Glass Sheet Breaking via Localized Support and Crack Propagation Control

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Solution Overview

Problem

Current glass breaking techniques struggle with cutting complex shapes, particularly those with small concave radii, due to difficulties in applying consistent bending stress and controlling crack propagation, leading to scrap generation and limited achievable geometries.

Innovation Solution

A method involving tracing a complex cutting line on the glass surface, using a cutting tool, and applying a local support force on the opposite face with controlled deformation zones to manage crack propagation, utilizing a flat support surface or suction elements to maintain precise stress control and prevent shear stresses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If pressure is applied to the offcut to break complex shapes, then the breaking operation can be performed, but bending stress cannot be created at every point along the cut line, leading to spalling and reduced cutting quality

Engineering Contradiction:
Improvebreaking operationVSAvoidcutting quality
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The support means is divided into multiple localized support points distributed along the cutting line, allowing independent stress application at each segment. This segmentation enables precise control of bending stress at every point along the complex cut line, preventing spalling while maintaining ease of breaking operation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The support means provides localized support specifically at points along the cutting line where stress is needed, rather than uniform support across the entire offcut. This local quality approach creates bending stress precisely where required at each segment of the cut line, eliminating spalling while maintaining manufacturing efficiency.

Inventive Principle:
Principle #3Local quality

2Adaptability or versatility

If support points are adjusted to break concave shapes with small radii, then breaking can be achieved, but the process becomes lengthy and delicate, generating significant scrap

Engineering Contradiction:
Improveconcave shape breakingVSAvoidbreaking speed
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The support means is designed to be movable and adjustable, allowing dynamic adaptation to different concave geometries and radii. This dynamic capability enables the system to handle various concave shapes efficiently without lengthy manual adjustment, maintaining high productivity while achieving versatile breaking of complex geometries with reduced scrap.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The position and force parameters of the support means can be dynamically changed to match different concave shape requirements. By automatically adjusting these parameters, the system adapts to various geometries quickly, maintaining high productivity while achieving versatile breaking capability with minimal scrap generation.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If additional cuts are placed around the periphery of the shape, then clean break of the primitive can be achieved, but sacrificial glass surface area is lost

Engineering Contradiction:
Improveclean breakVSAvoidsacrificial glass surface area
Core Design Contradiction:
Manufacturing precisionVSLoss of substance

Solution Approach 1:

The support means is positioned in advance along the cutting line to provide localized support during the breaking operation. This preliminary positioning eliminates the need for additional peripheral cuts, as the localized support ensures clean break directly along the desired cutting line, maintaining manufacturing precision while avoiding loss of sacrificial glass surface area.

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 enhances cutting quality by controlling crack propagation and reducing scrap generation, allowing for more precise breaking of complex shapes with improved control over deformation and stress distribution.

Implementation Method 1

tracing one or more superficial cracks on the surface of the glass using, for example, a glass cutter

Methodology Applied
Scientific EffectMechanical abrasion: Abrasion

Implementation Method 2

tracing one or more superficial cracks on the surface of the glass using, for example, a glass cutter or a laser

Methodology Applied
Scientific EffectLaser heating: Laser

Implementation Method 3

an operation of propagating the initial superficial crack through the thickness of the glass sheet

Methodology Applied
Scientific EffectBending stress: Deformation

Implementation Method 4

The breaking can be done on a soft mat. A force is applied to the fall by pressing down until it breaks and separates

Methodology Applied
Scientific EffectFracture mechanics: Fracture Mechanics

Implementation Method 5

a step of setting up planar support means arranged to generate a pressure force on or around the cutting line and the area to be broken

Methodology Applied
Scientific EffectPressure force: Pressure Increase

Implementation Method 6

The planar support means include a pair of suction cups or bells

Methodology Applied
Scientific EffectVacuum suction: Vacuum

Data Source

PatentEP3625181B1Method for breaking a glass sheet
Publication Date: 2023.12.27 SAINT GOBAIN VITRAGE SA
  • EP3625181B1 patent drawingFigure 1a~4
  • EP3625181B1 patent drawingFigure 5~7
  • EP3625181B1 patent drawingFigure 8~9

AI summary

The method comprises - a step of tracing a score line (2) on the surface of the glass, using a scoring tool (6); - a step of positioning flat bearing means (20) arranged to generate a pressing force on the score line; and - a step of breaking, using a local bearing means (10) applied to the opposite face (4B) and facing the score line (2), the local bearing means (10) being moved and pressed along the score line (2), on said opposite face (4B). Figure 2