Eddy Current Fastener Verification in Automated Installation

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Solution Overview

Problem

Existing automated fastener systems struggle to accurately identify the material of fasteners due to similarities in appearance and color, leading to potential installation of incorrect fasteners with inadequate strength, and existing hardness testing methods cause damage to fasteners.

Innovation Solution

An automated fastener system utilizing eddy current conductivity probes integrated at various points to non-destructively test the conductivity of fasteners, determining their material based on electrical conductivity measurements, and a processing system to compare these measurements against predetermined values for acceptance or rejection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If color vision systems are used to identify fastener material, then identification speed is improved, but measurement precision deteriorates because they cannot distinguish between similar colors or detect material under incorrect coatings

Engineering Contradiction:
Improveidentification speedVSAvoidmaterial identification accuracy
Core Design Contradiction:
SpeedVSMeasurement precision

Solution Approach 1:

The patent replaces optical/color-based identification systems with electrical conductivity measurement systems. The conductivity probe measures the electrical conductivity of the fastener, which directly correlates to the base material type. This substitution eliminates the limitations of color vision systems while maintaining automated identification speed, as conductivity measurement is both rapid and material-specific.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the identification parameter from optical properties (color) to electrical properties (conductivity). By measuring electrical conductivity, the system accesses a physical property that is intrinsic to the material and unaffected by surface coatings or color variations, thereby achieving both speed and precision in material identification.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If hardness testing methods are used to determine material, then measurement precision is improved, but object-generated harmful factors worsen due to damage to the fastener

Engineering Contradiction:
Improvematerial determination accuracyVSAvoidfastener damage
Core Design Contradiction:
Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The patent replaces mechanical hardness testing methods (which involve indentation, scratching, or compression) with electrical conductivity measurement. The conductivity probe makes light contact to measure electrical properties without applying destructive mechanical forces, thereby achieving material identification precision without causing fastener damage.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces electrical conductivity as an intermediary measurement parameter that correlates to material type without requiring direct mechanical interaction with the fastener. This intermediary measurement method provides material information while avoiding the harmful effects of mechanical testing.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If automated fastener selection is implemented, then productivity is improved, but reliability deteriorates due to potential installation of incorrect fasteners

Engineering Contradiction:
Improveassembly automation speedVSAvoidfastener installation correctness
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent implements a feedback mechanism where the conductivity probe measures the electrical conductivity of each fastener, and this measurement is fed back to the control system. The control system compares the measured conductivity against predetermined ranges for different material types, automatically identifying and selecting the correct fastener. This closed-loop feedback ensures both high productivity through automation and high reliability through accurate material verification.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces unreliable visual identification methods with electrical conductivity measurement for automated fastener selection. Since conductivity is an intrinsic material property that cannot be faked by surface coatings or color markings, the automated system achieves both high speed and high reliability in selecting the correct fastener material.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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

Enables accurate material identification of fasteners without damage, ensuring correct installation and preventing potential structural issues by distinguishing between different materials based on conductivity.

Implementation Method 1

an automated eddy current conductivity probe system comprising an eddy current conductivity probe assembly

Methodology Applied
Scientific EffectEddy current: Eddy Currents

Data Source

PatentEP4653860A1Automated fastener system and method having fastener conductivity testing
Publication Date: 2025.11.26 THE BOEING CO
  • EP4653860A1 patent drawingFigure 1
  • EP4653860A1 patent drawingFigure 2A~2B
  • EP4653860A1 patent drawingFigure 3A~3B

AI summary

There is provided an automated fastener system (10) having fastener conductivity testing (12). The automated fastener system (10) has an automated fastener holder assembly (40) holding fastener(s) (18); an automated fastener shuttle assembly (44) having shuttle cup(s) (46); an automated fastener inspection system (48) having an inspection center shaft (50), and inspection gripper fingers (52); an automated delivery system (56) having a delivery device (58); an automated fastener installation system (64) having an end effector (66) with an end effector center shaft (68), and end effector gripper fingers (70); an automated eddy current conductivity probe system (80); and a processing system (98). The eddy current conductivity probe system (80) has an eddy current conductivity probe assembly (82) integrated in one of, the one or more shuttle cups (46), the inspection center shaft (50), the inspection gripper fingers (52), the end effector center shaft (68), or the end effector gripper fingers (70). The eddy current conductivity probe assembly (82) contacts a selected fastener (18a) to perform the fastener conductivity testing (12), and to obtain an electrical conductivity measurement (14).