DE102016014564A1 - Measuring device for monitoring a machining process using measurement information acquired at different measuring positions - Google Patents

Abstract

The invention relates to a measuring device (12) for monitoring a machining process, which is connected to a machining device (14) for machining a workpiece (W) by means of a high-energy machining beam (56), the high-energy machining beam (56) being in a machining direction (BR). along a main processing path (H) relative to the workpiece (W) is movable. The measuring device (12) comprises an optical coherence tomograph (16) with a measuring beam source (26) for generating an optical measuring beam (28), and a movable measuring beam deflecting device (44) which is adapted to operate the optical measuring beam (28) during processing Direction of the main processing path (H) to a first measuring position (Pre) and / or to a second measuring position (In) and / or to a third measuring position (Post) on the workpiece (W) to relocate. The measuring device (12) comprises an evaluation device, the measurement information at the or a further first measurement position (Pre) and / or measurement information at the or a further second measurement position (In) and / or measurement information at or a further third measurement position (Post) Measure detected at the first and / or second and / or third measurement position (Pre, In, Post) measurement information recorded and / or evaluated.

Description

The invention relates to a measuring device for monitoring a machining process, a system for machining and monitoring a workpiece and a method for monitoring a machining process. The measuring apparatus is connected or connectable to a machining apparatus for machining a workpiece by means of a high-energy machining beam, wherein the high-energy machining beam is movable at a machining speed in a machining direction along a predetermined main machining path relative to the workpiece. The measuring device comprises an optical coherence tomograph with a measuring beam source for generating an optical measuring beam. Furthermore, the measuring device comprises at least one movable measuring beam deflecting device, which is set up to displace the optical measuring beam during machining substantially in the direction of the main machining path to a first measuring position and / or to a second measuring position and / or to a third measuring position on the workpiece. The first measuring position is viewed in the machining direction in front of a provided current processing position to detect by means of the optical measuring beam to be machined portion of the workpiece. The second measuring position lies in the region of the intended current processing position in order to detect an area of the workpiece that is being processed by means of the optical measuring beam. The third measuring position, viewed in the machining direction, lies behind the intended current machining position in order to detect a machined region of the workpiece by means of the optical measuring beam.

Such measuring devices, which allow a simultaneous monitoring of the machining during a machining of a workpiece, are known from the prior art and are used in particular in laser welding processes. In this case, a high-energy processing beam in the form of a laser processing beam is used, for example, to connect two or more workpieces or workpiece parts in the region of a lap joint, a seam joint and / or a joining edge. Essentially at the same time as the machining, measuring information is recorded on the workpiece by means of the optical measuring beam.

The measuring device may be coupled to the processing device and attached to a robot so that they are moved together by the robot in the processing direction along the main processing path. Alternatively or additionally, the relative movement between the workpiece and the processing beam can also be realized by displacing the processing beam and / or moving the workpiece. By movable optics, such as the movable Meßstrahlablenkeinrichtung, the optical measuring beam and / or the processing beam, in addition to or as an alternative to the robot movement on the workpiece to be relocated. In this case, for example, an oscillation movement of the optical measuring beam and / or the high-energy processing conflict can be generated.

In known measuring devices, the method of optical coherence tomography (OCT) is increasingly used. This is based on the basic principle of the interference of light waves and resulting effects. Optical coherence tomography makes it possible to detect differences in height along an optical measuring beam axis in the micrometer range. For this purpose, measuring light is generated by means of the measuring beam source of the optical coherence tomograph and separated by means of a beam splitter into the optical measuring beam and an optical reference beam. The optical measuring beam passes through a measuring arm and strikes the workpiece to be monitored or processed at one end of the measuring arm. At this the optical measuring beam is at least partially reflected and returned to the beam splitter. The reference optical beam passes through a reference arm and is at least partially reflected at one end of the reference arm, whereupon the reflected reference optical beam is also returned to the beam splitter. The superimposition of the reflected optical measuring beam and the reflected optical reference beam is finally detected in order to obtain height information about the respective measuring point at one of the measuring positions, taking into account the length of the reference arm.

Against this background, it is understood that measurement information acquired by means of an optical measuring beam in the sense of this invention can comprise height information of a measuring point at the respective measuring position, i. topographic information of the workpiece surface and / or information regarding the penetration depth of the machining beam. Furthermore, the measurement information may include further information, for example about the position of the measuring point and / or a measuring position on the workpiece, which can be linked to the height information.

Monitoring the processing by the measuring device according to the invention enables a comprehensive quality assurance of the machining process. In addition, performing position measurements in the sense of the invention can also be used to control the machining process can be used by adjusting process parameters according to the acquired measurement information during processing.

In order to ensure monitoring, quality assurance and process control, the optical measuring beam can be provided to scan a surrounding area of a current machining position on the workpiece. A measuring device configured for this purpose is, for example, in German Patent Application No. 10 2015 007 142.4 the applicant described. The measuring device proposed therein comprises a movable deflecting device according to the preamble of claim 1 of the present invention for displacing the measuring beam into at least a first measuring position, a second measuring position and / or a third measuring position during machining on the workpiece substantially in the direction of the main machining path ,

A disadvantage of these and other known OCT measuring devices, however, is that by means of the optical measuring beam next to the main processing path or instead of the main processing path, environmental areas are detected on the workpiece, which have an undesirably large distance from the main processing path. As a result, for example, environmental areas are monitored laterally of the main processing path, which have only a low relevance for quality assurance and process control and still bind resources of the measuring device during the measurement. In addition, such regions spaced relatively far from the main processing path may have particular features, such as imperfections or contaminants. These features are taken into account in detecting the spaced regions for quality assessment of the weld, although due to the large distance they do not have a direct impact on the quality of the weld.

The document DE 10 2011 012 729 A1 discloses a method and a measuring device intended to define a test area for performing three-dimensional edge detection. For this purpose, the measuring device described uses a line triangulation method, by means of which, first of all, a two-dimensional intensity image of a test contour and its surroundings is generated before a three-dimensional inspection of a workpiece. After a test head of the measuring device has completely traversed the test contour in a first pass and detected corresponding images, the measuring device generates a two-dimensional intensity image. This intensity image is then used as a basis for a three-dimensional inspection, which is also carried out in a second pass by means of the line triangulation method.

That in the document DE 10 2011 012 729 A1 However, the method described has the disadvantage that the lines of light required for the line triangulation method, unlike the optical measuring beam of the optical coherence tomography can not be coaxially coupled into an associated high-energy processing beam. This complicates the process monitoring, more precisely the quality assurance and process control, during processing. In addition, the repeated shutdown of the test contour is associated with an increased amount of time.

It is an object of the present invention to provide a measuring apparatus, method and system for monitoring a machining process that enables efficient and accurate quality assurance and process control.

This object is achieved by a measuring device having the features of claim 1, a system having the features of claim 12 and a method having the features of claim 13.

Preferred embodiments will be apparent from the dependent claims 2 to 11 and from the following description.

According to the invention, a measuring device of the aforementioned type is provided, which comprises an evaluation device, the measurement information at the or a further first measurement position and / or measurement information at the or a further second measurement position and / or measurement information at the or a further third measurement position in accordance with detected and / or evaluated measured information acquired the first and / or second and / or third measurement position.

Since the intended current machining position changes by the movement of the high-energy machining beam during machining and the measuring device according to the invention is adapted to displace the optical measuring beam around the current machining position, it is understood that during the machining process, measurement information at a plurality of first and / and second and / or third measuring positions are detectable.

The detection and / or evaluation of measurement information in accordance with already acquired measurement information according to the invention may comprise a determination of a monitoring area to be detected, for example by means of control the displacement of the optical measuring beam. Furthermore, the detection and / or evaluation of measurement information according to the invention can comprise setting a measurement resolution in the monitoring area in accordance with measurement information already acquired. Additionally or alternatively, the detection and / or evaluation of measurement information according to the invention in accordance with already acquired measurement information may include setting measurement information to be taken into consideration during an evaluation.

In one embodiment of the invention, the evaluation device can evaluate measurement information acquired at the third measurement position in accordance with measurement information acquired at the first and / or second measurement position. In other words, the present invention provides, for example, to use acquired measurement information for a region under processing or a region of the workpiece to be processed in order to improve the evaluation of measurement information acquired with respect to an already processed region of the workpiece. Thus, during the processing of the workpiece, the measuring device according to the invention can use measured information acquired at the first and / or second measuring position in order to define a monitoring area for optimum quality assurance at the third measuring position.

In a further embodiment, during the processing of the workpiece, the measuring device according to the invention can use measured information acquired at the first measuring position in order to define a monitoring area for optimum quality assurance and process control at the second measuring position. Thus, the measuring device can be set up to use acquired measurement information for a region of the workpiece to be processed in order to improve an evaluation of measurement information acquired for a region of the workpiece that is being processed.

Furthermore, the measuring device according to the invention can be set up in a further development to displace the optical measuring beam only to a multiplicity of first, second or third measuring positions. In this case, during the machining of the workpiece at a first, second or third measuring position, the measuring device can use the measured information acquired to determine a monitoring area for optimum quality assurance and process control at a further first, second or third measuring position of the plurality of measuring positions ,

Since the optical measuring beam can be coupled coaxially into the processing beam by the use of optical coherence tomography and can be displaced by means of the movable measuring beam deflection device to the various measuring positions in an (ambient) region of the intended current processing position, the above-described evaluation can be carried out substantially simultaneously for processing become. Thus, the monitoring area relevant for quality assurance and process control can be adapted parallel to the processing in accordance with the acquired measurement information in the first and / or second measurement position. It is therefore not necessary to determine the relevant monitoring area in an additional, separate measuring process. In addition, the flexible adaptation of the monitoring range to be used for the evaluation, for example, to properties of the main machining path, the workpiece to be machined and / or to process parameters of the machining, enables precise quality assurance as well as fast and accurate process control.

It is understood that the optical measuring beam can be displaceable in further embodiments of the measuring device according to the invention in addition to the first, second and / or third measuring position in further measuring positions in the surrounding area of the provided current processing position.

In one development of the invention, the optical measuring beam can be displaceable by means of the at least one movable measuring beam deflecting device or by means of a further movable measuring beam deflecting device at the first, second and / or third measuring position to a multiplicity of measuring points in a scanning direction transversely to the direction of the main machining path, around the workpiece by sampling measurement information at each of the plurality of measurement points in sections. The displacement of the optical measuring beam to the different measuring positions thus describes an alignment of the optical measuring beam to the measuring positions in which a plurality of measuring points can be scanned by means of the optical measuring beam. The displacement of the optical measuring beam to the measuring positions can be carried out independently of the scanning to be performed so that, for example, no measuring points are scanned during the displacement of the measuring beam between the measuring positions. Thus, the optical measuring beam can be aligned to different measuring positions, without that the measuring beam must follow a predetermined sampling curve. This increases the efficiency and speed of process monitoring. In addition, the distance between the measurement positions or between the measurement positions and the current processing position can be variable, which further increases the flexibility of the monitoring.

In the above development, the detection and / or evaluation of measurement information in accordance with previously acquired measurement information may include controlling the optical measurement beam to adjust the width, the symmetry and / or the direction of the scan across the main processing path. As a result, an automatic direction adjustment to the course of the main processing path can be achieved. Furthermore, the detection and / or evaluation of measurement information according to the invention in accordance with already acquired measurement information in the above development may include adjusting the measurement resolution by changing the number of measurement points to be scanned. For example, a higher sampling resolution may be set in a measurement region near the main processing path, while a measurement region further spaced from the main processing path is scanned at a lower resolution. Furthermore, the high-energy processing beam or an editing window can be controlled accordingly in accordance with acquired measurement information.

The main processing path can be scanned according to the invention equally or differently on both sides. The optical measuring beam may be displaceable along a discrete line for scanning the plurality of measuring points at the different measuring positions transversely to the direction of the main processing path. Also, the number of measurement points to be detected in the different measurement positions and the respective measurement distance can be adaptable transversely to the direction of the main processing path in the measurement positions. In particular, the adjustments and adjustments described above with regard to the third measurement position may be adaptable in accordance with measurement information acquired at the first and / or second measurement position.

According to a further embodiment of the invention, the scanning direction can be adjustable transversely to the direction of the main machining path in accordance with machining information, in particular in accordance with the machining direction and / or the machining speed. As a result, the measuring beam can be adapted dynamically and individually to the current machining process. Furthermore, the number of measuring points and thus the resolution of the scanning as well as the distance between the measuring positions can be predetermined as a function of the machining information.

In a refinement, the evaluation device of the measuring device according to the invention can be set up to measure a set of measuring points from the sampled at the or a further first, second and / or third measuring position in accordance with the measured information acquired at the first and / or second and / or third measuring position To select a plurality of measuring points, which are to be used for evaluating the detected at the one or more first, second and / or third measurement position measurement information. Measurement information sampled measuring points, which are not relevant for quality assurance and / or process control, can be deliberately neglected in the evaluation. In this way, the evaluation device can define the monitoring area to be used for quality assurance and process control, which is advantageous in terms of measuring accuracy and the required measuring and computing time.

An embodiment according to the invention provides that the measuring device detects an edge of the workpiece to be machined at the first measuring position and / or detects a molten bath at the second measuring position and / or detects a solidified weld seam of the workpiece at the third measuring position. In this embodiment, the evaluation device can use a detected edge position of the main machining path and / or the current molten bath position in order to define the monitoring area for the quality assurance and process control in the area of the cooled weld seam. This makes it possible to judge whether detected pores and spatters in the surrounding area of the main machining path are within or outside the defined monitoring area.

Furthermore, the evaluation device can be set up to determine, based on a comparison of the measurement information acquired at the third measurement position with the measurement information acquired at the first measurement position, a volume of the workpiece melted by the machining and / or a connection cross-section generated by the machining. As a result, for example, the weld quality can be assessed and compliance with certain standards can be controlled. The comparison can be made, for example, by a comparison of the profile of the joining edge to be processed detected at the first measuring position and the profile of the cooled weld detected at the third measuring position, i. the machined joint edge, done.

In one development of the invention, the evaluation device can be set up to determine the position of the current processing position relative to the edge of the workpiece to be processed on the basis of a comparison of the measurement information acquired at the first measurement position with the measurement information acquired at the second measurement position. For example, a lateral offset of the current processing position relative to the main processing path or to be processed Edge already detected during processing and corrected by an appropriate process control.

In another embodiment of the invention, the evaluation device can be set up to generate a search pattern from the measurement information acquired at the first or third measurement position. For this purpose, the evaluation device uses individual properties of the workpiece to be machined, such as its surface roughness, its surface structure, etc. The measurement information to be used to create the search pattern can be arbitrarily selected by a user of the measuring device according to the invention.

The evaluation device of the measuring device according to the invention can also be set up to compare the search pattern with measurement information acquired at a first and / or third measuring position in order to determine the machining speed and / or machining direction. In this case, the processing speed and / or machining direction need not be transmitted via a fieldbus interface, but can be determined by a profile comparison by means of autocorrelation or other methods of image processing from the acquired measurement information. It is understood that the measurement information used for the comparison described above can be detected in succession at the first and third measurement positions of the same measurement sequence, depending on the processing speed and / or speed of the displacement of the optical measurement beam. Alternatively, however, a search pattern can also be created from measurement information acquired at a first or third measurement position and compared with measurement information acquired at a later time of the processing process at a further first and / or further third measurement position.

According to one development of the invention, the measuring device can be set up to regulate a feed of a supplementary material supplied during the machining process for machining the workpiece, for example an additional wire, in accordance with the acquired measuring information, the machining direction and / or the machining speed.

In a further embodiment, the measuring device according to the invention can be set up to adapt a distance of the first measuring position and / or the third measuring position from the intended current processing position in accordance with the acquired measuring information, the machining direction and / or the machining speed. It is understood that this also the distance between the individual measuring positions is adjustable with each other. In particular, by adjusting the distance of the measurement positions to the current processing position or each other at the end of the processing process as described above, it can be ensured that at least one of the measurement positions is aligned with the cooled end region of the processed main processing path. Thus, measurement information for quality assurance can be detected in the entire area of the processed processing path.

Furthermore, the measuring device can be set up to adapt the alignment of the scanning direction, in particular in the third measuring position, in accordance with the acquired measuring information, the machining direction and / or the machining speed.

The invention further relates to a system for processing and monitoring a workpiece comprising a measuring device of the type described above and a processing device. The processing apparatus is configured to move a high-energy processing beam at a processing speed in a processing direction along a predetermined main processing path relative to the workpiece to machine the workpiece by the high-energy processing beam.

The measuring device provided in the system can have any features or feature combinations of the previously described developments and / or embodiments of the measuring device according to the invention.

• - Erzeugen eines optischen Messstrahls mittels einer Messstrahlquelle eines optischen Kohärenztomographen; und
• - Verlagern des optischen Messstrahls während des Bearbeitens im Wesentlichen in Richtung des Hauptbearbeitungspfads an eine erste Messposition und/oder an eine zweite Messposition und/oder an eine dritte Messposition auf dem Werkstück mittels wenigstens einer bewegbaren Messstrahlablenkeinrichtung.

Furthermore, the invention relates to a method for monitoring a machining process of a workpiece by means of a high-energy machining beam, which is carried out in particular by means of a measuring device of the type described above. The high energy machining beam is moved relative to the workpiece by a machining apparatus at a machining speed in a machining direction along a predetermined main machining path. The method according to the invention comprises the steps:

• Generating an optical measuring beam by means of a measuring beam source of an optical coherence tomograph; and
• - Moving the optical measuring beam during processing substantially in the direction of Hauptbearbeitungspfads to a first measuring position and / or to a second measuring position and / or to a third measuring position on the workpiece by means of at least one movable Meßstrahlablenkeinrichtung.

• - Erfassen und/oder Auswerten von Messinformationen an der oder einer weiteren ersten Messposition und/oder Messinformationen an der oder einer weiteren zweiten Messposition und/oder Messinformationen an der oder einer weiteren dritten Messposition nach Maßgabe von an der ersten und/oder zweiten und/oder dritten Messposition erfassten Messinformationen mittels einer Auswerteeinrichtung der Messvorrichtung.

The first measuring position, viewed in the machining direction, is located in front of an intended current machining position, so that an area of the workpiece to be machined is detected by means of the optical measuring beam. The second measuring position lies in the region of the intended current processing position, so that by means of the optical measuring beam a stationary area of the workpiece is detected. The third measuring position, viewed in the machining direction, lies behind the intended current machining position, so that a machined region of the workpiece is detected by means of the optical measuring beam. The method according to the invention further comprises the step:

• Detecting and / or evaluating measuring information at the or a further first measuring position and / or measuring information at the or a further second measuring position and / or measuring information at the or a further third measuring position in accordance with at the first and / or second and / or third measurement position detected measurement information by means of an evaluation of the measuring device.

The method according to the invention may comprise further steps in order to realize any of the aforementioned effects, working steps and / or operating states of the measuring device according to the invention. The same applies to the following explained aspects of the embodiments.

It is understood that the subject matter of the invention is not limited to the embodiments and / or developments described above. The described embodiments, developments and features can be combined as desired by the person skilled in the art, without departing from the subject matter of the invention.

• 1 eine Übersichtsansicht eines Ausführungsbeispiels des erfindungsgemäßen Systems zum Bearbeiten und überwachen eines Werkstücks;
• 2 ein Beispiel von Messpositionen und Messpunkten auf einem Werkstück;
• 3 ein weiteres Beispiel von Messpositionen und Messpunkten auf einem Werkstück zur Erläuterung von Funktionsprinzipien der erfindungsgemäßen Messvorrichtung;
• 4 einen Überlappstoß zweier miteinander zu verbindender bzw. verbundener Werkstückteile;
• 5 einen Stumpfstoß zweier miteinander zu verbindender bzw. verbundener Werkstückteile mit einem zwischen diesen liegenden Spalt;
• 6 ein erfasstes Profil eines zu bearbeitenden Überlappstoßes zweier Werkstückteile sowie ein erfasstes Profil eines bearbeiteten Überlappstoßes zweier Werkstückteile;
• 7 ein auf einem Werkstück festgelegtes und erfasstes Suchmuster.

Preferred embodiments of the invention are explained below with reference to the accompanying schematic drawings. They show:

• 1 an overview of an embodiment of the system according to the invention for processing and monitoring of a workpiece;
• 2 an example of measuring positions and measuring points on a workpiece;
• 3 a further example of measuring positions and measuring points on a workpiece for explaining functional principles of the measuring device according to the invention;
• 4 a lap joint of two workpiece parts to be joined together;
• 5 a butt joint of two to be joined or connected workpiece parts with a gap between them;
• 6 a recorded profile of a lap joint to be processed two workpiece parts and a detected profile of a processed lap joint of two workpiece parts;
• 7 a search pattern set and captured on a workpiece.

1 shows an overall arrangement of an embodiment of the system according to the invention, generally with the reference numeral 10 is designated. The system 10 includes a measuring device 12 and one with the measuring device 12 connected processing device 14 ,

The measuring device 12 includes an optical coherence tomograph 16 (OCT) with an OCT meter 18 that has a beam splitter 20 with a measuring arm 22 and a reference arm 24 connected is. Further, the OCT meter 18 with a measuring beam source 26 for generating an optical measuring beam 28 and a spectrometer 30 designed to detect a superimposed measuring radiation. Furthermore, the OCT meter 18 one in 1 shown circulator 32 include the beam splitter 20 via a transport fiber or a light guide 34 optionally with the measuring beam source 26 or the spectrometer 30 combines.

The measuring arm 22 of the optical coherence tomograph 16 is with a measuring optics 36 the measuring device 12 connected. Via an interface 38 the measuring optics 36 becomes the optical measuring beam 28 into the measuring optics 36 coupled and passes through a movable collimating lens 40 pointing in the direction of the arrow 42 is movable. In the measuring optics 36 the optical measuring beam hits 28 on a movable Meßstrahlablenkeinrichtung 44 , The movable measuring beam deflection device 44 is in the direction of the arrows 46 . 48 displaceable to the optical measuring beam 28 deflected in the desired manner, ie to the optical measuring beam 28 in the exemplary embodiment shown, during a machining process, either to shift to a first measuring position (Pre), a second measuring position (In) or a third measuring position (Post) on a workpiece W to be machined. The first measuring position (Pre) lies in a machining direction (BR), viewed in front of a provided current machining position, by means of the optical measuring beam 28 a region of the workpiece W to be machined, ie a joint, to be detected. The second measuring position (In) is in the range of the intended current processing position, by means of the optical measuring beam 28 To detect a machined portion of the workpiece W, ie, a generated molten pool. The third measuring position (post) is in Machining direction BR looks behind the intended current machining position to by means of the optical measuring beam 28 to detect a machined region of the workpiece W, ie a cooled weld.

Further, the movable measuring beam deflecting device 44 is displaceable in the direction of the arrows 46, 48 to the optical measuring beam 28 desirably shift at the individual measuring positions (Pre, In, Post) to a plurality of measuring points in order to scan the workpiece in the individual measuring positions (Pre, In, Post), which will be described below with reference to FIGS 2 and 3 is explained in more detail.

It is understood that the displacement of the optical measuring beam 28 by means of the movable measuring beam deflection device 44 in addition to the relative movement between the system 10 and the workpiece W to be machined, and thus superimposes this relative movement.

The movable measuring beam deflection device 44 is formed in the example shown in the form of a displaceable galvanometer scanner. Alternatively, in other embodiments of the measuring device according to the invention also an education in the form of another movable optical component is possible, such as a tumbling mirror, a rotatable wedge plate or the like. The measuring device 12 further includes an in 1 not shown evaluation device, for example, in the measuring device 12 can be integrated or located away from this and with the measuring device 12 can be connected. The evaluation device is used for processing and evaluation by means of the optical measuring beam 28 recorded measurement information for quality assurance and process control.

The processing device 14 has a processing optics 50 with an interface 52 on top of an optical fiber 54 a high energy machining beam 56 For example, a laser beam generated by a laser beam source, not shown, is coupled for processing the workpiece W. The workpiece W to be machined consists in the example shown of a first workpiece part W 'and a second separate workpiece part W ", which are to be joined together. In the in 1 the example shown, the two workpiece parts W, W "are arranged in an overlapping manner, so that a joint is shown in the form of a lap joint. This forms the intended main processing path (H) in the example shown. It is understood that as an alternative to the embodiment shown, also an editing and monitoring of any other workpiece impact by means of the system according to the invention 10 is possible, such as a butt joint with an intervening joint gap.

The high-energy processing beam 56 goes through in the processing optics 50 a collimation lens 58 that according to the arrow 60 is relocatable. As a result, the processing beam hits 56 on a half-transparent mirror 62 and becomes a movable further deflector 64 reflected. The movable further deflection device 64 is in 1 also formed in the form of a galvanometer scanner, extending in the direction of the two arrows 66 . 68 shift to the machining beam 56 distract in the desired manner. Instead of the galvanometer scanner shown, it is possible to form the further deflection device in the form of another displaceable optical component, such as a tumbling mirror, a rotatable wedge plate or the like.

The further deflection device 64 is a focus lens in the embodiment shown 70 downstream of the processing beam 56 will pass through and projected this for editing on the workpiece W and focused. It is understood that, alternatively, an upstream arrangement of the focus lens 70 to the further deflection device 64 is possible.

The measuring optics 36 the measuring device 12 and the editing optics 56 the processing device 14 are interconnected in a way that they share a common interface 72 exhibit. About this common interface 72 becomes the optical measuring beam 28 after being deflected by the movable measuring beam deflector 44 into the processing apparatus 14 coupled. More precisely, the optical measuring beam hits 28 on the half-transparent mirror 62 and passes through this, causing the optical measuring beam 28 the high-energy processing beam 56 essentially coaxially superimposed. Thus, the optical measuring beam hits 28 also on the movable further deflection 64 and then passes through the focus lens 70 after moving from the movable further deflector 64 has been distracted.

As from the in 1 can be seen, the optical measuring beam superimpose 28 and the high energy machining beam 56 exactly when the optical measuring beam 28 by means of the movable measuring beam deflection device 44 is aligned to the second measuring position (In) on the workpiece W, ie to the current machining position. This superposition is in the embodiment shown by a dot-dash line of the beam path between the other deflection 64 and the workpiece W shown. Is the optical measuring beam 28 by means of the movable measuring beam deflection device 44 The optical measuring beam points at the first measuring position (Pre) or the third measuring position (Post) on the workpiece W 28 a small offset to the high energy machining beam 56 on. The dashed lines between the other deflector 64 and the workpiece W mean in the embodiment shown that only the optical measuring beam 28 and not the high-energy processing beam 56 to the first and third measuring position (Pre, Post) is displaceable. It is understood that the distance between the first and the third measuring position (Pre, Post) and the second measuring position (In) and thus the offset between the measuring beam 28 and the processing beam 56 is comparatively small, so that despite this offset, a substantially coaxial superposition of the rays 28 . 56 is present.

2 shows a plan view of a partially machined workpiece W, in the exemplary sampling of a plurality of measuring points 74 by means of the optical measuring beam 28 in the three measuring positions (Pre, In, Post) is shown in the sense of the invention. In the example shown, the main machining path H corresponds to the joint between the workpiece parts W ', W "of the workpiece W and runs in the X direction. The joint was in the illustrated illustration by moving the high-energy machining beam 56 already partially processed in the machining direction BR. In the area of the current machining position 76 generates the processing beam on the workpiece W a Dampfkapillare, the so-called keyhole, with surrounding melt, whereby portions of the workpiece parts W, W "are melted on and welded together. While in the area of the first measuring position (Pre) the still unprocessed joining edge can be seen, the area of the third measuring position (post) shows the already processed, cooled weld seam.

At each of the three measuring positions (Pre, In, Post) is the optical measuring beam 28 on the multitude of measuring points 74 displaceable to the workpiece W for acquiring measurement information at the individual measuring points 74 scan. The exact scanning direction across the direction of the main machining path H, in which the individual measuring points 74 at one of the measuring positions (Pre, In, Post) and the respective number of measuring points 74 and the respective distance of the measuring points 74 from each other can be adjusted according to the machining process and in further embodiments of the in 2 different example shown. As can be seen in the exemplary embodiment shown, the scanning direction points in both the X and Y directions and is not exactly orthogonal to the direction of the main machining path H. As a result, the relative movement between the optical measuring beam and the workpiece can be compensated or at least taken into account ,

By means of the optical coherence tomography, height information of the sampled measuring points is obtained by means of the optical measuring beam 74 recorded at the different measuring positions (Pre, In, Post). The evaluation device of the measuring device is created from these detected height information 12 Profiles of Hauptbearbeitungspfads H, more precisely, the joining edge between the workpiece parts W ', W ". Exemplary profiles of an unprocessed joining edge (at the first measuring position) and a processed joining edge (at the third measuring position) are in 2 shown above the associated measuring position.

3 shows a further plan view of a partially machined workpiece W for illustrating functional principles of the measuring device 12 according to the invention.

According to a first exemplary operating principle of the invention, the optical measuring beam 28 initially shifted to the first measuring position (Pre), at the means of the measuring beam 28 the shown plurality of measuring points 74 is scanned transversely to the direction of the main processing path H to create a profile of the unprocessed joining edge between the workpiece parts W, W "from the measurement information acquired thereby. From the acquired measurement information or from the created profile of the joining edge, the evaluation device determines the exact position of the joining edge.

Subsequently, the optical measuring beam 28 moved to the third measuring position (post), at the also by means of the measuring beam 28 the shown plurality of measuring points 74 is scanned transversely to the direction of the main processing path H to create a profile of the processed joining edge between the workpiece parts W, W "from the measurement information acquired thereby. A subsequent evaluation of this profile allows a quality assessment of the processed joining edge, for example, by defects and splashes are detected in the area of the cooled weld. How out 3 can be seen, but at the third measuring position (post) also measuring points 74 scanned across the direction of the main machining path H, which are spaced from the cooled weld. Consideration of these spaced from the cooled weld measuring points 74 During the evaluation, the quality assessment of the weld can be falsified and the required measurement and calculation time increased.

For this reason, the evaluation device evaluates the at the third measuring position (post) acquired measurement information in accordance with the measured at the first measurement position (Pre) measurement information. More precisely, the evaluation device uses the measurement information acquired at the first measurement position (Pre) or the profile created therefrom and / or the position of the unprocessed joining edge in order to determine a monitoring region relevant for the evaluation of the measurement information acquired at the third measurement position (Post). The limits of a specified exemplary monitoring area are those in the 3 shown by the horizontal lines 76 . 78 at the third measuring position (post). In the example shown, the evaluation device evaluates at the third measuring position (post) thus only those at the between the lines 76 . 78 lying measuring points 76 recorded measurement information for a quality assessment. In order to determine the monitoring range and to correspondingly adapt the scanning resolution in this area, the evaluation device can also take into account other parameters of the machining process, such as the intensity of the machining beam, the material of the workpiece, the machining speed, in addition to the measurement information acquired at the first measuring position (Pre). Etc.

According to a second exemplary operating principle of the invention, the optical measuring beam 28 initially shifted to the second measuring position (In), at the means of the measuring beam 28 a plurality of measuring points are scanned repeatedly transversely to the direction of the main processing path H, which in the in 3 shown example by the oblique lines 80 . 82 . 84 is shown. From the measurement information acquired thereby, the evaluation device determines the position and / or the width of the produced molten bath, wherein the multiple scanning of a plurality of measuring points at the second measuring position (In) ensures that the maximum width of the molten bath is detected. To determine the maximum width of the molten bath, the optical measuring beam 28 on both sides of the main processing path H are shifted from outside to inside, so from a laterally spaced from the main processing path H area in the direction of the Hautpearbeitungspfads H to Schmelzbadgrenze out. Alternatively, the optical measuring beam 28 for determining the maximum width of the molten bath on both sides of the main processing path H are displaced from the inside to the outside, ie from the Hautpbearbeitungspfads H towards the spaced apart from this Schmelzbadgrenze out.

Subsequently, the optical measuring beam 28 moved to the third measuring position (post), at the also by means of the measuring beam 28 the shown plurality of measuring points 74 is scanned transversely to the direction of the main processing path H to create a profile of the processed joining edge between the workpiece parts W, W "from the measurement information acquired thereby. A subsequent evaluation of this profile allows a quality assessment of the processed joining edge, for example, by defects and splashes are detected in the area of the cooled weld. However, as described above, at the third measuring position (post), measuring points also become 74 scanned across the direction of the main machining path H, which are spaced from the cooled weld. Consideration of these spaced from the cooled weld measuring points 74 During the evaluation, the quality assessment of the weld can be falsified and the required measurement and calculation time increased.

For this reason, the evaluation device evaluates the measurement information acquired at the third measurement position (post) in accordance with the measurement information acquired at the second measurement position (In) according to the second functional principle. More precisely, the evaluation device uses the measurement information acquired at the second measurement position (In) or at least one of the determined widths of the melt pool in order to determine a monitoring range relevant for the evaluation of the measurement information acquired at the third measurement position (Post). The boundaries of a predetermined exemplary monitoring area are, as explained above, by the horizontal lines 76 . 78 at the third measuring position (post). Also, according to the second operating principle evaluates the evaluation at the third measuring position (post) thus only those at the between the lines 76 . 78 lying measuring points 76 recorded measurement information for a quality assessment. In addition to the measurement information acquired at the second measuring position (In), the evaluation device can also take into account further parameters of the machining process, such as the intensity of the machining beam, the material of the workpiece, the determination of the monitoring area and the corresponding adjustment of the scanning resolution in this area Processing speed, etc.

According to a third exemplary operating principle of the invention, the optical measuring beam 28 initially shifted to the first measuring position (Pre), at the means of the measuring beam 28 the shown plurality of measuring points 74 is scanned transversely to the direction of the main processing path H to create a profile of the unprocessed joining edge between the workpiece parts W, W 'from the measurement information acquired thereby. From the acquired measurement information or from the created profile of the joining edge, the evaluation device determines the exact position of the joining edge.

Subsequently, the optical measuring beam 28 shifted to the second measuring position (In), at the means of the measuring beam 28 a plurality of measuring points are scanned repeatedly transversely to the direction of the main processing path H, which in the in 3 shown example by the oblique lines 80 . 82 . 84 is shown. From the measurement information acquired thereby, the evaluation device determines the position and / or the width of the produced molten bath, wherein the multiple scanning of a plurality of measuring points at the second measuring position (In) ensures that the maximum width of the molten bath is detected.

From a comparison of the measured information acquired at the first measuring position (Pre) with the measured information acquired at the second measuring position (In) or from a comparison of the position derived therefrom of the joining edge and position of the molten bath, the evaluation device determines the position of the current processing position relative to the Joining edge and possibly causes a process control to correct an unwanted deviation.

By means of the above-described specific setting of a monitoring range to be used for the evaluation in accordance with the exemplary functional principles, the quality assurance and process control of a machining process by means of the measuring device according to the invention can be improved.

It is understood that the exemplary functional principles of the invention explained above can be combined as desired. For example, the optical measuring beam can be shifted several times to different measuring positions to enable optimal quality assurance and process control. Also, measurement information acquired at the various measurement positions can be compared in different ways with each other to establish a monitoring area and to ensure optimal quality assurance and process control.

The 4 and 5 show side views of workpiece parts to be joined W, W "of a workpiece W, wherein 4 a lap joint and 5 represent a butt joint with a joint gap S. By means of a dotted line is in the two 4 and 5 each indicated the profile of the joint after processing. Like from the 4 and 5 can be seen, created by optimal processing, a nearly fluid transition between a machined area near the joining edge, was melted in the material of the workpiece W, and a raw area of the workpiece W, which is spaced from the joining edge. Although the near-fluent transition is positive for workpiece quality, it makes it difficult to assess the quality of the machined joint. From the measurement information acquired by the optical measuring beam at the measuring position of the processed joint (at the third measuring position), it is often not clear where the machined area ends and where the unprocessed area of the workpiece begins.

By applying one or more of the above-described functional principles of the invention, however, the area to be evaluated for quality assurance can be set at the third measuring position. As a result, precise quality assurance and process control can be ensured even with a smooth transition between a machined area and an unprocessed area of a workpiece.

6 shows one by means of the optical measuring beam 28 recorded profile of a lap joint to be machined two workpiece parts (see solid line) and a means of the optical measuring beam 28 recorded profile of the processed lap joint of the two workpiece parts (see dotted line). Furthermore, are off 6 the limits defined according to the invention 86 . 88 of the monitoring area shown as dotted vertical lines.

By means of a comparison of the recorded profiles of the overlap between the borders 86 . 88 In the monitoring area, the evaluation device calculates, according to a further functional principle of the invention, a volume (hatched area) of the workpiece or of the workpiece parts which has been melted by the machining. Also, the evaluation device according to another functional principle of the invention based on a comparison of the detected profiles of the lap joint between the boundaries 86 . 88 of the monitoring area to determine a connection cross-section produced by the machining between the workpiece parts. Calculating the molten volume and / or determining the cross-sectional area created may further contribute to the quality assessment of the cooled weld and thus further improve quality assurance and process control.

7 FIG. 2 shows a search pattern 90, 92 created and recorded on a workpiece W by means of the evaluation device. In the example shown, the evaluation device detects individual surface features of the workpiece W by repeatedly scanning the workpiece W at the first measuring position (Pre). For example, features to the surface roughness of the workpiece W. The multiple scanning of a plurality of measuring points at the first and third measuring position (Pre, Post) is in 7 by lines 94 shown. The measuring device according to the invention can either initially several of the lines shown 94 at the first measuring position (Pre) and then several of the shown lines 94 at the third measuring position (post) or alternately one of the shown lines 94 at the first measuring position (Pre) and one of the shown lines 94 at the third measuring position (post).

From the individual surface features of the workpiece W detected by the scanning, the evaluation device creates the search pattern in the example shown 90 in the range of the first measuring position (Pre). The created search pattern 90 includes according to 7 Measurement information on surface features of the workpiece W from multiple scans. In alternative embodiments, however, it is possible for the created search pattern 90 only measurement information on surface features of the workpiece W from a single scan along a particular scan line 94 includes.

The created search pattern is saved and during the further processing with the acquired search pattern 92 from measured at a later time measured information compared. During the editing process can successively a variety of search patterns 92 captured and with the created search pattern 90 be compared.

Detects the evaluation that the detected pattern 92 the created search pattern 90 is equal to the time difference between creating the search pattern 90 and capturing the search pattern created 90 corresponding search pattern 92 calculates the machining speed of the machining process. In this case, the evaluation device can take into account further parameters of the machining process and the monitoring for calculating the machining speed, such as the orientation of the optical measuring beam 28, the position of the measuring positions, the displacement speed of the optical measuring beam 28 between the measuring positions, etc. In contrast to conventional measuring devices, a transmission of the processing speed by means of a field bus to the measuring device is not required, since the processing speed can be determined from the measured information acquired by means of the optical measuring beam.

In order to reduce the computational effort during the machining process, the evaluator can display a search window 96 within which are the ones created with the search pattern 90 to be compared search pattern 92 to be recorded. Depending on the processing speed and displacement speed of the optical measuring beam, the search window 96 and / or the detected search pattern 92 lie at the first or the third measuring position. Also, the search pattern created at the beginning 90 be created in an alternative embodiment at the third measurement position.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The 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

• DE 102015007142 [0007]
• DE 102011012729 A1 [0009, 0010]

Claims (13)

A measuring device (12) for monitoring a machining process, which is connected or connectable to a machining device (14) for machining a workpiece (W) by means of a high-energy machining beam (56), the high-energy machining beam (56) having a machining speed in a machining direction (BR ) is movable along a predetermined main machining path (H) relative to the workpiece (W), and wherein the measuring device (12) comprises: an optical coherence tomograph (16) having a measuring beam source (26) for generating an optical measuring beam (28), and at least a movable Meßstrahlablenkeinrichtung (44) which is adapted to the optical measuring beam (28) during processing substantially in the direction of Hauptbearbeitungspfads (H) to a first measuring position (Pre) and / or to a second measuring position (In) and / or to relocate to a third measuring position (post) on the workpiece (W), the first M viewed in the processing direction (BR) before a planned current processing position (76) is located in order to detect by means of the optical measuring beam (28) a region to be machined of the workpiece (W), wherein the second measuring position (In) in the provided current processing position (76) is to detect by means of the optical measuring beam (28) a working area of the workpiece (W), and wherein the third measuring position (post) in the processing direction (BR) considered behind the intended current processing position (76 ), in order to detect a machined region of the workpiece (W) by means of the optical measuring beam (28), characterized in that the measuring device (12) comprises an evaluation device, the measuring information at the or a further first measuring position (Pre) and / or Measurement information at or another second measurement position (In) and / or measurement information at or further third measurement position (post) in accordance with measured at the first and / or second and / or third measurement position (Pre, In, post) recorded measurement information and / or evaluated. Measuring device (12) after Claim 1 , characterized in that the optical measuring beam (28) by means of the at least one movable measuring beam deflection device (44) or by means of a further movable measuring beam deflection device at the first, second and / or third measuring position (Pre, In, Post) to a plurality of measuring points (74 ) in a scanning direction transversely to the direction of the main machining path (H) is displaceable to scan the workpiece (W) by detecting measurement information at each of the plurality of measuring points (74) in sections. Measuring device (12) after Claim 2 Characterized in that the scanning direction is adjustable transversely to the direction of the main processing path (H) on the basis of machining information, in particular in accordance with the machining direction (BR) and / or the processing speed. Measuring device (12) according to one of Claims 2 and 3 , characterized in that the evaluation device is set up in accordance with the measurement information acquired at the first and / or second and / or third measuring position (Pre, In, Post) a set of measuring points from the one or more first, second and / or third measuring position (Pre, In, Post) scanned plurality of measuring points (74) to be used for evaluating the acquired at the one or more first, second and / or third measuring position (Post) measurement information. Measuring device (12) according to one of the preceding claims, characterized in that the measuring device (12) detects an edge of the workpiece (W) to be machined at the first measuring position (Pre) and / or detects a molten bath at the second measuring position (In) and / or at the third measuring position (post) detects a solidified weld of the workpiece (W). Measuring device (12) after Claim 5 , characterized in that the evaluation device is set up on the basis of a comparison of the measured information acquired at the third measuring position (post) with the measured information acquired at the first measuring position (Pre) a volume of the workpiece (W) melted by the machining and / or a to determine the connection cross-section created by the machining. Measuring device (12) after Claim 5 or 6 , characterized in that the evaluation device is set up on the basis of a comparison of the measured information acquired at the first measuring position (Pre) with the measured information acquired at the second measuring position (In), the position of the current processing position (76) relative to the edge of the to be machined Workpiece (W) to determine. Measuring device (12) according to one of the preceding claims, characterized in that the evaluation device is adapted to create from the measured at the first or third measuring position (Pre, Post) measurement information, in particular to the surface roughness of the workpiece (W), a search pattern , Measuring device (12) after Claim 8 , characterized in that the evaluation device is set up to compare the search pattern with the measurement information acquired at the third measurement position (post) in order to determine the processing speed and / or processing direction. Measuring device (12) according to any one of the preceding claims, characterized in that the measuring device (12) is adapted, according to the acquired measurement information, the processing direction (BR) and / or the processing speed, a feed one during the machining process for processing the workpiece ( W) supplied additional material to regulate. Measuring device (12) according to one of the preceding claims, characterized in that the measuring device (12) is adapted to a distance of the first measuring position (Pre) and / or according to the acquired measurement information, the processing direction (BR) and / or the processing speed the third measuring position (post) of the intended current processing position (76) adapt. A system (10) for processing and monitoring a workpiece (W) comprising a measuring device (12) according to any one of the preceding claims and a processing device (14), said processing device (14) being adapted to convey a high energy processing beam (56) a machining speed in a machining direction (BR) along a predetermined main machining path (H) relative to the workpiece (W) to move to machine the workpiece (W) by means of the high-energy machining beam (56). Method for monitoring a machining process of a workpiece (W) by means of a high-energy machining beam (56), which in particular by means of a measuring device (12) according to one of Claims 1 to 11 the method comprising the steps of: - generating an optical measuring beam (28) by means of a measuring beam source (26) of an optical coherence tomograph (16); and - moving the optical measuring beam (28) during processing substantially in the direction of the main processing path (H) to a first measuring position (Pre) and / or to a second measuring position (In) and / or to a third measuring position (Post) on the Workpiece (W) by means of at least one movable Meßstrahlablenkeinrichtung (44); wherein the first measuring position (Pre) in the processing direction (BR) is located in front of a provided current processing position (76), so that an area of the workpiece (W) to be processed is detected by means of the optical measuring beam (28), wherein the second measuring position (In) is in the range of the intended current processing position (76), so that by means of the optical measuring beam (28) a working area of the workpiece (W) is detected, and wherein the third measuring position (post) in the processing direction (BR) behind the current provided Processing position (76) is located so that by means of the optical measuring beam (28) a machined portion of the workpiece (W) is detected; characterized in that the method comprises the step of: detecting and / or evaluating measurement information at the or a further first measurement position (Pre) and / or measurement information at the or a further second measurement position (In) and / or measurement information at or another third measuring position (post) in accordance with measuring information acquired at the first and / or second and / or third measuring position (Pre, In, Post) by means of an evaluation device of the measuring device (12).

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