Rotating Mold Glass Bending with Thermal Tempering

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Solution Overview

Problem

Existing methods for bending glass sheets struggle to produce monolithic hardened glass sheets with variable bending angles between 1 and 100° and narrow radii of curvature between 10 and 40 mm, which are essential for applications requiring aesthetic appeal, mechanical strength, and ease of cleaning, while also ensuring thermal tempering and safety features.

Innovation Solution

A method involving a rotating hardening furnace with an additional heating body and a specially designed mold that allows for targeted heating and curvature control, enabling the production of monolithic glass sheets with variable bending angles and narrow radii of curvature, using a glass sheet supported on a metallic mold and heated within a temperature-controlled chamber, followed by rapid cooling to achieve the desired curvature and mechanical properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If glass sheets are bent with a narrow radius of curvature (10-40 mm) to improve aesthetic appearance and support plane, then the mechanical strength and cleaning easiness are improved, but the manufacturing complexity and difficulty increase significantly

Engineering Contradiction:
Improvemechanical strengthVSAvoidmanufacturing complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The glass sheet is pre-heated to annealing temperature before bending, which softens the glass and enables it to be shaped into narrow radius curves without breaking. This preliminary heating action prepares the material to accept the complex bending operation that would otherwise be impossible on cold, brittle glass.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The temperature of the glass sheet is changed from ambient to annealing temperature during the bending process. This parameter change transforms the glass from a brittle solid to a more ductile state, allowing it to be bent into tight curves and then tempered to lock in the shape while maintaining strength.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If glass sheets are thermally tempered to provide safety features and mechanical strength, then the reliability and strength are improved, but the manufacturing process complexity increases

Engineering Contradiction:
Improvesafety featuresVSAvoidmanufacturing process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The bending and thermal tempering operations are merged into a single continuous process. The glass sheet is heated to annealing temperature, bent to the desired shape, and then rapidly cooled while maintaining the bend, thereby combining shaping and strengthening in one operation rather than as separate steps.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The heating, bending, and cooling operations are performed continuously without interrupting the glass sheet in its softened state. This continuous process ensures the glass maintains its shape while being tempered, avoiding the need for intermediate handling that would complicate the manufacturing process.

Inventive Principle:
Principle #20Continuity of useful action

3Manufacturing precision

If glass sheets are bent at high precision with variable angles (1-100°) and narrow radii (10-40 mm) to meet aesthetic and functional requirements, then the manufacturing precision is improved, but the device complexity and process difficulty increase

Engineering Contradiction:
Improvebending precisionVSAvoidprocess difficulty
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The heating and bending apparatus is designed to accommodate a wide range of bending angles (1-100°) and radii (10-40 mm) using the same basic mechanism. The system can be adjusted to produce different geometries without requiring specialized equipment for each configuration, thereby achieving high precision across multiple product variants.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

The method effectively produces glass sheets with enhanced mechanical strength, ease of cleaning, and aesthetic appeal, suitable for various applications including bathroom furniture and display counters, while ensuring thermal tempering and safety features, by achieving precise curvature and uniform cooling.

Implementation Method 1

the leaves of the glass sheet are heated by heating means so as to reduce the temperature gradient between the bending line and the leaves in order to avoid a thermal shock

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

the object of the invention is to provide a method of bending glass sheets in which the curvature is not directly linked to the shape of a mold or framework and where stirrups are suitable to apply bending force on the glass sheet when heated

Methodology Applied
Scientific EffectThermal shock: Thermal Shock

Data Source

PatentEP2860159B1Method for bending glass sheets and machine for carrying out the method
Publication Date: 2020.06.24 SFERA SRL
  • EP2860159B1 patent drawingFigure 1~3
  • EP2860159B1 patent drawingFigure 4~4a
  • EP2860159B1 patent drawingFigure 5

AI summary

A method for making glass sheets (5) comprising the steps of placing the sheet (5) on an angled support or mold (4), which supports the sheet (5) leaving a peripherally projecting portion, conveying the mold (4) and the sheet (5) inside a pre-heated chamber (6), heating the sheet (5) by convection and radiation, rotating the mold (4) and the sheet (5) so that the sheet (5) is bent by the force of gravity, thus laying completely on the mold (4), conveying the curved sheet (5) towards a rapid cooling area (40), in order to provide a surface tension, and finally conveying the sheet (5) in a discharge zone (50). The invention also claims a machine (60) able to carry out the above method and a glass sheet (5) thus obtained.