Method for modifying an airfoil shroud

Abstract

A turbine engine, bucket and method for modifying an airfoil shroud of turbine bucket is disclosed. A reference location is located in a second end edge of the airfoil shroud proximate a seal rail of the airfoil shroud. A relief cut is formed in the airfoil shroud to remove the reference location. Additionally, another reference location may be located in a first end edge of the airfoil shroud proximate the seal rail. Another relief cut may be formed in the airfoil shroud to remove the other reference location.

1 . A method for modifying an airfoil shroud located at a tip of a blade of an airfoil, the airfoil shroud having a first end edge, a second end edge, a leading edge and a trailing edge, the method comprising:
 locating a reference location in the second end edge of the airfoil shroud, the reference location being proximate a seal rail extending circumferentially from a radially outer surface of the airfoil shroud; and   forming a relief cut in the airfoil shroud to remove the reference location to thereby modify the airfoil shroud.   
     
     
         2 . The method of  claim 1 , further comprising:
 locating another reference location in the first end edge of the airfoil shroud, the other reference location being proximate the seal rail; and   forming another relief cut in the airfoil shroud to remove the other reference location.   
     
     
         3 . The method of  claim 2 , further comprising locating the reference location proximate a fillet of the seal rail on the trailing edge of the airfoil shroud and locating the other reference location proximate the fillet on the leading edge of the airfoil shroud. 
     
     
         4 . The method of  claim 2 , wherein forming the relief cut comprises forming a recess having a selected geometry in the second end edge of the airfoil shroud and forming the other relief cut comprises forming another recess of a selected geometry in the first end edge of the airfoil shroud. 
     
     
         5 . The method of  claim 4 , wherein forming the recess and the other recess comprises forming at least one arc-shaped recess. 
     
     
         6 . The method of  claim 2 , wherein forming the relief cut and the other relief cut further comprises machining at least one of the relief cut and the other relief cut. 
     
     
         7 . The method of  claim 1 , comprising replacing the airfoil in at least one of: (i) a second stage of a turbine engine; and (ii) a third stage of a turbine engine after forming the relief cut. 
     
     
         8 . A bucket comprising:
 an airfoil having an airfoil axis;   a shroud disposed at a tip of the airfoil, the shroud having a first end edge, a second end edge, a leading edge and a trailing edge;   a seal rail extending circumferentially from a radially outer surface of the shroud; and   a recess formed in the second end edge proximate the seal rail and on the leading edge of the airfoil.   
     
     
         9 . The bucket of  claim 8 , further comprising another recess formed in the first end edge proximate the seal rail and on the trailing edge of the airfoil. 
     
     
         10 . The bucket of  claim 10 , wherein the recess comprises a relief cut of a selected geometry and wherein the other recess comprises a relief cut of a selected geometry. 
     
     
         11 . The bucket of  claim 10 , wherein at least one of the geometry of the recess and the geometry of the other recess comprises an arc-shaped recess. 
     
     
         12 . The bucket of  claim 11 , wherein the arc-shaped recess is formed by machining. 
     
     
         13 . The bucket of  claim 10 , wherein the relief cut is formed to remove a reference location located in the second end edge proximate a fillet of the seal rail on the trailing edge and the other relief cut is formed to remove another reference location located in the first end edge proximate the fillet on the leading edge. 
     
     
         14 . The bucket of  claim 9 , wherein the bucket is configured to be placed in one of: (i) a second stage of a turbine engine; and (ii) a third stage of a turbine engine. 
     
     
         15 . A turbine engine comprising:
 a rotor;   a bucket to be placed on the rotor, the bucket comprising:   an airfoil having an airfoil axis;   a shroud disposed at a tip of the airfoil, the shroud having a first end edge, a second end edge, a leading edge and a trailing edge;   a seal rail extending circumferentially from a radially outer surface of the shroud; and   a recess formed in the second end edge proximate the seal rail and the leading edge of the airfoil.   
     
     
         16 . The turbine engine of  claim 15 , further comprising another recess formed in the first end edge proximate the seal rail and the trailing edge of the airfoil. 
     
     
         17 . The turbine engine of  claim 16 , wherein at least one of the recess and the other recess comprises a relief cut. 
     
     
         18 . The turbine engine of  claim 17 , wherein the relief cut is formed by at least one of machining or blending. 
     
     
         19 . The turbine engine of  claim 18 , wherein the relief cut includes a relief cut formed to remove a reference location located in the second end edge proximate a fillet of the seal rail on the trailing edge and the other relief cut formed to remove another reference location located in the first end edge proximate the fillet on the leading edge. 
     
     
         20 . The turbine engine of  claim 15 , wherein the bucket is located in at least one of: (i) a second stage of the turbine engine; and (ii) a third stage of the turbine engine.