Flexible Eddy Current Sensor Array for Low-Lift-Off Surface Inspection

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Solution Overview

Problem

Conventional eddy current array probes face challenges in maintaining consistent contact and minimizing lift-off while inspecting contoured workpieces, leading to signal noise and frequent probe damage, especially when detecting small flaws in large components.

Innovation Solution

A flexible eddy current array probe (ECAP) with a specialized sensor mount and biasing element, combined with a friction reduction material and signal analysis algorithm, maintains contact and minimizes lift-off, enhancing detection accuracy and reducing false indications.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a conventional eddy current array probe is used to inspect contoured workpieces, then the inspection coverage is achieved, but the contact consistency deteriorates leading to lift-off and signal noise

Engineering Contradiction:

Improvedetection accuracyVSAvoidcontact consistency

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent employs a flexible substrate to mount the eddy current sensor array, allowing the probe to conform to contoured workpiece surfaces. This flexibility maintains consistent contact between the sensor array and the inspected surface, eliminating lift-off issues and signal noise while preserving detection accuracy on complex geometries.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The probe assembly incorporates a biasing mechanism that dynamically adjusts the contact pressure between the sensor array and the workpiece surface. This dynamic adjustment ensures maintained contact during scanning operations, preventing lift-off and ensuring reliable signal acquisition throughout the inspection process.

Inventive Principle:

Principle #15Dynamics

2Productivity

If the probe is moved into proximity with contoured surfaces, then inspection coverage is achieved, but probe damage increases due to frequent contact

Engineering Contradiction:

Improveinspection coverageVSAvoidprobe durability

Core Design Contradiction:

ProductivityVSStrength

Solution Approach 1:

The flexible substrate acts as a compliant interface that absorbs mechanical stresses during scanning operations. This flexibility protects the delicate sensor array and electronic components from damage while enabling continuous contact with contoured surfaces for comprehensive inspection coverage.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The biasing mechanism and flexible mounting structure provide predetermined mechanical cushioning between the probe and workpiece. This cushioning effect prevents excessive contact forces that could damage the probe while maintaining sufficient contact for effective eddy current inspection throughout the scanning process.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Ease of operation

If conventional probes are used on contoured surfaces, then inspection is performed, but false indications increase due to lift-off

Engineering Contradiction:

Improveinspection capabilityVSAvoidsignal accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The flexible substrate enables the sensor array to conform to the workpiece surface geometry, maintaining zero or minimal lift-off during scanning. This consistent contact eliminates false indications caused by variable coupling conditions while preserving the ability to inspect complex contoured surfaces.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The biasing mechanism incorporates feedback through the flexible substrate's mechanical response, automatically adjusting contact pressure to maintain optimal coupling between the sensor array and workpiece surface. This feedback mechanism ensures accurate signals by preventing lift-off-induced false indications during the inspection process.

Inventive Principle:

Principle #23Feedback

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 solution improves detection accuracy and productivity by maintaining zero or near-zero lift-off and managing low-friction motion, reducing false defects and probe damage, while effectively inspecting contoured surfaces.

Implementation Method 1

Eddy current techniques are based on the principle of electromagnetic induction in which eddy currents are induced within the component under inspection

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

The eddy currents are induced in the component by alternating magnetic fields created in a coil of an eddy current probe

Methodology Applied

Scientific EffectEddy currents: Eddy Currents

Data Source

PatentEP4650767A1Inspection system and method using eddy current sensor array

Publication Date: 2025.11.19 GENERAL ELECTRIC CO

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AI summary

A sensor system (100) may include a sensor array (104) comprising a plurality of eddy current sensor elements, the sensor array (104) having a contact side and a mounting side opposite the contact side. The sensor system (100) may include a sensor mount (102) coupled to the mounting side of the sensor array (104). The sensor system (100) may include a biasing element (110) configured to bias the contact side of the sensor array (104) against an inspected surface of a component (202) and secure the sensor array (104) to the component (202) while the inspected surface moves relative to the sensor array (104) during data capture.