In-Line Seal Inspection Using Thermal, Photoelastic, and UV Imaging

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Solution Overview

Problem

Current seal testing methods for packaging are labor-intensive, destructive, and limited to offline processes, failing to effectively detect seal defects such as air penetration and microorganism intrusion, which compromise packaging integrity.

Innovation Solution

A non-destructive in-line seal quality monitoring system using thermography, photoelasticity, and ultraviolet vision systems to capture and analyze seal images, identifying defects through thermal signatures, strain variations, and fluorescence indicators, with a vision inspection engine determining seal quality and triggering corrective actions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional destructive seal testing methods are used, then seal quality can be verified, but the packaging article is destroyed and only limited offline testing is possible

Engineering Contradiction:
Improveseal quality verificationVSAvoidtesting throughput
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent replaces mechanical destructive testing methods with optical vision systems (thermography, photoelasticity, ultraviolet) that can detect seal defects non-destructively. This substitution enables in-line inspection without compromising packaging integrity, allowing continuous production flow while maintaining reliable seal quality verification

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

Solution Approach 2:

The vision systems create optical copies (images) of the seal area that can be analyzed without touching or damaging the actual packaging. Multiple imaging modes capture different physical properties (thermal, optical, fluorescent) to generate comprehensive seal quality assessment without physical contact

Inventive Principle:
Principle #26Copying

2Measurement precision

If traditional offline seal testing is performed, then seal defects can be detected, but the process is labor-intensive and time-consuming

Engineering Contradiction:
Improveseal defect detectionVSAvoidinspection time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system enables continuous in-line inspection of seals as packaging moves through the production line, eliminating stop-and-test offline procedures. Multiple sensors operate simultaneously and continuously to monitor seal quality without interrupting production flow, dramatically reducing inspection time while maintaining detection precision

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The vision systems perform seal inspection immediately after sealing while the packaging is still on the production line, before final packaging operations. This preliminary detection allows for real-time quality control and immediate corrective action without delaying subsequent production steps

Inventive Principle:
Principle #10Preliminary action

3Reliability

If multiple vision systems are used for comprehensive seal inspection, then detection reliability improves, but system complexity increases

Engineering Contradiction:
Improveseal defect detection reliabilityVSAvoidvision system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple vision systems (thermography, photoelasticity, ultraviolet) into a single integrated inspection station that processes packaging through one coordinated system. The merged system shares common infrastructure (imaging hardware, processing software, control mechanisms) while providing comprehensive multi-mode seal analysis, reducing overall system complexity compared to separate independent systems

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

Enables rapid, reliable detection of seal defects, ensuring packaging integrity while maintaining production efficiency by identifying and removing defective packages in real-time, reducing waste and enhancing consumer confidence.

Implementation Method 1

a vision system, which is a thermography vision system and comprises an image capture device, in this case a thermal imaging camera, which is configured to capture a thermal image of the seal area

Methodology Applied
Scientific EffectThermal radiation: Thermal Radiation

Implementation Method 2

a photoelasticity vision system, which comprises a light source, a first polarizer, a second polarizer and a photoelasticity image capture device

Methodology Applied
Scientific EffectPhotoelasticity: Photoelasticity

Implementation Method 3

a fluorescent electromagnetic energy intensity is higher in a region where a seal defect is located

Methodology Applied
Scientific EffectFluorescence: Fluorescence

Data Source

PatentEP3914903B1System for in-line inspection of seal integrity
Publication Date: 2026.01.28 CRYOVAC INC
  • EP3914903B1 patent drawingFigure 1
  • EP3914903B1 patent drawingFigure 2
  • EP3914903B1 patent drawingFigure 3~5

AI summary

A process for monitoring seal quality of a packaging article. In one embodiment, the process for monitoring the seal quality includes sealing a film to form packaging article and forming a seal area. The seal area is analyzed by a vision system to acquire image data of the seal area. A vision inspection engine analyzes the image date to determine the continuity of the seal, the strength of the seal, or both.