Glass Sheet Bending via Microwave Heating
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Solution Overview
Problem
Existing techniques for bending glass sheets, particularly those requiring complex shapes with large and small radii of curvature, face challenges in controlling temperature distribution and achieving precise curvature formation due to the thermal inertia of resistance heating methods, leading to inefficiencies and slow production.
Innovation Solution
The use of microwave radiation for localized heating of glass sheets preheated to a high temperature, allowing for rapid and controlled temperature increases in specific areas, enabling continuous processing and improved energy efficiency by concentrating heat input directly into the glass.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If resistance heating means are used for localized heating of glass sheets, then heating can be applied to specific zones, but thermal inertia causes difficulty in controlling heat supply and reduces production speed
Solution Approach 1:
The patent replaces resistance heating means with microwave heating means for localized heating of glass sheets. Microwave heating provides rapid and precise temperature control without the thermal inertia characteristic of resistance heating, thereby improving both temperature control precision and production speed in continuous bending processes
Solution Approach 2:
The patent changes the heating parameter from conventional resistance heating to microwave heating, enabling instantaneous and localized temperature increases in specific zones of the glass sheet without affecting adjacent areas, thus resolving the contradiction between precise temperature control and production efficiency
2Loss of energy
If resistance heating means are used for localized heating, then heating can be concentrated in specific areas, but energy efficiency is poor as most energy is dispersed in furnace elements
Solution Approach 1:
The patent substitutes resistance heating with microwave heating, which directly couples energy to the glass material through dielectric heating. This eliminates energy dispersion to furnace elements and supports structures, achieving both high energy efficiency and precise localized heating in the targeted zones
Solution Approach 2:
Microwave heating enables the glass sheet to heat itself through dielectric loss in the targeted zones. The microwave energy is absorbed directly by the glass material where needed, without requiring intermediate heating elements, thus improving energy efficiency and localization precision simultaneously
3Object-affected harmful factors
If gravity-based bending techniques are used for complex shapes, then optical defects are minimized, but achieving combinations of large and small radii of curvature is difficult
Solution Approach 1:
The patent applies localized microwave heating to specific zones of the glass sheet where small radius curvatures are required, while maintaining gravity-based bending in areas requiring large radii. This localized thermal softening enables complex shape formation without compromising optical quality in non-heated areas
Solution Approach 2:
The patent segments the heating process into localized microwave heating zones and gravity-based bending zones. By dividing the glass sheet into differently treated areas, the process achieves complex shapes with both large and small radii of curvature while maintaining optical quality through controlled localized intervention
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 formation of complex glass shapes with high precision and speed, reducing production time and energy waste while maintaining uniformity in temperature across the glass sheet, even during continuous scrolling.
Implementation Method 1
localized heating is carried out by means of the application of microwave radiation
Implementation Method 2
The efficiency of the microwave heating, namely the local increase in the temperature of the sheet for a determined power output, is a function of the temperature of the sheet to which these microwaves are applied
Implementation Method 3
the traditional techniques which use the bending of the softened glass under the effect of its own weight
Data Source
Figure 1A~2D
Figure 3~4
AI summary
The present invention relates to a technique for bending glass sheets by gravity, in which the sheets, which are placed in a frame for imparting them the final peripheral shape, are heated during a first step to a temperature close to the softening temperature by passing them in a tunnel furnace essentially heated with resistors in which the glass sheets optionally experience a first or partial bending, and in which during a second step, and optionally simultaneously with the completion of the bending of the first step, the sheets are submitted to the local and controlled application of microwaves for increasing the temperate and facilitating the bending in the exposed areas.