Patent Publication Number: US-2016243655-A1

Title: Component repair using confined laser drilling

Description:
FIELD OF THE INVENTION 
     The present disclosure relates to a method and system for repairing a component using a confined laser drill. 
     BACKGROUND OF THE INVENTION 
     Turbines are widely used in industrial and commercial operations. A typical commercial steam or gas turbine used to generate electrical power includes alternating stages of stationary and rotating airfoils. For example, stationary vanes may be attached to a stationary component such as a casing that surrounds the turbine, and rotating blades may be attached to a rotor located along an axial centerline of the turbine. A compressed working fluid, such as but not limited to steam, combustion gases, or air, flows through the turbine, and the stationary vanes accelerate and direct the compressed working fluid onto the subsequent stage of rotating blades to impart motion to the rotating blades, thus turning the rotor and performing work. 
     An efficiency of the turbine generally increases with increased temperatures of the compressed working fluid. However, excessive temperatures within the turbine can reduce the longevity of the airfoils in the turbine and thus increase repairs, maintenance, and outages associated with the turbine. As a result, various designs and methods have been developed to provide cooling to the airfoils. For example, a cooling media can be supplied to a cavity inside the airfoil to convectively and/or conductively remove heat from the airfoil. In particular embodiments, the cooling media can flow out of the cavity through cooling passages in the airfoil to provide film cooling over the outer surface of the airfoil. 
     As temperatures and/or performance standards continue to increase, the materials used for the airfoil become increasingly thin, making reliable manufacture of the airfoil increasingly difficult. For example, certain airfoils are cast from a high alloy metal, with a thermal barrier coating applied to the outer surface of such airfoils to enhance thermal protection. Through continued use, however, the cooling holes in the airfoils can become clogged with debris or other contaminates and the thermal barrier coating can become worn down or chipped. Additionally, in certain cases, the airfoil can undergo plastic deformation such that the location and/or orientation of the holes may change from an original location and/or orientation. 
     Certain airfoils can be repaired to address the above issues. However, it is generally an expensive and time consuming process to correctly clear out each of the cooling holes and re-apply a thermal barrier coating. For example, certain systems for re-applying thermal barrier coatings require each of the airfoil&#39;s cooling holes to be covered. Accordingly, a system and method for both determining which, if any, of the cooling holes are clogged and for removing any debris would be particularly beneficial. Further, a system and method for re-applying a thermal barrier coating without requiring each of the cooling holes to be covered or otherwise protected during the application would also be particularly beneficial. 
     BRIEF DESCRIPTION OF THE INVENTION 
     Aspects and advantages of the invention are set forth below in the following description, or may be obvious from the description, or may be learned through practice of the invention. 
     In one exemplary aspect of the present disclosure, a method is provided for repairing one or more holes in a near wall of a component. The method includes determining updated hole information of a first hole in the near wall of the component. The updated hole information includes an updated location of the first hole. The method also includes directing a confined laser beam of a confined laser drill towards the near wall of the component at the updated location of the first hole to drill through a coating of the component extending over and/or positioned in the first hole. The method also includes sensing a characteristic of light reflected from the updated location of the first hole, and determining the confined laser beam of the confined laser drill has drilled through the coating of the component extending over and/or positioned in the first hole based on the sensed characteristic of light reflected from the updated location of the first hole. 
     In one exemplary embodiment of the present disclosure, a system is provided for repairing one or more holes in a near wall of a component. The system includes a confined laser drill utilizing a confined laser beam, a sensor positioned to sense a characteristic of light reflected from an updated location of a first hole in the near wall of the component, and a controller operably connected to the confined laser drill and the sensor. The controller is configured to determine updated hole information of the first hole in the near wall of the component. The updated hole information of the first hole includes the updated location of the first hole in the near wall. The controller is further configured to direct the confined laser beam towards the near wall of the component at the updated location of the first hole to drill through a portion of the coating of the component extending over and/or positioned in the first hole. The controller is further configured to receive information from the sensor indicative of the sensed characteristic of light, and determine the confined laser beam of the confined laser drill has drilled through the portion of the coating extending over and/or positioned in the first hole based on the characteristic of light sensed by the sensor. 
     These and other features, aspects and advantages of the present disclosure will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and, together with the description, serve to explain the principles of the disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A full and enabling disclosure of the present disclosure, including the best mode thereof to one skilled in the art, is set forth more particularly in the remainder of the specification, including reference to the accompanying figures, in which: 
         FIG. 1  is a simplified cross-sectional view of a turbine section of an exemplary gas turbine that may incorporate various embodiments of the present disclosure. 
         FIG. 2  is a perspective view of an exemplary airfoil according to an embodiment of the present disclosure. 
         FIG. 3  is a schematic view of a system for repairing an airfoil according to an exemplary embodiment of the present disclosure. 
         FIG. 4  is another schematic view of the exemplary system of  FIG. 3 . 
         FIG. 5  is yet another schematic view of the exemplary system of  FIG. 3 . 
         FIG. 6  is a flow diagram of a method for repairing an airfoil according to an exemplary aspect of the present disclosure. 
         FIG. 7  is a schematic view of a system for repairing an airfoil according to another exemplary embodiment of the present disclosure. 
         FIG. 8  is another schematic view of the exemplary system of  FIG. 7 . 
         FIG. 9  is a flow diagram of a method for repairing an airfoil according to another exemplary aspect of the present disclosure. 
         FIG. 10  is a flow diagram of a method for repairing an airfoil according to yet another exemplary aspect of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Reference now will be made in detail to embodiments of the disclosure, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the disclosure, not limitation of the disclosure. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present disclosure without departing from the scope or spirit of the disclosure. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present disclosure covers such modifications and variations as come within the scope of the appended claims and their equivalents. Although exemplary embodiments of the present disclosure will be described generally in the context of manufacturing an airfoil for a turbomachine for purposes of illustration, one of ordinary skill in the art will readily appreciate that embodiments of the present disclosure may be applied to other articles of manufacture and are not limited to a system or method for manufacturing an airfoil for a turbomachine unless specifically recited in the claims. For example, in other exemplary embodiments, aspects of the present disclosure may be used to manufacture an airfoil for use in the aviation context, to manufacture other components of a gas turbine, and/or to manufacture an airfoil or other component in a steam turbine. 
     As used herein, the terms “first”, “second”, and “third” may be used interchangeably to distinguish one component from another and are not intended to signify location or importance of the individual components. Similarly, the terms “near” and “far” may be used to denote relative position of an article or component and are not intended to signify any function or design of said article or component. 
     Referring now to the drawings,  FIG. 1  provides a simplified side cross-section view of an exemplary turbine section  10  of a gas turbine according to various embodiments of the present disclosure. As shown in  FIG. 1 , the turbine section  10  generally includes a rotor  12  and a casing  14  that at least partially define a gas path  16  through the turbine section  10 . The rotor  12  is generally aligned with an axial centerline  18  of the turbine section  10  and may be connected to a generator, a compressor, or another machine to produce work. The rotor  12  may include alternating sections of rotor wheels  20  and rotor spacers  22  connected together by a bolt  24  to rotate in unison. The casing  14  circumferentially surrounds at least a portion of the rotor  12  to contain a compressed working fluid  26  flowing through the gas path  16 . The compressed working fluid  26  may include, for example, combustion gases, compressed air, saturated steam, unsaturated steam, or a combination thereof. 
     As shown in  FIG. 1 , the turbine section  10  further includes alternating stages of rotating blades  30  and stationary vanes  32  that extend radially between the rotor  12  and the casing  14 . The rotating blades  30  are circumferentially arranged around the rotor  12  and may be connected to the rotor wheels  20  using various means. In contrast, the stationary vanes  32  may be peripherally arranged around the inside of the casing  14  opposite from the rotor spacers  22 . The rotating blades  30  and stationary vanes  32  generally have an airfoil  38  shape, with a concave pressure side, a convex suction side, and leading and trailing edges, as is known in the art. The compressed working fluid  26  flows along the gas path  16  through the turbine section  10  from left to right as shown in  FIG. 1 . As the compressed working fluid  26  passes over the first stage of rotating blades  30 , the compressed working fluid expands, causing the rotating blades  30 , rotor wheels  20 , rotor spacers  22 , bolt  24 , and rotor  12  to rotate. The compressed working fluid  26  then flows across the next stage of stationary vanes  32  which accelerate and redirect the compressed working fluid  26  to the next stage of rotating blades  30 , and the process repeats for the following stages. In the exemplary embodiment shown in  FIG. 1 , the turbine section  10  has two stages of stationary vanes  32  between three stages of rotating blades  30 ; however, one of ordinary skill in the art will readily appreciate that the number of stages of rotating blades  30  and stationary vanes  32  is not a limitation of the present disclosure unless specifically recited in the claims. 
       FIG. 2  provides a perspective view of an exemplary airfoil  38 , such as may be incorporated into the rotating blades  30  or stationary vanes  32 , according to an embodiment of the present disclosure. As shown in  FIG. 2 , the airfoil  38  generally includes a pressure side  42  having a concave curvature and a suction side  44  opposed to the pressure side  42  having a convex curvature. The pressure and suction sides  42 ,  44  are separated from one another to define a cavity  46  inside the airfoil  38  between the pressure and suction sides  42 ,  44 . The cavity  46  may provide a serpentine or tortuous path for a cooling media to flow inside the airfoil  38  to conductively and/or convectively remove heat from the airfoil  38 . In addition, the pressure and suction sides  42 ,  44  further join to form a leading edge  48  at an upstream portion of the airfoil  38  and a trailing edge  50  at a downstream portion of the airfoil  38 . A plurality of cooling passages  52  in the pressure side  42 , suction side  44 , leading edge  48 , and/or trailing edge  50  may provide fluid communication with the cavity  46  through the airfoil  38  to supply the cooling media over an outer surface  34  of the airfoil  38 . As shown in  FIG. 2 , for example, the cooling passages  52  may be located at the leading and trailing edges  48 ,  50  and/or along either or both of the pressure and suction sides  42 ,  44 . The exemplary airfoil  38  further defines an opening  54  at a base and of the airfoil  38  wherein cooling media, such as compressed air from a compressor section of the gas turbine, may be provided to the cavity  46 . 
     One of ordinary skill in the art will readily appreciate from the teachings herein that the number and/or location of the cooling passages  52  may vary according to particular embodiments, as may the design of the cavity  46  and the design of the cooling passages  52 . Accordingly, the present disclosure is not limited to any particular number or location of cooling passages  52  or to any specific cooling passage  52  or cavity  46  design unless specifically recited in the claims. 
     In certain exemplary embodiments, a wall of the airfoil  38  may include a thermal barrier coating  36  applied over at least a portion of an outer surface  34  of a metal portion  40  of the airfoil  38  (see  FIG. 3 ), covering the underlying metal portion  40  of the airfoil  38 . The thermal barrier coating  36 , if applied, may include low emissivity or high reflectance for heat, a smooth finish, and/or good adhesion to the underlying outer surface  34 . 
     Part 1 
     Referring now to  FIG. 3 , a schematic view of an exemplary system  60  of the present disclosure is provided. The system  60  may be used in, for example, repairing a component for a gas turbine. More particularly, for the embodiment depicted, the system  60  is used for repairing one or more holes or cooling passages  52  in an airfoil  38  of a gas turbine, such as the airfoil  38  discussed above with reference to  FIG. 2 . It should be appreciated, however, that although the system  60  is described herein in the context of repairing the airfoil  38 , in other exemplary embodiments, the system  60  may be used in repairing any other suitable component for a gas turbine. For example, the system  60  may be used in repairing transition pieces, nozzles, combustion liners, effusion or impingement plates, vanes, shrouds, or any other suitable part. 
     Exemplary system  60  generally includes a confined laser drill  62  configured to direct a confined laser beam  64  towards a near wall  66  of the airfoil  38 . The confined laser beam  64  defines a beam axis A. The near wall  66  of the airfoil  38  is positioned adjacent to the cavity  46  of the airfoil. Various embodiments of the confined laser drill  62  may generally include a laser mechanism and a collimator (not shown). As is discussed in greater detail below, the system  60  further includes a controller  68  in operable communication with the confined laser drill  62 . The laser mechanism may include any device capable of generating a laser beam  70  and the collimator may be any device configured to reshape a diameter of the beam  70  to achieve a better focus feature when the beam  74  is being focused into a different media, such as a glass fiber or water. Accordingly, as used herein, the collimator includes any device that narrows and/or aligns a beam of particles or waves to cause the spatial cross section of the beam to become smaller. For example, in certain embodiments, the collimator may receive the laser beam  70  along with a fluid, such as deionized or filtered water. An aperture or nozzle may then direct the laser beam  70  inside a liquid column  72  toward the airfoil  38 . The liquid column  72  may have a pressure of approximately 2,000 to 3,000 pounds per square inch. However, the present disclosure is not limited to any particular pressure for the liquid column  72  unless specifically recited in the claims. Additionally, it should be appreciated, that as used herein, terms of approximation, such as “about” or “approximately,” refer to being within a ten percent margin of error. 
     The liquid column  72  may be surrounded by a protection gas, such as air, and act as a light guide and focusing mechanism for laser beam  70 . Accordingly, liquid column  72  and laser beam  70  may together form the confined laser beam  64  utilized by the confined laser drill  62  and directed at the airfoil  38 . As is discussed in greater detail below, the confined laser beam  64  may be utilized by the confined laser drill  62  in repairing the one or more cooling passages  52  in the near wall  66  of the airfoil  38 . 
     With continued reference to  FIG. 3 , the system  60  further includes an exemplary backstrike protection mechanism  74 . Exemplary backstrike protection mechanism  74  depicted includes a gas  76  flowing inside the airfoil  38 . As used herein, the term “gas” may include any gaseous media. For example, the gas  76  may be an inert gas, a vacuum, a saturated steam, a superheated steam, or any other suitable gas that may form a gaseous flow inside cavity  46  of the airfoil  38 . Gas  76  flowing inside airfoil  38  may have a pressure roughly commensurate with the pressure of the liquid of liquid column  72 , or any other pressure sufficient to disrupt confined laser beam  64 . More particularly, gas  76  may have any other pressure sufficient to generate a sufficient kinetic moment or speed to disrupt liquid column  72  within the cavity  46  of the airfoil  38 . For example, in certain exemplary embodiments, gas  76  flowing inside the airfoil  38  may have a pressure greater than approximately twenty-five pounds per square inch, although the present disclosure is not limited to any particular pressure for the gas  76  unless specifically recited in the claims. In this manner, gas  76  prevents confined laser beam  64  from striking an inside surface of the cavity  46  of the airfoil  38  opposite from the cooling passages  52  in the near wall  66 . More particularly, gas  76  prevents confined laser beam  64  from striking a far wall  78  of the airfoil  38  after the confined laser beam has broken through the near wall of the airfoil. 
     As used herein, the term “breakthrough,” “breaking through,” and cognates thereof refer to when confined laser beam  64  extends continuously and uninterruptedly through the near wall  66  of the airfoil  38  along beam axis A of confined laser beam  64 . Subsequent to any breakthrough of confined laser beam  64  through near wall  66  of airfoil  38 , at least a portion of said confined laser beam  64  may pass therethrough into, for example, the cavity  46  of the airfoil  38 . 
     The exemplary system  60  of  FIG. 3  additionally includes a sensor  80  operably connected with the controller  68 . The sensor  80  may be an optical sensor configured to sense a characteristic of light and send a signal to the controller  68  indicative of the sensed characteristic of light. Further, for the exemplary embodiment depicted, the sensor  80  is positioned to sense a characteristic of light directed along the beam axis A away from the near wall  66  of the airfoil  38 , e.g., reflected and/or redirected light from the cooling passage  52 . In certain exemplary embodiments, the sensor  80  may be an oscilloscope sensor suitable for sensing one or more of the following characteristics of light: an intensity of light, one or more wavelengths of light, an amount of light, a reflected pulse width, a reflected pulse rate, a shape of a light pulse in time, and a shape of a light pulse in frequency. 
     Moreover, for the embodiment depicted, the sensor  80  is offset from the beam axis A and is configured to sense a characteristic of reflected light along the beam axis A by redirecting at least a portion of the reflected light with a redirection lens  82 . Redirection lens  82  is positioned in the beam axis A, i.e., intersecting the beam axis A, at approximately a forty-five degree angle with the beam axis A. However, in other exemplary embodiments, redirection lens  82  may define any other suitable angle with respect to the beam axis A. Additionally, redirection lens  82  may include a coating on a first side (i.e., the side closest to near wall  66  of airfoil  38 ) which redirects at least a portion of the reflected light traveling along the beam axis A away from the near wall  66  of the airfoil  38  to the sensor  80 . The coating may be what is referred to as a “one-way” coating such that substantially no light traveling along the beam axis towards the near wall  66  of the airfoil  38  is redirected by the lens or its coating. For example, in certain embodiments, the coating may be an electron beam coating (“EBC”) coating. 
     It should be appreciated, however, that in other exemplary embodiments, the sensor  80  may instead be positioned in the beam axis A, and the laser beam  70  may be redirected. Alternatively, the sensor  80  may be positioned offset from the beam axis A outside the airfoil  38  and configured to sense a characteristic of light from the hole  52  by defining a line of sight with the hole  52 . In still other embodiments, one or more additional sensors (not shown) may be positioned within the cavity  46 , or alternatively outside the opening  54  of the cavity  46  and directed into the cavity  46 . It should further be appreciated that in still other embodiments, the sensor  80  may actually be a plurality of sensors positioned at any suitable location inside the cavity  46  and/or outside the airfoil  38 . 
     Referring still to the exemplary system  60  of  FIG. 3 , the controller  68  may be any suitable processor-based computing device, and may be in operable communication with, e.g., the confined laser drill  62 , the sensor  80 , and the backstrike protection mechanism  74 . For example, suitable controllers  68  may include one or more personal computers, mobile phones (including smart phones), personal digital assistants, tablets, laptops, desktops, workstations, game consoles, servers, other computers and/or any other suitable computing devices. As shown in  FIG. 3 , the controller  68  may include one or more processors  84  and associated memory  86 . The processor(s)  84  may generally be any suitable processing device(s) known in the art. Similarly, the memory  86  may generally be any suitable computer-readable medium or media, including, but not limited to, RAM, ROM, hard drives, flash drives, or other memory devices. As is generally understood, the memory  86  may be configured to store information accessible by the processor(s)  84 , including instructions or logic  88  that can be executed by the processor(s)  84 . The instructions or logic  88  may be any set of instructions that when executed by the processor(s)  84  cause the processor(s)  84  to provide a desired functionality. For instance, the instructions or logic  88  can be software instructions rendered in a computer-readable form. When software is used, any suitable programming, scripting, or other type of language or combinations of languages may be used to implement the teachings contained herein. In particular embodiments of the present disclosure, for example, the instructions or logic  88  may be configured to implement one or more of the methods described below with reference to  FIG. 6, 9 , or  10 . Alternatively, the instructions can be implemented by hard-wired logic  88  or other circuitry, including, but not limited to application-specific circuits. Moreover, although controller  68  is depicted schematically separate from sensor  80 , in other exemplary embodiments, sensor  80  and controller  68  may be integrated into a single device positioned at any suitable location. 
     In order to repair an airfoil, it may be necessary to deduce certain information regarding the one or more cooling holes  52  in the airfoil  38 . For the embodiment of  FIG. 3 , the exemplary system  60  is configured to deduce certain information regarding the one or more holes  52  in the airfoil  38  using the confined laser drill  62  and the sensor  80  to determine a repair status of the one or more holes  52 . More particularly, the exemplary system  60  is configured to determine a location of each hole  52 , a vector of each hole  52 , and whether or not such hole  52  is clogged. 
     For example, referring still to  FIG. 3 , the system  60  is configured to determine a material into which the confined laser beam  64  is being directed based on the characteristic of light sensed by the sensor  80 . In certain embodiments, the characteristic of light sensed by the sensor  80  may be one or more wavelengths of light reflected during drilling operations. Different materials absorb and reflect light from the confined laser beam  64  at different wavelengths. Accordingly, the reflected light sensed by the sensor  80  during drilling operations may define a wavelength or a pattern of wavelengths indicative of the material into which the confined laser beam  64  is directed. For example, light sensed by the sensor  80  when drilling into the metal portion  40  of an airfoil  38  may define a pattern of wavelengths that is distinct from a pattern of wavelengths defined by light sensed by the sensor  80  when drilling into debris  90  positioned in the one or more cooling holes  52 , which may in turn be distinct from a pattern of wavelengths defined by the light sensed by the sensor  80  when the confined laser beam is passing completely through the near wall  66  of the airfoil  38  and is not being directed into the metal portion  40  of the airfoil  38 . It should be appreciated, however, that in other exemplary embodiments, the characteristic of light sensed by the sensor may additionally, or alternatively, include any other characteristic indicative of a material into which confined laser beam is being directed. 
     Accordingly, in certain embodiments, the exemplary system  60  may deduce certain information of the one or more holes  52  using the confined laser beam  64  of the confined laser drill  62  essentially as a probe. More particularly, in certain embodiments, the controller  68  may receive original hole information of the one or more cooling holes  52  in the airfoil  38 . The original hole information may include an original location of the one or more holes  52  and original vector of the one or more holes  52 . Such original hole information may be received in the form of an original design file, such as a CAD design file, or any other suitable format. 
     As is depicted in  FIG. 3 , the controller  68  may direct the confined laser beam  64  of the confined laser drill  62  at an original location of a first hole  92  and along an original vector of the first hole  92 . Notably, the confined laser drill  62  may be operating at a reduced power level to reduce a risk of damaging the near wall  66  of the airfoil  38 . For the embodiment depicted, the first hole  92  is in the original location and defines a vector V 1  that is unchanged from the original vector. Additionally, for the embodiment depicted, no debris  90  is present in the first hole  92 . Accordingly, when the confined laser beam  64  of the confined laser drill  62  is directed at the original location of the first hole  92  and along the original vector the first hole  92 , the confined laser beam  64  passes completely through the near wall  66  of the airfoil  38  such that the confined laser beam  64  is not directed into the near wall  66  the airfoil  38 . The system  60  may determine that the confined laser beam  64  is passing completely through the near wall  66  the airfoil  38  (e.g., based on the characteristic of light sensed by the sensor  80 ) and therefore determine the first hole  92  is complete and unclogged and may confirm the original location and original vector of the first hole  92 . It should be appreciated, that as used herein, determining a material into which the confined laser beam  64  is being directed includes determining that confined laser beam  64  is not being directed into any material of the near wall  66  and instead is passing completely through the near wall  66 , i.e, passing completely through a hole in the near wall  66 . 
     By contrast, referring now to  FIG. 4 , the confined laser beam  64  of the confined laser drill  62  is directed at an original location of a second hole  94  and along an original vector of the second hole. The location of the second hole  94  is the same as the original location of the second hole  94  and a vector V 2  defined by the second hole  94  is the same as the original vector of the second hole  94 . However, in the embodiment depicted, debris  90  is positioned in the second hole  94 , such that the confined laser beam  64  does not pass completely through the near wall  66  of the airfoil  38  at the second hole  94 . The system  60  may determine the confined laser beam  64  is being directed into debris  90  based on the characteristic of light sensed by the sensor  80 . In response, the system  60  may increase a power of the confined laser drill  62  such that the confined laser beam  64  of the confined laser drill  62  ablates the debris  90 , i.e., drills through the debris  90 . Once the confined laser drill  62  has drilled through the debris  90 , and the confined laser beam  64  has passed completely through the near wall  66  the airfoil  38  and is not being directed into the near wall  66  the airfoil  38 , the system  60  may determine the second hole  94  is complete and unclogged and may confirm the original location and original vector of the second hole  94 . 
     Referring now to  FIG. 5 , the confined laser beam  64  of the confined laser drill  62  is directed at the original location of a third hole  96  and along an original vector of the third hole  96 . For the embodiment depicted, however, the near wall  66  of the airfoil  38  has undergone plastic deformation such that the third hole  96  in the near wall  66  is no longer in its original location and a vector V 3  of the third hole  96  no longer extends along its original vector (original hole shown in phantom). Accordingly, when the confined laser beam  64  of the confined laser drill  62  is directed at the original location of the third hole  96  and along the original vector of the third hole  96 , the system  60  may determine the confined laser beam  64  is being directed at least partially into the near wall  66  of the airfoil  38 . In certain embodiments, the system  60  may flag the hole  96  for manual inspection, or alternatively may perform a searching or repair subroutine designed to determine a new location and a new vector of the third hole  96 . Such a repair subroutine may, for example, move in a spiral-shaped pattern around the original location of the third hole  96  until it is determined the confined laser beam  64  of the confined laser drill  62  has passed completely through the near wall  66  of the airfoil  38 , or is being directed into debris  90  positioned in the third hole  96 . At such point, the system  60  may determine the new hole information for the third hole  96 . 
     Referring now to  FIG. 6 , a flow diagram is provided of an exemplary method ( 200 ) of repairing one or more holes in a near wall of a airfoil, such as the airfoil depicted in  FIG. 2  and described above. The exemplary method ( 200 ) of  FIG. 6  may be used in conjunction with the system  60  depicted in  FIGS. 3 through 5  and described above. Accordingly, although the exemplary method ( 200 ) is described in the context of repairing an airfoil, the exemplary method ( 200 ) may additionally, or alternatively, be used in conjunction with repairing any other suitable components of a gas turbine. 
     The exemplary method ( 200 ) includes at ( 202 ) receiving with a controller original hole information of the first hole in the near wall of the airfoil. The original hole information of the first hole received at ( 202 ) includes an original location of the first hole and an original vector of the first hole. The exemplary method ( 200 ) further includes at ( 204 ) directing a confined laser beam of the confined laser drill toward the near wall of the airfoil at the original location of the first hole and along the original vector of the first hole. More particularly, in certain exemplary aspects, the confined laser beam may define a beam axis and directing the confined laser beam along the original vector of the first hole at ( 204 ) may include directing the confined laser beam along the original vector of the first hole such that the beam axis of the confined laser beam is aligned or substantially aligned with the original vector of the first hole. 
     The exemplary method ( 200 ) further includes at ( 206 ) sensing a characteristic of light reflected from the original location of the first hole. In certain exemplary aspects, sensing a characteristic of light at ( 206 ) may include sensing a characteristic of light indicative of a material, if any, into which the confined laser beam is being directed. For example, in certain exemplary aspects, sensing a characteristic of light at ( 206 ) may include sensing one or more wavelengths of light reflected from the original location of the first hole. It should be appreciated, however, that in other exemplary aspects, sensing a characteristic of light at ( 206 ) may additionally, or alternatively include sensing any other suitable characteristic(s) of light indicative of a material, if any, into which the confined laser beam is being directed. 
     The method ( 200 ) additionally includes at ( 208 ) determining a repair status of the first hole based on the characteristic of light sensed at ( 206 ). More particularly, for the embodiment depicted, determining a repair status the first hole at ( 208 ) includes at ( 210 ) determining a material, if any, into which the confined laser beam is being directed based on the characteristic of light sensed at ( 206 ). 
     In a first alternative of the exemplary aspect depicted, the first hole may be in the original location and may extend along the original vector. Additionally, the first hole may not include any debris or other contaminants clogging or otherwise blocking passage through the first hole. In such an alternative, determining a material, if any, into which the confined laser beam is being directed at ( 210 ) includes at ( 212 ) determining the confined laser beam is passing completely through the near wall of the airfoil at the first hole such that the confined laser beam is not being directed into the near wall of the airfoil. In response to determining the confined laser beam is passing completely through the near wall of the airfoil at ( 212 ), the method ( 200 ) further includes at ( 214 ) determining the hole is complete and unclogged and at ( 216 ) confirming the original hole information of the first hole. 
     Referring still to  FIG. 6 , and the first alternative, in response to confirming the original hole information of the first hole at ( 216 ), determining a repair status of the first hole at ( 208 ) further includes at ( 218 ) determining updated hole information. More particularly, the method includes at ( 218 ) determining an updated location of the first hole and an updated vector of the first hole. Notably, for the first alternative, the updated hole information is equal to the original hole information, i.e., the updated location of the first hole is equal to the original location of the first hole and the updated vector of the first hole is equal to the original vector of the first hole. 
     In a second alternative, however, the first hole may be in the original location and may extend along the original vector, but may include debris or other contaminants clogging or otherwise blocking passage through the first hole. Accordingly, determining the repair status of the first hole at ( 208 ), or more particularly, determining at ( 210 ) a material, if any, into which the confined laser beam is being directed includes at ( 220 ) determining the confined laser beam is being directed into debris positioned within the first hole. In response to determining the confined laser beam is being directed into debris positioned within the first hole at ( 220 ), the method ( 200 ) may further include at ( 222 ) modifying an operational parameter of the confined laser drill to drill through the debris positioned within the first hole in the near wall of the airfoil. For example, in certain exemplary aspects, modifying an operational parameter at ( 222 ) may include controlling the power of the confined laser drill to drill through the debris positioned within the first hole in the near wall of the airfoil. For example, modifying an operational parameter at ( 222 ) may include increasing a power of the confined laser drill, or alternatively may include decreasing a power of the confined laser drill. However, in other exemplary aspects, the exemplary method ( 200 ) may not include modifying an operational parameter at ( 222 ) and instead, for example, the drill may already be operating at a sufficient power level to drill through such debris. In still other exemplary aspects, however, the exemplary method ( 200 ) may not drill through the debris, and may instead flag the hole for manual inspection. 
     Referring still to the second alternative, once the confined laser beam has drilled through any and all debris positioned within the first hole, determining a repair status of the first hole at ( 208 ) further includes at ( 212 ) determining the confined laser beam of the confined laser drill is passing completely through the near wall of the airfoil. Similar to the first alternative discussed above, the exemplary method ( 200 ) subsequently includes at ( 214 ) determining the hole is complete and unclogged and at ( 216 ) confirming the original hole information of the first hole. Furthermore, the method ( 200 ) includes at ( 218 ) determining updated hole information. In such an alternative, the updated hole information is again equal to the original hole information. 
     Additionally, in a third alternative, the first hole may not be in the original location and/or may not extend along the original vector. In such an alternative, determining a material, if any, into which the confined laser beam is being directed at ( 210 ) includes at ( 224 ) determining the confined laser beam is being directed at least partially into the near wall of the airfoil (which may include, e.g., a metal portion of the airfoil and/or a coating on the metal portion of the airfoil). In response, determining a repair status the first hole at ( 208 ) additionally includes at ( 226 ) determining the near wall of the airfoil has been at least partially deformed and, for the exemplary aspect depicted, executing at ( 228 ) a searching or repair subroutine to determine new information the first hole. The new information of the first hole may include a new location of the first hole and a new vector of the first hole. The repair subroutine may, in certain aspects, move the confined laser drill in a spiral-shaped pattern about the original location of the first hole to determine the new location of the first hole and/or the new vector of the first hole. In such an alternative, determining a repair status the first hole at ( 208 ) may also include determining updated hole information at ( 218 ). In such an alternative, the updated hole information determined at ( 218 ) is equal to the new hole information determined at ( 228 ). More particularly, in such an alternative, an updated location of the first hole is equal to the new location of the first hole and an updated vector of the first hole is equal to the new vector of the first hole. Furthermore, in such an alternative, determining the updated hole information at ( 218 ) may additionally include updating hole information of one or more additional holes in view of the updated hole information of the first hole. More particularly, in such an alternative, the method ( 200 ) may estimate new hole information for one or more additional holes based on an amount of deformation of the component indicated by the new hole information of the first hole determined at ( 228 ). 
     It should be appreciated, however, that in other exemplary aspects, the method ( 200 ) may additionally or alternatively include, for example, flagging the first hole for manual review in response to determining at ( 224 ) the confined laser beam is being directed at least partially into the near wall of the airfoil and/or determining at ( 226 ) the near wall of the airfoil has been at least partially deformed. Further, in other exemplary aspects, the repair subroutine may include any other suitable method for determining new information of the first hole. 
     Although not depicted in  FIG. 6 , the exemplary method ( 200 ) may further include determining updated hole information for a plurality of cooling holes in the airfoil, such as all of the cooling holes in a near wall of an airfoil. Accordingly, the method ( 200 ) may further include receiving with the controller original hole information of a second hole in the near wall of the airfoil. The original hole information of the second hole may also include an original location of the second hole and an original vector of the second hole. The method ( 200 ) may further include directing the confined laser beam of the confined laser drill towards the near wall of the airfoil at the original location of the second hole and along the original vector of the second hole such that the beam axis of the confined laser beam is substantially aligned with the original vector of the second hole. The method ( 200 ) may further include sensing a characteristic of light reflected from the original location of the second hole and determining a repair status of the second hole based on the sensed characteristic of light reflected from the original location of the second hole. The method ( 200 ) may also include determining updated hole information of the second hole. Notably, in certain exemplary aspects, determining a repair status of the second hole may include any and all of the alternatives discussed above determining the repair status of the first hole at ( 208 ). 
     The exemplary method ( 200 ) depicted in  FIG. 6  may assist in the repair of an airfoil. More particularly, clearing debris from the one or more cooling holes may allow such cooling holes to operate properly. Additionally, the information deduced may, e.g., facilitate additional steps in the repair process. For example, the information deduced using the exemplary method ( 200 ) may facilitate one or both of the exemplary method ( 300 ) described below with reference to  FIG. 9  and the exemplary method ( 400 ) described below with reference to  FIG. 10 . Additionally, or alternatively, the information deduced using the exemplary method ( 200 ) may allow for a determination to be made whether or not additional repair is possible, or whether and to what extent additional repair of such an airfoil is necessary. 
     Moreover, although not depicted, the exemplary method ( 200 ) of  FIG. 6  may further include moving the confined laser drill to the locations of additional holes and repeating the processes discussed herein determine updated hole information for each of the respective additional holes. 
     Part 2 
     Referring now to  FIG. 7 , a schematic view of an exemplary system  60  is provided for repairing one or more holes  52  in a near wall  66  of an airfoil  38  of a gas turbine. The exemplary system  60  depicted in  FIG. 7  may be configured to work in conjunction with the exemplary system  60  of  FIG. 3  and may be configured in substantially the same manner as exemplary system  60  of  FIG. 3 . Accordingly, the same or similar numbering may refer to the same or similar parts. 
     For example, the exemplary system  60  of  FIG. 7  includes a confined laser drill  62  utilizing a confined laser beam  64 , a sensor  80 , and a controller  68  operably connected to the confined laser drill  62  and the sensor  80 . As is depicted, the sensor  80  is positioned to sense a characteristic of light reflected along a beam axis A of the confined laser beam A away from the airfoil  38 . For example, when the confined laser beam is directed at a first hole  92  in the near wall  66  of the airfoil  38 , the sensor  80  is configured to sense light from an updated location of the first hole  92  in the near wall  66  of the airfoil  38 . 
     The exemplary system  60  of  FIG. 7  may be utilized subsequent to determining updated hole information of one or more of the cooling holes  52  in the near wall  66  of the airfoil  38 . The updated hole information may include an updated location of the respective holes  52  and an updated vector of the respective holes  52 . In certain embodiments, determining the updated hole information may be accomplished utilizing the exemplary method ( 200 ) described above with reference to  FIG. 6 , or alternatively using any other suitable method. 
     Moreover, the exemplary system  60  of  FIG. 7  may be utilized subsequent to re-coating the outer surface  34  of the airfoil. Re-coating the outer surface  34  of the airfoil  38  may include adding one or more of a thermal barrier coating  36 , bond coating  98 , an environmental barrier coating (which may consist of multiple layers of different materials), or any other suitable coating. As is depicted, re-coating the outer surface  34  of the airfoil  38  includes coating at least a portion of the one or more holes  52  in the near wall  66  of the airfoil  38 . Accordingly, subsequent to re-coating the outer surface  34  of the near wall  66  of the airfoil  38 , the one or more holes  52  in the near wall  66  of the airfoil  38  may be at least partially covered by the coating and/or have coating positioned therein (as shown). 
     However, the exemplary system  60  of  FIG. 7  is capable of removing the coating covering the one or more holes  52  and/or positioned in the one or more holes  52  without damaging the underlying metal portion  40  of the near wall  66  of the airfoil  38 . More particularly, the exemplary system  60  of  FIG. 7  is capable of determining the material into which the confined laser beam  64  of the confined laser drill  66  is being directed and/or determining a depth to which the confined laser beam  64  has drilled using the one or more characteristics of light sensed with the sensor  80 . 
     For example, as discussed above, the sensor  80  may sense one or more characteristics of light indicative of the material into which the confined laser beam  64  of the confined laser drill  62  is being directed. For example, the sensor  80  may sense one or more wavelengths of light. The sensor  80  may additionally, or alternatively, sense one or more characteristics of light indicative of a depth to which the confined laser beam  64  of the confined laser drill  62  has drilled. For example, the sensor  80  may sense one or more of a reflected pulse rate, reflected pulse width, an intensity of light, an amount of noise in the intensity of light, or any other suitable characteristic. It should be appreciated, however, that in still other embodiments, the sensor  80  may additionally, or alternatively, sense any other suitable characteristics of light indicative of one or both of the material into which the confined laser beam  64  is being directed and a depth to which the confined laser beam  64  has drilled. 
     Accordingly, as is depicted in  FIG. 7 , the confined laser drill  62  may be positioned to direct the confined laser beam  64  over the first hole  92  in the near wall  66  of the airfoil  38  to remove the coating extending over and/or positioned in the first hole  92  in the near wall  66  of the airfoil  38 . More particularly, the confined laser drill  62  may be moved to an updated location of the first hole  92  to drill through the coating extending over and/or positioned in the first hole  92  (as shown). Notably, the confined laser drill  62  may be positioned such that the beam axis A of the confined laser beam  64  does not extend substantially along a vector V 1  defined by the first hole  92 , or more specifically, along an updated vector of the first hole. More particularly, for the embodiment depicted, the confined laser drill  62  is positioned such that the beam axis A of the confined laser beam  64  is substantially perpendicular to the outer surface  34  of metal portion  40  of the near wall  66 . Such a configuration may allow for a more expedient repair process. It should be appreciated, however, that in other exemplary embodiments, the confined laser drill  62  may be positioned such that the beam axis A of the confined laser beam  64  extends along, or substantially along, the updated vector of the first hole  92 . 
     Referring now to  FIG. 8 , the exemplary system  60  is depicted having drilled through the coating extending over and/or positioned in the first hole  92  in the near wall  66  of the airfoil  38 . Based on the one or more characteristics of light sensed by the sensor  80 , the system  60  may determine that the confined laser drill  62  has drilled through the coating extending over and/or positioned in the first hole  92  in the near wall  66  of the airfoil  38 . The system  60  may then cease drilling operations to prevent unnecessary damage to the first hole  92  in the near wall  66  of the airfoil  38 . Notably, however, in certain exemplary embodiments, an opening of the first hole  92  may be larger than a width of the confined laser beam  64 . Accordingly, in such an exemplary embodiment, the system  60  may continue drilling—covering an entirety of the location of the first hole, i.e., an entirety of the opening of the first hole—until the entirety of the coating extending over and/or positioned in the opening of the first hole has been drilled through and removed. 
     Subsequent to completing removal of the coating extending over and/or positioned in the first hole, the exemplary system  60  may move to an updated location of the second hole  94 , to an updated location of the third hole  96 , etc. to remove the coating extending over and/or positioned in each of the plurality of cooling holes  52  in the near wall  66  of the airfoil  38 . 
     Referring now to  FIG. 9 , a flow diagram is provided of an exemplary method ( 300 ) of repairing one or more holes in a near wall of an airfoil, such as the airfoil depicted in  FIG. 2  and described above. The exemplary method of  FIG. 9  may be used in conjunction with the system  60  depicted in  FIGS. 7 and 8  and described above. Accordingly, although the exemplary method ( 300 ) is describe in the context of repairing an airfoil, the exemplary method ( 300 ) may additionally, or alternatively, be used in conduction with repairing any other suitable component of the gas turbine. 
     The exemplary method ( 300 ) of  FIG. 9  includes at ( 302 ) determining updated hole information of the first hole using the confined laser drill. The updated hole information of the first hole determined at ( 302 ) may include an updated location of the first hole and an updated vector of the first hole. In certain exemplary aspects, determining the updated hole information of the first hole at ( 302 ) may be accomplished using the exemplary method ( 200 ) depicted in  FIG. 6  and described above. For example, in certain aspects, determining the updated hole information of the first hole at ( 302 ) may include receiving original information of the first hole in the near wall of the airfoil, the original information including an original location of the first hole and an original vector of the first hole; determining the first hole is complete and unclogged; and confirming the original hole information of the first hole. Alternatively, however, in other exemplary aspects, any other suitable means or method may be used for determining the updated hole information of the first hole at ( 302 ). 
     Subsequent to determining the updated hole information of the first hole at ( 302 ), the exemplary method ( 300 ) may further include at ( 304 ) applying a coating to an outer surface of the near wall of the airfoil. Applying the coating at ( 304 ) to the outer surface of the near wall of the airfoil may be done without applying any covering or other similar protection to the first hole. Accordingly, applying the coating at ( 304 ) may include applying the coating to at least partially extend over and/or be positioned in the first hole. 
     Referring still to the exemplary method ( 300 ) of  FIG. 9 , the exemplary method ( 300 ) additionally includes at ( 306 ) directing a confined laser beam of the confined laser drill towards the near wall of the airfoil at the updated location of the first hole to drill through the coating extending over and/or positioned in the first hole of the near wall. In certain exemplary aspects, the confined laser beam may define a beam axis and directing the confined laser beam of the confined laser drill towards a near wall of the airfoil at ( 306 ) may include directing the confined laser beam towards a near wall of the airfoil such that the beam axis of the confined laser beam is not parallel to the updated vector of the first hole. For example, in certain exemplary aspects, directing the confined laser beam of the confined laser drill towards the near wall of the airfoil at ( 306 ) may include directing the confined laser beam towards the near wall of the airfoil such that the beam axis of the confined laser beam is substantially perpendicular to the outer surface of the near wall of the airfoil. Such a configuration may allow for more expedient removal of the coating extending over and/or positioned in the first hole in the near wall of the airfoil. 
     It should be understood, however, that in other exemplary aspects, the beam axis may define any suitable angle relative to the updated vector of the first hole. For example, in other exemplary aspects, confined laser beam may be directed towards the near wall of the airfoil such that the beam axis extends substantially along the updated vector of the first hole. 
     Referring still to  FIG. 9 , the exemplary method ( 300 ) additionally includes at ( 308 ) sensing a characteristic of light reflected from the updated location of the first hole. Moreover, the exemplary method includes at ( 310 ) determining the confined laser beam of the confined laser drill has drilled through the coating of the airfoil extending over and/or positioned in the first hole in the near wall of the airfoil based on the characteristic of light sensed at ( 308 ). For the exemplary aspect depicted, sensing at ( 308 ) a characteristic of light reflected from the updated location the first hole includes sensing one or more characteristics of light indicative of a material into which the confined laser beam is being directed. More particularly, in the exemplary aspect depicted, sensing at ( 308 ) a characteristic of light reflected from the updated location the first hole includes at ( 312 ) sensing one or more wavelengths of light reflected from the updated location of the first hole. However, in other exemplary aspects, sensing at ( 308 ) a characteristic of light reflected from the updated location of the first hole may additionally, or alternatively, include sensing any other characteristics of light indicative of the material into which the confined laser beam is being directed. 
     Additionally, for the exemplary aspect depicted, determining at ( 310 ) the confined laser beam of the confined laser drill has drilled through the coating of the airfoil includes at ( 314 ) determining the material into which the confined laser beam of the confined laser drill is being directed. By way of example, as discussed above, the one or more wavelengths of light reflected from an area into which the confined laser beam is being directed may be indicative of the material into which the confined laser beam is being directed. More particularly, once it is determined that the confined laser beam is being directed into a metal portion of the near wall of the airfoil, it may be determined that confined laser beam has drilled through the coating extending over and/or positioned in the first hole in the near wall of the airfoil. 
     Accordingly, the exemplary method ( 300 ) depicted may allow for re-coating of the near wall of the airfoil during repair operations without taking measures to cover or otherwise prevent such coating from extending over and/or being positioned in the one or more cooling holes in the near wall of the airfoil. Such a process may allow for a much more cost-efficient and time-efficient method for repairing an airfoil or other component for a gas turbine. 
     Referring now to  FIG. 10 , a flow diagram is provided of another exemplary method ( 400 ) for repairing one or more holes in a near wall of an airfoil, such as the airfoil  38  depicted in  FIG. 2  and described above. The exemplary method ( 400 ) of  FIG. 10  may be used in conjunction with the system  60  depicted in  FIGS. 7 and 8  and described above. Additionally, the exemplary method ( 400 ) of  FIG. 10  is similar to the exemplary method ( 300 ) of  FIG. 9 , and thus similar numbering may refer to the same or similar steps. 
     For example, the exemplary method ( 400 ) of  FIG. 10  includes at ( 402 ) determining updated hole information of the first hole using the confined laser drill and at ( 404 ) applying a coating to an outer surface of the near wall of the airfoil, such that the coating at least partially extends over and/or is positioned in the first hole. Additionally, the exemplary method ( 400 ) of  FIG. 10  includes at ( 406 ) directing a confined laser beam of the confined laser drill towards the near wall of the airfoil at the updated location of the first hole to drill through the portion of the coating extending over and/or positioned in the first hole. Moreover, the exemplary method ( 400 ) of  FIG. 10  includes at ( 408 ) sensing a characteristic of light reflected from the updated location of the first hole and at ( 410 ) determining confined laser beam of the confined laser drill has drilled through the coating of the airfoil at the updated location of the first hole based on the characteristic of light sensed at ( 408 ). 
     However, for the exemplary method ( 400 ) of  FIG. 10 , sensing a characteristic of light at ( 408 ) includes sensing one or more characteristics of light indicative of a depth to which the confined laser beam has drilled. More particularly, for the exemplary aspect depicted, sensing a characteristic of light at ( 408 ) includes sensing at ( 412 ) one or both of a reflected pulse width and a reflected pulse frequency of the light reflected from the updated location of the first hole. It should be appreciated, however, that in other exemplary aspects, sensing a characteristic of light at ( 408 ) may additionally, or alternatively, include sensing any other characteristics of light indicative of a depth to which the confined laser beam has drilled. 
     Additionally, for the exemplary aspect depicted in  FIG. 10 , determining the confined laser beam of the confined laser drill has drilled through the coating of the airfoil at ( 410 ) includes at ( 414 ) determining a depth to which the confined laser beam of the confined laser drill has drilled. More specifically, for the exemplary aspect depicted, the method ( 400 ) further includes at ( 416 ) determining a depth of the coating and at ( 418 ) comparing the depth to which the confined laser beam of the confined laser drill has drilled, determined at ( 414 ), to the depth of the coating determined at ( 416 ). For example, the exemplary method ( 400 ) may determine a depth of the coating at ( 416 ) by applying the coating to a tab or coupon, the tab being separate from the airfoil, when the coating is applied to the outer surface of the airfoil at ( 404 ), and measuring a depth of the coating on the tab. The depth of the coating on the tab may be indicative of the depth of the coating on the outer surface of the airfoil and thus may be indicative of the depth to which the confined laser beam of the confined laser drill must drill to clear the coating extending over and/or positioned in the first hole. Once the determined depth to which the confined laser beam of the confined laser drill has drilled is equal to or within a predetermined threshold of the determined depth of the coating, the method ( 400 ) may determine the confined laser beam of the confined laser drill has drilled through the portion of the coating of the airfoil at the updated location of the first hole extending over and/or positioned in the first hole. 
     Notably, in certain exemplary aspects, the exemplary method ( 400 ) may additionally include modifying a geometry of the first hole in accordance with certain parameters inputted in the repair process. For example, during the repair process, it may be determined that, e.g., for better aerodynamic properties, an opening of the first hole on the near wall of the airfoil should be wider, should be deeper, and/or should define a different shape. Accordingly, the confined laser drill may drill deeper than the coating extending over and/or positioned in the first hole to provide a desired updated geometry of the first hole. 
     Moreover, although not depicted, the exemplary method ( 300 ) of  FIG. 9  and/or the exemplary method ( 400 ) of  FIG. 10  may further include moving the confined laser drill to updated locations of additional holes and repeating the processes discussed herein to drill through a portion of the coating extending over and/or positioned in each of the respective additional holes. 
     This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or system  60  and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other and examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.