Thermoforming Sheet Inspection Under Continuous Conveyance

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Solution Overview

Problem

Existing thermoforming machines rely heavily on human inspection for detecting defects, leading to significant time loss and material waste, especially when the thermoformable material sheet is conveyed continuously without interruptions between feeding and stacking, and the cutting station is a die-cutter, making automation difficult.

Innovation Solution

An automated inspection system is integrated into the thermoforming machine, featuring imaging devices and a light source for optimal image capture, combined with machine learning algorithms to analyze images for defect detection, allowing continuous inspection without interruptions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If human inspection is used to detect defects in thermoformed products, then the inspection process can be performed with simple equipment, but the response time is slow and material waste is significant

Engineering Contradiction:
Improveresponse time between defect detection and production parameter adjustmentVSAvoidautomation level of inspection process
Core Design Contradiction:
Loss of timeVSExtent of automation

Solution Approach 1:

The patent replaces manual human inspection with an automated optical inspection system comprising imaging devices (cameras), light sources, and computer processing units. This substitution eliminates the mechanical limitation of human response time and enables real-time defect detection and analysis, directly resolving the contradiction between fast response time and automation level.

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

Solution Approach 2:

The inspection system is designed to autonomously detect defects, analyze images through computer programs, and trigger alerts or adjustments without human intervention. The system serves itself by continuously monitoring the production line and automatically responding to defects, achieving both high automation and rapid response simultaneously.

Inventive Principle:
Principle #25Self-service

2Productivity

If the thermoformable material sheet is conveyed continuously without interruptions between feeding and stacking, then productivity is improved, but inspection automation becomes difficult especially with die-cutting stations

Engineering Contradiction:
Improvecontinuous sheet conveyance efficiencyVSAvoidinspectability of continuously conveyed sheet
Core Design Contradiction:
ProductivityVSExtent of automation

Solution Approach 1:

The patent implements continuous inspection throughout the entire production process by positioning imaging devices along the continuous conveyance path. The inspection system operates without interruptions, capturing images of the material sheet as it moves continuously from feeding through die-cutting to stacking, maintaining both productivity and automation.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The patent uses optical imaging to detect defects in the continuous moving sheet by capturing two-dimensional images that can be analyzed computationally. This dimensional approach allows inspection of the continuously conveyed material without stopping the production line, resolving the contradiction between continuous conveyance and inspectability.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Manufacturing precision

If die-cutting station is used to cut thermoformed articles from the sheet, then manufacturing precision is improved, but inspection automation becomes more difficult due to continuous conveyance

Engineering Contradiction:
Improvedie-cutting precisionVSAvoiddefect detection difficulty in die-cutting process
Core Design Contradiction:
Manufacturing precisionVSDifficulty of detecting and measuring

Solution Approach 1:

The inspection system is positioned to detect defects in the material sheet before the die-cutting operation occurs. By performing preliminary inspection upstream of the die-cutting station, the system can identify defective areas that would otherwise be cut into finished products, preventing waste while maintaining die-cutting precision.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The inspection system provides real-time feedback about defects detected in the material sheet to the production control system. This feedback loop enables immediate detection and response to quality issues in the die-cutting process, making defect detection easier and more automated while preserving the precision of die-cutting operations.

Inventive Principle:
Principle #23Feedback

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 and accurate defect detection, reducing response times and material waste by automating the inspection process, optimizing production efficiency in machines with continuous sheet conveyance and die-cutting stations.

Implementation Method 1

a light source configured to emit diffused light, the light source comprising a light-emitting element and a light diffuser

Methodology Applied
Scientific EffectLight emission: Light

Data Source

PatentEP4647238A1Thermoforming machine
Publication Date: 2025.11.12 WM THERMOFORMING MACHINES SA
  • EP4647238A1 patent drawingFigure 1
  • EP4647238A1 patent drawingFigure 2
  • EP4647238A1 patent drawingFigure 3

AI summary

A thermoforming machine (100) is described, comprising: - a feeding station (2) feeding a thermoformable material sheet (1); - a thermoforming station (4) comprising a series of cavities, each cavity corresponding to an article to be thermoformed; - a cutting station (5) configured to die-cut the thermoformed material sheet (1'); - at least one stacking station (8) arranged according to the feeding direction (A) downstream of the said cutting station (5); a conveying system comprising a gripping member configured to continuously convey a sheet (1,1'), without releasing it, from said feeding station (2) to said at least one stacking station (8); characterised by comprising at least one inspection apparatus (60) configured to have at least one portion of said thermoformed material sheet (1') in an inspection area (41), said inspection area being flat and defining an inspection plane (42), said inspection apparatus (60) comprising a displaying system (40) comprising: - a plurality of imaging devices (43); - a light source configured to emit diffused light, the light source comprising a light-emitting element (46) and a light diffuser (47); - a module for transmitting the detected images to a processing unit comprising a computer programme configured for the detection of defects.