Thermal Imaging Inspection of Packaging Web Heat Seals

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Solution Overview

Problem

Current methods for evaluating the quality of heat-sealing a sealing strip to a packaging web in packaging machines rely on qualitative and/or quantitative checks by trained operators, which have limitations and require human intervention.

Innovation Solution

An automatic sealing quality control system using industrial artificial vision and electronic computing resources, including visible-light and thermal imaging cameras, to detect and identify defects in the heat-sealing process, assessing the quality of the sealing based on captured digital images.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If manual inspection by trained operators is used to evaluate sealing quality, then human judgment and experience can be applied, but the process requires continuous human intervention and is time-consuming

Engineering Contradiction:
Improvesealing quality evaluation accuracyVSAvoidautomation level of inspection process
Core Design Contradiction:
Measurement precisionVSExtent of automation

Solution Approach 1:

The patent replaces manual mechanical inspection with an automated optical inspection system using cameras and image processing algorithms. The system captures images of the sealing strip and packaging web, then uses computer vision technology to automatically detect and evaluate sealing defects, eliminating the need for continuous human intervention while maintaining or improving inspection accuracy.

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

Solution Approach 2:

The inspection system performs self-evaluation by automatically analyzing sealing quality without requiring external human operators. The image processing algorithms independently assess sealing defects, classify their severity, and generate quality evaluations, enabling the system to serve itself in the inspection task.

Inventive Principle:
Principle #25Self-service

2Productivity

If automated vision systems are implemented to evaluate sealing quality, then automation and productivity are improved, but the system complexity and initial setup requirements increase

Engineering Contradiction:
Improveinspection throughput and speedVSAvoidcomplexity of automated inspection system
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The vision system is designed to perform multiple inspection functions using a single integrated platform. It can detect various types of sealing defects (adhesion issues, discontinuities, dimensional variations), classify their severity, and provide comprehensive quality evaluation, making the complex system worthwhile through its multi-functional capabilities that replace multiple manual inspection tasks.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent introduces image processing algorithms and software intermediaries that bridge the gap between the optical sensors and the quality evaluation output. These intermediaries process raw images, extract relevant features, and translate them into meaningful quality metrics, managing the system complexity by organizing the inspection workflow into manageable processing stages.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If multiple camera systems are used for comprehensive sealing evaluation, then measurement precision and defect detection capability are improved, but calibration complexity and time requirements increase

Engineering Contradiction:
Improvedefect detection accuracyVSAvoidcalibration time and setup duration
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system performs preliminary calibration using standardized test patterns or reference objects before actual production inspection begins. This preliminary action establishes the baseline parameters for the multi-camera system, including spatial relationships and measurement scales, so that once calibrated, the system can operate efficiently without repeated calibration during production, reducing ongoing time losses.

Inventive Principle:
Principle #10Preliminary action

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 system enables accurate, automated evaluation of the heat-sealing quality, reducing human involvement and improving the reliability of packaging by identifying macro and micro defects in real-time.

Implementation Method 1

a second digital camera (20) designed to capture thermal digital images

Methodology Applied
Scientific EffectThermal radiation: Thermal Radiation

Implementation Method 2

the packaging web 3 and the sealing strip 6 are first web-fed to the heat-sealing station 7, where they are heated by a first heating unit 8

Methodology Applied
Scientific EffectHeating: Heating

Data Source

PatentEP4306305B1Evaluating the sealing quality of a sealing strip sealed to a packaging web in a packaging machine
Publication Date: 2025.12.17 TETRA LAVAL HOLDINGS & FINANCE SA
  • EP4306305B1 patent drawingFigure 1
  • EP4306305B1 patent drawingFigure 2~3
  • EP4306305B1 patent drawingFigure 4~5

AI summary

An automatic heat-sealing quality control system (12) to automatically control a quality of a heat-sealing of a sealing strip (6) to a longitudinal edge of a packaging web (3) at a heat-sealing station (7) in a packaging machine (1), where sealed packages (5) containing pourable food products are continuously produced from a continuous vertical tube (2) filled with the pourable food product and formed by longitudinally folding the packaging web (3) to overlap longitudinal edges thereof and then heat-sealing the overlapping longitudinal edges. The system (12) comprises a thermal imaging camera (20) designed to operate in the electromagnetic spectrum invisible to human eye to capture and output thermal digital images.