivity of at least 99% to at most 99.98%.

Alternatively, it is also possible to use a polarization beam splitter instead of the deflection mirror, in which case the optical working beam is preferably linearly polarized. The polarization is at least partially destroyed by the remission, in particular scattering, in which case the polarization direction perpendicular to the incident working beam only contains the remitted signal. The polarization beam splitter thus preferably reflects the incident light of the optical working beam that is linearly polarized with a specific polarization direction and transmits the polarization direction perpendicular to the specific polarization direction - or vice versa.

In one embodiment, the remitted light of the optical working beam is detected by a separate detection device. In particular, in this case, each beam device or each optical working beam is assigned a separate detection device, so that it can always be clearly determined from which location in the working field remitted light is detected by which optical working beam. However, it is also possible for remitted light of a first optical working beam to be detected on the optical axis of the first working beam, with remitted light of a second optical working beam being detected by a separate detection device assigned to the second optical working beam. If a separate detection device is assigned to an optical working beam, in particular, on the one hand, a deflection element for displacing the optical working beam and, on the other hand, a deflection element of the separate detection device are controlled synchronously, so that remitted light can be detected by the detection device at any time from exactly the location at which the assigned one optical working beam is currently aligned.

According to a further development of the invention, it is provided that a position of the contour sections of the building platform in the probing areas is recognized based on the detected signal values, the position of the building platform with respect to the at least one coordinate being derived from the recognized position of the contour sections in the probing areas. In this way, very precise information about the position of the construction platform can advantageously be derived directly. In particular, the position of the contour sections can be recognized based on the detected signal values if the signal values are detected as a function of location, or if signal values detected as a function of time are transformed or converted into location-dependent signal values.

Alternatively or additionally, an apparent geometric property of the construction platform is determined from the recorded signal values, the position of the construction platform with respect to the at least one coordinate being derived from the apparent geometric property of the construction platform. This represents a particularly simple and less computationally intensive design.

In one embodiment, an apparent diameter of the construction platform is determined as the apparent geometric property. In particular, if the optical working beam is shifted continuously - in particular diametrically - over the entire construction platform to a second scanning area from a first scanning area, an apparent diameter can be obtained from the time-dependent signal values, taking into account a known - in the simplest case, constant - displacement speed of the optical working beam Construction platform can be determined. In this case, when a first contour section is reached in the first probing area, a level of the detected signal values increases, in particular discontinuously or abruptly, while the level drops, in particular discontinuously or abruptly, when a second contour section is reached in the second probing area. The apparent diameter can be determined from the time difference between the unsteady rise and the unsteady fall of the level, taking into account the displacement speed of the optical working beam.

In particular, the position of the construction platform with respect to the at least one coordinate is derived based on a comparison of the apparent geometric property with an associated known geometric property of the construction platform. In particular, an actual diameter of the construction platform is used as the known geometric property of the construction platform.

By comparing the apparent diameter with the actual diameter, conclusions can be drawn about the position of the construction platform. In particular, the apparent diameter is smaller than the actual diameter if the build platform is too deep relative to the build plane and is therefore further away from the scanner device or is tilted, while the apparent diameter is larger than the actual diameter if the build platform is positioned relative to the Construction level is too high and therefore closer to the scanner device.

In particular, if the tilting of the construction platform is determined separately, in particular in a manner explained in more detail below, the exact height of the construction platform can be determined from the comparison of the apparent diameter with the actual diameter, taking the tilting into account.

According to a further development of the invention, it is provided that a plurality of optical working beams are displaced over at least one scanning area of the at least two scanning areas, with signal values of light remitted from the at least one scanning area being recorded for each working beam of the plurality of working beams, and the position of the Construction platform is derived with respect to the at least one coordinate from the signal values assigned to the working beams. In this way, particularly precise information about the position of the construction platform can be obtained, both with regard to the height coordinate and with regard to the at least one angular coordinate.

In particular, the optical working beams are shifted synchronously. In the context of the present technical teaching, the fact that the optical working beams are displaced synchronously is understood in particular to mean that the optical working beams are aligned with a respective common point in the target plane for the arrangement of the working surface of the construction level at each time of the displacement, whereby the common point in the work area is relocated. The target plane is oriented parallel to the construction level and in particular is arranged offset downwards from the construction level by the predetermined application layer thickness for the powder material. If the work surface of the construction platform is arranged in the target plane and parallel to it, the optical working beams meet at a point on the work surface at every point in time during their displacement, and the remitted light from the optical working beams comes from the same common point at every point in time and is therefore also detected synchronously.

If the work surface of the construction platform is arranged above or below the target level, the optical working beams no longer meet at a common point, and the remitted light is emitted from different points on the work surface at each point in time of the displacement, with the different optical working beams being assigned remitted light is also not detected synchronously, at least in the area of the contour sections.

The optical working beams are emitted onto the construction platform from different directions, i.e. they fall onto the work surface at different angles. In particular, the scanner devices assigned to the different optical working beams are arranged at different locations.

If the construction platform is tilted, the positions of the optical working beams on the work surface change relative to one another as they move across the work surface. This is particularly true if the construction platform is tilted in such a way that the first probing area is arranged below the target plane and the second probing area is arranged above the target plane - or vice versa.

According to a further development of the invention, it is provided that the position of the construction platform with respect to the at least one coordinate is derived from a local and/or temporal offset between signal values that are assigned to different working beams of the plurality of working beams. Due to the previously explained relationships regarding the arrangement of the optical working beams on the work surface, the position of the construction platform can be deduced from the local and/or temporal offset between signal values assigned to different working beams.

Alternatively or additionally, it is provided that the position of the construction platform with respect to the at least one coordinate is derived from a difference in the local and/or temporal offset of the signal values assigned to the various working beams between the at least two probing areas. The majority of working beams are shifted over the at least two scanning areas. In particular, each of the working beams for which signal values are processed in the embodiment described here is shifted over the at least two scanning areas, that is to say in particular over all scanning areas considered here, in particular from a first one Probing area - in particular diametrically - over the entire construction platform up to a second probing area. Again, based on the previously explained relationships regarding the arrangement of the optical working beams on the work surface, the position of the construction platform can be deduced from the difference in the local and/or temporal offset of the different working beams.

According to a further development of the invention, it is provided that the position of the construction platform with respect to the at least one coordinate is derived from sudden changes in the detected signal values. As already stated, there is a sudden, in particular discontinuous change in the detected signal values, particularly when a contour section is reached in a probing area, from which conclusions can be drawn about the position of the construction platform.

According to a further development of the invention, it is provided that the manufacturing device is calibrated by correcting an expected position of the building platform with respect to the at least one coordinate based on the derived position of the building platform. In this case, the calibration can advantageously be carried out purely mathematically, and an actual correction of the position of the construction platform is not necessarily required.

Alternatively or additionally, an instruction is issued to an operator of the manufacturing device to correct the position of the construction platform. The instructions particularly include information on how to correct the position of the construction platform. The operator can then manually correct the position of the build platform.

Alternatively, the manufacturing device is calibrated by correcting an actual position of the construction platform in the manufacturing device based on the derived position, in particular based on a deviation of the derived position from the expected position. In this case, the position of the construction platform is advantageously corrected. In one embodiment, the position of the building platform is corrected manually. In another embodiment, the position of the construction platform is automatically corrected.

According to a further development of the invention, it is provided that the position of the construction platform is derived with respect to a height coordinate and/or an angular coordinate as the at least one coordinate. The at least one coordinate is therefore in particular selected from a group consisting of a height coordinate, an angular coordinate, and a combination of a height coordinate and an angular coordinate.

The object is also achieved by creating a manufacturing device for the generative manufacturing of a component from a powder material, which has a blasting device, the blasting device being set up to generate an optical working beam in order to produce a component generatively from a powder material by means of the optical working beam. The manufacturing device also has a construction platform that can be adjusted with respect to at least one coordinate and can be arranged in a working field of the manufacturing device, which is set up to produce a component generatively from the powder material on the construction platform, and also a scanner device that is set up to relocate the optical working beam the working field, a detection device which is set up to detect remitted light of the optical working beam, and finally a control device which is set up to control the scanner device for moving the optical working beam in order to obtain signal values of the detection device during the displacement of the optical working beam - in particular locally - and / or time-dependent - and to derive a position of the construction platform with respect to the at least one coordinate from the recorded signal values. In connection with the manufacturing device, there are in particular the advantages that have already been explained previously in connection with the method.

In one embodiment, the manufacturing device has a plurality of beam devices for generating a plurality of optical working beams, or the beam device is set up to generate a plurality of optical working beams.

The scanner device preferably has at least one scanner, in particular a galvanometer scanner, piezo scanner, polygon scanner, MEMS scanner, and/or a working head or processing head that can be displaced relative to the working field.

A working head or processing head that can be displaced relative to the working field is understood here in particular to mean an integrated component of the manufacturing device, which has at least one radiation outlet for at least one optical working beam, the integrated component, that is to say the working head, as a whole along at least one direction of displacement, preferably along two perpendicular displacement directions, can be displaced relative to the working field. Such a working head can in particular be designed in a portal design or be guided by a robot. In particular, the working head can be designed as a robot hand of a robot.

The scanner device, in particular a deflection element of the scanner device, is arranged off-center, in particular with respect to the working field, in particular with respect to a correct installation position of the construction platform. If the manufacturing device has a plurality of scanner devices, in particular a plurality of deflection elements assigned to different optical working beams, in particular all deflection elements are each arranged off-center. The scanner devices of the plurality of scanner devices, in particular the deflection elements of the plurality of deflection elements, are not arranged on a common straight line parallel to the construction plane, in particular they are not arranged on any common straight line.

In an embodiment in which the manufacturing device has a plurality of optical working beams, a scanner device is preferably assigned to each optical working beam. In particular, the manufacturing device has a plurality of scanner devices for displacing a plurality of optical working beams.

The manufacturing device is in particular set up for selective laser sintering. Alternatively or additionally, the manufacturing device is set up for selective laser melting.

A metallic or ceramic powder in particular can preferably be used as the powder material.

The beam device is designed in particular as a laser. The energy beam is thus advantageously generated as an intensive beam of coherent electromagnetic radiation, in particular coherent light.

The control device is preferably selected from a group consisting of a computer, in particular a personal computer (PC), a plug-in card or control card, and an FPGA board. In a preferred embodiment, the control device is an RTC5 or RTC6 control card from SCANLAB GmbH, in particular in the embodiment currently available on the date determining the seniority of the present property right.

The detection device in particular has a photodiode or is designed as a photodiode.

According to a further development of the invention, it is provided that the control device is set up to carry out a method according to the invention or a method according to one or more of the previously described embodiments.

In particular, the control device is set up to correct an expected position of the construction platform with respect to the at least one coordinate based on the derived position of the construction platform - in particular purely mathematically. In this case, the calibration can advantageously be carried out purely mathematically, and an actual correction of the position of the construction platform is not necessarily required. Alternatively or additionally, the control device is set up to issue an instruction to an operator of the manufacturing device to correct the position of the construction platform, the instruction in particular comprising information on how the position of the construction platform is to be corrected. The operator can then manually correct the position of the build platform.

According to a further development of the invention, it is provided that the manufacturing device has an adjusting device which is set up to adjust the construction platform with respect to the at least one coordinate, the control device being operatively connected to the adjusting device and set up to control the adjusting device. In particular, the control device is set up to correct an actual position of the construction platform in the manufacturing device based on the derived position, in particular based on a deviation of the derived position from the expected position, in particular by suitable control of the adjusting device.

In particular, the control device is set up to control the adjustment device directly depending on the detected signal values or depending on the position of the construction platform derived from the detected signal values. Alternatively or additionally, the control device is in particular set up to control the adjustment device depending on the derived position, in particular depending on the deviation of the derived position from the expected position, in order to correct the actual position of the construction platform in the manufacturing device - in particular automatically.

According to a further development of the invention, it is provided that the detection device is set up to detect light of the optical working beam remitted along an optical axis of the optical working beam.

According to a further development of the invention it is provided that the detection device is arranged on an optical axis of the optical working beam. It is also possible for at least one optical working beam to have a separate one Detection device is assigned. In particular, it is possible for a separate detection device to be assigned to a first working beam of a plurality of working beams, with a detection device assigned to the second optical working beam being arranged on the optical axis of a second optical working beam of the plurality of optical working beams. If a separate detection device is assigned to an optical working beam, the control device is in particular set up to synchronously control the scanner device assigned to the optical working beam and, on the other hand, a deflection element of the separate detection device, so that remitted light from exactly the location can be detected by the detection device at any time which the assigned optical working beam is currently aligned.

In particular, the manufacturing device has at least one feature that was previously explained explicitly or implicitly for the manufacturing device in connection with the method.

The object is finally also solved by creating a computer program that has machine-readable instructions, based on which a method according to the invention or a method according to one or more of the previously described embodiments is carried out when the computer program is on a computing device, in particular the control device of a manufacturing device according to the invention or a manufacturing device according to one or more of the previously described embodiments. In connection with the computer program, there are in particular the advantages that have already been explained previously in connection with the method or the manufacturing device.

• 1 eine schematische Darstellung eines Ausführungsbeispiels einer generativen Fertigungsvorrichtung;
• 2 eine schematische Darstellung einer ersten Ausführungsform eines Verfahrens zum Kalibrieren der generativen Fertigungsvorrichtung, und
• 3 eine schematische Darstellung einer zweiten Ausführungsform des Verfahrens zum Kalibrieren der generativen Fertigungsvorrichtung.

The invention is explained in more detail below with reference to the drawing. Show:

• 1 a schematic representation of an exemplary embodiment of a generative manufacturing device;
• 2 a schematic representation of a first embodiment of a method for calibrating the generative manufacturing device, and
• 3 a schematic representation of a second embodiment of the method for calibrating the generative manufacturing device.

1 shows a schematic representation of an exemplary embodiment of a generative manufacturing device 1.

The manufacturing device 1 for the generative manufacturing of a component from a powder material has at least one jet device 3, which is set up to generate an optical working beam 5 in order to generatively manufacture a component from a powder material by means of the optical working beam 5.

The manufacturing device 1 also has a construction platform 9 that can be adjusted with respect to at least one coordinate and can be arranged in a working field 7 of the manufacturing device 1, which is set up so that a component can be manufactured generatively from the powder material on the construction platform 9.

In addition, the manufacturing device 1 has at least one scanner device 11, which is set up to relocate the at least one optical working beam 5 in the working field 7.

Furthermore, the manufacturing device 1 has a detection device 13, which is set up to detect light 15 of the optical working beam 5 remitted in particular along an optical axis A of the optical working beam 5. In particular, the detection device 13 is arranged on the optical axis A.

Finally, the manufacturing device 1 has a control device 17, which is set up to control the scanner device 11 for displacing the optical working beam 5 in order to detect signal values of the detection device 13 during the displacement of the optical working beam 5 - in particular depending on location and / or time, and to derive a position of the construction platform 9 with respect to the at least one coordinate from the recorded signal values.

In the exemplary embodiment shown here, the manufacturing device 1 in particular has a focusing unit 19, in particular a dynamic focusing unit 19, in order to always focus the optical working beam 5 precisely on the working field 7, in particular the construction platform 9, regardless of a current functional position of the scanner device 9. This requires dynamic focusing, in particular because the distance of a location 20 currently targeted by the optical working beam 5 from the scanner device 9 varies with the current position of this location 20 and thus also with the current functional position of the scanner device 9. This in turn results from the flat geometry of the working field 7, at least in the perfectly aligned state of the construction platform 9, and the type of displacement of the optical working beam 5 by the scanner device 9, with locations at a constant distance from the scanner device 9 on a Hemisphere would be arranged around the scanner device 9.

A deflection mirror 21 is arranged in the beam path of the optical working beam 5, through which the optical working beam 5 is deflected from the beam device 3 to the scanner device 11. The deflection mirror 21 has a reflectivity that is less than 100%. Therefore, it is partially transparent for the light 15 remitted along the optical axis A, which is at least partially transmitted through the deflection mirror 21 along the optical axis A and thus reaches the detection device 13. In this case, a converging lens 23 is preferably arranged in the beam path of the remitted light 15 behind the deflection mirror 21, which focuses the remitted light 15 onto the detection device 13, in particular images the location 20 onto the detection device 13. Instead of the deflection 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.

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

In particular, the manufacturing device 1 has an adjusting device 25, which is set up to adjust the construction platform 9 with respect to the at least one coordinate. The control device 17 is operatively connected to the adjusting device 25 and is set up to control the adjusting device 25 in particular as a function of the position of the building platform 9 derived from the detected signal values, in particular in order to determine an actual position of the building platform 9 in the manufacturing device 1 based on the derived position, in particular based on a deviation of the derived position from an expected position.

The control device 17 is in particular set up to carry out a method for calibrating the manufacturing device 1, which is explained in more detail below.

2 shows a schematic representation of a first embodiment of a method for calibrating the generative manufacturing device 1.

Identical and functionally identical elements are provided with the same reference numbers in all figures, so that reference is made to the previous description.

As part of the method for calibrating the generative manufacturing device 1, the optical working beam 5 is displaced over at least two probing areas 27 of the working field 7 that are spaced apart from one another. The probing areas 27 are chosen so that a contour section 29 of the building platform 9 is expected in each of the probing areas 27. Signal values of the light 15 remitted from the scanning areas 27 are recorded. A position of the building platform 9 with respect to the at least one coordinate is derived from the detected signal values, and the manufacturing device 1 is calibrated based on the derived position of the building platform 9. In particular, a first probing area 27.1 with a first contour section 29.1 and a second probing area 27.2 with a second contour section 29.2 are shown here.

Symbolically - with a small circle - the optical working beam 5 is also shown on the working field 7 for each of the probing areas 27, in particular as it appears at the level of a work surface 33 of the construction platform 9.

In an exemplary embodiment of the method, not shown here, it is provided that the signal values are recorded depending on the location. In particular, the signal values in this case are recorded depending on the functional position of the scanner device 11.

In the exemplary embodiment of the method shown here, the signal values are recorded as a function of time.

It is possible for a position of the contour sections 29 of the build platform 9 in the probing areas 27 to be recognized directly based on the detected signal values, the position of the build platform 9 with respect to the at least one coordinate being derived from the recognized position of the contour sections 29 in the probing areas 27.

At the in 2 In the initial example of the method shown, an apparent geometric property, in particular an apparent diameter of the construction platform 9, is determined from the recorded signal values, the position of the construction platform 9 with respect to the at least one coordinate being determined from the apparent geometric property of the construction platform 9, in particular based on a comparison of the apparent geometric ones Property is derived with an associated known geometric property of the construction platform 9, in particular its actual diameter.

In particular, the position of the construction platform 9 with respect to the at least one coordinate is derived from sudden changes in the detected signal values.

In 2 A diagram is also shown in which the time-dependent signal values are plotted as voltage values V recorded at the detection device 13 as a function of the time t. Alternatively or additionally, current values can also be detected on the detection device 13, in particular an irradiation-dependent current of the detection device 13 designed as a photodiode. In particular, a contrast between the construction platform 9 and a gap 37 between a chamber floor 35 of the manufacturing device 1 surrounding the construction platform 9 on the one hand and the construction platform 9 on the other hand. Alternatively, it is assumed in particular that the work surface 33 scatters much more diffusely than the chamber floor 35.

The working beam 5 is shifted, in particular, starting from the first probing area 27.1 diametrically across the working surface 33 of the construction platform 9 into the second probing area 27.2. At a first time t _{1 ,} the working beam 5 reaches the first contour section 29.1 of the construction platform 9, and the voltage V detected in the detection device 13 increases suddenly. During the displacement of the working beam 5 over the working surface 33, the detected voltage V remains constant. At a second time t _2, the working beam 5 sweeps over the second contour section 29.2, and the detected voltage V drops suddenly. The abrupt or discontinuous rise and the abrupt or discontinuous fall of the voltage V can be recognized in the control device 17 and the first time t ₁ and the second time t ₂ can be determined from this. Knowing the preferably constant displacement speed of the working beam 5, the displacement distance of the working beam 5 over the work surface 33 can be calculated from the difference between the two times t ₁ , t ₂ and the apparent diameter of the construction platform 9 can thus be obtained. This is now compared with the known, actual diameter of the construction platform 9. Assuming that the building platform 9 is arranged horizontally in the correct angular orientation, the following applies: If the apparent diameter corresponds to the actual diameter, the building platform 9 is arranged at the correct installation height aligned with the chamber floor 35. If the apparent diameter is smaller than the actual diameter, the building platform 9 is arranged too deep, below the chamber floor 35; If, on the other hand, the apparent diameter is larger than the actual diameter, the building platform 9 is too high and is arranged above the chamber floor 35. In particular, the difference between the apparent diameter and the actual diameter can also be used to determine the - in particular absolute - deviation from the correct installation position.

The same picture results if the construction platform 9 is installed at the correct height if a plurality of optical working beams 5 are used instead of one optical working beam 5, the working beams 5 being aligned with a common point on the work surface 33 at any time of their displacement. In particular, the remitted light 15 is detected for each optical working beam 5 in a separately assigned detection device 13 arranged on the respective optical axis, so that the same thing is detected for each optical working beam 5 2 schematically illustrated diagram for the voltage curve of the recorded signal values is obtained.

3 shows a schematic representation of a second embodiment of the method for calibrating the generative manufacturing device 1.

Here, in particular, the use of three optical working beams 5, namely a first optical working beam 5.1, a second optical working beam 5.2 and a third optical working beam 5.3, is shown.

In particular, the position of the construction platform 9 with respect to the at least one coordinate is derived from a local and/or temporal offset between signal values that are assigned to different working beams 5 of the plurality of working beams 5. Alternatively or additionally, it is provided that the position of the construction platform 9 with respect to the at least one coordinate is derived from a difference in the local and/or temporal offset of the signal values assigned to the various working beams 5 between the at least two probing areas 27.

In particular, the working beams 5.1, 5.2, 5.3 are displaced together from the first probing area 27.1 via the working surface 33 to the second probing area 27.2.

At a) a situation is shown in which the construction platform 9 is installed too high above the chamber floor 35. Since the working beams 5 coming from the respective assigned scanner devices 11 arranged at different locations are arranged at a common point in the construction plane or in the target plane for the arrangement of the work surface 33, they meet when the work surface 33 is positioned outside the target -Plane is not in a common point on the work surface 33. Rather, without limiting the generality, if the work surface 33 is arranged too high, here, for example, the third optical working beam 5.3 precedes the other two optical working beams 5.1, 5.2. The V,t diagram summarizes the time-detected signal values assigned to the respective optical working beams 5 arranged and arranged on the respective optical axes A detection devices 13 are shown. A dashed line shows a signal curve V(t) for the detection device 13 assigned to the third optical working beam 5.3, and a solid line shows the matching and thus coincident temporal signal curves V(t) for the first optical working beam 5.1 and the second optical working beam 5.2 shown. Since the third optical working beam 5.3 leads the other optical working beams 5.1, 5.2, the unsteady rise and fall of the voltage V are observed earlier for it than for the other two optical working beams 5.1, 5.2. This results in a first time offset Δt ₁ of the discontinuous rises and a second time offset Δt ₂ of the discontinuous drops. From these time offsets, the position of the construction platform 9 can be deduced based on the known geometric progressions of the optical working beams 5. In particular, if the installation height is incorrect without tilting, Δt ₁ = Δt ₂ applies.

At b) a situation is shown in which the construction platform 9 is arranged tilted, in particular in such a way that the first contour section 29.1 is arranged below the chamber floor 9 and the second contour section 29.2 is arranged above the chamber floor 35.

The position of the various optical working beams 5 relative to one another corresponds here in the second scanning area 27.2 to the position previously explained in connection with a), but in the first scanning area 27.1 the position of the optical working beams 5 is inverted, since they are in the construction plane or the Cross the target plane, and here the work surface 33 is arranged below the chamber floor 35. Thus, in this situation, the third optical working beam 5.3 precedes the other two optical working beams 5.1, 5.2 in the first scanning area 27.1. after, while it advances in the second probing area 27.2 - as in a). Accordingly, the discontinuous increase in the voltage V for the third optical working beam 5.3 in the first scanning region 27.1 is to be expected later than for the other two optical working beams 5.1, 5.2, while the discontinuous decrease in the second scanning region 27.2 for the third optical working beam 5.3 - as at a) - takes place earlier than for the other two optical working beams 5.1, 5.2. From the temporal offsets Δt ₁ , Δt ₂ , in particular from a difference between the temporal offsets Δt ₁ , Δt ₂ , the local position of the contour sections 29.1, 29.2 and thus the tilting of the construction platform 9 can be deduced. In particular, when the construction platform 9 is tilted, Δt ₁ ≠ Δt ₂ applies, the height being undetermined.

Advantageously, in a first step, the tilting of the construction platform 9 is determined and corrected if necessary, after which the height of the construction platform 9 is determined in a second step by carrying out the method again.

Claims (15)

Method for calibrating a generative manufacturing device (1), with the following steps: - Displacing an optical working beam (5) of the generative manufacturing device (1) over at least two spaced-apart probing areas (27) of a working field (7), in which a construction platform (9) adjustable with respect to at least one coordinate is arranged, the probing areas (27) are chosen so that a contour section (29) of the building platform (9) is expected in each of the probing areas (27); - Detecting signal values of light (15) of the optical working beam (5) remitted from the scanning areas (27); - Deriving a position of the construction platform (9) with respect to the at least one coordinate from the recorded signal values, and - Calibrating the manufacturing device (1) based on the derived position of the construction platform (9). Procedure according to Claim 1 , wherein the signal values are recorded as a function of location, in particular as a function of a functional position of a scanner device (11) set up to relocate the optical working beam (5), and/or as a function of time. Method according to one of the preceding claims, wherein signal values of light (15) remitted from the scanning areas (27) along an optical axis (A) of the optical working beam (5) are recorded as the signal values. Method according to one of the preceding claims, wherein - based on the detected signal values, a position of the contour sections (29) of the building platform (9) in the probing areas (27) is recognized, and the position of the building platform (9) with respect to the at least one coordinate from the recognized position of the contour sections (29) in the probing areas (27) is derived, or where - An apparent geometric property of the building platform (9) is determined from the recorded signal values, the position of the building platform (9) with respect to the at least one coordinate from the apparent geometric property of the building platform (9), in particular based on a comparison of the apparent geometric property with an assigned, known geometric property of the construction platform (9). Method according to one of the preceding claims, wherein a plurality of optical working beams (5) are displaced over at least one scanning area (27) of the at least two scanning areas (27), with signal values from for each working beam (5) of the plurality of working beams (5). The light (15) remitted from the at least one scanning area (27) is detected, and the position of the construction platform (9) with respect to the at least one coordinate is derived from the signal values assigned to the working beams (5). Procedure according to Claim 5 , wherein the position of the construction platform (9) with respect to the at least one coordinate - from a local and / or temporal offset between signal values that are assigned to different working beams (5) of the plurality of working beams (5), and / or - from a difference in The signal values assigned to the local and/or temporal offset of the different working beams (5) between the at least two scanning areas (27), the plurality of working beams (5) being displaced over the at least two scanning areas (27), are derived. Method according to one of the preceding claims, wherein the position of the construction platform (9) with respect to the at least one coordinate is derived from sudden changes in the detected signal values. Method according to one of the preceding claims, wherein the manufacturing device (1) is calibrated by - an expected position of the building platform (9) with respect to the at least one coordinate is corrected based on the derived position of the building platform (9), or in that - an actual position of the construction platform (9) in the manufacturing device (1) is corrected based on the derived position, in particular based on a deviation of the derived position from the expected position. Method according to one of the preceding claims, wherein the position of the construction platform (9) is derived with respect to a height coordinate and/or an angular coordinate as the at least one coordinate. Manufacturing device (1) for the generative manufacturing of a component from a powder material, with - a jet device (3) which is set up to generate an optical working beam (5) in order to produce a component generatively from a powder material by means of the optical working beam (5), - a construction platform (9) that can be adjusted with respect to at least one coordinate and can be arranged in a working field (7) of the production device (1), which is set up to produce a component generatively from the powder material on the construction platform (9), - a scanner device (11) which is set up to relocate the optical working beam (5) in the working field (7), - a detection device (13) which is set up to detect remitted light (15) of the optical working beam (5), and with - a control device (17) which is set up to control the scanner device (11) for displacing the optical working beam (5), in order to detect signal values of the detection device (13) during the displacement of the optical working beam (5), and a position the construction platform (9) to derive the at least one coordinate from the recorded signal values. Manufacturing device (1). Claim 10 , wherein the control device (17) is set up to carry out a method according to one of Claims 1 until 9 to carry out. Manufacturing device (1) according to one of Claims 10 or 11 , with an adjusting device (25) which is set up to adjust the construction platform (9) with respect to the at least one coordinate, wherein the control device (17) is operatively connected to the adjusting device (25) and is set up to adjust the adjusting device (25) in particular depending on the position of the building platform (9) derived from the detected signal values, in particular in order to control an actual position of the building platform (9) in the manufacturing device (1) based on the derived position, in particular based on a deviation of the derived position from an expected position, to correct. Manufacturing device (1) according to one of Claims 10 until 12 , wherein the detection device (13) is set up to detect light (15) of the optical working beam (5) remitted along an optical axis (A) of the optical working beam (5). Manufacturing device (1) according to one of the Claims 10 until 13 , wherein the detection device (13) is arranged on an optical axis (A) of the optical working beam (5). Computer program comprising machine-readable instructions on the basis of which a method according to one of the Claims 1 until 9 is carried out when the computer program is run on a computing device, in particular the control device (17) of a manufacturing device (1) according to one of the Claims 10 until 14 , running.

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