Eddy Current Probe Automatic Calibration for Turbomachine Holes
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Solution Overview
Problem
Current non-destructive testing by eddy currents for metal parts with holes is inefficient due to the need for frequent manual calibration, which leads to significant time loss and reduced precision, especially in complex geometries like turbomachine disc fixing holes, where calibration parts must be changed frequently and positioning can become misaligned.
Innovation Solution
A method and installation where a calibration part with a similar hole is aligned with the test hole, allowing the eddy current probe to collect calibration and inspection data during the same travel, eliminating the need for manual intervention and maintaining precision through automatic calibration without changing the reference frame.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual calibration is performed frequently using separate calibration parts, then calibration accuracy can be maintained, but inspection time increases significantly and productivity decreases
Solution Approach 1:
The patent combines the calibration hole and inspection hole into a single integrated structure. The calibration part includes a calibration hole and an inspection hole that are positioned to allow the eddy current probe to perform both calibration and inspection operations during the same passage through the part, eliminating the need for separate calibration steps and reducing inspection time significantly
Solution Approach 2:
The calibration hole is pre-positioned within the calibration part at a specific location that allows the probe to automatically perform calibration before or during the inspection of the inspection hole. This preliminary calibration action is built into the part structure itself, eliminating the need for manual recalibration between inspections
2Measurement precision
If calibration part is removed and repositioned for each inspection, then calibration can be performed, but positioning accuracy deteriorates and reliability decreases
Solution Approach 1:
The calibration hole and inspection hole are merged into a single integrated calibration part structure. The probe passes through both holes in sequence during one operation, ensuring that the calibration reference frame remains fixed and stable throughout the entire inspection process, eliminating positioning errors that occur when removing and repositioning calibration parts
Solution Approach 2:
The calibration part serves as a stable intermediary reference structure that remains fixed during the inspection process. The calibration hole and inspection hole are positioned within this stable reference frame, allowing accurate calibration and inspection without the need to remove or reposition the calibration part between operations
3Measurement precision
If separate calibration and inspection operations are performed, then calibration can be conducted, but operational complexity increases and ease of operation decreases
Solution Approach 1:
The patent merges calibration and inspection operations into a single integrated process. The eddy current probe passes through the calibration hole and inspection hole in sequence during one continuous operation, automatically performing calibration followed by inspection without requiring separate manual interventions or complex operational procedures
Solution Approach 2:
The calibration part is designed as a multi-functional component that serves both as a calibration reference and as the object to be inspected. The same structural element (the calibration part with its dual holes) performs both calibration and inspection functions, simplifying the overall operational process and eliminating the need for separate calibration and inspection procedures
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
This approach significantly reduces the time required for calibration and improves the reliability and precision of non-destructive testing by enabling simultaneous data collection and automatic calibration, enhancing the efficiency of inspecting metal parts with complex geometries like turbomachine disc fixing holes.
Implementation Method 1
Non-destructive testing by eddy currents consists of moving an electromagnetic sensor (a coil through which a high-frequency current passes) in the vicinity of a metal part to be tested and identifying defects (heterogeneity or cavity, in particular) by detecting a variation of impedance of the sensor
Implementation Method 2
The probe includes a rounded end (spherical or olive-shaped) split to have a certain elasticity and including an aforementioned sensor
Data Source
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Figure 3
Figure 4~5
AI summary
Automatic eddy current testing of a straight hole made in a metal part. An eddy current probe (13) is carried by a displacement system (17) associated with a positioning base (25) which carries a calibration piece (35) having a hole similar to the hole to be tested and aligned with an orifice of the latter.