Optical Prepreg Inspection for Carbon Fiber Resin Defects

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Solution Overview

Problem

Existing methods for producing prepreg fail to accurately detect defects on both surfaces of the prepreg, particularly when a release paper is present, leading to incomplete inspection and potential defects in the final product.

Innovation Solution

A method utilizing optical devices with light irradiation and reception systems, along with defect judgment apparatuses, to classify defects such as streak-like resin missing, foreign matter contamination, and carbon fiber fuzz defects by comparing intensity values of reflected light with set threshold values, allowing for precise identification and marking of defects on both surfaces of the prepreg.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If visual inspection is used to detect defects in prepreg, then inspection can be performed, but inspection accuracy varies between persons and requires extremely high concentration power

Engineering Contradiction:
Improvedefect detection accuracyVSAvoidinspection operation difficulty
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent replaces manual visual inspection with an automated optical inspection system that uses light irradiation and light reception devices to detect defects. This substitution eliminates human variability and concentration requirements while providing consistent, objective defect detection through automated image processing and analysis.

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

2Manufacturing precision

If release paper is used during resin impregnation, then resin transfer to carbon fiber bundle is improved, but defect detection on the surface opposed to release paper becomes impossible

Engineering Contradiction:
Improveresin impregnation qualityVSAvoiddefect detection accessibility
Core Design Contradiction:
Manufacturing precisionVSDifficulty of detecting and measuring

Solution Approach 1:

The patent performs defect detection on the resin film surface before the resin impregnation process occurs. By inspecting the release paper surface with the optical system prior to laminating the carbon fiber bundle, the system can identify defects that would otherwise be hidden during subsequent processing, allowing for early defect identification without compromising resin impregnation quality.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If multiple inspection steps are implemented to detect defects on both surfaces, then inspection completeness is improved, but inspection time increases

Engineering Contradiction:
Improveinspection completenessVSAvoidinspection time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent combines multiple inspection functions into a single integrated optical inspection system that can detect defects on both surfaces of the prepreg simultaneously. By merging the light irradiation and light reception functions with automated image processing, the system achieves comprehensive defect detection without requiring separate manual inspection steps, thereby reducing total inspection time while maintaining high reliability.

Inventive Principle:
Principle #5Merging (Combining)

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 enables reliable detection and classification of defects on both surfaces of the prepreg, reducing inspection time and improving the quality of the final product by ensuring thorough defect identification and correction.

Implementation Method 1

the surface of the resin film formed by coating the release paper with a resin to be impregnated into the carbon fiber bundle is irradiated with light to identify a defect in the surface

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP2730914B1Prepreg production method
Publication Date: 2016.07.13 TORAY INDUSTRIES INC
  • EP2730914B1 patent drawingFigure 1~2
  • EP2730914B1 patent drawingFigure 3~4

AI summary

Provided is a method of producing prepreg including a carbon fiber bundle and a resin which is impregnated thereinto, including: a resin sheet inspection step of, by inspecting, with an optical device, in a resin sheet made of a release paper and a resin film which is formed by coating the release paper with a resin to be impregnated into a carbon fiber bundle, the surface of the resin film, detecting a defect in the surface of the resin film which would be the cause of a defect in the prepreg to be produced, and judging the type of the detected defect; or a prepreg sheet inspection step of, by inspecting, with an optical device, the surface of the prepreg after the release paper is separated from the prepreg sheet which is formed by impregnating a resin forming the resin film into the carbon fiber bundle, detecting defects in the surface of the prepreg, and judging the type of the detected defect.