DE102020112635A1 - Laser scanner system and method for processing a workpiece - Google Patents

Abstract

The approach presented here relates to a laser scanner system (100) for processing a workpiece (105). The laser scanner system (100) has a laser scanner (115) having a processing area (110) and a sensor scanner (125) having a sensor area (120). The laser scanner (115) has a laser (130) and a first scanner (135) coupled to the laser (130). The laser (130) is designed to provide a laser beam (140). The first scanner (135) is designed to guide a processing point (145) of the laser beam (140) over the processing area (110) in order to process the workpiece (105) located within the processing area (110). The sensor scanner (125) has an optical sensor (150) and a second scanner (155) which is designed to guide an image field (160) of the optical sensor (150) over the sensor area (120) for processing of the workpiece (105) to be monitored. The laser scanner (115) and the sensor scanner (125) are arranged at an angle (□) to one another and the second scanner (155) is designed to direct the image field (160) of the optical sensor (150) onto the processing point (145) .

Description

The present approach relates to a laser scanner system for machining a workpiece and a method for machining a workpiece.

the DE 10 2015 102 111 A1 describes a multi-head laser system with a sensor unit.

Disclosure of the invention

Against this background, a laser scanner system for processing a workpiece and a method for processing a workpiece according to the main claims are presented with the present approach. Advantageous refinements result from the respective subclaims and the following description.

The advantages that can be achieved with the approach presented are that a laser scanner system is created in which the machining of a workpiece can be monitored very well using simple sensors.

A laser scanner system for processing a workpiece has a laser scanner having a processing area and a sensor scanner having a sensor area. The laser scanner has a laser and a first scanner coupled to the laser. The laser is designed to provide a laser beam. The first scanner is designed to guide a processing point of the laser beam over the processing area in order to process the workpiece located within the processing area. The sensor scanner has an optical sensor and a second scanner which is designed to guide an image field of the optical sensor over the sensor area in order to monitor processing of the workpiece. The laser scanner and the sensor scanner are arranged at an angle to one another and the second scanner is designed to direct the image field of the optical sensor onto the processing point.

Such a laser scanner system enables the workpiece to be processed by laser welding. The weld pool formed during laser welding or the processed zone emits electromagnetic radiation in the infrared range (IR range), which can be detected by the optical sensor and resolved both spatially and temporally. The spatial extent and intensity of the radiation provide information about the energy flow in the workpiece and the energy input. Parameters for process monitoring can be derived from this. The energy input into the workpiece differs depending on which material is being processed. For example, the energy input in plastics is lower than in metals and less in metals than ceramics. According to Wien's radiation law, the emitted electromagnetic radiation in the IR range shifts to longer-wave wavelengths with lower energy input. The optical sensor can be a thermographic camera, such as an infrared camera, for example, which is designed to create a thermographic image of its field of view. A monitoring of the processing of the workpiece is sufficiently enabled thanks to the sensor scanner arranged at an angle to the laser scanner, even when long-wave wavelengths are emitted. An alignment of the processing area and the sensor area can advantageously be coordinated with one another. In this way, an inexpensive optical sensor can advantageously be used, the image field of which can be directed particularly easily and precisely to the processing point by the second scanner as required, thanks to the angular arrangement of the laser scanner in relation to the sensor scanner.

The processing area can, for example, have a central axis and the sensor area a further central axis, the central axis and the further central axis intersecting at the angle on a processing plane. Such a coordinated alignment of the processing area and the sensor area enables the processing of the workpiece to be monitored always in an optically easily sensible area. The angle can be selected here so that it enables a large number of common points of intersection of the central axes on the processing plane within the processing area and the sensor area.

According to one embodiment, the laser scanner and the sensor scanner are arranged at an angle between 5 degrees and 40 degrees to one another. For example, the laser scanner and the sensor scanner can be arranged at an angle of 30 degrees or 29 degrees to one another.

The laser scanner system can furthermore have a control unit for the synchronized control of the first scanner and the second scanner. For example, the first scanner and the second scanner can be controlled in such a way that a further angle between the laser beam and an observation channel between the optical sensor and the image field always remains the same, that is, quasi-axially. This enables synchronized, for example always simultaneous, monitoring and processing of the processing point.

The sensor scanner can have at least one focusing lens or converging lens, in particular which can be arranged between the optical sensor and the second scanner in order to focus or collect incident observation beams from the second scanner to the optical sensor. The observation rays can be infrared rays incident through the observation channel of the optical sensor that is generated depending on the orientation of the second scanner. In this way, observation beams sensed by the optical sensor can be focused or collected in advance. A very small image field can also be generated in this way, for example.

It is also advantageous if the first scanner has at least one movable mirror for deflecting the laser beam and, additionally or alternatively, the second scanner has at least one further movable mirror for guiding the image field. By means of such mirrors, the rays and additionally or alternatively the observation channel can be directed quickly and easily in a desired direction.

The second scanner can also have a scanner focusing lens on a side facing away from the optical sensor. In this way, observation beams incident in the second scanner can be focussed in advance and, in addition or as an alternative, a very small image field can be generated.

It is also advantageous if, according to one embodiment, the laser scanner system has a further sensor scanner having a further sensor area with a spectrometer and a third scanner for directing a further image field of the spectrometer to the processing point in order to detect a material composition of the workpiece. This creates an expansion of the laser scanner system presented here to include a further analysis area for the workpiece.

The further sensor scanner can be arranged at an additional angle to the laser scanner. The additional angle can be selected to be suitable for an expected sensible spectral range of the spectrometer.

The laser scanner system can furthermore have a calibration device for calibrating the first scanner and the second scanner. This enables an alignment of the laser beam and the observation channel of the optical sensor that is always correctly matched to one another.

A method for machining a workpiece has a step of providing, a step of activating, a step of guiding and a step of straightening. In the step of providing, a laser scanner having a processing area, which has a laser for providing a laser beam and a first scanner coupled to the laser for guiding a processing point of the laser beam over the processing area, and a sensor scanner having a sensor area with an optical sensor and a second Scanner provided for guiding an image field of the optical sensor over the sensor area, the laser scanner and the sensor scanner being arranged at an angle to one another in the step of providing. In the activation step, the laser beam is activated in order to machine the workpiece located within the machining area. In the guiding step, the machining point of the laser beam is guided over the machining area. In the straightening step, the image field of the optical sensor is directed onto the processing point in order to monitor processing of the workpiece.

• 1 bis 4 je eine schematische Darstellung eines Laserscannersystems zum Bearbeiten eines Werkstücks gemäß einem Ausführungsbeispiel;
• 5 eine schematische Darstellung einer Kalibriereinrichtung eines Laserscannersystems gemäß einem Ausführungsbeispiel; und
• 6 ein Ablaufdiagramm eines Verfahrens zum Bearbeiten eines Werkstücks gemäß einem Ausführungsbeispiel.

The approach is explained in more detail below with reference to the accompanying drawings. Show it:

• 1 until 4th each a schematic representation of a laser scanner system for processing a workpiece according to an exemplary embodiment;
• 5 a schematic representation of a calibration device of a laser scanner system according to an embodiment; and
• 6th a flowchart of a method for machining a workpiece according to an embodiment.

In the following description of advantageous exemplary embodiments of the present approach, identical or similar reference numerals are used for the elements shown in the various figures and having a similar effect, a repeated description of these elements being dispensed with.

1 shows a schematic representation of a laser scanner system 100 for machining a workpiece 105 according to an embodiment.

The laser scanner system 100 has an edit area 110 having laser scanner 115 and a sensor area 120 having sensor scanner 125 on. The laser scanner 115 has a laser 130 and one with the laser 130 paired first scanner 135 on. The laser 130 is designed to use a laser beam 140 provide. The first scanner 135 is designed to be a processing point 145 of the laser beam 140 over the editing area 110 to run around within the editing area 110 located workpiece 105 to to edit. Thus, the edit point 145 any point within the machining area 110 cover. The sensor scanner 125 has an optical sensor 150 and a second scanner 155 on, which is designed to provide an image field 160 of the optical sensor 150 over the sensor range 120 to lead to a machining of the workpiece 105 to monitor. The field of view 160 is significantly smaller than the sensor range 120 . The field of view 160 can be similar to the edit point 145 over the entire sensor range 120 so that the entire sensor area 120 using the sensor scanner 125 can be monitored. The second scanner 155 is controlled according to an embodiment in such a way that the image field 160 of the optical sensor 150 continuously to the processing point 145 is directed. The field of view 160 can thus be synchronized with a movement of the machining point 145 be moved to the field of view 160 with the edit point 145 to carry with you.

The laser scanner 115 and the sensor scanner 125 are arranged at an angle α to one another.

The laser 130 is designed according to this embodiment for laser welding. The weld pool formed during laser welding or the processed zone emits electromagnetic radiation in the infrared range (IR range), which is generated by the optical sensor 150 is detectable and resolvable both spatially and temporally. With the optical sensor 160 According to this exemplary embodiment, it is a thermographic camera such as, for example, an infrared camera, which is used to create a thermographic image of its image field 160 is trained. The editing area 110 is according to this embodiment on a processing level 165 of the laser scanner system 100 or the workpiece 105 from the sensor area 120 completely overlapped. The sensor area 120 and the editing area 110 According to an alternative exemplary embodiment, overlap at least partially on the processing plane 165 . According to this embodiment is the sensor area 120 at the processing level 165 equal to or larger than the machining area 110 .

The editing area 110 according to this exemplary embodiment has a central axis and the sensor area 120 another central axis, the central axis and the further central axis on the machining plane 165 cut at the angle α. According to one embodiment, the laser beam runs 140 along the central axis of the machining area 110 when the laser beam 140 not through the first scanner 135 is distracted. The image field runs accordingly 160 along the central axis of the sensor area 120 when the image field 160 not through the second scanner 155 is distracted

According to this exemplary embodiment, the angle α has an angle range between 5 degrees and 40 degrees. According to this embodiment, the laser scanner 115 and the sensor scanner 125 arranged at an angle α of 30 degrees or 29 degrees to each other.

The first scanner 135 According to this exemplary embodiment, has at least one movable mirror for deflecting the laser beam 140 and / or the second scanner 155 at least one further movable mirror for deflecting the image field 160 on.

The laser scanner system 100 furthermore, according to this exemplary embodiment, has a control unit 170 for synchronized control of the first scanner 135 and the second scanner 155 on. According to one embodiment, the control unit controls 170 the first scanner 135 and the second scanner 155 such that another angle between the laser beam 140 and an observation channel 175 between the optical sensor 150 and the field of view 160 always the same, i.e. quasi-axially, remains. According to this exemplary embodiment, the further angle corresponds or is similar to the angle □. Thus is the control unit 170 trained the first scanner 135 and the second scanner 155 to be controlled in such a way that the processing point 145 continuous within the image field 160 is located.

The laser scanner system 100 has, according to an exemplary embodiment, a further sensor scanner merely by way of example 180 which has a further sensor area, wherein the further sensor scanner 180 a spectrometer and a third scanner for directing a further image field of the spectrometer onto the processing point 145 has to a material composition of the workpiece 105 to recognize. The further sensor scanner 180 is according to an embodiment at an additional angle to the laser scanner 115 arranged. According to one exemplary embodiment, the additional angle corresponds to or is similar in terms of amount to the angle α.

A working distance 185 between the working plane 165 and the laser scanner 115 According to this exemplary embodiment, corresponds essentially to a working distance 185 between the working plane 165 and the sensor scanner 125 and / or the further sensor scanner 180 .

With the laser scanner system presented here 100 are the laser scanner 115 and the sensor scanner 125 not guided coaxially, so even with low energy inputs or temperatures at for example laser material processing of plastics, this can be monitored very well. A process control in scanner-based laser material processing with the sensor scanner 125 is very precise here, since according to an exemplary embodiment only a very small image field 160 is recorded. Because of the large wavelength range ⌷ of, for example, two to 14 µm of the infrared camera, a coaxial guide with the laser is necessary 130 not possible.

The laser scanner system presented here 100 therefore enables a very high resolution and quasi-axial sensor guidance for scanning systems.

In an application example of the laser scanner system 100 the optical sensor is carried along 150 in the form of the IR camera via the second scanner 155 . Such entrainment can be carried out using the control unit 170 being controlled. The second scanner 155 is located according to this embodiment above the processing plane 165 , which can also be referred to as the "working level". Ideally, the second scanner is 155 as shown here, at the same height and close to the first scanner 135 appropriate. Furthermore is the second scanner 155 according to this embodiment by the defined angle α to the optical axis of the first scanner 135 tilted. The field of view 160 the IR camera is using the second scanner 155 , which is not used for laser processing, over the workpiece 105 guided. The mirror (s) of the second scanner 155 are mirrored according to this embodiment, ideal for the IR camera. According to this exemplary embodiment, the observation channel 175 in the form of an IR camera channel simultaneously with the laser 130 , which can also be called "process laser". For this purpose, according to this exemplary embodiment, both scanners are / were 135 , 155 coordinated with a correction file, this process is carried out in 5 described in more detail. A high-resolution real-time process monitoring of a process zone is thus realized. According to an alternative embodiment, a high-resolution thermographic image is generated by scanning and stitching the work area.

Advantages of the laser scanner system 100 are a higher resolution and a quasi-axial sensor guidance. Smaller / cheaper scanners can also be used 155 be used as IR scanners and IR cameras with a smaller chip. This enables an inexpensive solution. Spectral properties of the parallel scanner and the optics are advantageously independent of the laser channel of the laser 130 and thus optimally adjustable to an application. According to this exemplary embodiment, there is also an expansion to a third scanner, here the further sensor scanner 180 , realized to parallel a laser-induced plasma spectroscopy, abbreviated “LIBS”, independent of the laser 130 but to be set at the same time / place - this enables process control. An extension to other scanners requires a special, non-standard scanner card - but does not pose a problem in principle.

2 shows a schematic representation of a laser scanner system 100 for machining a workpiece 105 according to an embodiment. This can be the in 1 described laser scanner system 100 act, with the difference that the sensor scanner 125 according to this embodiment, at least one focusing lens 200 or, according to an alternative embodiment, has a converging lens. The focusing lens 200 or, according to this exemplary embodiment, the converging lens is between the optical sensor 150 and the second scanner 155 arranged to incident observation rays 205 from the second scanner 155 to the optical sensor 150 to focus or collect. With the observation beams 205 According to this exemplary embodiment, it is through the observation channel 175 of the optical sensor 150 incident infrared rays. According to this exemplary embodiment, the optics of the IR camera are selected in such a way that a smaller image field 160 is shown on the chip of the camera. According to this exemplary embodiment, so-called “post objective scanning”, that is to say scanning with an adaptation lens, can be carried out.

3 shows a schematic representation of a laser scanner system 100 for machining a workpiece 105 according to an embodiment. This can be the in 1 described laser scanner system 100 act, with the difference that the sensor scanner 125 according to this embodiment, the converging lens instead of the focusing lens 300 , also called a collimation lens. Furthermore, the second scanner 155 according to this embodiment on one of the optical sensor 150 remote side a scanner focusing lens 305 on.

In other words, according to this exemplary embodiment, there is between an IR camera chip and the second scanner 155 a collimation optics in the form of the converging lens 300 appropriate. To the second scanner 155 In addition or as an alternative, additional focusing optics are attached, which enable the working field to be mapped onto the camera chip in a similar way to an F-Theta using the so-called “Pre Objective Scanning”. Thus, according to this exemplary embodiment, scanning can be carried out with a scanning system arranged in front of the objective.

4th shows a schematic representation of a laser scanner system 100 for machining a workpiece 105 according to an embodiment. This can be one of the in one of the 1 until 3 described laser scanner systems 100 act, with the difference that the laser beam 140 and the observation channel 175 were adjusted in an adjustment angle of, for example, 29 or 30 degrees to one direction. The laser beam 140 and the observation channel 175 intersect according to this exemplary embodiment on the processing plane 165 continue at the angle α.

5 shows a schematic representation of a calibration device 500 a laser scanner system 100 according to an embodiment. This can be one of the in one of the 1 until 4th described laser scanner systems 100 act, according to this embodiment, the calibration device 500 for calibrating the first scanner and the second scanner.

According to this exemplary embodiment, the first scanner and the second scanner are aligned with one another using the calibration device 500 can be carried out automatically. The calibration device does this 500 For example, a sample workpiece is lasered with a defined grid of laser points 505 and taking a picture 510 from each laser point 505 with the IR camera via the second scanner, which can also be called from "IR scanner". According to an alternative embodiment, the IR camera for the calibration process is exchanged for another camera with a different wavelength range, for example less than 1100 nm, the scanner being aligned with this other camera and a laser beam of the laser scanner and the other camera at the end of the Calibration process is swapped back. According to one exemplary embodiment, both cameras have a precisely fitting receptacle for the scanner so that comparability is guaranteed. According to this exemplary embodiment, the grid is implemented in the form of a matrix with three rows and three columns, as an example. The aim here is that the laser point 505 each in the center of the image 512 of the individual images 510 should be. The calibration device 500 is designed to be a vector 515 from a mismatch of the divergent pixels from the center of the image 512 to the laser point 505 to determine. According to one embodiment, the vectors obtained are 515 implemented in a correction file to calibrate the scanner. This process is from the calibration facility 500 according to an embodiment iteratively and / or software-supported, for example by image processing, can be carried out.

6th shows a flow chart of a method 600 for machining a workpiece according to an exemplary embodiment. This can be a process 600 act that of the one in one of the 1 until 5 described laser scanner system is feasible or controllable.

The procedure 600 has a step 605 of deploying, one step 610 of activation, one step 615 of leadership and a step 620 of straightening up. In step 605 of providing a laser scanner having a processing area, which has a laser for providing a laser beam and a first scanner coupled to the laser for guiding a processing point of the laser beam over the processing area, and a sensor scanner having a sensor area with an optical sensor and a second scanner for Guiding an image field of the optical sensor over the sensor area provided, wherein in step 605 of providing the laser scanner and the sensor scanner are arranged at an angle to one another. In step 610 After activation, the laser beam is activated in order to process the workpiece located within the processing area. In step 615 When guiding, the processing point of the laser beam is guided over the processing area. In step 620 During the alignment, the image field of the optical sensor is directed onto the processing point in order to monitor processing of the workpiece.

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was 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.

Patent literature cited

• DE 102015102111 A1 [0002]

Claims (11)

Laser scanner system (100) for processing a workpiece (105), the laser scanner system (100) having the following features: a laser scanner (115) having a processing area (110), a laser (130) for providing a laser beam (140) and a first scanner (135) coupled to the laser (130) for guiding a processing point (145) of the laser beam (140) over the processing area (110) in order to process the workpiece (105) located within the processing area (110), and a a sensor area (120) having a sensor scanner (125) with an optical sensor (150) and a second scanner (155) for guiding an image field (160) of the optical sensor (150) over the sensor area (120) in order to process the workpiece ( 105), characterized in that the laser scanner (115) and the sensor scanner (125) are arranged at an angle (□) to one another and the second scanner (155) is designed to display the image field ( 160) of the optical sensor (150) to be directed at the processing point (145). Laser scanner system (100) according to Claim 1 , in which the processing area (110) has a central axis and the sensor area (120) has a further central axis, the central axis and the further central axis intersecting on a processing plane (165) at the angle (□). Laser scanner system (100) according to one of the preceding claims, in which the laser scanner (115) and the sensor scanner (125) are arranged at an angle (□) between 5 degrees and 40 degrees to one another. Laser scanner system (100) according to one of the preceding claims, with a control unit (170) for the synchronized control of the first scanner (135) and the second scanner (155). Laser scanner system (100) according to one of the preceding claims, in which the sensor scanner (125) has at least one focusing lens (200) or converging lens (300), in particular which is arranged between the optical sensor (150) and the second scanner (155) in order to focus or collect incident observation beams (205) from the second scanner (155) to the optical sensor (150). Laser scanner system (100) according to one of the preceding claims, in which the first scanner (135) has at least one movable mirror for deflecting the laser beam (140) and / or the second scanner (155) has at least one further movable mirror for guiding the image field (160) having. Laser scanner system (100) according to one of the preceding claims, in which the second scanner (155) has a scanner focusing lens (305) on a side facing away from the optical sensor (150). Laser scanner system (100) according to one of the preceding claims, with a further sensor scanner (180) having a further sensor area with a spectrometer and a third scanner for directing a further image field of the spectrometer onto the processing point (145) in order to determine a material composition of the workpiece (105) to recognize. Laser scanner system (100) according to Claim 8 , in which the further sensor scanner (180) is arranged at an additional angle to the laser scanner (115). Laser scanner system (100) according to one of the preceding claims, with a calibration device (500) for calibrating the first scanner (135) and the second scanner (155). Method (600) for machining a workpiece (105), the method (600) comprising the following steps: Providing (605) a laser scanner (115) having a processing area (110), a laser (130) for providing a laser beam (140) and a first scanner (135) coupled to the laser (130) for guiding a processing point (145) of the laser beam (140) over the processing area (110), and a sensor scanner (125) having a sensor area (120) with an optical sensor (150) and a second scanner (155) for guiding an image field (160) of the optical sensor ( 150) over the sensor area (120), wherein in step (605) of providing the laser scanner (115) and the sensor scanner (125) are arranged at an angle (□) to one another; Activating (610) the laser beam (140) in order to machine the workpiece (105) located within the machining area (110); Guiding (615) the processing point (145) of the laser beam (140) over the processing area (110); and Directing (620) the image field (160) of the optical sensor (150) to the processing point (145) in order to monitor a processing of the workpiece (105).

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