AIRFOIL CROPPING TOOL
Publication Date: 2016-Sep-26
The IP.com Prior Art Database
An airfoil cropping tool is configured to be attached to a turbine engine airfoil. The tool includes a guide surface used to accurately mark the airfoil or to guide a tool for a cropping operation on the airfoil.
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AIRFOIL CROPPING TOOL
 An airfoil cropping tool is configured to be attached to a turbine engine airfoil. The tool includes a guide surface used to accurately mark the airfoil or to guide a tool for a cropping operation on the airfoil.
 This disclosure relates generally to gas turbine engines and more particularly to internal airfoils of such engines.
 A gas turbine engine includes multiple stages, each stage including a plurality of airfoils. In use, the airfoils often experience foreign object damage ("FOD") resulting in material loss and stress concentrations in the surrounding material. The affected areas need to be removed for the airfoils to continue to operate, in order to avoid crack propagation and additional damage.
 Component repair is carried out by removing or "cropping" damaged portions of the airfoil. Existing methods for cropping airfoils are largely manual, for example a grinding or cutting operation may be carried out using hand-held power tools. The boundary of the area to be cropped must be manually marked out based on engineering descriptions.
 Described herein is a tool for convenient guidance of a cropping operation.
BRIEF DESCRIPTION OF THE DRAWINGS
 The concept may be best understood by reference to the following description taken in conjunction with the accompanying drawing figures, in which:
 FIG. 1 is a schematic side elevation view of a turbomachinery blade of a gas
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 FIG. 2 is a schematic side elevation view of an airfoil cropping tool;
 FIG. 3 is a front elevation view of the cropping tool of FIG. 2;
 FIG. 4 is a rear elevation view of the cropping tool of FIG. 2;
 FIG. 5 is a top plan view of the cropping tool of FIG. 2;
 FIG. 6 is an enlarged view of a portion of the turbomachinery blade of FIG. 1 showing a cropping tool mounted thereto; and
 FIG. 7 is an enlarged view of a portion of the turbomachinery blade of FIG. 1 showing a guideline marked thereon.
DETAILED DESCRIPTION OF THE CONCEPT
 Illustrated in FIG. 1 is an exemplary turbomachinery blade 10 for a gas turbine engine. The blade 10 includes a dovetail 12, a shank 14, and an airfoil 16. The airfoil 16 extends in span from a root 18 to a tip 20 and includes opposed pressure and suction sides 22, 24 respectively extending in chord between a leading edge 26 and a trailing edge 28.
 In use, the airfoil 16 is subject to FOD as described above. Impacts with the airfoil 16 will result in physical damage such as a dent or nick 29, as well as a zone of residual stresses surrounding the area of physical damage. These are cropped as described above.
 The size and shape of the area to be cropped (i.e. the damaged area and surrounding affected zone) can be determined by engineering analysis of the specific damage to the specific component. In conventional practice an engineer must convey a description of t...