WO2024037783A1 - Mesure à résolution spatiale de l'encrassement d'un verre de protection d'un outil laser - Google Patents

Mesure à résolution spatiale de l'encrassement d'un verre de protection d'un outil laser Download PDF

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Publication number
WO2024037783A1
WO2024037783A1 PCT/EP2023/068889 EP2023068889W WO2024037783A1 WO 2024037783 A1 WO2024037783 A1 WO 2024037783A1 EP 2023068889 W EP2023068889 W EP 2023068889W WO 2024037783 A1 WO2024037783 A1 WO 2024037783A1
Authority
WO
WIPO (PCT)
Prior art keywords
protective glass
laser
laser beam
detectors
light
Prior art date
Application number
PCT/EP2023/068889
Other languages
German (de)
English (en)
Inventor
Matthias Fichter
Jan Wagner
Original Assignee
Trumpf Laser Gmbh
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Trumpf Laser Gmbh filed Critical Trumpf Laser Gmbh
Publication of WO2024037783A1 publication Critical patent/WO2024037783A1/fr

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/08—Devices involving relative movement between laser beam and workpiece
    • B23K26/082—Scanning systems, i.e. devices involving movement of the laser beam relative to the laser head
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/70—Auxiliary operations or equipment
    • B23K26/702—Auxiliary equipment
    • B23K26/707—Auxiliary equipment for monitoring laser beam transmission optics

Definitions

  • the invention relates to an operating method for a laser tool and a laser tool, wherein a laser beam emerges through a protective glass.
  • the optics of laser tools are often protected from contamination by protective glasses.
  • contamination can be, for example, weld spatter or other particles. Dirt often accumulates on the protective glass. The one through the protective glass
  • the laser beam emerging towards the workpiece is scattered by the dirt or otherwise deflected. On the one hand, this reduces the light output of the laser beam available for processing the workpiece. on the other hand Laser radiation reflected from the dirt can damage optical components of the laser tool.
  • an operating method for a laser tool is provided.
  • the laser tool can be designed, for example, as a laser welding head or as a laser cutting head or can include a laser welding head or a laser cutting head.
  • the laser tool is preferably a laser tool according to the invention described below.
  • a laser beam is deflected using scanner optics and emerges through a protective glass.
  • the protective glass is thus arranged on the exit side of the scanner optics and possibly a focusing optics of the laser tool.
  • the laser beam is deflected and can be moved across a workpiece. This changes The position at which the laser beam passes through the protective glass also changes.
  • the scanner optics can be formed with a galvoscanner.
  • the detectors are used to detect the light of the laser beam that is deflected, in particular scattered, on the protective glass from the direction of propagation of the laser beam.
  • This part of the laser beam is also referred to below as scattered light or scattered light components.
  • the detectors are preferably each designed as a scattered light sensor.
  • the scattered light sensors can each have a photodiode.
  • the detectors can each have a thermal imaging camera.
  • at least three, preferably at least six, detectors are provided.
  • the detectors are usually evenly distributed around the protective glass. By using multiple detectors, the fact can be taken into account that dirt on the protective glass can scatter the laser light of the laser beam in different directions. Scattered laser light from the laser beam is referred to as scattered light components.
  • the term multiple detectors is defined in this document as a number of two or more detectors.
  • a level of the laser light deflected, in particular scattered, on the protective glass is detected by the detectors depending on the position of the scanner optics. In other words, it measures how much laser light is present at the current position of the scanner optics, i.e. H. is deflected, in particular scattered, from the direction of propagation of the laser beam in the area of the protective glass currently irradiated by the laser beam.
  • the contamination of the protective glass is thus recorded in a spatially resolved manner. This location-dependent contamination information can be used for further operation of the laser tool.
  • the level of the laser light deflected, in particular scattered, on the protective glass is compared with a predefined limit value. This allows for the respective position of the scanner optics or the corresponding position Information can be obtained on the protective glass as to whether the protective glass is sufficiently clean or impermissibly dirty.
  • the limit value can be set when installing the currently used protective glass using a reference measurement. To do this, the laser beam can be moved once over the protective glass while the respective level of scattered light is recorded. Different optical properties, in particular different scattering properties, of different protective glasses can be compensated for in this way.
  • the limit value can be determined by applying a predefined percentage or absolute markup to the amount of deflected, in particular scattered, laser light determined on the new protective glass.
  • exceeding the limit value and the associated position of the scanner optics are saved. Storing this information can be done particularly easily in a matrix. By evaluating the stored information, it can be easily determined in which areas the protective glass is excessively dirty.
  • Areas of the protective glass for which the limit value was found to be exceeded are particularly preferably left out for further operation of the laser tool with the protective glass. This can increase the service life of the protective glass, the time from inserting the protective glass to replacing it. This also increases the operating time of the laser tool between changing the protective glass. The amount of setup time required to change the protective glass is thus reduced and the productivity of the laser tool is increased.
  • the protective glass can be replaced. On the one hand, this can ensure that the protective glass is only replaced when the protective glass is heavily soiled overall. On the other hand, it ensures that There is always a sufficiently large area of the protective glass available without disturbing dirt.
  • the level of the laser light deflected, in particular scattered, on the protective glass can be determined by relating the scattered light power to the light power of the laser beam.
  • the scattered light power describes the light power of the part of the laser beam that is deflected, in particular scattered, on the protective glass. This takes into account that - given the contamination of the protective glass - the scattered light output is typically proportional to the light output of the laser beam.
  • a parameter of the level of the laser light deflected, in particular scattered, on the protective glass, and the position of the scanner optics can be stored in a matrix.
  • the parameter of the level can in particular be the scattered light power itself or the scattered light power related to the light power of the laser beam.
  • the parameter can be the exceedance or non-exceedance of a predefined limit value.
  • the stored parameter can be displayed depending on the location. A color-coded display makes it particularly easy to detect contamination.
  • the measured values of the multiple detectors can be added to determine the level of the laser light deflected, in particular scattered, on the protective glass.
  • the portions of the laser light that are deflected or scattered in different directions are taken into account together. If specific contamination on the protective glass deflects or scatters to different extents in different directions, this is taken into account and compensated for.
  • the level of the laser light deflected, in particular scattered, on the protective glass is determined continuously while the laser tool is being used to process a workpiece.
  • the Monitoring and, if necessary, compensation for contamination is carried out in real time during ongoing processing. This avoids downtime of the laser tool to determine contamination of the protective glass. It also ensures that current information about the degree of contamination of the protective glass is always available.
  • the scope of the present invention also includes a laser tool
  • the laser tool can be, for example, a laser welding head or a laser cutting head or can include a laser welding head or a laser cutting head.
  • the laser tool according to the invention enables the operating method according to the invention described above to be carried out.
  • the control device is programmed to evaluate measured values from the detectors and to control the laser light source and the scanner optics.
  • the detectors are used to detect the light of the laser beam that is deflected, in particular scattered, on the protective glass from the direction of propagation of the laser beam.
  • the detectors are preferably arranged on the outer circumference of the protective glass.
  • the scanner optics can be formed with a galvoscanner.
  • the protective glass can be designed as a plane-parallel and typically circular pane.
  • the detectors can each be designed as a scattered light sensor.
  • the detectors preferably each have a photodiode.
  • the photodiodes can each be coupled to an edge surface of the protective glass via a fiber optic light guide.
  • the detectable laser light reaches the detectors via the fiber optic light guides. In this way, a precise measurement of the scattered light can be carried out in a simple manner.
  • the detectors can each have a thermal imaging camera.
  • the thermal imaging cameras are aimed at the protective glass and advantageously detect dirt that heats up when the laser beam hits it.
  • the detectors are preferably connected in parallel. In this way, the measured values of the several detectors can be added by simply setting up the corresponding electrical circuitry, so that the
  • Protective glass contains the parts of the material scattered in different directions
  • the laser tool can have a device for measuring the light output of the laser beam. This makes it possible to relate the scattered light power measured by the detectors to the light power of the laser beam.
  • the device for measuring the light power of the laser beam can have a dichroic mirror and a light power sensor, in particular a photodiode.
  • the light power sensor can be arranged behind the dichroic mirror, so that a small portion of the laser light of the laser beam, which is predominantly reflected by the dichroic mirror, is supplied to the light power sensor.
  • FIG. 1 shows a laser tool according to the invention with a laser light source, a scanner optics and a protective glass on which several scattered light sensors are arranged as detectors, in a schematic sectional view;
  • FIG. 2 shows a schematic top view of the protective glass and the scattered light sensors of the laser tool from FIG. 1;
  • Fig. 3 shows a schematic flow diagram of an operating method according to the invention using the laser tool from Figure 1.
  • Figure 1 shows a laser tool 10, for example a laser welding head.
  • the laser tool 10 is used to process a workpiece 12.
  • the laser tool 10 has a laser light source 14. During operation, the laser light source 14 emits a laser beam 16, compare step 102 in Figure 3. Only one central axis of the laser beam 16 or its components is shown in Figure 1. A control device 18 is used to control the laser tool 10. It goes without saying that the laser light source 14 and the control device 18 can also be and typically are arranged outside the processing head of the laser tool 10.
  • the laser beam 16 may first impinge on a dichroic mirror 20 of a device 22 for measuring the light power.
  • the dichroic mirror 20 reflects a vast majority of the laser beam 16.
  • a scanner optics 26 which can include, for example, a mirror 28 that can be pivoted by means of a galvoscanner (not shown) or other pivoting drive.
  • a galvoscanner not shown
  • the laser beam 16 is directed to different locations on the workpiece 12, compare step 106.
  • This is indicated in Figure 1 with solid and dashed lines for two exemplary positions of the pivotable mirror 28, whereby for the dashed configuration is appended to the corresponding reference numbers with an apostrophe ()'.
  • the laser beam 16 can be focused on the workpiece 12 by a focusing optics 30.
  • the laser beam 16 passes through a protective glass 32.
  • the protective glass 32 is arranged on the laser tool 10 on the beam exit side.
  • the protective glass 32 protects the components of the laser tool 10 behind it from contamination 42, for example weld spatter coming from the workpiece 12.
  • the Scattered light sensors 34 serve as detectors 35 for detecting the laser light of the laser beam 16 that is deflected from its direction of propagation on the protective glass 32.
  • the scattered light sensors 34 each include a photodiode 36, which is coupled to a peripheral edge surface 40 of the protective glass 32 via a glass fiber light guide 38.
  • the detectors 35 could also each include a thermal imaging camera, not shown.
  • the detectors 35 are arranged evenly distributed around the circumference of the protective glass 32.
  • the detectors 35 are connected in parallel, so that the portions of the laser light of the laser beam 16 that are scattered or otherwise deflected on the protective glass 32 and which are detected by the detectors 35 are added together.
  • This total proportion of the deflected, in particular scattered, laser light is position-dependent, i.e. H. measured depending on the position of the scanner optics 26, see step 108.
  • the detectors 35, the scanner optics 26, the light power sensor 24 and the laser light source 14 are connected to the control device 18 via lines not shown.
  • the scattered light power measured by the scattered light sensors 34 is compared to the total light power of the laser beam 16, compare step 110.
  • the proportion of the scattered light power in the total light power of the laser beam 16 is compared with a predefined limit value.
  • the proportion of scattered light can be determined as part of a reference measurement immediately after installation of the new protective glass 32 in the manner described above for the area intended for radiation. This proportion can be multiplied by a given factor to obtain the limit value.
  • the laser beam 16 may hit a clean area of the protective glass 32.
  • the laser beam 16 passes through the protective glass 32 essentially unhindered and hits the workpiece 12 for processing. This is shown in Figure 1 with solid lines.
  • the scattered light sensors 34 only measure a very low scattered light output. Their share of the total light output is therefore below the specified limit.
  • the proportion of the scattered light output in the total light output and/or the fall below the limit value are stored in a step 114 for the corresponding position of the scanner optics 26 or the associated area of the protective glass 32, for example in the control device 18.
  • the laser beam 16 is deflected in other directions by means of the scanner optics 26. This is indicated in Figure 3 by the repetition of steps 102 to 112.
  • contamination 42 for example a weld spatter
  • contamination 42 for example a weld spatter
  • the scanner optics 26 If the scanner optics 26 is in a second position during further operation, the laser beam 16 'reflected by the pivotable mirror 28 hits the contamination 42. The reflected laser beam 16' therefore only hits the workpiece 12 in a weakened form. Scattered light components 44 of the reflected one Laser beam 16 'are scattered by the contamination 42 to the scattered light sensors 34. Due to the size and type of contamination 42, the ratio of the control light output and the total light output of the reflected laser beam 16' exceeds the predefined limit. This ratio or the exceeding of the limit value are saved for the second position or the associated area of the protective glass 32 when the cut 114 is carried out again.
  • the contaminated area is left out, see step 116.
  • the control device 18 is programmed to do this, the scanner optics 26 to control that the laser beam 16 does not hit the contamination 42.
  • the laser tool 10 can be moved relative to the workpiece 12 so that the contaminated area or areas of the protective glass 32 are not required for the processing to be carried out.
  • the protective glass 32 is replaced in a step 118.
  • a limit value for the proportion of scattered light output to the total light output can be determined as part of a reference measurement.
  • the laser tool 10 is then used with the new protective glass 32 as described above.
  • Control device 18 dichroic mirror 20
  • Scanner optics 26 swiveling mirror 28
  • Emitting 102 a laser beam

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  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • Mechanical Engineering (AREA)
  • Length Measuring Devices By Optical Means (AREA)
  • Laser Beam Processing (AREA)

Abstract

L'invention concerne un procédé de fonctionnement pour un outil laser (10), un faisceau laser (16) étant dévié au moyen d'une unité optique de balayage (26) et sortant à travers un verre de protection (32), autour duquel une pluralité de capteurs de lumière diffusée (34) est disposée et le niveau de la lumière laser déviée, en particulier diffusée, au niveau du verre de protection (32) étant mesuré par les capteurs de lumière diffusée (34) en fonction de la position de l'unité optique de dispositif de balayage (26).
PCT/EP2023/068889 2022-08-17 2023-07-07 Mesure à résolution spatiale de l'encrassement d'un verre de protection d'un outil laser WO2024037783A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102022120714.5A DE102022120714A1 (de) 2022-08-17 2022-08-17 Ortsaufgelöste Messung der Verschmutzung eines Schutzglases eines Laserwerkzeugs
DE102022120714.5 2022-08-17

Publications (1)

Publication Number Publication Date
WO2024037783A1 true WO2024037783A1 (fr) 2024-02-22

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PCT/EP2023/068889 WO2024037783A1 (fr) 2022-08-17 2023-07-07 Mesure à résolution spatiale de l'encrassement d'un verre de protection d'un outil laser

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Country Link
DE (1) DE102022120714A1 (fr)
WO (1) WO2024037783A1 (fr)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19839930C1 (de) * 1998-09-02 1999-09-09 Jurca Optoelektronik Gmbh Verfahren zur Überwachung der Funktionalität des transparenten Schutzelementes einer transparenten Laseroptik sowie Einrichtung zur Durchführung dieses Verfahrens
DE10113518A1 (de) 2001-03-20 2002-10-02 Precitec Kg Verfahren zur Messung des Verschmutzungsgrades eines Schutzglases eines Laserbearbeitungskopfs sowie Laserbearbeitungsanlage zur Durchführung des Verfahrens
DE69837379T2 (de) * 1997-01-24 2007-12-13 Permanova Lasersystem Ab Verfahren und Vorrichtung zur Prüfung des Zustandes eines Schutzglases bei der Laserbearbeitung
US20220111599A1 (en) * 2020-10-14 2022-04-14 General Electric Company Systems and methods for handling optical anomalies on optical elements of an additive manufacturing machine

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE9403822U1 (de) 1994-03-08 1995-07-06 Berkenhoff & Drebes GmbH, 35614 Aßlar Überwachungsvorrichtung für Laserstrahlung
DE50214771D1 (de) 2002-04-20 2010-12-30 Haas Laser Gmbh & Co Kg Einrichtung zur Überwachung eines optischen Elements eines Bearbeitungskopfes einer Maschine zur thermischen Bearbeitung eines Werkstücks
DE20314918U1 (de) 2003-09-25 2005-02-03 Scansonic Gmbh Vorrichtung zur Überwachung eines Schutzglases einer Laseroptik auf Bruch und/oder Verschmutzung
DE102012102785B3 (de) 2012-03-30 2013-02-21 Marius Jurca Verfahren und Überwachungseinrichtung zur Erfassung und Überwachung der Verschmutzung einer optischen Komponente in einer Vorrichtung zur Lasermaterialbearbeitung
DE102018102828B4 (de) 2018-02-08 2020-03-12 Scansonic Mi Gmbh Verfahren zur Überwachung eines Schutzglases

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE69837379T2 (de) * 1997-01-24 2007-12-13 Permanova Lasersystem Ab Verfahren und Vorrichtung zur Prüfung des Zustandes eines Schutzglases bei der Laserbearbeitung
DE19839930C1 (de) * 1998-09-02 1999-09-09 Jurca Optoelektronik Gmbh Verfahren zur Überwachung der Funktionalität des transparenten Schutzelementes einer transparenten Laseroptik sowie Einrichtung zur Durchführung dieses Verfahrens
DE10113518A1 (de) 2001-03-20 2002-10-02 Precitec Kg Verfahren zur Messung des Verschmutzungsgrades eines Schutzglases eines Laserbearbeitungskopfs sowie Laserbearbeitungsanlage zur Durchführung des Verfahrens
DE10113518B4 (de) * 2001-03-20 2016-05-19 Precitec Kg Verfahren zur Messung des Verschmutzungsgrades eines Schutzglases eines Laserbearbeitungskopfs sowie Laserbearbeitungsanlage zur Durchführung des Verfahrens
US20220111599A1 (en) * 2020-10-14 2022-04-14 General Electric Company Systems and methods for handling optical anomalies on optical elements of an additive manufacturing machine

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