Method for operating a coordinate measuring machine and device for carrying out

Abstract

Method for determining measuring points on at least one surface area of ​​a workpiece using a sensor, wherein the sensor has a linear or areal detection area perpendicular to the measuring direction, within which several measuring points are detected by one or more measuring channels, and wherein measuring points on surface areas are detected in one or more different sensor positions relative to the workpiece, wherein the detected surface areas exhibit a curvature and / or an angle to the measuring direction of the sensor at least partially within the detection area of ​​the sensor or at least within the area detected along a measuring path, and wherein, if at least one quality criterion is not met, one or more measuring points are excluded from the evaluation or corrected.

Description

[0001] The subject matter of an independent invention is a method for determining measuring points on one or more surface areas of a workpiece by means of a sensor and a method for operating the sensor in a coordinate measuring machine as well as a coordinate measuring machine for carrying out the method.

[0002] The invention relates in particular to the measurement of workpieces having curved surface areas which are detected by a sensor, wherein several different rotational-swivel positions are assumed relative to one another between the sensor and the workpiece.

[0003] Methods for determining measurement points on the surface of workpieces using a sensor in a coordinate measuring machine are known, for example, from the documents WO2022251395, WO2022251396, WO2022251397, and WO2022251398. In these methods, suitable rotational and pivoting positions of the sensor are determined for the differently inclined surface areas by segmenting the surface points to be measured into groups with the same inclination, i.e., the direction of the normal vector of the surface at which the measurement point is located. This requires the discrete examination of the surface normal for each individual measurement point, which is computationally complex. The determined rotational and pivoting positions must then all be assumed separately and only record the measurement points that can be measured at that time. For segmentation, the acceptance angle of the respective sensor must be precisely known.However, this is not the same for all surfaces, but depends on the surface properties (reflection and scattering behavior). This does not provide a solution for any surface, especially for previously unknown ones.

[0004] Furthermore, the method described in the aforementioned documents is only designed for point-measuring sensors. For linear or area-measuring sensors with multiple offset measuring channels, segmentation would have to be performed for the entire detection range of the sensor. However, this is only possible for non-curved surface areas or areas whose inclinations lie entirely within the permissible acceptance angle of the sensor. The acceptance angle can also vary within the detected area, for example, being smaller at the edges (due to the aperture of the optics used, for example) or smaller on one side (due to the oblique measuring direction in triangulation sensors, for example). For curved surfaces, the surface inclinations detected by the individual measuring channels can therefore exceed the acceptance angle for at least some channels.A reliable, complete recording of the areas to be measured is therefore very complex.

[0005] Furthermore, the method described in the aforementioned documents is only designed for rotary-swivel joints for sensors. Solutions for rotating and swiveling the workpiece, even in combination with rotating and swiveling the sensor, are not disclosed.

[0006] For the acquisition of measuring points on surface areas with linear or area-measuring sensors, DE102017107343 and DE102017129221 are known to the applicant. DE102017107343 describes an optical, chromatic distance sensor with multiple measuring beams distributed along a line. To increase the resolution in the line direction (lateral resolution), i.e., perpendicular to the preferred scanning direction, it is proposed to move the measuring line slightly rotated around the measuring direction. It is also proposed to arrange the measuring channels on multiple lines in a matrix. DE102017129221 describes a method in which, to increase the resolution in the lateral direction, several parallel lines are arranged offset perpendicular to the line direction and additionally offset in the line direction by a fraction of the distance between the measuring beams in the direction of the lines.The offset perpendicular to the line direction can, for example, correspond to the distance between the measuring beams in the line direction. Another solution proposed is to arrange several measuring lines rotated around the measuring direction, e.g., in a cross-shaped arrangement, i.e., to arrange two measuring lines perpendicular to each other. A solution for detecting curved surface areas is not disclosed.

[0007] The object of the present invention is therefore to provide a simple method in which the areas to be measured on the workpiece can be completely captured. Valid measurement points should be obtained for all areas, in particular without having to previously define a separate rotation / swivel position of the sensor for each individual measurement point. Furthermore, the method should also be applicable to unknown surfaces with unknown surface properties. In particular, the method should provide a solution for sensors with linear or planar detection areas.

[0008] To achieve this, the invention provides that several sensor positions are specified relative to the workpiece, preferably along one or more measuring paths, so that all surface areas on the workpiece to be measured are detected, and then invalid measuring points are filtered out or corrected by checking the measuring points for compliance or non-compliance with at least one quality criterion.

[0009] For this purpose, measuring paths are preferably arranged with an overlap to ensure that valid measuring points from another sensor position are available, particularly for surface areas where invalid measuring points are detected by measuring channels at the edges of the detection area with inclinations greater than the acceptance angle.

[0010] Instead of considering individual measurement points, the surface areas to be measured are broken down into standard geometry elements whose surface inclinations are known from the target information. This reduces computational effort.

[0011] A method according to the invention for determining measuring points on one or more surface areas of a workpiece with a sensor therefore provides that the sensor has a linear or planar detection area formed perpendicular to the measuring direction, within which a plurality of measuring points are detected by one or more measuring channels each, in particular a distance value is determined by determining the respective sensor deflection along the measuring direction of the sensor (sensor axis), and wherein measuring points on surface areas are detected in one or more different sensor positions relative to the workpiece, preferably a plurality of sensor positions distributed offset from one another along a measuring path at least in a translational direction,wherein the detected surface areas have a curvature and / or an angle to the measuring direction of the sensor at least in some areas within the detection range of the sensor or at least within the area detected along a measuring path, and is characterized in that if at least one quality criterion is not met, one or more measuring points are excluded from the evaluation or corrected, preferably by adding further, in particular adjacent, recorded measuring points.

[0012] In particular, the invention is characterized in that for the plurality of sensor positions, in particular for the plurality of measuring paths and / or within one or within the plurality of measuring paths, a plurality of rotational and / or pivoting positions are assumed between the workpiece and the sensor, wherein the rotational and / or pivoting positions are assumed by adjusting the rotational and / or pivoting position of the sensor arranged on a rotational and / or pivoting joint and / or by rotating and / or pivoting the workpiece arranged on a rotational and / or pivoting axis.

[0013] Preferably, the measuring point recording along a measuring path is carried out during the movement along the measuring path.

[0014] It should also be emphasized that the surface areas detected in the multiple sensor positions by the sensor's detection range, in particular the multiple measuring paths, partially overlap.

[0015] The invention is also characterized by the fact that measurement points in the overlapping areas are excluded from the evaluation or corrected based on the quality criterion.

[0016] It is worth emphasizing that the surface areas of the workpiece to be measured and / or the position of the measuring points to be recorded are taken from the CAD and / or PMI data assigned to the workpiece.

[0017] PMI data (Product and Manufacturing Information) includes, in addition to the geometry description of the CAD elements (CAD data), the dimensions defined by the designer, including tolerances and reference elements.

[0018] In particular, the invention is characterized in that the various sensor positions are determined with the aid of the target data such as CAD data and / or PMI data of the workpiece, in particular the surface normals of the areas in which measuring points are recorded.

[0019] Preferably, it is provided that the determination of the sensor positions takes place taking into account a maximum permissible angle between the surface normal and the measuring direction of the sensor, wherein the surface normal is not taken into account for all measuring points detected in the respective sensor position by the plurality of measuring channels, in particular not for measuring points detected by measuring channels that exceed a specified maximum distance from the center and / or from an edge of the detection range of the sensor in a direction perpendicular to the measuring direction of the sensor.

[0020] This takes into account the fact that with multiple measurement channels and curved surfaces, a suitable rotation / swivel position cannot be available for all measurement channels at the same time. The measurement points not considered are usually those that would be filtered out based on a quality criterion anyway, because the acceptance angle (maximum permissible angle between the surface normal and the sensor's measuring direction) is exceeded for them.

[0021] It should also be emphasized that one or more of the following criteria are used to indicate non-compliance with a quality criterion for the respective measuring point: - Exceeding a maximum angle between the surface normal and the measuring direction of the sensor, wherein the direction of the surface normal is preferably taken from the target data, and wherein the measuring direction and the direction of the surface normal are determined taking into account the rotational and / or pivoting position of the workpiece and / or sensor, - Exceeding a maximum permissible distance of the measuring point from the center and / or an edge of the detection area, - falling below a minimum permissible SNR (signal to noise ratio) and / or falling below a minimum permissible intensity value and / or exceeding a maximum permissible intensity value of the measurement signal of the measurement channel assigned to the measurement point, - Falling below a minimum permissible value and / or exceeding a maximum permissible value for the sensor deflection of the respective measuring channel(s), - Exceeding a maximum permissible difference of the measurement signal and / or the position of the measurement point determined therefrom, in particular the distance value, to measurement signals or the position of neighboring measurement points, whereby neighboring measurement points are measurement points recorded in the identical or a different sensor position in the local environment of the measurement point on the workpiece surface, - Exceeding a maximum permissible difference between the position of the measuring point and the position based on the target data or the position based on a standard geometry formed from the surrounding measuring points, - Exceeding a maximum permissible difference between the position of the measuring point and the position based on the target data or the position based on a standard geometry formed from surrounding measuring points, whereby the maximum permissible difference is set in such a way that a fixed proportion of all measuring points assigned to the respective standard geometry exceeds it, whereby preferably the standard geometry is set in such a way that, without taking into account the measuring points exceeding the maximum difference, the maximum deviation of the remaining measuring points from the standard geometry is minimal, - Falling below a specified minimum number of neighboring measuring points (measuring point group), for all of which a specified maximum distance to a neighboring measuring point group is exceeded.

[0022] Considering the distance of the measuring point from the center and / or an edge of the detection range is useful, as the accuracy of the sensor or the acceptance angle can vary depending on the position of the measuring channel detecting the measuring point within the sensor's detection range. For example, if the measurement direction runs along the optical axis of an imaging optic, the acceptance angle and the accuracy are highest in the center. However, if a measuring beam is detected at an angle by an imaging optic, or if the measuring beam itself is oblique, the acceptance angle can be higher towards an edge of the detection range.

[0023] Based on these considerations, it is also intended to correct the measurement signal or the measured value calculated from it for the measuring point depending on the position of the measuring channel within the detection range, for example in order to correct imaging errors of the optics, which usually increase towards the edge.

[0024] A further inventive concept provides for a correction of the measurement signal or the measured value calculated from it depending on the angle between the surface normal and the measuring direction of the sensor in order to correct for influences caused by the limited aperture of the optics and the influence of the off-center use of the optics, which increases with the angle. This angle-dependent correction is thus particularly preferably combined with the aforementioned correction depending on the distance of the measuring point from the center and / or an edge of the detection area.

[0025] Exceeding or falling below the intensity value corresponds to a so-called intensity filter.

[0026] When considering the sensor deflection, the difference to locally neighboring measuring points, and the nominal data, it is assumed that the local environment of the measuring point does not exhibit any discontinuities, unless these are known from the nominal data (CAD data). If discontinuities arise from the neighbors, this indicates that the permissible acceptance angle has been exceeded—that is, the maximum permissible angle between the surface normal and the sensor's measuring direction for the respective surface condition.

[0027] Due to overlapping acquisition, locally redundant data may be present on the surface, but this data may be located in different sensor positions and, in particular, in the relative rotational and pivotal positions of the workpiece and sensor. This data may be located locally adjacent or in identical positions. These data may differ with respect to one or more of the quality criteria, allowing less suitable measurement points to be discarded or corrected, while still ensuring sufficient measurement points cover the entire surface area.

[0028] The invention is also characterized in that if one of the quality criteria is not met, the measuring point is corrected by taking into account the measuring signals or the position of the measuring points of neighboring recorded measuring points, in particular the measuring point to be corrected is corrected or replaced by means of averaging, median formation or interpolation of these.

[0029] In a particularly noteworthy manner, the invention provides that the measurement signal and / or measured value of measuring channels are corrected based on the distance from the center of the detection area and / or the angle between the surface normal and the measuring direction of the sensor, preferably additionally based on the surface roughness of the detected workpiece area.

[0030] In particular, the invention is characterized in that after application of the quality criterion, remaining measurement points are combined to form a triangulated surface representation.

[0031] Preferably, at least one sensor is used: - optical distance sensor according to the Foucault principle or - chromatic distance sensor or - confocal distance sensor or - chromatic confocal distance sensor or - Autofocus sensor or - triangulation sensor, in particular pattern projection sensor or photogrammetry sensor, or - Light field sensor such as light field camera or - 3D camera such as Time of Flight camera or stereo camera or - interferometric distance sensor, in particular white light interferometer, preferably the sensor has several measuring channels or the sensor has one measuring channel which can be directed to different locations within the detection area and thus forms several measuring channels.

[0032] It should also be emphasized that each measuring channel is assigned a measuring beam.

[0033] The invention is also characterized in that the sensor is operated in a coordinate measuring machine (CMM), preferably in a multi-sensor CMM together with at least one further optical, tactile or tactile-optical sensor.

[0034] To achieve this, the invention also provides a device in the form of a coordinate measuring machine (CMM) for carrying out the aforementioned method, wherein the CMM comprises at least one sensor and means for relative movement between the workpiece and the sensor, preferably at least means for relative movement in one, two or three translational, in particular Cartesian, axes, which is characterized in that the coordinate measuring machine has additional means for relative movement about at least one axis of rotation, in that the sensor originates from a rotary joint or a rotary-swivel joint and / or in that the workpiece originates from a rotary axis or a rotary-swivel axis.

[0035] In particular, the invention is characterized in that the CMM is designed as a multi-sensor CMM and has at least one further optical, tactile or tactile-optical sensor, wherein the sensors originate from a common and / or multiple quills, preferably another sensor originates from a separate rotary joint or separate rotary-swivel joint or together with at least one further sensor originates from a rotary joint or a rotary-swivel joint.

[0036] The subject of an independent invention is a method for operating a coordinate measuring machine with a distance sensor for measuring workpieces, in particular tools, in particular for wear detection.

[0037] To detect wear on workpieces in the form of tools, particularly tools with at least one cutting edge, such as rotary tools such as milling cutters or cutting inserts, the cutting edges and their rounding are generally measured. For this purpose, envelope contour measurement methods exist, for example, as described in the applicant's DE102011056819. However, this only examines the cutting edge itself. Pre-wear on the flanks or chip surfaces behind the cutting edge cannot be assessed this way. Even if wear marks such as chippings in these areas extend into the cutting edge, they cannot be distinguished from the rounding of the cutting edge.

[0038] The applicant's DE102019105766 describes a method in which measurement points in front of or behind the cutting edge are recorded using an optical distance sensor. However, the evaluation of the data obtained in this way with regard to wear is not described.

[0039] In particular, wear detection is not possible from the measurement data alone, as available sensors have difficulty detecting the very small deviations present here. Automated evaluation, in particular, is not known due to the textured surfaces with grinding marks and abrasion. Furthermore, direct wear measurement is practically impossible for unknown tools, for which no precise target data is available.

[0040] A further object of the present invention is therefore to provide an automatable method for detecting wear marks on workpieces designed as tools, in particular on rotary tools such as end mills or cutting inserts. The method should be applicable, in particular, without precise knowledge of the tool parameters, such as pitch, number of cutting edges, chamfer width, etc. It should also be possible to determine the profile of the first flank. The method should also be applicable for detecting even small wear marks in the range of less than 5 µm. For this purpose, the wear should be detected separately from the edge rounding of the cutting edge.

[0041] To achieve this, the invention provides for the surface of the workpiece to be detected in the region of a face adjacent to the cutting edge using a distance sensor, preferably an optical distance sensor with a linear or planar detection range. In the case of rotary tools, the first flank can be measured, and in the case of cutting inserts, the chip face can be measured. In particular, in the case of shank tools, the sensor detects the surface while the rotary axis rotates while the sensor is continuously fed. The resulting helical path should have a slight overlap so that the faces are detected without gaps. In the case of cutting inserts, the surface is detected in a meandering pattern. If corresponding measuring points are available for the workpiece to be measured (rejection contour), these are compared with a reference (reference contour) after fitting using a Gaussian fit, and deviations are displayed or indicated in color-coded format.made available for further processing. A key feature of the invention is the comparison of the defective part contour with a reference contour.

[0042] A method according to the invention for operating a coordinate measuring machine, which has at least one distance sensor (sensor) and a rotary unit designed to rotate the workpiece and / or at least one translation unit designed for translation between the workpiece and the distance sensor, such as a measuring axis, provides that a plurality of measuring points on the surface of the workpiece are recorded by the distance sensor in several rotational positions and / or translational positions between the workpiece and the distance sensor, wherein the workpiece is a tool with one or more cutting edges (tool cutting edges), and is characterized in that measuring points are recorded in one or more areas adjacent to the one or more tool cutting edges, in particular on at least one chip and / or flank surface,and that the measuring points (bad part contour) are compared with reference measuring points (reference contour) of a master part measurement of an identical workpiece or with the target data of the workpiece and deviations are displayed on a display and / or made available for further evaluation.

[0043] In particular, the invention is characterized in that the deviations are determined in the direction of the workpiece axis or in the direction of the cutting back.

[0044] This has the advantage that any dirt present on the surface is not recognized as a deviation.

[0045] Preferably, before the comparison, the defective part contour is fitted to the reference contour by means of 3D Gauss fitting.

[0046] It should also be emphasized that the master part measurement is carried out on an unworn or unused tool.

[0047] The invention is also characterized in that the deviations are used to assess the wear of the tool, in particular of a tool cutting edge, in particular of breakouts, for example wear marks.

[0048] It is worth emphasizing that the invention provides that the measuring points are recorded on the respective first flank of the cutting edge, in particular in the case of rotary tools, or on the chip surface, in particular in the case of cutting inserts.

[0049] In particular, the invention is characterized in that the distance sensor is an optical distance sensor with a point-shaped, line-shaped or area-shaped detection range, preferably a chromatic or chromatic-confocal distance sensor or Foucault sensor or autofocus sensor or triangulation sensor, in particular a pattern projection sensor or photogrammetry sensor, or light field sensor such as a light field camera or 3D camera such as a time-of-flight camera or stereo camera or interferometric distance sensor, in particular a white light interferometer, or that the distance sensor is a tactile or tactile-optical probe, in particular a scanning probe.

[0050] The use of a chromatic line sensor or an equivalent sensor is particularly preferred for rapid measurement of metallic or shiny workpiece surfaces.

[0051] Preferably, the optical distance sensor has a plurality of measuring channels for simultaneously recording a plurality of measuring points distributed along a measuring line (line sensor).

[0052] It should also be emphasized that measuring points are recorded along at least one measuring path, wherein the workpiece and sensor are moved relative to each other on a helical path, in particular by combining a translational movement of the sensor and workpiece relative to each other and a rotational movement (rotation) of the tool, or wherein the workpiece and sensor are moved relative to each other on a meandering path, in particular by translational movements of the sensor and workpiece relative to each other.

[0053] Helical paths are preferred for rotary tools, and meandering paths for cutting inserts.

[0054] The invention is also characterized in that the measuring point recording takes place during the movement, in particular during the rotation and / or the translational movement.

[0055] In a particularly noteworthy manner, the invention provides that measuring points are recorded along the helical path or along several measuring paths, wherein the helical path is so pronounced or the several measuring paths are offset from one another in such a way that the area detected by the measuring line or the areal detection area partially overlaps.

[0056] When using helical tracks, the pitch of the helix can be designed to be correspondingly low, so that the areas partially overlap during successive revolutions of the helix. Multiple helical tracks, which are recorded offset in the direction of the tool axis, can also overlap by selecting an offset smaller than the width of the helical track, i.e., the line length or area width of the sensor's detection area. If multiple measuring tracks are used in a purely translational sequence, the multiple measuring tracks can overlap laterally, for example, on a meander.

[0057] In particular, the invention is characterized in that the plurality of measuring points, in particular the plurality of measuring paths, are detected in several different rotational positions or rotation-swivel positions between the workpiece and the sensor, in that the sensor originates from a rotational or rotation-swivel joint and / or the workpiece originates from a rotational or rotation-swivel axis.

[0058] The subject of an independent invention is a method for image processing measurement with a coordinate measuring machine and a correspondingly designed coordinate measuring machine with image processing sensor.

[0059] In the known methods for image processing measurement with coordinate measuring machines (CMMs), the areas of the workpiece to be measured are illuminated by incident or transmitted light in the visible range, and the image processing sensor comprises a camera, such as a CCD or CMOS camera, that is sensitive in the corresponding spectral range. Workpieces or workpiece areas can be measured by ensuring that the light used for illumination and captured by the camera is sufficiently influenced by the workpiece, for example, reflected or scattered, to create a shadow (with transmitted light illumination) or a reflected image (with incident light illumination), thus creating an image of the workpiece.

[0060] A disadvantage of the known methods, however, is that only those areas that can be directly imaged by the visible light spectrum can be imaged. In particular, areas covered by materials that are not transparent to the visible light spectrum, such as silicon (which is only transparent in the infrared wavelength range of approximately 1.2 - approximately 15 µm), sapphire, or sodium chloride, cannot be dimensionally measured using state-of-the-art image processing.

[0061] Infrared light sources and cameras sensitive to the infrared range, such as NIR (near-infrared) or SWIR (short-wave infrared) cameras, are also known. However, these are not used in dimensional metrology in CMMs with image processing sensors.

[0062] A further object of the present invention is therefore to provide a method and a device which enable dimensional measurements of geometric properties on workpieces or workpiece regions which, when illuminated with a light source and imaged onto an image processing sensor, are at least partially covered by a layer of the workpiece which is not transparent or at least hardly transparent to light in the visible range.

[0063] To achieve this, the invention provides for infrared light to be used for illumination with the light source. Preferably, the camera used is at least partially sensitive in the infrared range.

[0064] A method according to the invention for the dimensional measurement of geometric properties on workpieces using a coordinate measuring machine provides that the coordinate measuring machine comprises at least one image processing sensor, wherein the image processing sensor comprises at least one camera and wherein at least one light source, in particular at least one incident light source such as bright field incident light or dark field incident light and / or at least one transmitted light source is assigned to the image processing sensor, and wherein the workpiece or at least workpiece regions are illuminated by means of the light source, and wherein the workpiece or at least workpiece regions are imaged onto the camera of the image processing sensor, preferably wherein the image processing sensor has an imaging optics, and is characterized in that the measurement is carried out on workpiece regions,for which the light from the light source for imaging the workpiece areas onto the camera must penetrate at least one layer (cover layer) of the workpiece which is not transparent or at least barely transparent (transmission less than 10%, preferably less than 5%, particularly preferably less than 1%) to light in the visible range, by operating the light source in the infrared range.

[0065] In particular, the invention is characterized in that the workpiece areas are at least partially covered by the covering layer when illuminated with the light source and / or when imaged onto the camera, in particular when illuminated with a reflected light source they are covered at least in the direction of the image processing sensor or when illuminated with a transmitted light source they are covered in the direction of the image processing sensor and / or in the direction of the transmitted light source.

[0066] Preferably, the cover layer contains at least silicon, sapphire and / or sodium chloride.

[0067] It is also important to note that the camera used is one that is at least partially sensitive to the infrared wavelength range, for example a CCD or CMOS black and white or color camera or SWIR or NIR camera.

[0068] To achieve this, the invention also provides a device for carrying out the method, which is characterized in that the coordinate measuring machine with image processing sensor has at least one light source, in particular a reflected light source such as a bright field reflected light or a dark field reflected light and / or a transmitted light source, which is designed to be operable as an infrared light source.

[0069] Preferably, the camera of the image processing sensor is designed to be at least partially sensitive to the infrared wavelength range, preferably the camera is a CCD or CMOS camera or SWIR or NIR camera.

[0070] The subject of an independent invention is a device and a method for determining geometric features on workpieces using an optical sensor in a coordinate measuring machine.

[0071] In the known methods for determining geometric features on workpieces with an optical sensor in a coordinate measuring machine (CMM), optical sensors are operated that detect features on an underside and features on an upper side by re-clamping or rotating the workpiece. Corresponding sensors include, for example, image processing sensors that comprise an image capture device such as a camera with imaging optics (imaging beam path) arranged in front of it. Illumination devices such as transmitted light (transmitted light device) and / or incident light (incident light device such as bright field incident light or dark field incident light) are assigned to these sensors. A transmitted light device for this purpose comprises a light source that is arranged on the side of the workpiece facing away from the sensor, for example under a measuring table, and is aligned with the optical axis of the sensor, and is possibly moved laterally with the sensor.In transmitted light measurement, the side facing away from the sensor (underside) is recorded, namely the shadow that can be observed from the top side of the workpiece, for example places where the workpiece has corresponding recesses or edges. In order to avoid imaging errors, telecentric imaging optics and diffuse lighting are used. With vertical workpiece walls, the shadow corresponds to the position of the wall, hole or edge over the entire depth. With sloping walls such as those on spheres, imaging errors can occur if the focus is not on the exact height at which the outermost edge is located and telecentric illumination (parallel transmitted light) is used. A reflected light device comprises one or more light sources that are either integrated in the beam path of the sensor (usually the case with bright field incident light) or next to or on the surface.are arranged around the sensor (usually the case with dark field incident light). With incident light illumination, structures on the top side or depressions that can be observed from above are measured. For an accurate measurement, the focus is on the top side or the depression of the workpiece. Depending on the inclination of the structure to be detected, steep bright field illumination and / or shallow dark field illumination (usually controllable sector by sector) is used. Features on the top side and bottom side are recorded one after the other, with the corresponding illumination being switched and, if necessary, focusing on the structure to be recorded. Simultaneous measurement of structures that are present at different heights on the workpiece, for example on the underside and on the top side, and which may require different illumination for their measurement (transmitted light orincident light) is not known using the same sensor via image processing.

[0072] From the applicant's EP1238244, an autofocus method using contrast value determination is known. In this method, the optical sensor comprises multiple beam paths with a shared front optics to simultaneously capture multiple focal planes. The measurement is limited to an autofocus measurement for distance determination, which only takes place on the top side of the workpiece and under the same illumination. An image processing measurement for determining structures using an image processing sensor is not provided and would be conceivable only for the top side.

[0073] The determination of geometric features within the scope of the present invention comprises the dimensional measurement of workpiece features, whereby distances, angles, diameters, straightness or other dimensional quantities at or between the features are determined.

[0074] A disadvantage of the known methods is that capturing features on the top and bottom of a workpiece using image processing measurement with a single optical sensor takes a long time, as either the workpiece must be re-clamped or both sides of the workpiece must be captured sequentially using a transmitted-light measurement and a reflected-light measurement. Simultaneous image processing measurement at multiple workpiece heights, whose relative positions are unknown, is not possible. Simultaneous image processing measurement of the top and bottom requires different illumination, which would mutually interfere with the measurements, as blurred images would interfere with the other measurement.

[0075] A further object of the present invention is therefore to enable faster image processing measurement of workpiece structures compared to the prior art when the structures are to be measured on both sides of the workpiece. In particular, simultaneous image processing measurement at several different workpiece heights whose relative positions are not known in advance should be enabled. Furthermore, in particular, simultaneous image processing measurement at several different workpiece heights or workpiece sides that require different illumination (transmitted light illumination and incident light illumination) should be enabled. The multiple images resulting in this process should not interfere with each other or should only interfere with each other to a minimal extent, thus enabling precise image processing measurement.Alternatively or additionally, the invention also provides for the application for a simultaneous autofocus measurement at different workpiece heights with the inventive optical sensor, in particular the image processing sensors contained therein.

[0076] To achieve this, the invention provides that an optical sensor comprising at least two image processing sensors (BV sensors), whose imaging beam paths run through a common front system, is designed and operated in such a way that at least two of the image processing sensors record image data from the workpiece simultaneously or almost simultaneously. In this case, the plurality of image processing sensors each evaluates recorded image data within a defined wavelength range of the measuring radiation, wherein the wavelength ranges do not overlap or only partially overlap. In this way, the invention enables the simultaneous measurement of structures on the underside (transmitted light measurement) and the top side (incident light measurement) of a workpiece using the identical front system, without these measurements interfering with each other using the two image processing sensors. For example, the position, the diameter and / or the shape orThe form deviation of a through hole in a workpiece such as a plate can be measured simultaneously on both the underside and the top side of the workpiece. This reduces the overall measurement time.

[0077] Preferably, the simultaneous transmitted and reflected light illumination also occurs in separate wavelength ranges, with these wavelength ranges each at least partially overlapping with the wavelength ranges in which the respective associated image processing sensor evaluates image data. For example, a transmitted light source emits blue light, and the image processing sensor capturing the underside of the workpiece is sensitive to the blue wavelength range, while a reflected light source emits red light, to which the image processing sensor capturing the top side of the workpiece is sensitive. The assignment can also be the other way around or occur in other separate wavelength ranges.

[0078] The invention provides several solutions for implementing the separate wavelength ranges in which the multiple image processing sensors evaluate the image data. A dichroic splitter can be provided to divide the measurement radiation into the multiple, for example, two, wavelength ranges. Alternatively or additionally, an optical filter can be used in one or more of the imaging beam paths in the respective no longer common region, which limits the spectrum of the measurement radiation reaching the respective image processing sensor. A corresponding restriction of the spectrum can also be achieved, if necessary, by using only one of the color channels of a color camera as the image capture device of the respective image processing sensor for evaluating the image data.

[0079] To ensure that the respective image processing sensor correctly measures the structure assigned to it on the corresponding workpiece side or height, it must be ensured that the multiple image processing sensors sharply image the assigned structures using their imaging beam paths, i.e. are focused on them, which means that the respective structure is located within the depth of field of the respectively assigned imaging beam path. The invention provides several solutions for this. Either the depth of field of at least one of the two imaging beam paths is sufficiently large that both imaging beam paths sharply image the two workpiece sides or heights simultaneously, i.e. both depths of field in total are so large that both workpiece sides or heights can be focused, and / or the working distance is adjustable, preferably CNC adjustable, for at least one imaging beam path.To adjust the optical sensor to the distance from the workpiece required for the measurement, the measuring axes of the coordinate measuring machine are preferably used. For example, one of the image processing sensors can be used to focus on the assigned workpiece side or height using an autofocus measurement. The working distance of the other image processing sensor is then adjusted to the other workpiece side or height if its depth of field is not large enough to image it sharply.

[0080] The invention also provides that the optical imaging scales of the multiple imaging beam paths are designed to be different.

[0081] When two image processing sensors are referred to in the present invention, the invention also provides for the use of more than two image processing sensors, wherein the multiple assigned wavelength ranges overlap little or not at all. This allows structures at more than two different heights on the workpiece to be measured simultaneously. For example, multiple incident light sources can be provided that emit light in different wavelength ranges, so that image processing sensors sensitive to these wavelength ranges can measure structures at different heights on the workpiece separately.

[0082] A method according to the invention for determining geometric features on workpieces with an optical sensor in a coordinate measuring machine provides an optical sensor comprising at least two image processing sensors (BV sensors), wherein each image processing sensor (BV sensor) comprises at least one image capturing device such as a camera and an optical imaging beam path associated therewith for recording image data of the workpiece, wherein the plurality of imaging beam paths run through a common optical front system and image measuring radiation coming from the direction of the workpiece onto the respectively associated image capturing devices, and wherein at least one transmitted light device and at least one incident light device such as bright field incident light and / or dark field incident light are operated to generate the measuring radiation, and is characterized in thatthat each of the plurality of image processing sensors evaluates a defined wavelength range of the measuring radiation when recording the image data, whereby the wavelength ranges evaluated by the plurality of image processing sensors do not overlap or only partially overlap, and that at least two of the image processing sensors record image data from the workpiece simultaneously or almost simultaneously.

[0083] Nearly simultaneous means that during image acquisition, the time offset during the lateral relative movement between the workpiece and the sensor is so small that both image processing sensors still capture the structure to be captured, such as a hole, within the image field. Typically, the image field is selected to be large enough to ensure that sufficient distance remains between the workpiece structure and the edge of the image field so that the structure to be captured does not leave the image field during the time offset. A typical time offset is less than one second, preferably less than one-tenth of a second. The smallest possible time offset is preferred to enable high relative speeds.

[0084] In particular, the invention is characterized in that the image processing sensors measure features, for example edges, on structures that are present on different sides of the workpiece and / or that extend between these sides, wherein preferably a first image processing sensor detects features on the underside and a second image processing sensor detects features on the top side of the workpiece.

[0085] Preferably, it is provided that the image processing sensors measure features, for example edges, on structures that extend between several different heights on the workpiece, preferably between the underside and the top side or recesses on the underside or top side, wherein the structures have at least one through opening such as an edge or bore or cone with a vertically or obliquely running wall, wherein preferably a first image processing sensor detects features at the first height and a second image processing sensor detects features at the second height of the workpiece.

[0086] It should also be emphasized that the working distances of the imaging beam paths of the image processing sensors are nominally designed to be the same and the depth of field of at least two imaging beam paths are designed such that their sum corresponds at least to the distance between a first height to be detected and a second height to be detected on the workpiece or the different sides of the workpiece.

[0087] This first solution according to the invention therefore provides that the depth of field of the two imaging beam paths is sufficiently large that both heights or sides of the workpiece can be captured sharply at the same time with the same nominal working distance. Corresponding telecentric optics have, for example, depths of field in the range of 0.5 mm to a few millimeters, whereby flat workpieces such as circuit boards or wafers can be measured simultaneously in the area of ​​openings such as bores on both sides. The two imaging beam paths can then preferably be optically designed identically and are separated by an optical splitter. The splitter is located, for example, between the last optical component such as the last lens and the cameras, so that the identical imaging lenses are used for both imaging beam paths and form the front system.Alternatively, additional imaging lenses, which may be structurally identical or different, can be arranged between the splitter and the cameras.

[0088] The invention is also characterized in that the working distances of the imaging beam paths of the image processing sensors are designed to be different and the depths of field of at least two imaging beam paths are designed such that their sum corresponds at least to the distance between a first height to be detected and a second height to be detected on the workpiece or the different sides of the workpiece, reduced by the difference between the working distances.

[0089] This second inventive solution therefore intentionally provides for a different working distance between two imaging beam paths. This allows different heights on the workpiece to be focused, corresponding to the difference between the working distances. Even smaller and larger height differences can be focused, as long as they lie within the sum of the two depths of field. This allows a larger overall height range to be covered with correspondingly large depths of field.

[0090] In a particularly advantageous manner, the invention provides that the working distance of at least one image processing sensor is set, preferably to a working distance which differs from the working distance of at least one further image processing sensor by at least the distance between a first height to be detected and a second height to be detected on the workpiece or the different sides of the workpiece.

[0091] This further solution according to the invention therefore provides that the working distance of at least one image processing sensor is adjusted relative to another image processing sensor such that the working distances differ by the height difference to be detected. This creates a particularly high degree of flexibility with regard to the detectable workpiece heights and thicknesses.

[0092] In particular, the invention is characterized in that the working distance of at least one first image processing sensor is set, preferably to a working distance which differs from the working distance of at least the second image processing sensor by at least the distance between a first height to be detected and a second height to be detected on the workpiece or the different sides of the workpiece, reduced by the sum of the depths of field of the imaging beam paths of the first and a second image processing sensor.

[0093] This further solution according to the invention therefore provides that the working distance of at least one image processing sensor is adjusted relative to another image processing sensor such that the working distances differ by the height difference to be detected, while also taking into account that this adjustment only needs to be made within the scope of the sum of the depths of field. This creates further flexibility with regard to detectable workpiece heights and thicknesses.

[0094] Preferably, the transmitted light illumination is assigned to the image processing sensor with the greater working distance (first image processing sensor).

[0095] It should also be emphasized that the incident light illumination is assigned to the image processing sensor with the shorter working distance (second image processing sensor).

[0096] The invention is also characterized in that transmitted light illumination and incident light illumination at least partially generate measuring radiation within the wavelength range evaluated by the respectively assigned image processing sensor.

[0097] In a particularly noteworthy manner, the invention provides that transmitted light illumination and incident light illumination generate measuring radiation in mutually separate wavelength ranges, or that transmitted light illumination and incident light illumination generate measuring radiation in wavelength ranges that only partially overlap, wherein measuring radiation generated in the overlapping region is only evaluated by one of the image processing sensors.

[0098] In particular, the invention is characterized in that the wavelength ranges assigned to the multiple BV sensors are determined by: - Wavelength-selective beam splitting, for example by means of at least one dichroic splitter (dichroit) and / or - Use of optical filters such as bandpass filters or shortpass filters or longpass filters in the respective imaging beam path and / or - Adjusting the wavelength-dependent sensitivity of the respective camera, for example by using different color channels of a color camera.

[0099] Preferably, the distance between the optical sensor and the workpiece is adjusted by focusing, such as autofocus measurement of the structure, on one of the sides of the structure or workpiece to be detected with one of the BV sensors.

[0100] It should also be emphasized that the adjustment of the distance between the optical sensor and the workpiece is carried out by focusing, such as autofocus measurement of the structure, on both sides of the structure or workpiece to be detected with at least one of the several image processing sensors.

[0101] Simultaneous focusing on both sides of the workpiece is possible and provided if the depth of field of the imaging beam paths is sufficiently large. If the working distance between the imaging beam paths is the same, focusing with one of the image processing sensors is sufficient. This then detects one of the sides to be captured, preferably the one that can be captured with the illumination assigned to the respective image processing sensor, for example using an autofocus process, and then adjusts the distance accordingly. If both sides or heights can be captured with one illumination, it is also provided that the position of both sides or heights to be captured are detected and the distance is then set centrally to them. If the working distances of the imaging beam paths are different, it is provided that both image processing sensors each detect one side or height and determine the respective position for focusing.The position is then preferably adjusted taking into account both determined heights, for example to an average value or a value at which both imaging beam paths operate within their depth of field.

[0102] The invention is also characterized in that the adjustment of the distance between the optical sensor and the workpiece is carried out by moving at least the measuring axis of the coordinate measuring machine, which runs in the direction or almost in the direction in which the optical axis of the imaging beam paths runs between the front system and the workpiece.

[0103] It is worth emphasizing that the invention provides that the working distance of at least one image processing sensor is automatically adjusted, in particular is CNC-controlled.

[0104] In particular, the invention is characterized in that the adjustment of the working distance of at least one image processing sensor, preferably the image processing sensor which was not used for adjusting the distance between the optical sensor and the workpiece, is carried out by focusing, such as autofocus measurement of the structure, on one of the sides of the structure or the workpiece to be detected, preferably by focusing on the other side which is not used for adjusting the distance between the optical sensor and the workpiece.

[0105] Preferably, the adjustment of the working distance is carried out by manipulating optical assemblies, in particular moving one or more lenses or lens groups and / or changing the refractive power of at least one lens such as a liquid lens or TAG lens and / or changing the optical path length by changing the thickness of a plate such as a plane plate and / or changing the distance of the camera to the optical assemblies.

[0106] It should also be emphasized that the manipulation is carried out for optical assemblies that are arranged within the beam path of the respective BV sensor, preferably additionally for optical assemblies that are arranged in the common beam path.

[0107] The invention is also characterized in that the adjustment of the distance between the optical sensor and the workpiece is repeated after manipulation of optical assemblies arranged in the common beam path, preferably the adjustment of the working distance and the distance between the optical sensor and the workpiece is carried out iteratively.

[0108] In a particularly noteworthy manner, the invention provides that the image recording of the image processing sensors takes place during the at least lateral relative movement between the optical sensor and the workpiece, preferably wherein images recorded in succession from each image processing sensor capture spatially overlapping sections of the workpiece, preferably with an overlap of at least 50%.

[0109] In particular, the invention is characterized in that at least one optical unit comprising one or more lenses and / or optical plates and / or beam deflection devices and / or beam splitters and / or combinations of at least two of these is used for the front system.

[0110] Preferably, the optical axes of the imaging beam paths between the front system and the workpiece are designed to run parallel or almost parallel.

[0111] It should also be emphasized that the optical axes of the imaging beam paths between the front system and the workpiece are designed to run without any lateral offset or at least with a slight lateral offset of less than 1 mm, preferably less than 0.5 mm, particularly preferably less than 0.1 mm.

[0112] The invention also provides a device for determining geometric features on workpieces with an optical sensor in a coordinate measuring machine, wherein the optical sensor comprises at least two image processing sensors (BV sensors), wherein each image processing sensor (BV sensor) comprises at least one image capturing device such as a camera and an optical imaging beam path associated therewith for recording image data of the workpiece, wherein the plurality of imaging beam paths run through a common optical front system and measuring radiation coming from the direction of the workpiece can be imaged onto the respectively associated image capturing devices, and wherein the coordinate measuring machine has at least one transmitted light device and at least one incident light device such as bright field incident light and / or dark field incident light for generating the measuring radiation, which is characterized in thatthat with each of the plurality of image processing sensors, a defined wavelength range of the measuring radiation can be evaluated when recording the image data, wherein the wavelength ranges evaluated by the plurality of image processing sensors do not overlap or only partially overlap, and that at least two of the image processing sensors are designed for the simultaneous or almost simultaneous recording of image data from the workpiece.

[0113] In particular, the invention is characterized in that features, for example edges, on structures that are present on different sides of the workpiece and / or that extend between these sides can be measured with the image processing sensors, wherein features on the underside of the workpiece can preferably be detected with the first image processing sensor and features on the top side of the workpiece can preferably be detected with the second image processing sensor.

[0114] It is preferably provided that the image processing sensors can be used to measure features, for example edges, on structures that extend between several different heights on the workpiece, preferably between the underside and the top side or recesses on the underside or top side, wherein the structures have at least one through opening such as an edge or bore or cone with a vertically or obliquely running wall, wherein features at the first height can preferably be detected with the first image processing sensor and features at the second height of the workpiece can be detected with the second image processing sensor.

[0115] It should also be emphasized that the working distances of the imaging beam paths of the image processing sensors are nominally designed to be the same and the depth of field of at least two imaging beam paths are designed such that their sum corresponds at least to the distance between a first height to be detected and a second height to be detected on the workpiece or the different sides of the workpiece.

[0116] The invention is also characterized in that the working distances of the imaging beam paths of the image processing sensors are designed to be different and the depths of field of at least two imaging beam paths are designed such that their sum corresponds at least to the distance between a first height to be detected and a second height to be detected on the workpiece or the different sides of the workpiece, reduced by the difference between the working distances.

[0117] In a particularly advantageous manner, the invention provides that the working distance of at least one image processing sensor is set, preferably to a working distance which differs from the working distance of at least one further image processing sensor by at least the distance between a first height to be detected and a second height to be detected on the workpiece or the different sides of the workpiece.

[0118] In particular, the invention is characterized in that the working distance of at least one first image processing sensor is adjustable, preferably to a working distance which differs from the working distance of at least the second image processing sensor by at least the distance between a first height to be detected and a second height to be detected on the workpiece or the different sides of the workpiece, reduced by the sum of the depths of field of the imaging beam paths of the first and a second image processing sensor.

[0119] Preferably, the transmitted light illumination is assigned to the image processing sensor with the greater working distance (first BV sensor).

[0120] It should also be emphasized that the incident light illumination is assigned to the image processing sensor with the shorter working distance (second BV sensor).

[0121] The invention is also characterized in that the transmitted light illumination and the incident light illumination can at least partially generate measuring radiation within the wavelength range evaluated by the respectively assigned image processing sensor.

[0122] In a particularly advantageous manner, the invention provides that measuring radiation can be generated in mutually separate wavelength ranges using the transmitted light illumination and the incident light illumination, or that measuring radiation can be generated in wavelength ranges that only partially overlap using the transmitted light illumination and the incident light illumination, wherein measuring radiation generated in the overlapping region can only be evaluated by one of the image processing sensors.

[0123] In particular, the invention is characterized in that at least one of the following means is arranged to determine the wavelength ranges assigned to the plurality of BV sensors: - Wavelength-selective beam splitter, for example at least one dichroic splitter (dichroit) and / or - optical filter such as bandpass filter or shortpass filter or longpass filter in the respective imaging beam path and / or - Adjustment device for the wavelength-dependent sensitivity of the respective camera, e.g. color camera with adjustability for using one of the different color channels of the color camera.

[0124] Preferably, it is provided that the distance between the optical sensor and the workpiece can be adjusted by focusing, preferably by autofocus measurement of the structure, wherein the focusing on one of the sides of the structure or workpiece to be detected can be carried out with one of the BV sensors.

[0125] It should also be emphasized that the distance between the optical sensor and the workpiece can be adjusted by focusing, preferably by autofocus measurement of the structure, wherein the focusing on both sides of the structure or workpiece to be detected can be carried out with at least one of the several image processing sensors.

[0126] The invention is also characterized in that for adjusting the distance between the optical sensor and the workpiece, at least one measuring axis of the coordinate measuring machine is arranged and movable, which runs in the direction or almost in the direction in which the optical axis of the imaging beam paths runs between the front system and the workpiece.

[0127] It is worth emphasizing that the invention provides that the working distance of at least one image processing sensor can be automatically adjusted, in particular CNC-controlled.

[0128] In particular, the invention is characterized in that the setting of the working distance of at least one image processing sensor, preferably the image processing sensor which was not used for setting the distance between the optical sensor and the workpiece, is adjustable by focusing, such as autofocus measurement of the structure, on one of the sides of the structure or the workpiece to be detected, preferably by focusing on the other side not used for setting the distance between the optical sensor and the workpiece.

[0129] Preferably, it is provided that the working distance is adjustable by manipulating optical assemblies, in particular moving one or more lenses or lens groups and / or changing the refractive power of at least one lens such as a liquid lens or TAG lens and / or changing the optical path length by changing the thickness of a plate such as a plane plate and / or changing the distance of the camera to the optical assemblies.

[0130] It should also be emphasized that optical assemblies arranged within the beam path of the respective BV sensor can be manipulated, preferably additionally for optical assemblies arranged in the common beam path.

[0131] The invention is also characterized in that the adjustment of the distance between the optical sensor and the workpiece is repeatable after manipulation of optical assemblies arranged in the common beam path, preferably the adjustment of the working distance and the distance between the optical sensor and the workpiece is iteratively carried out.

[0132] In a particularly noteworthy manner, the invention provides that the image recording of the image processing sensors can be carried out during the at least lateral relative movement between the optical sensor and the workpiece, preferably wherein spatially overlapping sections of the workpiece can be detected in images recorded successively by each image processing sensor, wherein preferably an overlap of at least 50% can be set.

[0133] In particular, the invention is characterized in that the front system comprises at least one optical unit consisting of one or more lenses and / or optical plates and / or beam deflection devices and / or beam splitters and / or combinations of at least two of these.

[0134] Preferably, the optical axes of the imaging beam paths between the front system and the workpiece are arranged parallel or almost parallel.

[0135] It should also be emphasized that the optical axes of the imaging beam paths between the front system and the workpiece are arranged without lateral offset or at least with a slight lateral offset of less than 1 mm, preferably less than 0.5 mm, particularly preferably less than 0.1 mm.

[0136] Further details, advantages and features of the invention emerge not only from the claims, the features derived therefrom - individually and / or in combination - but also from the following description of the Fig. 1.

[0137] It shows: Fig. 1 an embodiment of the device according to the invention for measuring with an infrared light source in a coordinate measuring machine and Fig. 2 an embodiment of the method according to the invention for determining geometric features on workpieces with an optical sensor.

[0138] Based on the Fig. 1 shows an example of the invention. An exemplary CMM 1 (shown without measuring axes and connecting elements between the measuring table 5 holding the workpiece 4 and the sensor 2) comprises an image processing sensor 2, to which the light sources 3, namely a bright-field incident light 3a, a dark-field incident light 3b, and a transmitted light 3c, are assigned. The transmitted light 3c can be a diffusely emitting transmitted light or a directed light emitting, so-called telecentric transmitted light, in which an optic is arranged in front of the light source that forms almost parallel light. The measuring table 5 can be penetrated by the light from the transmitted light source 3c and thus consists of a frame and a transparent cover plate 5a made of, for example, glass.The workpiece 4 contains geometric properties 4a to be measured, such as edges or openings 4a-1 or surface structures 4a-2, as well as at least either the cover layer 4b-1, which is arranged between the transmitted light source 3c and the workpiece section 4a-1, or the cover layer 4b-2, which is arranged between the incident light source 3a, 3b and the workpiece section 4a-2, and extends from a measuring table 5, beneath which the transmitted light source 3c is arranged. The imaging of the workpiece 4 or the workpiece regions containing the respectively recorded geometric properties 4a-1, 4a-2 onto the camera 2a of the image processing sensor 2 takes place through the imaging optics 2b. At least one of the light sources 3a, 3b, 3c is designed as an infrared light source. The infrared light penetrates the cover layer 4b-1 or4b-2 at least partially and is at least partially absorbed and / or reflected and / or scattered by the underlying solid sections 4c of the workpiece 4 in order to realize the imaging of the geometric property 4a to be measured onto the camera 2a.

[0139] Based on the Fig. 2 illustrates the invention by way of example. The optical sensor 10 according to the invention is a component of the coordinate measuring machine (CMM) (not shown). The workpiece 14 to be measured originates from a measuring table 15, which is also a component of the CMM, and, for example, implements the lateral movement of the workpiece 14 relative to the optical sensor 10 by means of measuring axes. Alternatively, the CMM can also have measuring axes that implement the movement of the optical sensor 10 in one or both lateral directions. The optical sensor 10 originates, for example, from the quill of the CMM and can thus be displaced, among other things, in a vertical direction by means of the measuring axes of the CMM, for example, to focus on a workpiece surface or height 14a, 14b, 14c, for example, by means of an autofocus measurement with one of the image processing sensors 11, 12.The optical sensor 10 comprises two image processing sensors 11, 12, which each consist of at least one image capture device in the form of the camera 11a, 12a and one associated optical imaging beam path 11b, 19, 18, 16 or 12b, 18, 16. The two optical imaging beam paths have the common front system 16 and their optical axis 17 runs parallel from the front system 16 in the direction of the workpiece 14, preferably without lateral offset or at least with very little lateral offset, so that transverse to the optical axis 17, i.e. in the lateral direction, the same section of the workpiece 14 is captured, but at different heights along the direction of the optical axis 17. The front system 16 comprises an optical unit, for example having one or more front lenses, alternatively or additionally also a plate, preferably a plane-parallel plate.Alternatively or additionally, the front system 16 can also be formed by a beam splitter, for example the dichroic 18.

[0140] The two optical imaging beam paths are separated at the dichroic lens 18, with the wavelength range of the measuring radiation 20 that transmits the dichroic lens 18 to the image processing sensor 12 (first BV sensor) and the wavelength range of the measuring radiation 20 that is reflected at the dichroic lens 18, after being deflected at the mirror 19, passing to the image processing sensor 11 (second BV sensor) and being evaluated by the respective image processing sensor 11, 12 to record the image data of the workpiece 14. In addition, the CMM has the transmitted light device 13c and at least one incident light device in the form of the bright-field incident light 13a and / or in the form of the dark-field incident light 13b to generate the measuring radiation 20.

[0141] The first BV sensor 12, for example, only evaluates the wavelength range of the measuring radiation 20 that is generated by the transmitted-light device 13c, in that the transmitted-light device 13c generates light in a first, for example, blue wavelength range, which is transmitted or at least partially transmitted by the dichroic lens 18. As a result, the first BV sensor 12 detects the structure on the underside 14a of the workpiece 14, here, for example, the lower exit 14a of a through-hole. The second BV sensor 11, for example, only evaluates the wavelength range of the measuring radiation 20 that is generated by the incident-light device in the form of the dark-field incident light 13b, in that the incident-light device 13c generates light in a second, for example, red wavelength range, which is reflected or at least partially reflected by the dichroic lens 18.As a result, the second image processing sensor 11 detects the structure on the upper side 14b of the workpiece 14, i.e., the upper exit 14b of the through-bore. Not shown is the possibility of a third image processing sensor, which, via a further optical splitter such as a dichroic, detects and evaluates measuring radiation 20 in a third wavelength range of a reflected light device in the form of bright-field incident light 13a, in order to measure, for example, the structure 14c on a surface with a slightly lower height than the structure 14b. Alternatively or additionally, the structure 14c can also be a structure with a different inclination, so that structures illuminated at the same or different heights by means of bright-field incident light 13a and dark-field incident light 13b can be measured simultaneously, without the two incident light sources being recorded superimposed in the image data.

[0142] In addition to focusing one of the two image processing sensors 11, 12 (first BV sensor) on a first of the structures 14a, 14b (first structure), it may be necessary for the other image processing sensor 11, 12 (second BV sensor) to be focused on the other of the structures 14a, 14b (second structure). This is the case if the depth of field of the second BV sensor is not large enough to capture the second structure sharply even if the first BV sensor has focused on the first structure. When focusing the second BV sensor, the position of the optical sensor 10 must not be adjusted at all or only to the extent that the first BV sensor still captures the first structure sharply. The permissible travel path is therefore limited by the depth of field of the first BV sensor.Therefore, the invention provides for the solution that the working distance of at least one of the two image processing sensors 11, 12 is adjustable, preferably CNC-adjustable or CNC-controllable. In the . Fig. In the example shown in Figure 2, the movable lens groups 12b-2 and 12b-3 are provided in the beam path of the image processing sensor 12. Alternatively, only one movable lens group can be provided, or other manipulation of optical assemblies can be performed, for example, changing the refractive power of at least one lens such as a liquid lens or TAG lens and / or changing the optical path length by changing the thickness of a plate such as a plane plate and / or changing the distance of the camera 12a from the optical assemblies 12b, 18, 16. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] WO 2022251395

[0003] WO 2022251396

[0003] WO 2022251397

[0003] WO 2022251398

[0003] DE 102017107343

[0006] DE 102017129221

[0006] DE 102011056819

[0037] DE 102019105766

[0038] EP 1238244

[0072]

Claims

[1] Method for determining measuring points on one or more surface areas of a workpiece with a sensor, wherein the sensor has a linear or planar detection area formed perpendicular to the measuring direction, within which a plurality of measuring points are detected by one or more measuring channels, in particular a distance value is determined by determining the respective sensor deflection along the measuring direction of the sensor (sensor axis), and wherein measuring points on surface areas are detected in one or more different sensor positions relative to the workpiece, preferably a plurality of sensor positions distributed offset from one another along a measuring path at least in a translational direction,wherein the detected surface areas have a curvature and / or an angle to the measuring direction of the sensor at least in some areas within the detection range of the sensor or at least within the area detected along a measuring path, , characterized by that if at least one quality criterion is not met, one or more measuring points are excluded from the evaluation or corrected, preferably by adding further, in particular neighboring, measuring points. [2] Coordinate measuring machine (CMM) for carrying out the method according to at least claim 1, wherein the CMM comprises at least one sensor and means for relative movement between the workpiece and the sensor, preferably at least means for relative movement in one, two or three translational, in particular Cartesian, axes, characterized bythat the coordinate measuring machine has additional means for relative movement about at least one axis of rotation, in that the sensor originates from a rotary joint or a rotary-swivel joint and / or in that the workpiece originates from a rotary axis or a rotary-swivel axis. [3] Method for operating a coordinate measuring machine, which has at least one distance sensor (sensor) and a rotary unit designed to rotate the workpiece and / or at least one translation unit designed to translate between the workpiece and the distance sensor, such as a measuring axis, wherein the distance sensor records a plurality of measuring points on the surface of the workpiece in several rotational positions and / or translational positions between the workpiece and the distance sensor, wherein the workpiece is a tool with one or more cutting edges (tool cutting edges), characterized bythat measuring points are recorded in one or more areas adjacent to the one or more tool cutting edges, in particular on at least one chip and / or flank surface, and that the measuring points (bad part contour) are compared with reference measuring points (reference contour) of a master part measurement of an identical workpiece or with the target data of the workpiece and deviations are shown on a display means and / or made available for further evaluation. [4] Method for the dimensional measurement of geometric properties on workpieces with a coordinate measuring machine, comprising at least one image processing sensor, wherein the image processing sensor comprises at least one camera and wherein at least one light source, in particular at least one incident light source such as bright field incident light or dark field incident light and / or at least one transmitted light source is assigned to the image processing sensor, and wherein the workpiece or at least workpiece regions are illuminated by means of the light source, and wherein the workpiece or at least workpiece regions are imaged onto the camera of the image processing sensor, preferably wherein the image processing sensor has an imaging optics, characterized bythat the measurement is carried out on workpiece areas for which the light from the light source, in order to image the workpiece areas onto the camera, has to penetrate at least one layer (cover layer) of the workpiece which is not transparent or at least barely transparent (transmission less than 10%, preferably less than 5%, particularly preferably less than 1%) for light in the visible range, by operating the light source in the infrared range. [5] Device for carrying out the method according to at least claim 4, characterized by that the coordinate measuring machine (1) with image processing sensor (2, 2a, 2b) has at least one light source (3, 3a, 3b, 3c), in particular incident light source (3a, 3b) such as bright field incident light (3a) or dark field incident light (3b) and / or transmitted light source (3c), which is designed to be operable as an infrared light source. [6] Method for determining geometric features on workpieces with an optical sensor in a coordinate measuring machine, wherein the optical sensor comprises at least two image processing sensors (BV sensors), wherein each image processing sensor (BV sensor) comprises at least one image capturing device such as a camera and an optical imaging beam path associated therewith for recording image data of the workpiece, wherein the plurality of imaging beam paths run through a common optical front system and image measuring radiation coming from the direction of the workpiece onto the respectively associated image capturing devices, and wherein at least one transmitted light device and at least one incident light device such as bright field incident light and / or dark field incident light are operated to generate the measuring radiation, characterized bythat each of the plurality of image processing sensors evaluates a defined wavelength range of the measuring radiation when recording the image data, wherein the wavelength ranges evaluated by the plurality of image processing sensors do not overlap or only partially overlap, and that at least two of the image processing sensors record image data from the workpiece simultaneously or almost simultaneously. [7] Device for determining geometric features (14a, 14b, 14c) on workpieces (14) with an optical sensor (10) in a coordinate measuring machine, wherein the optical sensor (10) comprises at least two image processing sensors (BV sensors) (11, 12), wherein each image processing sensor (BV sensor) (11, 12) comprises at least one image capturing device (11a, 12a) such as a camera and an optical imaging beam path (11b, 12b, 18, 19, 16) associated therewith for recording image data of the workpiece (14), wherein the plurality of imaging beam paths run through a common optical front system (16) and measuring radiation (20) coming from the direction of the workpiece (14) can be imaged onto the respectively associated image capturing devices (11a, 12a), and wherein the coordinate measuring machine comprises at least one Transmitted light device (13c) and at least one incident light device (13a,13b) such as bright field incident light (13a) and / or dark field incident light (13b), characterized by that with each of the plurality of image processing sensors (11, 12) a defined wavelength range of the measuring radiation (20) can be evaluated when recording the image data, wherein the wavelength ranges evaluated by the plurality of image processing sensors (11, 12) do not overlap or only partially overlap, and that at least two of the image processing sensors (11, 12) are designed for the simultaneous or almost simultaneous recording of image data from the workpiece.

Images