Thin Glass Sheet Rolling System with Cross Temperature Gradient
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Solution Overview
Problem
Existing glass manufacturing systems face challenges in producing high-quality thin glass sheets with thicknesses below 150 μm, as they either incur high production costs or yield inferior surface quality, and are limited by the viscosity requirements of the fusion draw and slot draw processes, which restrict the types of glass that can be used.
Innovation Solution
A glass manufacturing system that includes a delivery system for molten glass transitioning from guided to free fall flow, a rolling roll pair to form the glass sheet, and a temperature-controlled environment with a cross temperature gradient to stretch the glass, ensuring a substantially constant thickness, optionally using compensated, edge, or pulling roll pairs to achieve the desired thickness and surface quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If fusion draw or slot draw processes are used to produce thin glass sheets, then glass sheets with thicknesses below 150 μm can be produced, but production costs increase and surface quality deteriorates
Solution Approach 1:
The patent changes the key parameter of glass viscosity by controlling the cooling rate during rolling. By maintaining viscosity between 10,000-50,000 poises through controlled cooling, the glass can be rolled into thin sheets (below 150 μm) with high surface quality while avoiding the high costs and quality issues of fusion draw processes
Solution Approach 2:
The patent replaces the fusion draw mechanical system with a rolling system. Instead of using complex fusion draw equipment that produces high costs and quality issues, the invention uses a simpler rolling mechanism that achieves thin sheet production with better surface quality and lower production costs
2Adaptability or versatility
If fusion draw or slot draw processes are used, then thin glass sheets can be produced, but the glass viscosity must be greater than 50,000 poises which limits glass composition choices
Solution Approach 1:
The patent changes the viscosity parameter range from >50,000 poises (fusion draw requirement) to 10,000-50,000 poises (rolling process optimal range). This is achieved by controlling the cooling rate during rolling, allowing use of a broader range of glass compositions including those with lower inherent viscosities that would be unsuitable for fusion draw processes
3Ease of manufacture
If rolling process is used to form thin glass sheets, then production costs decrease and surface quality improve, but achieving uniform thickness becomes more difficult
Solution Approach 1:
The patent applies local quality by using rolls with specifically designed surface profiles and temperatures. The rolls have varying local properties (temperature distribution, surface texture) to compensate for non-uniform thickness distribution, enabling the rolling process to produce sheets with uniform thickness while maintaining low production costs and high surface quality
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 system effectively produces high-quality thin glass sheets with thicknesses less than 100 μm and surface roughness as low as 0.25 nm Ra, while maintaining high throughput and reducing production costs, and is capable of handling glasses with viscosities below 50,000 poises, achieving uniform thickness and high strain points.
Implementation Method 1
a rolling roll pair having two rolling rolls which receive the molten glass free falling from the delivery system and roll the molten glass to form a glass sheet
Implementation Method 2
drawing and stretching the glass sheet in a temperature controlled environment with a cross temperature gradient where two outer edges of the glass sheet are exposed to a hotter temperature than a central portion of the glass sheet
Implementation Method 3
The temperature controlled environment provides the cross temperature gradient to stretch the glass sheet such that the glass sheet has a substantially constant thickness
Implementation Method 4
a delivery system where molten glass transitions from a guided flow to a free fall flow
Data Source
AI summary
A glass manufacturing system and method are described herein for forming a high quality thin glass sheet. In one embodiment, the glass manufacturing system and method use at least one of a compensated rolling roll, a temperature controlled environment and edge rolls to form a high quality thin glass sheet that has a thickness less than about 2 mm and more preferably less than about 100 μm.