EP1591188A1 - Procédé et dispositif pour enlever un revêtement - Google Patents

Procédé et dispositif pour enlever un revêtement Download PDF

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Publication number
EP1591188A1
EP1591188A1 EP04010208A EP04010208A EP1591188A1 EP 1591188 A1 EP1591188 A1 EP 1591188A1 EP 04010208 A EP04010208 A EP 04010208A EP 04010208 A EP04010208 A EP 04010208A EP 1591188 A1 EP1591188 A1 EP 1591188A1
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EP
European Patent Office
Prior art keywords
spectrum
laser
coating material
coating
removal
Prior art date
Legal status (The legal status 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 status listed.)
Withdrawn
Application number
EP04010208A
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German (de)
English (en)
Inventor
Thomas Beck
Georg Dr. Bostanjoglo
Stefan Krause
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Siemens AG
Original Assignee
Siemens AG
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 Siemens AG filed Critical Siemens AG
Priority to EP04010208A priority Critical patent/EP1591188A1/fr
Publication of EP1591188A1 publication Critical patent/EP1591188A1/fr
Withdrawn legal-status Critical Current

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B08—CLEANING
    • B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
    • B08B7/00—Cleaning by methods not provided for in a single other subclass or a single group in this subclass
    • B08B7/0035—Cleaning by methods not provided for in a single other subclass or a single group in this subclass by radiant energy, e.g. UV, laser, light beam or the like
    • B08B7/0042—Cleaning by methods not provided for in a single other subclass or a single group in this subclass by radiant energy, e.g. UV, laser, light beam or the like by laser

Definitions

  • the present invention relates to a method and a Apparatus for removing a coating from one Substrate by means of laser radiation.
  • TBC Thermal Barrier coating
  • MCrAlY coating is intended in the context of present description of a coating of a metallic alloy to understand the chromium (Cr) and Aluminum (A1), and in the y for yttrium or a Rare earth element and M for iron (Fe), cobalt (Co) or nickel (Ni).
  • TBC coatings are usually ceramic coatings and serve for thermal insulation of the metallic Main body of the turbine blade before direct contact with the hot gas.
  • TBCs made by plasma spraying require one certain surface roughness of the coated Substrate material, which is either a base material or another coating, for example an MCrAlY coating, can be because the liability of the Coating material on the substrate mechanically.
  • TBC coating can be removed. This happens so far with abrasive processes, i. Grinding process, causing the Roughness of the substrate is changed so much that a recoating by atmospheric plasma spraying is no longer possible.
  • These shovels will then be in the Usually coated by an EB-PVD method, or it The entire MCrAlY coating is removed and a new one MCrAlY coating and then a new TBC coating Applied by APS.
  • DE 692 08 688 T2 discloses a material removal process and a material removal system which pulsed light from a flashlamp or equivalent use pulsed light from a high energy light source, to remove the material to be removed. To determine, when the appropriate amount of material has been removed is the reflected back from the target area radiation of Flash lamp detected and regarding the presence of a prescribed color intensity, differing from a known Color intensity of the material layer to be removed differentiates, monitors.
  • a Coating in particular a ceramic coating
  • a TBC coating from a substrate, which a substrate material is made by means of laser radiation irradiation takes place at which the material of the Coating, hereinafter referred to as coating material, should be removed, with laser radiation.
  • the substrate can in the process according to the invention either the base material of coated component or another, under the zu coating to be removed.
  • the Wavelength and / or intensity of the laser radiation is or is adapted to the coating material such that the Irradiation leads to the removal of the coating material. It In this case, a continuous measurement of the spectrum of the Process lighting of the removed material and a Comparing the measured spectrum with at least one Reference spectrum. The removal is at the previous location stopped as soon as the comparison between the measured Spectrum and the reference spectrum at a predetermined Results in comparison.
  • the inventive method is also suitable for removing coatings from Turbine components such as turbine blade and in particular for removing coatings from gas turbine components.
  • the reflected Light of the flash lamp analyzed. It is exploited that the coating materials and / or substrate materials have different spectral absorption behavior. Since the absorbed wavelengths in the reflected light a have reduced intensity can be determined by analysis the intensity of a wavelength of the reflected light characterize the materials. This approach does not work though when irradiated with light takes place, which has only one wavelength. The on the other hand, the method according to the invention can also be used find when the irradiation with light of a single Wavelength occurs, as is often the case with laser radiation Case is.
  • a comparison of the measured spectrum with at least one Reference spectrum can be a comparison of the measured spectrum with the spectrum of the coating material as Reference spectrum done. The ablation is then terminated once the measured spectrum is no longer with the Reference spectrum matches.
  • This procedure can especially useful if one and the same Coating material on a variety of different Substrates use, since no information about the Substrate material needs to be present. In other words, it can do the same for a lot of different substrates Reference spectrum use find.
  • a comparison between the measured spectrum and the reference spectrum a comparison of the measured spectrum with the spectrum of Substrate material to be made as a reference spectrum. The Ablation is then terminated as soon as the measured spectrum with matches the reference spectrum.
  • This procedure can especially useful if a variety different coating materials on the same substrate be used.
  • this embodiment advantageous to use, if not only one Coating, but several superposed Coatings should be removed, as in this case only one reference spectrum, namely that of the Substrate material, is necessary.
  • the termination of the ablation can in the process according to the invention be realized in a simple manner that the Irradiation with the laser radiation is terminated. alternative it is possible to stop the ablation thereby achieve that the wavelength and / or the intensity of the Laser radiation is changed or become such that the Irradiation with the changed laser radiation no longer leads to a removal of the coating material.
  • the irradiation with the laser radiation takes place in inventive method in particular pulse-shaped.
  • the Measuring the spectrum of process lighting and comparing of the measured spectrum with the at least one Reference spectrum then takes place, for example, all n Laser pulses, where n is an arbitrary integer, preferably an integer between one and five and especially one is.
  • a laser pulse for removing material can, if a Measuring the spectrum is to take place, an analysis pulse preceded, whose energy density is high enough, plasma too generate, but whose performance is so low that no significant material removal takes place.
  • the Wavelength and / or intensity of the laser radiation is or be in this embodiment depending on the degree of Deviation changed so that the Ablation rate increased or decreased.
  • This can with pulsed irradiation, for example by changing the Pulse duration and / or the pulse intensity done.
  • the removal rate to reduce if e.g. an admixture of Reference spectrum (of the substrate spectrum) in the measured Spectrum but not a pure reference spectrum (Substrate spectrum) is measured.
  • the admixture would suggest that the coating may have become thinner but has not been completely removed. To the to take account of thinner coating and order Damage to the substrate material as low as possible hold, it is beneficial to the ablation rate too to reduce.
  • Laser radiation includes a laser device for generating Laser radiation whose wavelength and / or intensity such is adapted to the coating material or are that the irradiation for removing the coating material leads.
  • the laser device is used to irradiate the coated substrate with the laser radiation.
  • the Inventive device further comprises a with the Laser device for outputting a control signal for controlling the laser device and with an analysis device for Receiving a characteristic measurand connected Control device.
  • the control device is so to Controlling the laser device based on a comparison of characteristic measured variable with a reference size designed that when the coating material on the irradiated point is eroded, the laser device the Irradiation with the laser radiation terminated at this point or the wavelength and / or intensity of the Laser radiation changed so that no removal of the Substrate material is more.
  • the device according to the invention comprises a Spectral analysis device for analyzing the spectrum of the Process lighting of the removed material and outputting the result of the analysis as the characteristic measure.
  • the device according to the invention is particularly suitable for Performing the method according to the invention.
  • the laser device can in particular use a laser adjustable laser wavelength and / or adjustable Include laser power. This is an adjustment of the Laser light to the ablated coating material possible, so that the highest possible impact is achieved can.
  • the device according to the invention can, for example, for Removing coatings from turbine components such as Turbine blades and in particular for removing Coatings of gas turbine components are used.
  • the laser device may be a pulsed laser with an adjustable pulse duration.
  • the laser device may be a pulsed laser with an adjustable pulse duration.
  • Device is the spectral analysis device with a Filter device for filtering out the wavelength of the Laser equipped.
  • the filter device can thereby for example, on interference or absorption filters based. With the help of the filter device can fade of the measured spectrum by the much more intense scattered Laser radiation can be avoided.
  • Fig. 1 shows a device according to the invention for removal a coating by means of laser radiation.
  • Fig. 2 and 3 show possible time courses of the Intensity of laser radiation, with which the irradiation takes place.
  • Fig. 4 shows a section of a coated Gas turbine blade at the beginning of irradiation with Laser radiation in a schematic representation.
  • Fig. 5 shows the detail of Figure 4 in advanced Irradiation time.
  • the Device 10 comprises a laser device 12 with a laser 14, the laser wavelength adjustable and a laser control unit 16.
  • the laser control unit serves to determine the laser wavelength, the laser intensity and, if a pulsed mode of operation is used, the Pulse duration and to set the intervals between the pulses and to control. With the laser radiation is the too removing coating irradiated.
  • Possible courses of the laser intensity of pulsed laser radiation are shown schematically in FIGS. 2 and 3 as a function of time.
  • the intensity and / or the wavelength of the laser radiation before the time T 0 , at which the removal of the coating at the irradiated point is terminated, is adjusted such that the coating material is vaporized and / or melted from the irradiated point of the component or is ablated.
  • the time averaged intensity with which a coating is irradiated can be pulsed operation of the laser 14 by suitably setting the pulse amplitude, the Pulse duration and / or the time interval between the Set pulses.
  • the pulse durations of the pulsed laser are preferably less than 500 ns.
  • FIG. 4 and FIG Figure 5 show a schematic representation of a Section of a gas turbine blade 101 with an on it applied coating 102, in the embodiment from a ceramic coating or TBC coating is formed. Also, you can get more coatings be present, for example, one under the TBC coating MCrAlY coating (not shown). Of the Simplicity of the illustration is shown in FIGS. 4 and 5 only a coating 102 shown in the Presence of several coatings the top one Coating the coating sequence represents.
  • the coating 102 at the previously irradiated point is removed (Fig. 5), evaporated instead of Coating material, the substrate material of Gas turbine blade 101, so that the plasma 107 'of previously existing plasma 107 different.
  • the emission spectrum of the process lighting changes.
  • the Radiation 109 'of the plasma 107' of the substrate material shows So a different emission spectrum than the radiation 109 of the Plasma 107 of the coating material.
  • the device 10 comprises a Spectral analysis device 20 with a spectrometer 24 and an upstream filter 22.
  • the Spectral analysis device 20 serves to reduce the spectrum of the process lighting occurring during the evaporation process, i. which emitted from the plasma due to its high temperature Radiation 109 or 109 'to analyze.
  • the filter 22 prevents the process lights from being reflected Laser light, which has a higher intensity than that Has process lights, is superimposed.
  • the device 10 comprises a Control unit 30, which with the laser device 12, the Spectral analysis device 20 and with a memory 40th connected is.
  • the control unit 30 receives from the Spectral analysis unit 20 the analysis result, i. the Spectrum of the plasma 107 representing data.
  • the Analysis result represents a characteristic measure for the plasma 107, that is for the evaporated material dar.
  • the characteristic measured variable is then in the control unit 30th compared with a stored in the memory 40 reference size. Depending on the result of this comparison, the irradiation is on the irradiated point continued, or the laser power is lowered so that further erosion of the irradiated spot is no longer done.
  • the laser power Shut down if the comparison shows that measured spectrum with the spectrum of the substrate material matches. In this case, it must be assumed that upon continuation of the ablation, the substrate material would be removed.
  • a double redundancy can be achieved if one Comparison of the measured spectrum with the spectrum of the coating material as well as with the spectrum of Substrate material takes place. Once the measured spectrum no longer with the spectrum of the coating material matches or the spectrum measured with the spectrum of the substrate material, the laser power becomes shut down.
  • the shutdown of the laser power at a time T 0 which results from the comparison that no coating 102 is present at the irradiated point of the gas turbine blade 101 (see Fig. 5) is shown in Figures 2 and 3.
  • the shutdown can be done, for example, by reducing the pulse duration or the pulse power.
  • the shutdown occurs in that the amplitude of the laser radiation is reduced.
  • the reduction of the average laser power takes place in that the frequency of the laser radiation or both the amplitude and the frequency of the laser radiation is reduced or become constant amplitude.
  • it is also possible to completely stop the irradiation with the laser radiation at time T 0 as shown in Fig. 2.
  • the laser 14 may shut down the laser power or stopping the irradiation on the previously irradiated Move to another location on the coated gas turbine blade 101, and the removal of the Coating 102 can continue at this new location become.
  • the device 10 according to the invention also comprises a Terminal 42.
  • Reference 42 can be used for reference spectra be written in the memory 40. That's it possible, adapted reference spectra in the memory 40 to write if a change of the workpiece, of which the Coating is removed takes place. By choosing the appropriate reference spectrum or the appropriate Reference spectra, the device can be removed to the Coating and / or the substrate material of the workpiece be adjusted.
  • the laser control unit 16 integrated into the laser device.
  • the laser control unit 16 it is also possible to use the laser control unit 16 to integrate into the control unit 30.
  • the memory 40 is not integrated into the device itself be.
  • the device 10 with a external memory containing one or more reference spectra contains, to connect. It can then, for example, too several devices on a common external Memory, for example. In the context of a network, access.
  • the actually for the removal of coating material provided laser pulse to precede an analysis pulse let plasma whose energy density is high enough generate, but whose performance is so low that no significant material removal takes place. Analyzing the Process lighting then takes place on the basis of the analysis pulse generated plasma.
  • the analysis pulse can, for example, by a be realized very short pulse.
  • the use of a Analysis pulse offers the advantage of being so good at analyzing as no material removal is necessary, so that the removal can be stopped before a significant material removal of the substrate or other non-ablative layer he follows.
  • the coating is not will always be completely removed, but without transition that there is usually a transitional phase in which both coating material and substrate material evaporated and / or melted. Accordingly becomes the emission spectrum of the process lighting does not It is gradually changing from one to another Spectrum into the other spectrum. During this Transition phase, it may be useful to the material removal reduce excessive removal of the substrate material to avoid.
  • the method according to the invention is therefore a determination of the Degree of deviation of the measured spectrum from Reference spectrum. The wavelength and / or intensity of the Laser radiation is then dependent on the degree of Deviation changed so that the speed reduced material removal. Especially good is the Regulate material removal in the transitional phase, if the measured spectrum with both the spectrum of Coating material as well as with the substrate material is compared.
EP04010208A 2004-04-29 2004-04-29 Procédé et dispositif pour enlever un revêtement Withdrawn EP1591188A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP04010208A EP1591188A1 (fr) 2004-04-29 2004-04-29 Procédé et dispositif pour enlever un revêtement

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EP04010208A EP1591188A1 (fr) 2004-04-29 2004-04-29 Procédé et dispositif pour enlever un revêtement

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Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102006028250A1 (de) * 2006-06-20 2007-12-27 Carl Zeiss Microimaging Gmbh Verfahren zur Überwachung von Laserbearbeitungsprozessen
DE102008006625B4 (de) * 2008-01-29 2011-07-14 ThyssenKrupp Steel Europe AG, 47166 Verfahren und Vorrichtung zur Überwachung des Laserstrahlschweißens von beschichteten Platinen
DE102011001710A1 (de) * 2011-03-31 2012-10-04 Thyssenkrupp Steel Europe Ag Verfahren und Vorrichtung zur Laserstrahlbearbeitung eines Werkstücks
WO2012150413A1 (fr) * 2011-05-02 2012-11-08 Snecma Procédé de nettoyage et de décapage d'une aube de turbomoteur au moyen d'un laser impulsionnel
EP2716788A1 (fr) * 2012-10-08 2014-04-09 Siemens Aktiengesellschaft Procédé destiné à supprimer une couche métallique sur un substrat
CN105792951A (zh) * 2013-12-03 2016-07-20 西门子能源公司 热障涂层的熔剂辅助激光去除
DE102020202722A1 (de) 2020-03-03 2021-09-09 Trumpf Laser- Und Systemtechnik Gmbh Verfahren zum Bearbeiten eines Werkstücks und Bearbeitungssystem

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5281798A (en) * 1991-12-24 1994-01-25 Maxwell Laboratories, Inc. Method and system for selective removal of material coating from a substrate using a flashlamp
DE4320341A1 (de) * 1993-06-21 1994-12-22 Fraunhofer Ges Forschung Verfahren zum Abtragen von Deckschichten von Glasbauteilen mit Laserstrahlung und Vorrichtung zur Durchführung des Verfahrens
DE4320408A1 (de) * 1993-06-21 1994-12-22 Fraunhofer Ges Forschung Verfahren zur Prozeßkontrolle und -regelung bei der Oberflächenbearbeitung von Werkstücken mit gepulster Laserstrahlung
DE19619137A1 (de) * 1996-05-11 1997-11-13 Urenco Deutschland Gmbh Verfahren zum Diagnostizieren einer Oberfläche und anschließendem selektiven Abtragen von Schichten
US5864114A (en) * 1994-03-10 1999-01-26 Toshiharu Ishikawa Coating removal apparatus using coordinate-controlled laser beam

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5281798A (en) * 1991-12-24 1994-01-25 Maxwell Laboratories, Inc. Method and system for selective removal of material coating from a substrate using a flashlamp
DE4320341A1 (de) * 1993-06-21 1994-12-22 Fraunhofer Ges Forschung Verfahren zum Abtragen von Deckschichten von Glasbauteilen mit Laserstrahlung und Vorrichtung zur Durchführung des Verfahrens
DE4320408A1 (de) * 1993-06-21 1994-12-22 Fraunhofer Ges Forschung Verfahren zur Prozeßkontrolle und -regelung bei der Oberflächenbearbeitung von Werkstücken mit gepulster Laserstrahlung
US5864114A (en) * 1994-03-10 1999-01-26 Toshiharu Ishikawa Coating removal apparatus using coordinate-controlled laser beam
DE19619137A1 (de) * 1996-05-11 1997-11-13 Urenco Deutschland Gmbh Verfahren zum Diagnostizieren einer Oberfläche und anschließendem selektiven Abtragen von Schichten

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102006028250A1 (de) * 2006-06-20 2007-12-27 Carl Zeiss Microimaging Gmbh Verfahren zur Überwachung von Laserbearbeitungsprozessen
DE102008006625B4 (de) * 2008-01-29 2011-07-14 ThyssenKrupp Steel Europe AG, 47166 Verfahren und Vorrichtung zur Überwachung des Laserstrahlschweißens von beschichteten Platinen
DE102011001710A1 (de) * 2011-03-31 2012-10-04 Thyssenkrupp Steel Europe Ag Verfahren und Vorrichtung zur Laserstrahlbearbeitung eines Werkstücks
US9387555B2 (en) 2011-03-31 2016-07-12 Thyssenkrupp Steel Europe Ag Method and apparatus for machining a workpiece by means of a laser beam
RU2604406C2 (ru) * 2011-05-02 2016-12-10 Снекма Способ очистки и зачистки лопатки газотурбинного двигателя посредством импульсного лазера
WO2012150413A1 (fr) * 2011-05-02 2012-11-08 Snecma Procédé de nettoyage et de décapage d'une aube de turbomoteur au moyen d'un laser impulsionnel
FR2974746A1 (fr) * 2011-05-02 2012-11-09 Snecma Procede de nettoyage et de decapage d'une aube de turbomoteur au moyen d'un laser impulsionnel
CN103501926A (zh) * 2011-05-02 2014-01-08 斯奈克玛 使用脉冲激光器清洁和清除涡轮轴发动机叶片的方法
JP2014519569A (ja) * 2011-05-02 2014-08-14 スネクマ パルスレーザを用いてターボシャフトエンジンブレードを洗浄し剥離するための方法
CN103501926B (zh) * 2011-05-02 2017-02-15 斯奈克玛 使用脉冲激光器清洁和清除涡轮轴发动机叶片的方法
US9415462B2 (en) 2011-05-02 2016-08-16 Snecma Method for cleaning and stripping a turboshaft engine blade using a pulsed laser
EP2716788A1 (fr) * 2012-10-08 2014-04-09 Siemens Aktiengesellschaft Procédé destiné à supprimer une couche métallique sur un substrat
CN105792951A (zh) * 2013-12-03 2016-07-20 西门子能源公司 热障涂层的熔剂辅助激光去除
DE102020202722A1 (de) 2020-03-03 2021-09-09 Trumpf Laser- Und Systemtechnik Gmbh Verfahren zum Bearbeiten eines Werkstücks und Bearbeitungssystem

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