Patent Grant
9895771
The invention relates to ablating a coating using a laser. In particular, the invention relates to a laser apparatus that operates at conditions for removal of coatings such that the process is environmentally beneficial in comparison to other removal mechanisms.
Laser-based coating removal systems use pulses of light from high power lasers to ablate or vaporize the paint or other coating from a surface. Ablation is the thermochemical disassociation, vaporization, and removal of material because of the incident convective and radiant energy.
Commercially-available lasers have the capability to generate pulses of radiant energy for suitable duration to achieve ablation conditions without significant convective heat transfer. Specifically, laser-induced ablation can be limited to the material surface through the appropriate selection of laser wavelength and active control of the radiative heat transfer rate and duration. The important application is the removal of the coatings and finishes from substrate structures that must be protected and reused. The radiative energy input must be significant, but the heat conduction into the substrate must be minimized. The amount of heat conduction into the substrate is affected by the radiant energy and the material surface of the substrate. The wavelength, irradiance, and pulse width of the radiant energy impact the amount of heat conduction into the substrate. The substrate properties, including transmissivity, absorptivity, emissivity, density, specific heat, thermal conductivity, and ablation onset thermochemistry (i.e. melt, vaporization, and surface chemical reaction temperatures), also affect the heat conduction into the substrate.
Wavelength is an important parameter because it must be selected to minimize the transmissivity of the radiant energy into the substrate. Thus, the radiant energy is absorbed at the surface. A high absorptivity of the material surface is also valuable, as this reduces the amount of laser energy needed to achieve a desired ablation rate. In many applications, such as metal substrates below a surface coating, low substrate absorptivity is also advantageous, because this limits the potential for ablation after the surface material is removed. Alternatively, substrate ablation for highly absorbing substrates may need to be limited by the use of active surface recognition prior to the initiation of the laser radiant energy pulse.
Embodiments of the present invention are directed to a laser-based coating removal method and system to remove an identified coating in a process that is environmentally beneficial in comparison to other removal mechanisms. The method comprises directing a laser pulse to a first position on a surface having an identified coating. The laser pulse rapidly elevates the surface temperature at the first position and causes the coating to disassociate from the surface. After the coating has disassociated from the surface it is able to be collected and safely disposed.
In one aspect a laser-based method of removing a coating from a surface comprises directing a laser pulse to a first position on the surface, removing the coating from the first position by rapidly elevating a surface temperature of the first position using the laser pulse and thereby disassociating the coating from the surface and collecting the disassociated coating. In some embodiments the coating comprises an environmentally harmful substance such as Hexavalent Chromium. In some embodiments the coating comprises Diamond-Like Carbon (DLC) or Vitrified Contaminant Material (CMAS). In some embodiments, the surface temperature of the first position is elevated to the oxidation temperature of the DLC and it is converted to vapor-phase carbon dioxide before it is collected. In further embodiments, the surface temperature of the first position is elevated so that the components of the CMAS are disassociated from the surface by disrupting the chemical bonds and the admixture is disaggregated. In still further embodiments, the surface temperature of the first position is elevated to a temperature at which the hexavalent chromium is disassociated from the surface and reduced to a particulate form of trivalent chromium. In some embodiments, the disassociated coating is collected by a waste collector. In further embodiments, the heat conduction into the surface from the laser pulse is limited. In some embodiments, the disassociation occurs essentially independent of the laser wavelength. In some embodiments, the laser pulse is moved to a second position in order to remove a coating from the second position.
In another aspect, a laser-based coating removal system comprises a surface comprising a coating and a laser based removal apparatus comprising a laser source to provide a laser pulse to a first position on the surface, wherein the laser source removes the coating from the surface by rapidly elevating a surface temperature of the first position using the laser pulse and thereby disassociating the coating from the surface. In some embodiments, the coating comprises an environmentally harmful substance such as Hexavalent Chromium. In some embodiments, the coating comprises Diamond-Like Carbon (DLC) or Vitrified Contaminant Material (CMAS). In some embodiments, the surface temperature of the first position is elevated to the oxidation temperature of the DLC and it is converted to vapor-phase carbon dioxide before it is collected. In further embodiments, the surface temperature of the first position is elevated so that the components of the CMAS are disassociated from the surface by disrupting the chemical bonds and the admixture is disaggregated. In still further embodiments, the surface temperature of the first position is elevated to a temperature at which the hexavalent chromium is disassociated from the surface and reduced to a particulate form of trivalent chromium. In some embodiments, the disassociated coating is collected by a waste collector. In some embodiments, the heat conduction into the surface from the laser pulse is limited. In further embodiments, the disassociation occurs essentially independent of the laser wavelength.
In a further aspect, a method for removing Diamond-Like Carbon (DLC) from a surface comprises directing a laser pulse to a first position on the surface, elevating a surface temperature of the first position using the laser pulse to an oxidation temperature of the DLC thereby converting it to vapor-phase carbon dioxide and collecting the disassociated DLC from the surface.
In still a further aspect, a method of removing Vitrified Contaminant Material (CMAS) from a surface comprises directing a laser pulse to a first position on the surface, elevating a surface temperature of the first position using the laser pulse to disassociate the components of the CMAS from the surface and disaggregating the admixture and collecting the disassociated CMAS from the surface.
In another aspect, a method for removing Hexavalent Chromium from a surface comprises directing a laser pulse to a first position on the surface, elevating a surface temperature of the first position using the laser pulse to a temperature at which the hexavalent chromium is disassociated from the surface and reduced to a particulate form of trivalent chromium and particulate effluent, and collecting the trivalent chromium and particulate effluent from the surface.
Embodiments of the invention are described relative to the several views of the drawings. Where appropriate and only where identical elements are disclosed and shown in more than one drawing, the same reference numeral will be used to represent such identical elements.
Reference will now be made in detail to implementations of a laser-based coating removal system and method as illustrated in the accompanying drawings. The same reference indicators will be used through the drawings and the following detailed description to refer to the same or like parts. In the interest of clarity, not all of the routine features of the implementations described herein are shown and described. It will also be appreciated that in the development of any such actual implementation, numerous implementation-specific decisions be made to achieve the developer's specific goals, such as compliance with application and business related constraints, and that these specific goals will vary from one implementation to another and from one developer to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking of engineering for those of ordinary skill in the art having the benefit of this disclosure.
Embodiments of the present invention are directed to a laser-based coating removal method and system to remove an identified coating from a surface in a process that is environmentally beneficial in comparison to other removal mechanisms. The system comprises a laser source to provide a laser light, a routing element coupled to the laser source and configured to direct the laser light onto a target region of the surface thereby removing the coating from the target region. In some embodiments, the system comprises a detection means to detect the coating as the coating disassociates from the target region of the surface. In some embodiments, the system comprises a waste collector for collecting the coating that has been removed.
A laser-based method for removing an identified coating from a surface is able to remove the identified coating in an environmentally beneficial manner. A laser pulse is directed to the surface in order to raise the temperature on the surface of the coating. When the temperature of the surface reaches a critical point, the coating disassociates from the surface and is able to be collected and safely disposed. Using a laser-based method avoids media-blast or chemically based processes that are time consuming and generate significant toxic waste. The laser-based method rapidly raises the temperature of the surface to its critical point under strictly controlled operating parameters in order to induce the desired effects.
In some embodiments, the system and method is used to selectively remove the identified coatings Diamond-Like Carbon (DLC), Vitrified Contaminants (CMAS), and primers and paints containing hexavalent chromium in an environmentally beneficial manner. However, the system is able to selectively remove other environmentally harmful chemicals as desired.
Diamond-Like Carbon (DLC)
DLC exists in different forms of carbon atoms that display some of the typical properties of diamond. DLC is applied as coatings to other materials in order to benefit from the diamond-like properties. Particularly, the value of a DLC coating accrues from its ability to provide properties of diamond to the surface of almost any material. These properties include hardness, wear, resistance, x-ray transparency, high thermal conductivity, and low friction. For example, a DLC film friction coefficient against polished steel ranges from 0.05-0.20. DLC is often applied in order to reduce the abrasive wear in high-load bearing surfaces, cutting tools, and press molds.
Removal of the DLC coating for substrate inspection and repair poses a significant challenge because of the coating's hardness and chemical resistance. Consequently, DLC film removal is sometimes attempted using an oxygen-dominated plasma beam to generate an appropriate ionized oxygen gas flow rate that etches the DLC film in a manner proportional to the treatment time. Alternatively, DLC may be removed by electrolyzing the film in an acid solution. However, these methods are limited by the processing rate, incomplete removal of the DLC film, access to confined spaces, field operability and/or waste chemical generation.
A laser-based method for DLC removal is able to remove DLC by impinging high irradiance laser pulses on a target DLC surface in an oxygen-rich environment. The laser pulse contacts the surface and immediately elevates the DLC to its carbon dioxide temperature, thereby rapidly and cleanly converting the DLC to vapor phase carbon dioxide. When the DLC has been converted to the vapor phase carbon dioxide it is able to be collected and safely disposed. Additionally, the limited heat conduction into the substrate provided by the laser process protects the coated surface from damage. In some embodiments, closed-loop feedback control immediately suppresses the beam when the DLC coating is completely removed.
Vitrified Contaminant Material (CMAS)
Operation of gas turbine engines in typical environments leads to ingestion of significant mounts of sand, dust, volcanic ash, and other atmospheric contaminants and containing oxides of Calcium, Magnesium, Aluminum, and Silicon (CMAS). In the high temperature, high pressure sections of these engines, the contaminants vitrify and accumulate on the turbine flow surfaces. The accumulations cannot be readily removed with conventional media blast or chemical exposure methods. Consequently, the conventional cleaning methods entail dismantling the engine, removing the contaminated component and then exposing the surfaces to a highly-concentrated acid bath for a protracted period. The acid baths are a toxic exposure hazard to personnel and the environment while only partially removing the contaminants.
A laser-based method is able to remove the CMAS quickly and completely from exposed surfaces and small openings such as bleed air holes, pores, cracks, and crevices. In some embodiments, laser-based cleaning may be accomplished in situ or on subassemblies removed from the engine. A high irradiance laser pulse produces a rapid temperature rise of the surface of the CMAS and simultaneously disassociates the CMAS components, disrupts the amorphous chemical bonds and disaggregates the admixtures. Once the CMAS is disassociated from the surface, purge air is able to be directed towards the point of ablation and adjacent vacuum collectors result in a rapid and thorough cleaning of the surfaces within the focal range of the laser delivery device.
Hexavalent Chromium Removal and Conversion to Trivalent
Paints and primers such as used in numerous applications include compounds containing hexavalent chromium, often in the form of zinc chromate (ZnCr04). ZnCr04 is a chemical compound containing the chromate anion, appearing as an odorless yellow solid powder and is used industrially in chromate conversion coatings. Its use as a corrosion resistant agent was applied to aluminum alloy parts first in commercial aircraft, then in military aircraft. During the 1940's and 1950's it was used as paint in the wheel wells of retractable landing gear of military aircraft to protect the aluminum from corrosion. It is also used on many systems as a primer.
Chromates such as ZnCr04 have been linked to occupational diseases, specifically dermatitis, nasal irritation, and lung cancer. As a result, numerous organizations have directed abatement programs and with varying degrees of success. Removal of ZnCr04 coatings using standard abrasive methods such as media blast or sanding, or the use of solvents results in an unacceptable level of operator exposure and generates large toxic waste streams.
A laser-based ablation method for zinc chromate rapidly removes the zinc chromate coat without damaging the substrate material while simultaneously converting the hexavalent chromium to less toxic particulate forms of trivalent chromium (Cr2O3). The less-toxic particulate effluent is then able to be collected by conventional filtration techniques. Impingement of a high irradiance laser pulse on the surface of a coating with ZnCr04 rapidly raises the surface temperature of the coating to a value at which the hexavalent chromium is reduced to its triavalent form. For example, in some embodiments, the elevated temperature created by the laser pulse drives the following equilibrium chemical reaction completely to the right.
4ZnCr04+ . . . →4ZnO(solid)+2Cr2O3(solid)+3O2+ . . . .
As shown in
In some embodiments, the routing element 504 and the detection means 508 are of the type as described in the co-owned U.S. Pat. No. 7,633,033 and entitled “Color Sensing for Laser Decoating”, which is hereby incorporated by reference. In some embodiments, the waste collector 510 of the type as described in the co-owned U.S. Pat. No. 7,009,141 and entitled “Laser Scanning Head with Rotary Scanning Coaxial Refractive Optics”, which is also hereby incorporated by reference.
The laser pulse is able to comprise a fluence in the range of 1-10 Joules per square centimeter (J/cm2) depending on the coating and the substrate. In some embodiments, the irradiance of the laser pulse is in the range of 6-60 MegaWatts per square cm (MW/cm2). Particularly, the laser pulse power is sufficient in combination with the laser optics and beam quality to achieve the desired irradiance. Additionally, the laser ablation is achieved essentially independent of the laser wavelength because Diamond-Like Carbon (DLC), Vitrified Contaminants (CMAS), and chromate-containing coatings have low transmissivity for the typical industrial laser wavelengths in the range of 0.3 μm to 10.6 μm. Further, the method is minimally affected by the laser pulse duration. Specifically, in some embodiments, the method uses a laser with a delivered average power of 350 W providing a fluence of 5 J/cm2 and irradiance of 35 MW/cm2.
In its application, a laser-based method of removing a coating from a surface is able to remove an identified coating from the surface and in an environmentally beneficial manner. Particularly, a laser pulse is able to be directed to a position on a surface in order to elevate the surface temperature to a critical temperature at which a coating is disassociated from the surface. Once the coating disassociates from the surface it is able to be collected and safely disposed. Thus, it is clear that the coating removal system described herein has numerous advantages. Specifically, the coating removal system is able to efficiently remove environmentally harmful coatings on a surface in a process that is environmentally beneficial in comparison to other removal mechanisms Particularly, the laser-based method rapidly raises the temperature of the surface to its critical point under strictly controlled operating parameters in order to induce the desired effects. As a result, the laser-based method avoids media-blast or chemically based processes that are time consuming and generate significant toxic waste.
The present invention has been described in terms of specific embodiments incorporating details to facilitate the understanding of the principles of construction and operation of the invention. Such reference herein to specific embodiments and details thereof is not intended to limit the scope of the claims appended hereto. It will be apparent to those skilled in the art that modifications may be made in the embodiment chosen for illustration without departing from the spirit and scope of the invention.
This application claims priority of U.S. provisional application, Ser. No. 61/604,368, filed Feb. 28, 2012, and entitled “Laser Ablation for the Environmentally Beneficial Removal of Three Substances; Diamond-Like-Carbon (DLC), Vitrified Contaminant Materials (CMAS), and Paints/Primers containing Hexavalent Chromium,” which is incorporated herein by reference.
| Number | Name | Date | Kind |
|---|---|---|---|
| 3624553 | Van-Tran | Nov 1971 | A |
| 3626141 | Daly | Dec 1971 | A |
| 3657707 | McFarland et al. | Apr 1972 | A |
| 3843865 | Nath | Oct 1974 | A |
| 3941973 | Luck, Jr. et al. | Mar 1976 | A |
| 4114018 | Von Allmen et al. | Sep 1978 | A |
| 4148057 | Jesse | Apr 1979 | A |
| 4207874 | Choy | Jun 1980 | A |
| 4328068 | Curtis | May 1982 | A |
| 4398790 | Righini et al. | Aug 1983 | A |
| 4449043 | Husbands | May 1984 | A |
| 4521070 | Scottini et al. | Jun 1985 | A |
| 4543477 | Doi et al. | Sep 1985 | A |
| 4564736 | Jones et al. | Jan 1986 | A |
| 4566937 | Pitts | Jan 1986 | A |
| 4584455 | Tomizawa | Apr 1986 | A |
| 4588885 | Lovoi et al. | May 1986 | A |
| 4644948 | Lang et al. | Feb 1987 | A |
| 4654532 | Hirshfield | May 1987 | A |
| 4665377 | Harpaintner | May 1987 | A |
| 4671848 | Miller et al. | Jun 1987 | A |
| 4676586 | Jones et al. | Jun 1987 | A |
| 4687918 | Hughes et al. | Aug 1987 | A |
| 4695698 | Mayor et al. | Sep 1987 | A |
| 4707073 | Kocher | Nov 1987 | A |
| 4729621 | Edelman | Mar 1988 | A |
| 4737004 | Amitay et al. | Apr 1988 | A |
| 4737628 | Lovoi | Apr 1988 | A |
| 4749840 | Piwczyk | Jun 1988 | A |
| 4756756 | Woodroffe | Jul 1988 | A |
| 4762385 | Fuse | Aug 1988 | A |
| 4799755 | Jones | Jan 1989 | A |
| 4807954 | Oyamada et al. | Feb 1989 | A |
| 4818049 | Assenheim et al. | Apr 1989 | A |
| 4818062 | Schifres et al. | Apr 1989 | A |
| 4821943 | Gaudin et al. | Apr 1989 | A |
| 4842360 | Caro et al. | Jun 1989 | A |
| 4844574 | Chande | Jul 1989 | A |
| 4844947 | Kanser et al. | Jul 1989 | A |
| 4859075 | Sutter, Jr. et al. | Aug 1989 | A |
| 4876444 | Field | Oct 1989 | A |
| 4880959 | Baum et al. | Nov 1989 | A |
| 4900891 | Vega et al. | Feb 1990 | A |
| 4920994 | Nachbar | May 1990 | A |
| 4928695 | Goldman et al. | May 1990 | A |
| 4931616 | Usui et al. | Jun 1990 | A |
| 4960988 | Simms | Oct 1990 | A |
| 4986664 | Lovoi | Jan 1991 | A |
| 4994567 | Crisp et al. | Feb 1991 | A |
| 4994639 | Dickinson et al. | Feb 1991 | A |
| 5006268 | Griffaton | Apr 1991 | A |
| 5014207 | Lawton | May 1991 | A |
| 5040479 | Thrash | Aug 1991 | A |
| 5068750 | Cook et al. | Nov 1991 | A |
| RE33777 | Woodroffe | Dec 1991 | E |
| 5081350 | Iwasaki et al. | Jan 1992 | A |
| 5107445 | Jensen et al. | Apr 1992 | A |
| 5113802 | Le Blanc | May 1992 | A |
| 5151134 | Boquillion et al. | Sep 1992 | A |
| 5194723 | Cates et al. | Mar 1993 | A |
| 5210944 | Monson | May 1993 | A |
| 5216808 | Martus | Jun 1993 | A |
| 5229593 | Cato | Jul 1993 | A |
| 5245682 | Ortiz et al. | Sep 1993 | A |
| 5281798 | Hamm et al. | Jan 1994 | A |
| 5291570 | Filgas et al. | Mar 1994 | A |
| 5293023 | Haruta et al. | Mar 1994 | A |
| 5328517 | Cates et al. | Jul 1994 | A |
| 5333218 | Ortiz et al. | Jul 1994 | A |
| 5355063 | Boone et al. | Oct 1994 | A |
| 5364390 | Taboada et al. | Nov 1994 | A |
| 5371582 | Toba et al. | Dec 1994 | A |
| 5373140 | Nagy et al. | Dec 1994 | A |
| 5386112 | Dixon | Jan 1995 | A |
| 5395362 | Sacharoff et al. | Mar 1995 | A |
| 5446256 | Cartry | Aug 1995 | A |
| 5451765 | Gerber | Sep 1995 | A |
| 5526167 | Peng | Jun 1996 | A |
| 5531857 | Engelsberg et al. | Jul 1996 | A |
| 5548113 | Goldberg et al. | Aug 1996 | A |
| 5558666 | Dewey et al. | Sep 1996 | A |
| 5571335 | Lloyd | Nov 1996 | A |
| 5581346 | Sopori | Dec 1996 | A |
| 5589089 | Usegi | Dec 1996 | A |
| 5592879 | Waizmann | Jan 1997 | A |
| 5610753 | Kessler et al. | Mar 1997 | A |
| 5613509 | Kolb | Mar 1997 | A |
| 5637245 | Shelton | Jun 1997 | A |
| 5643476 | Garmire et al. | Jul 1997 | A |
| 5656186 | Mourou et al. | Aug 1997 | A |
| 5662762 | Ranalli | Sep 1997 | A |
| 5720894 | Neev | Feb 1998 | A |
| 5767479 | Kanaoka | Jun 1998 | A |
| 5780806 | Ferguson | Jul 1998 | A |
| 5784162 | Cabib et al. | Jul 1998 | A |
| 5790046 | Blossfeld | Aug 1998 | A |
| 5805275 | Taylor | Sep 1998 | A |
| 5845646 | Lemelson | Dec 1998 | A |
| 5864114 | Fukuda | Jan 1999 | A |
| 5889253 | Kanaoka | Mar 1999 | A |
| 5954712 | Goodman | Sep 1999 | A |
| 5986234 | Mathews et al. | Nov 1999 | A |
| 6040549 | Kanaoka | Mar 2000 | A |
| 6040553 | Ross | Mar 2000 | A |
| 6165170 | Wynne et al. | Dec 2000 | A |
| 6215094 | Dausinger et al. | Apr 2001 | B1 |
| 6285002 | Ngoi et al. | Sep 2001 | B1 |
| 6288362 | Thomas et al. | Sep 2001 | B1 |
| 6313435 | Shoemaker et al. | Nov 2001 | B1 |
| 6323457 | Jung | Nov 2001 | B1 |
| 6347976 | Lawton et al. | Feb 2002 | B1 |
| 6383177 | Balle-Peterson et al. | May 2002 | B1 |
| 6384370 | Tsunemi et al. | May 2002 | B1 |
| 6414263 | Uchida | Jul 2002 | B1 |
| 6437285 | Thomas et al. | Aug 2002 | B1 |
| 6494960 | Macdonald et al. | Dec 2002 | B1 |
| 6635844 | Yu | Oct 2003 | B2 |
| 6664499 | Brink et al. | Dec 2003 | B1 |
| 6693255 | Freiwald | Feb 2004 | B2 |
| 6864478 | Schroder | Mar 2005 | B2 |
| 6924457 | Koyoma et al. | Aug 2005 | B2 |
| 6927917 | Kiruma | Aug 2005 | B2 |
| 7009141 | Wool et al. | Mar 2006 | B1 |
| 7170030 | Haight | Jan 2007 | B2 |
| 7265033 | Shigematsu et al. | Sep 2007 | B2 |
| 7381383 | Yokoyama | Jun 2008 | B1 |
| 7397014 | Hart et al. | Jul 2008 | B2 |
| 7407591 | De Battisti et al. | Aug 2008 | B2 |
| 7408130 | Sonoda et al. | Aug 2008 | B2 |
| 7429470 | Lee | Sep 2008 | B2 |
| 7452476 | Bayer et al. | Nov 2008 | B2 |
| 7525065 | Engler | Apr 2009 | B2 |
| 7535565 | Viertl et al. | May 2009 | B1 |
| 7632420 | Thomas | Dec 2009 | B2 |
| 7633033 | Thomas et al. | Dec 2009 | B2 |
| 7800014 | Thomas et al. | Sep 2010 | B2 |
| 7867404 | Deutsch | Jan 2011 | B2 |
| 8030594 | Thomas et al. | Oct 2011 | B2 |
| 8182609 | Le Claire | May 2012 | B1 |
| 8246172 | Amano | Aug 2012 | B2 |
| 8348655 | Kazusako et al. | Jan 2013 | B2 |
| 8604380 | Howerton et al. | Dec 2013 | B2 |
| 8687189 | Agrawal et al. | Apr 2014 | B2 |
| 8980639 | Clark et al. | Mar 2015 | B2 |
| 20020134770 | Freiwald et al. | Sep 2002 | A1 |
| 20020153361 | Sakamoto | Oct 2002 | A1 |
| 20030040164 | Inoue et al. | Feb 2003 | A1 |
| 20030062349 | Suh et al. | Apr 2003 | A1 |
| 20030169167 | Fey et al. | Sep 2003 | A1 |
| 20040045497 | Kriews et al. | Mar 2004 | A1 |
| 20040057047 | Knebel | Mar 2004 | A1 |
| 20040199151 | Neuberger | Oct 2004 | A1 |
| 20040219286 | Flanagan | Nov 2004 | A1 |
| 20050072612 | Maggio | Apr 2005 | A1 |
| 20050150878 | Thomas et al. | Jul 2005 | A1 |
| 20050211680 | Li | Sep 2005 | A1 |
| 20050224474 | Kilburn | Oct 2005 | A1 |
| 20050233547 | Noda et al. | Oct 2005 | A1 |
| 20060000488 | Claar et al. | Jan 2006 | A1 |
| 20060151433 | Chang et al. | Jul 2006 | A1 |
| 20060186098 | Caristan | Aug 2006 | A1 |
| 20060273896 | Kates | Dec 2006 | A1 |
| 20070000885 | Thomas et al. | Jan 2007 | A1 |
| 20070051708 | Talwar et al. | Mar 2007 | A1 |
| 20070224768 | Chaplick et al. | Sep 2007 | A1 |
| 20080006615 | Rosario et al. | Jan 2008 | A1 |
| 20090007933 | Thomas et al. | Jan 2009 | A1 |
| 20090242527 | Anger | Oct 2009 | A1 |
| 20100033817 | Ono | Feb 2010 | A1 |
| 20100093112 | Takagi et al. | Apr 2010 | A1 |
| 20100134628 | Pfitzner et al. | Jun 2010 | A1 |
| 20100176101 | Costin et al. | Jul 2010 | A1 |
| 20100243625 | Osako | Sep 2010 | A1 |
| 20100272961 | Costin, Jr. | Oct 2010 | A1 |
| 20110024400 | Rumsby | Feb 2011 | A1 |
| 20110088720 | Varanasi et al. | Apr 2011 | A1 |
| 20110168679 | Qi et al. | Jul 2011 | A1 |
| 20110186553 | Chung | Aug 2011 | A1 |
| 20110206071 | Karavitis | Aug 2011 | A1 |
| 20110240617 | Ku | Oct 2011 | A1 |
| 20120086934 | Digonnet | Apr 2012 | A1 |
| 20130036380 | Symons | Feb 2013 | A1 |
| 20130136744 | Bouche | May 2013 | A1 |
| 20130199732 | Niwa et al. | Aug 2013 | A1 |
| Number | Date | Country |
|---|---|---|
| 91646 | Oct 1983 | EP |
| 2 661 371 | Apr 1990 | FR |
| 2 689 423 | Apr 1990 | FR |
| 2 246 099 | Jan 1992 | GB |
| 2 402 230 | Dec 2004 | GB |
| 2481190 | Dec 2011 | GB |
| 01203090 | Aug 1989 | JP |
| 02263854 | Oct 1990 | JP |
| 05082276 | Apr 1993 | JP |
| 05138377 | Jun 1993 | JP |
| 10309516 | Nov 1998 | JP |
| 2000103607 | Apr 2000 | JP |
| 2001300755 | Jan 2001 | JP |
| 200168829 | Mar 2001 | JP |
| 361161781 | Jun 2003 | JP |
| 8301400 | Apr 1983 | WO |
| 2004039531 | Oct 2004 | WO |
| Entry |
|---|
| Friedrich, Craig. “Laser Ablation”. Precision Micromanufacturing Processes: Applied to Miniaturization Technologies. Michigan Technological University (Published 1998) (Retrieved on Dec. 15, 2015 from Archive.org snapshot dated Jul. 5, 2010). |
| Kononenko et al., “Ablation of CVD diamond with nanosecond laser pulses of UV-IR range”, Apr. 1998, Elsevier, Diamond and Related Materials, vol. 7, pp. 1623-1627. |
| Motelica-Heino et al., “Macro and microchemistry of trace metals in vitrified domestic wastes by laser ablation ICP-MS and scanning electron microprobe X-Ray energy dispersive spectroscopy” , Aug. 1998, Elsevier, Talanta , pp. 407-422. |
| Hagans et al., “Chromate Conversion Coatings”, Dec. 1994, ASM Handbook, vol. 5: Surface Engineering, pp. 405-411. |
| Robertson, “Diamond-like amorphous carbon”, Dec. 2002, Elsevier, Materials Science and Engineering R, vol. 37, pp. 129-281. |
| “Photonic Cleaning Process Moves to Heavy Industry,” Mar. 1997, p. 22, Photonics Spectra. |
| Freiwald et al., “Laser Ablation of Contaminants from Concrete and Metals Surfaces,” Dec. 1994, pp. 1-53, F2 Associates, Incorporated. |
| INTA, “Radiant Energy Based Cleaning and Coating Removal Technology Comparison,” Aug. 8, 1994, pp. 1-26,, Manufacturing Technology Special Advanced Studies. |
| Barone, Philip A. “Automated Laser Paint Stripping (ALPS),” Jun. 1, 1992, pp. AD92-206-1 through AD92-206-17, Society of Manufacturing Engineers. |
| “The Company The Technology,” Apr. 1997, General Lasertronics Corporation. |
| “Lasertronics Corporate Overview,” Apr. 1997, Lasertronics Engineering Excellence. |
| “Lasertronics Aircraft Paint Removal,” Apr. 1997, Lasertronics Engineering Excellence. |
| “Lasertronics Radiation/Medical Decontamination,” Apr. 1997, Lasertronics Engineering Excellence. |
| “Lasertronics Grafitti Abatement,” Apr. 1997, Lasertronics Engineering Excellence. |
| “Lasertronics Lead-Based Paint Removal,” Apr. 1997, Lasertronics Engineering Excellence. |
| Driscoll et al., “Handbook of Optics,” Dec. 1978, pp. 13-6 through 13-10, McGraw-Hill Book Company. |
| Liu et al., “Paint Removal Using Lasers,” Jul. 20, 1995, pp. 4409-4414, Applied Optics, vol. 34, No. 21. |
| Lovoi, Paul, “Laser Paint Stripping Offers Control and Flexibility,” Nov. 1994, pp. 75-80, Laser Focus World. |
| Bonkowski et al., “CW Laser Paint Stripping,” Aug. 1991, pp. 1-20, The Laser Institute and National Science and Engineering Research Council. |
| Lovoi, Paul, “Laser/Robot Paint Stripping, Laser Ablation Coating Removal,” Apr. 1988, International Technical Associates. |
| Tavernier et al., “Photoluminescence from laser assisted debonded epitaxial GaN and ZnO films”, Applied Physics Letters 74(18), pp. 2678-2680 (May 3, 1999). |
| Horie et al., “Interface structure modified by plasma-surface interaction and its effect on ablative hole opening process in bilayer system of Te Sef film and a fluorocarbon subbing layer”, Journal of Applied Physics 77, 162-166 (Jan. 1995), American Institute of Physics. |
| Number | Date | Country | |
|---|---|---|---|
| 20130220982 A1 | Aug 2013 | US |
| Number | Date | Country | |
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| 61604368 | Feb 2012 | US |
