Glass Edge Smoothing Using Dual-Wavelength Laser Heating

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Solution Overview

Problem

Existing methods for smoothing glass pane edges, such as grinding and chemical treatments, are difficult to predict and can lead to micro-cracks and uneven strengthening, while laser methods face challenges in controlling thermal stresses and reproducing results.

Innovation Solution

A method using two lasers with specific wavelengths (6 µm to 12 µm and 0.30 µm to 2.00 µm) to create local heating areas on the glass edge, where the first laser melts the surface and the second laser controls cooling rates to minimize stress and achieve uniform rounding without deforming the glass body.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If mechanical grinding or chemical etching is used to smooth glass edges, then the edges can be rounded, but micro-cracks are created and glass strength decreases

Engineering Contradiction:
Improveedge roundingVSAvoidglass strength
Core Design Contradiction:
ShapeVSStrength

Solution Approach 1:

The patent replaces mechanical grinding and chemical etching processes with a laser-based thermal processing system. The laser beam locally heats and melts the glass edge material, which then solidifies into a rounded shape, eliminating the need for mechanical contact that causes micro-cracks and strength degradation

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

Solution Approach 2:

The invention utilizes the phase transition of glass material from solid to liquid and back to solid through controlled laser heating and cooling. The laser melts the glass edge (solid to liquid transition), and the subsequent rapid cooling causes re-solidification into a rounded shape, achieving edge smoothing without mechanical stress

Inventive Principle:
Principle #36Phase transitions

2Shape

If laser heating is used to smooth glass edges, then uniform rounding is achieved, but thermal stresses are created during rapid cooling

Engineering Contradiction:
Improveedge uniformityVSAvoidthermal stress
Core Design Contradiction:
ShapeVSStress or pressure

Solution Approach 1:

The patent applies preliminary heating to a broader area of the glass edge before the main laser processing. This pre-heating step ensures that the entire edge region reaches a temperature where the glass becomes sufficiently plastic and uniform, preventing thermal stress during subsequent rapid cooling and solidification

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The laser processing is divided into two distinct stages: a preliminary heating phase that covers a broader area to create uniform temperature distribution, and a main processing phase that applies concentrated energy for precise rounding. This segmentation allows control over thermal stress development

Inventive Principle:
Principle #1Segmentation

3Loss of substance

If conventional edge smoothing methods are used, then material can be removed, but the process is difficult to predict and reproduce

Engineering Contradiction:
Improvematerial removalVSAvoidprocess reproducibility
Core Design Contradiction:
Loss of substanceVSManufacturing precision

Solution Approach 1:

The patent replaces unpredictable mechanical and chemical removal processes with a laser-based system where material removal is precisely controlled by optical energy input. The laser parameters (power, speed, focal position) can be accurately measured and reproduced, ensuring consistent material removal and rounding results

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

Solution Approach 2:

The invention controls the laser processing parameters (wavelength, power, scanning speed, focal position) to precisely regulate material removal rate and rounding characteristics. By maintaining consistent parameter settings, the process achieves high reproducibility and predictability in edge smoothing operations

Inventive Principle:
Principle #35Parameter changes

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 method allows for reproducible, stress-free, and uniform edge smoothing, preventing micro-cracks and enhancing glass strength at the edge area, while maintaining the integrity of the glass body.

Implementation Method 1

A pane edge (3) of a glass pane (4) is irradiated by a first laser beam (1a) from a first laser (1) with a wavelength of 6 µm to 12 µm and a first local heating area (1b) is generated via a first laser beam (1a)

Methodology Applied
Scientific EffectLaser heating: Laser

Implementation Method 2

the glass pane (4) is exposed to a second laser beam (2a) from a second laser (2) with a wavelength of 0.30 µm to 2.00 µm and a second local heating area (2b) adjacent to the first local heating area (1b) below the edge of the pane (3) is generated via the second laser beam (2a)

Methodology Applied
Scientific EffectLaser heating with penetration: Laser

Implementation Method 3

causes the edge of the pane to melt in the (first) local heating area (1b) to a depth of 2 mm to 3 mm

Methodology Applied
Scientific EffectMelting and solidification: Melting

Data Source

PatentEP2731748B1Method for smoothing the edges of a sheet of glass
Publication Date: 2018.03.07 SAINT GOBAIN VITRAGE SA
  • EP2731748B1 patent drawingFigure 1
  • EP2731748B1 patent drawingFigure 2
  • EP2731748B1 patent drawingFigure 3

AI summary

The invention relates to a method for smoothing the edges of a glass pane, wherein ° a. a first laser beam (1a) from a first laser (1) having a wavelength of 6 µm to 12 µm is applied to a pane edge (3) of a glass pane (4), a first local heating region (1b) is produced in the glass pane (4) on the pane edge (3), and the first local heating region (1b) has an area having a width of 0.1 mm to 2 mm and is heated to a temperature above the transition temperature of the glass and causes a melting of the pane edge (3) in the first local heating region (1b) to a depth of 2 mm to 3 mm, ° b. a second laser beam (2a) from a second laser (2) having a wavelength from 0.30 µm to 2.00 µm is applied to the glass pane (4), and a second local heating region (2b) adjacent to the first local heating region (1b) is produced in the glass pane (4) below the pane edge (3), and ° c. the first laser beam (1a) is guided along the pane edge (3), and the second laser beam (2a) is guided parallel to the pane edge (3), wherein the second laser beam (2a) is guided at the same height or behind at a distance of at most 20 mm to 50 mm from the first laser beam (1a).