Cold Bending Thin Glass Using Support Mold

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Solution Overview

Problem

The challenge lies in producing curved laminated glass panes with thin glass sheets, as conventional hot bending methods are energy-intensive and prone to breakage, and cold bending results in inconsistent contact pressure, leading to optical defects and delamination.

Innovation Solution

A method involving a support mold to cold-bend thin glass panes into a defined shape, ensuring uniform contact pressure and mechanical stability, while the thicker glass pane is pre-bent and laminated using a thermoplastic interlayer, eliminating the need for hot bending of the thin glass.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If hot bending is used to bend thin glass panes, then the glass can be shaped, but the process is energy-intensive and the glass is prone to breaking

Engineering Contradiction:
Improvecurved shape of glass paneVSAvoidenergy consumption
Core Design Contradiction:
ShapeVSUse of energy by moving object

Solution Approach 1:

The patent changes the temperature parameter from hot bending (high temperature) to cold bending (room temperature or low temperature). The thin glass pane is bent at temperatures below its softening point, eliminating the need for energy-intensive heating while still achieving the desired curved shape through mechanical pressure applied during lamination.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the thermal-mechanical bending process with a purely mechanical cold-bending process. Instead of using heat to soften the glass and then applying mechanical force, the invention applies mechanical pressure directly to the thin glass pane during lamination to achieve bending without thermal energy input.

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

2Use of energy by moving object

If thin glass panes are cold-bent directly during lamination, then energy consumption is reduced, but the contact pressure is not constant leading to optical defects and delamination

Engineering Contradiction:
Improveenergy consumptionVSAvoidoptical quality and bond stability
Core Design Contradiction:
Use of energy by moving objectVSManufacturing precision

Solution Approach 1:

The patent introduces a support mold as an intermediary element between the pressing mechanism and the thin glass pane. The support mold has a curved surface that matches the desired final shape and provides uniform distributed pressure across the glass surface during cold bending, ensuring constant contact pressure and preventing optical defects and delamination while maintaining low energy consumption.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Weight of moving object

If thin and thick glass panes with different compositions are laminated, then weight is reduced, but bending in pairs becomes difficult or impossible due to different softening temperatures

Engineering Contradiction:
Improveweight of glazingVSAvoidbending process compatibility
Core Design Contradiction:
Weight of moving objectVSEase of manufacture

Solution Approach 1:

The patent segments the bending process into two separate operations: (1) the thick glass pane is pre-bent to its final curved shape using conventional hot bending before lamination, and (2) the thin glass pane is cold-bent during the lamination process itself. This segmentation eliminates the need for both panes to have compatible softening temperatures, allowing the use of different glass compositions optimized for各自的 applications while maintaining manufacturing feasibility.

Inventive Principle:
Principle #1Segmentation

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 produces laminated glass panes with high optical and mechanical quality, reducing the risk of delamination and enhancing the stability of the bond between the thin and thick glass sheets.

Implementation Method 1

the first pane of glass is cold bent into a shape defined by the support mold

Methodology Applied
Scientific EffectCold bending: Cold-forming

Implementation Method 2

the restoring force of the cold-bent thin glass pane

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 3

the intermediate layer is then heated with the aid of IR radiation

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 4

heated with the aid of IR radiation

Methodology Applied
Scientific EffectInfrared radiation: Infrared Radiation

Implementation Method 5

heated to at least its softening point

Methodology Applied
Scientific EffectSoftening: Melting

Data Source

PatentEP3544809B1Method for the production of a curved laminated glass pane with a thin glass sheet
Publication Date: 2023.06.14 SAINT GOBAIN VITRAGE SA
  • EP3544809B1 patent drawingFigure 1~2
  • EP3544809B1 patent drawingFigure 3~4
  • EP3544809B1 patent drawingFigure 5~6

AI summary

The invention relates to a method for producing a composite glass pane, at least comprising: placing a first glass pane (1) having a thickness of less than or equal to 1 mm on a support form (4), wherein the first glass pane (1) is curved into a shape determined by the support form (4); placing at least one thermoplastic film (3) on the first glass pane (1); placing a curved second glass pane (2) having a thickness of greater than or equal to 1.5 mm on the thermoplastic film (3); and connecting the first glass pane (1) to the second glass pane (2) via the thermoplastic film (3) into a composite glass pane by lamination.