Glass Substrate Roll Speed Control for Crack Defect Reduction

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Solution Overview

Problem

The existing glass substrate manufacturing processes face challenges in predicting and reducing crack defects, which lead to glass breakage and optical property deterioration due to deviations in roller speeds and material conditions.

Innovation Solution

A method and apparatus that utilize partial least squares regression analysis to predict crack defect rates based on operational factors and roll rotational speeds, allowing for real-time adjustment of roll speeds to minimize crack defects during the glass substrate manufacturing process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the moving speed of sheet glass and the circumferential speeds of transporting rollers are not synchronized, then fine flaws occur on glass surfaces, but increasing measurement and control complexity is required to prevent speed deviation

Engineering Contradiction:
Improvesurface qualityVSAvoidroller speed control system
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent implements a feedback control system where the moving speed of the sheet glass is measured and used to control the circumferential speeds of the transporting rollers. Speed sensors detect the actual glass speed, and this information is fed back to the control system which adjusts the roller speeds accordingly, creating a closed-loop control mechanism that automatically compensates for speed deviations without requiring complex manual measurement and adjustment procedures

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces complex mechanical speed synchronization mechanisms with an automated control system that uses electrical sensors and control algorithms. Instead of relying on mechanically coupled rollers or complex gear systems to maintain speed synchronization, the invention uses electronic speed measurement and control to achieve the same result with simpler mechanical components

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

2Reliability

If crack defect prediction is not performed, then crack defects occur in glass substrates causing breakage and optical deterioration, but implementing prediction requires complex data analysis systems

Engineering Contradiction:
Improvecrack defect preventionVSAvoidprediction system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements a self-service prediction system where the manufacturing process itself generates the data needed for crack defect prediction. Sensors during the glass forming process automatically collect information about operating conditions, and this data is used by the control system to predict potential crack defects without requiring external inspection equipment or complex additional measurement systems

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent performs crack defect prediction before the glass substrate is completed and shipped. By analyzing operating conditions during the forming process and predicting potential defects in advance, the system allows for preventive adjustments to be made during manufacturing rather than requiring complex post-manufacturing inspection and sorting systems

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

This approach enables the development of a predictive model that accounts for about 61% of crack defect occurrences, allowing for real-time optimization of roll speeds to reduce crack defect rates effectively.

Implementation Method 1

cooling a glass substrate transported by a plurality of rolls rotating at a predetermined speed

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Data Source

PatentEP3686166B1Apparatus and method for manufacturing glass substrate
Publication Date: 2024.02.28 LG CHEM LTD
  • EP3686166B1 patent drawingFigure 1
  • EP3686166B1 patent drawingFigure 2~3
  • EP3686166B1 patent drawingFigure 4

AI summary

The present invention relates to a method and an apparatus for manufacturing a glass substrate, and according to one aspect of the present invention, there is provided a method for manufacturing a glass substrate, comprising steps of: cooling a glass substrate transported by a plurality of rolls rotating at a predetermined speed; predicting a crack defect rate of the glass substrate in accordance with a plurality of predictive factors related to crack defects of the glass substrate and rotational speed information of the respective rolls, in the transport process, and adjusting the rotational speed of each roll so that the crack defect rate of the glass substrate is lowered.