Abstract:
A method for coating a turbine engine component comprises the steps of: providing a turbine engine component having at least one sacrificial attachment on a first side; grasping the turbine engine component via the at least one sacrificial attachment to position a first surface of the turbine engine component relative to a source of coating material; and applying a coating to said first side.

Description:
BACKGROUND 
       [0001]    The present disclosure is directed to a method and system for holding a combustor panel during a coating process. 
         [0002]    Combustor panels are susceptible to hot corrosion and oxidation attack during service. Many panels experience burn-through before their service interval is met. This leads to the need to replace the panels before the interval is up and causing other inefficiencies in the engine. Metallic coatings are applied to increase the life of the combustor panels. The objective of a typical coating operation is to coat the entire workpiece. However, this is impossible in an overlay coating system without either multiple insertions or touch-coating (slurry coating) afterwards. Aluminide coatings could coat 100% of the part using gas phase or pack technology, but overlay coatings provide better protection. Both of these options add cost and require an extra technical step. 
         [0003]    Thus, there is a need for an improved approach for applying overlay coatings to combustor panels. 
       SUMMARY 
       [0004]    In accordance with the present disclosure, there is provided a method for coating a turbine engine component which broadly comprises the steps of: providing a turbine engine component having at least one sacrificial attachment on a first side; grasping the turbine engine component via the at least one sacrificial attachment to position a first surface of the turbine engine component relative to a source of coating material; and applying a coating to the first surface. 
         [0005]    In another and alternative embodiment, the method further comprises rotating the turbine engine component by 180 degrees while grasping the turbine engine component via the at least one sacrificial attachment; and applying a coating to a second surface of the turbine engine component opposed to the first surface. 
         [0006]    In another and alternative embodiment, the method further comprises removing the at least one sacrificial attachment. 
         [0007]    In another and alternative embodiment, the removing step comprises machining the at least one sacrificial attachment. 
         [0008]    In another and alternative embodiment, the turbine engine component providing step comprises casting the turbine engine component with a sacrificial attachment located in one of a least vunerable location on the turbine engine component and a location where the turbine engine component is reinforced. 
         [0009]    In another and alternative embodiment, the at least one sacrificial attachment has a threaded end and the grasping step comprises engaging the threaded end. 
         [0010]    In another and alternative embodiment, the at least one sacrificial attachment comprises a pair of ears placed along opposite sides of the turbine engine component and the grasping step comprises grasping the ears. 
         [0011]    In another and alternative embodiment, the at least one sacrificial attachment is welded to the turbine engine component. 
         [0012]    Further, in accordance with the present disclosure, there is provided a system for coating a turbine engine component which broadly comprises: the turbine engine component having at least one sacrificial attachment on at least one side; a source of coating material; and means for grasping the turbine engine component via the at least one sacrificial attachment to position a first surface of the turbine engine component relative to the source of coating material. 
         [0013]    In another and alternative embodiment, the turbine engine component is a combustor panel. 
         [0014]    In another and alternative embodiment, the at least one sacrificial attachment comprises a stud integrally formed with the turbine engine component. 
         [0015]    In another and alternative embodiment, the stud is located on a rear surface of the turbine engine component. 
         [0016]    In another and alternative embodiment, the system further comprises a stress concentrator located at a base of said stud. 
         [0017]    In another and alternative embodiment, the system further comprises the stud having a threaded end. 
         [0018]    In another and alternative embodiment, the grasping means comprises a holder having an opening through which the stud passes and a nut and washer arrangement for engaging the threaded end. 
         [0019]    In another and alternative embodiment, the at least one sacrificial attachment comprises a pair of ears attached to opposed edges of the turbine engine component. 
         [0020]    In another and alternative embodiment, the grasping means comprises a system for gripping each of the ears. 
         [0021]    In another and alternative embodiment, the system further comprises means for rotating the turbine engine component while the at least one sacrificial attachment is being grasped so that a second surface of the turbine engine component is coated. 
         [0022]    In another and alternative embodiment, the at least one sacrificial attachment is welded to the turbine engine component. 
         [0023]    Other details of the method and system for holding a combustor panel during a coating process are set forth in the following detailed description and the accompanying drawings, wherein like reference numerals depict like elements. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0024]      FIG. 1  is a rear view of a turbine engine component having a sacrificial attachment; 
           [0025]      FIG. 2  is a side view of the turbine engine component of  FIG. 1  attached to a holding device; 
           [0026]      FIG. 3  is a rear view of the turbine engine component and holding device of  FIG. 2 ; 
           [0027]      FIG. 4  is a perspective view of the turbine engine component rotated 180 degrees; 
           [0028]      FIG. 5  is a schematic representation of a turbine engine component having a sacrificial attachment with a stress concentrator at its base; and 
           [0029]      FIG. 6  is a rear view of a turbine engine component wherein the sacrificial attachments are two ears. 
       
    
    
     DETAILED DESCRIPTION 
       [0030]    Referring now to  FIG. 1 , there is shown a rear view of a turbine engine component  10  to be coated. The turbine engine component  10  may be a combustor panel. The turbine engine component  10  may be formed from any suitable metallic or ceramic material. The turbine engine component  10  may be a cast structure, a machined structure, or a structure formed by additive manufacturing techniques. 
         [0031]    As can be seen from  FIGS. 1-4 , the turbine engine component  10  may be arcuate in shape. The rear surface  14  of the turbine engine components may have a plurality of non-sacrificial studs  13  projecting out of the rear surface. 
         [0032]    The turbine engine component  10  may be formed with one or more sacrificial attachments  12  which can be grasped or held during the coating process. The sacrificial attachment(s)  12  can be integrally formed with the turbine engine component  10  such as by casting the sacrificial attachment(s) with the turbine engine component  10 . Each sacrificial attachment  12  may be formed from the same material as the turbine engine component  10  or may be formed from a different material than the material forming the turbine engine component  10 . The sacrificial attachment(s)  12  may be located in a non-critical area of the turbine engine component  10 . For example, the sacrificial attachment(s)  12  may be located in a least vunerable location on the turbine engine component  10  and/or a location where the turbine engine component  10  is reinforced. 
         [0033]    The sacrificial attachment  12  can take the form of a threaded or a non-threaded stud or rod projecting from the rear side  14  of the turbine engine component. The stud or rod may have any shape which is convenient to hold during coating. The sacrificial attachment  12  may be a cast structure which is cast with the turbine engine component  10  or may be a stud or rod welded to the turbine engine component  10 . 
         [0034]    Referring now to  FIGS. 2-4 , the coating device (not shown), such as a cathodic arc coater, may include a member  16  for positioning surfaces of the turbine engine component  10  relative to a source  20  of coating material. The positioning member  16  may have at one end a device for grasping the sacrificial attachment(s)  12 . For example the positioning member  16  may comprise a bar  17  having an opening  18  for receiving an end of the sacrificial attachment  12 . The grasping device may be a washer and nut arrangement  22  for securing the sacrificial attachment  12  to the positioning member  16  if the sacrificial attachment  12  has a threaded end  23 . Alternatively, if the sacrificial attachment  12  is unthreaded, it may be provided with a plurality of tabbed protrusions which act as the gripping device. In such a situation, a washer may be placed over the end of the sacrificial attachment  12  and the tabbed protrusions may be folded back to contact the washer surfaces. 
         [0035]    During the coating process, the front side  24  of the turbine engine component may initially face a source of coating material  20  until a required coating thickness is achieved on the front surface of the panel. Thereafter, the turbine engine component  10  may be rotated 180 degrees while the turbine engine component  10  is being grasped by the at least one sacrificial attachment  12 . If necessary, the turbine engine component  10  may be waved at the source  20  of coating material. The coating process then continues to get coating coverage on the rear side  14  and rear surface of the turbine engine component  10  including around the non-sacrificial studs  13  and the sacrificial attachment(s)  12 . In order to rotate the turbine engine component  10 , the positioning member  16  may be rotationally connected to the coater. 
         [0036]    After the coating process has been completed, the turbine engine component with the sacrificial attachment  12  may be uncoupled from the positioning member  16 . If desired, this can be done by cutting or removing the sacrificial attachment  12 . The removal or cutting of the sacrificial attachment  12  can be done in any suitable way such as by machining the sacrificial attachment  12  off. Alternatively, the sacrificial attachment  12  may be a breakable tab. The tab may take the form of a single fin which is removable. 
         [0037]    Referring now to  FIG. 5 , if desired, a stress concentrator  29  may be included at a base of the sacrificial attachment  12 . The stress concentrator  29  would allow the sacrificial attachment  12  to be easily removed. 
         [0038]    Referring now to  FIG. 6 , instead of the sacrificial attachment  12  being a threaded or unthreaded stud/rod and being located on the rear side of the turbine engine component  10 , the sacrificial attachments could be formed by a pair of rectangular ears  30  located on side edges  40  and  42  of the turbine engine component  10 . The ears  30  may be integrally formed with the component  10  such as by casting. The ears  30  may be formed from the same material as the turbine engine component  10  or a material compatible with the material forming the turbine engine component  10 . 
         [0039]    During the coating operation, a suitable holding/positioning device  50  would grasp each of the ears  30  so that the front side  24  of the component  10  initially faces a coating source  20 . After a coating having a required thickness is deposited on the front surface of the front side  24 , the turbine engine component  10  is rotated by  180  degrees so that the rear side  14  faces the coating source  20 . After a coating of a required thickness has been deposited, the holding/positioning device  50  can be removed from the ears  30 . Thereafter, the ears  30  may be machined off or otherwise removed. 
         [0040]    The use of the sacrificial attachment(s)  12  or the ears  30  allows for a coating to be applied to turbine engine components  10 , such as combustor panels, so that nearly the entire component  10  can be coated with the exception of a relatively small sacrificial area. As noted before, the sacrificial attachment(s)  12  and the ears  30  can be placed in the least vunerable location(s) on the component  10  or in a location or locations where the thickness of the turbine engine component  10  can be reinforced. The addition of the coating to the turbine engine component  10  is beneficial since it will assist the turbine engine component  10  to meet life expectancies and reduce overhaul and replacement costs. 
         [0041]    There has been provided in accordance with the instant disclosure a method and system for holding a combustor panel during a coating process. While the method and system have been described in the context of specific embodiments thereof, other unforeseen alternatives, modifications, and variations may become apparent to those skilled in the art having read the foregoing description. Accordingly, it is intended to embrace those alternatives, modifications, and variations as fall within the broad scope of the appended claims.