Optical Ply Mapping for Composite Repair Machining Inspection

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Solution Overview

Problem

Current bonded repair methods for composite materials in aeronautics lack reliable and non-destructive validation techniques for machining and bonding phases, leading to variability and uncertainty in the execution and quality of repairs, especially due to geometric singularities and material variations.

Innovation Solution

An automated ply-to-ply machining control system using optical image analysis to characterize the surface condition of repaired parts, determining pixel orientation, constructing cartography, estimating machining quality, and archiving results, which includes a digital data processing unit linked with light sources and a camera to provide accurate and reproducible assessments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If automated optical inspection system is implemented, then measurement precision and reproducibility improve, but device complexity increases

Engineering Contradiction:
Improvemachining quality assessment precisionVSAvoidinspection system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The inspection system divides the complex task of machining quality assessment into distinct functional modules: illumination sources for different lighting conditions, image capture devices for data collection, and digital processing units for analysis. This segmentation allows each component to be optimized independently while maintaining overall system precision.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces digital image processing as an intermediary between the physical machining process and quality assessment. The optical inspection system captures images of the machined surface, and digital algorithms analyze these images to determine machining quality, acting as a mediator that translates physical characteristics into measurable data without direct mechanical contact.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If automated optical inspection system is implemented, then productivity improves, but device complexity increases

Engineering Contradiction:
Improveinspection speedVSAvoidinspection system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The inspection system enables continuous quality assessment during the machining process by implementing automated optical inspection that can operate continuously without manual intervention. The system maintains continuous monitoring capability through automated image capture and processing, eliminating the discontinuous nature of manual inspection methods.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The patent replaces manual visual inspection with an automated optical inspection system that uses digital imaging and computer processing. This substitution eliminates the mechanical limitations of human inspection speed and consistency, achieving higher productivity through automated electronic systems that can process images rapidly and continuously.

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

3Reliability

If automated optical inspection system is implemented, then reliability of validation improves, but device complexity increases

Engineering Contradiction:
Improverepair validation reliabilityVSAvoidinspection system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The inspection system implements feedback mechanisms by capturing images of the machined surface, processing these images digitally, and using the analysis results to validate machining quality. The system provides feedback on whether the machining meets specified criteria, enabling reliable validation of repair processes through automated decision-making based on objective image analysis.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent utilizes changes in optical parameters (lighting conditions, image brightness, contrast) to reliably detect machining quality variations. By systematically varying illumination angles and analyzing corresponding image parameter changes, the system achieves reliable validation of repair processes through objective measurement of surface characteristics.

Inventive Principle:
Principle #35Parameter changes

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

Enhances the speed, reproducibility, and reliability of machining quality assessments, providing a more precise and reliable validation of repair processes compared to manual visual methods, ensuring higher mechanical integrity of composite structures.

Implementation Method 1

taking of images according to illuminations of different orientation of a surface of the machined part to be inspected according to the orientations and the optical characteristics of the machined folds

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP3541626B1Method and system for inspecting ply-by-ply machining of multilayer materials
Publication Date: 2021.07.07 BAYAB IND
  • EP3541626B1 patent drawingFigure 1a~1b
  • EP3541626B1 patent drawingFigure 2~3
  • EP3541626B1 patent drawingFigure 4~5

AI summary

The invention aims to achieve a rapid, reproducible and reliable characterization of the quality of ply-by-ply machining of multilayer materials. This method for inspecting ply-by-ply machining of a part (10) made of multilayer composite material under repair by machining a ply-by-ply staggered or continuously sloped cut out in a stack of plies of various successive orientations consists in taking images (IA to ID), under lighting of different orientations (12), of a surface area (10a) of the machined part (10) to be inspected; performing an analysis by comparing the images (IA to ID) pixel by pixel (P0) in order to define the orientation of each pixel (P0) as corresponding to that of the image in which this pixel has a higher brightness; if the pixel has a similar brightness in all the images (IA à ID), this pixel (Pr) is attributed to a resin; constructing a map (5) in units of ply of the surface area to be inspected (10a) by applying the preceding analysis to all of the pixels; estimating a machining quality level from the map (5) produced, and archiving (2m) each map (5) thus produced as a machining result.