Automated Optical Inspection of Turbine Disk Edgebreak Contours
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Solution Overview
Problem
Current methods for inspecting the edgebreaks of turbine disk slots are time-consuming and prone to errors, with low gage repeatability and reproducibility, which can lead to missed defects and reduced component life.
Innovation Solution
A method and apparatus that uses a sensor and instrument to accurately inspect the contour of turbine disk slots by securing the disk, positioning the instrument to follow the edge contour, and converting signals into data points for comparison against predetermined values, enhancing inspection speed and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual wax-and-trace technique is used for inspecting edgebreaks, then inspection can be performed, but inspection time is excessive (up to ten minutes per slot) and gage repeatability and reproducibility are poor (approaching 50 percent error)
Solution Approach 1:
The patent replaces the manual mechanical wax-and-trace inspection system with an automated optical measurement system. The apparatus uses a light source, camera, and image processing algorithm to automatically capture and analyze edgebreak contours, eliminating manual wax application, removal, and visual alignment steps. This substitution dramatically improves measurement precision while reducing inspection time to seconds per slot.
Solution Approach 2:
The patent introduces a wax-free intermediary medium (refractive index matching fluid) that allows direct optical access to the edgebreak contour without manual trace application. This intermediary enables the optical system to directly visualize and measure the contour geometry, eliminating the need for physical wax traces and manual alignment procedures.
2Manufacturing precision
If rounded edges are made smaller to maintain slot geometry, then manufacturing precision is improved, but discontinuous regions from broaching are not adequately removed, requiring follow-up machining
Solution Approach 1:
The patent performs preliminary removal of discontinuous regions during the broaching operation itself by optimizing the broach tooth geometry and sequence. The broach is designed with specific tooth profiles that progressively remove material to achieve both the required slot geometry and adequate edgebreak in a single pass, preventing the need for follow-up machining operations.
Solution Approach 2:
The patent changes the broaching parameters including tooth profile geometry, tooth spacing, and feed rate to optimize the edgebreak formation. By adjusting these parameters, the process achieves the dual objective of maintaining precise slot geometry while adequately removing discontinuous regions to ensure component reliability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method significantly reduces inspection time and improves gage repeatability and reproducibility, allowing for more efficient and reliable detection of edgebreaks, thereby extending the life of turbine engine components.
Implementation Method 1
The instrument is in physical contact with the surface of the contour; transmitting a signal from the sensor based upon movement of the instrument
Data Source
AI summary
A method and tooling for inspecting a contour of an edge of a cutout formed in a disk, each cutout fixedly receiving a turbine blade. A first device receives the disk containing the cutouts. A second device has a sensor associated with the movement of an instrument, the first device securing the disk at a predetermined orientation to the sensor. The disk is secured to the first device, the instrument being directed along the cutout defining a path substantially parallel to a surface of the contour, the instrument remaining in physical contact with the surface of the contour. The sensor transmits a signal associated with instrument movement to an algorithm to convert the signal to two-dimensional positions along the tangent path along the surface of the contour. The acceptability of the edge contour of the cutout is determined by comparing the two-dimensional positions to predetermined ranges of values.