Rolling Thin Glass Ribbon with Friction Interlayer
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Solution Overview
Problem
Thin glass ribbons, particularly those 0.3 mm or thinner, pose challenges in rolling due to differential thickness and camber, leading to angled side walls and potential damage during handling and unwinding, as they are sensitive to surface defects and require careful handling to avoid stress points that cause cracks.
Innovation Solution
The use of an interleaf material with a sufficient static coefficient of friction, compliance, and specific width, along with reduced web tension and pressure between layers, helps counteract differential thickness and camber effects, ensuring straight side walls and maintaining roll integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If thin glass ribbon is rolled with conventional methods, then handling is facilitated, but differential thickness and camber cause angled side walls and potential damage
Solution Approach 1:
A Teflon® interleaf is introduced between layers of glass ribbon during rolling. This intermediary material provides a non-stick surface that prevents direct glass-to-glass contact, reducing stress points and allowing the glass to be rolled without damage while maintaining straight side walls through controlled friction and compliance
Solution Approach 2:
The rolling parameters are modified by using low web tension and low pressure between layers. This parameter change prevents excessive force from acting on the differential thickness and camber, allowing the glass ribbon to be rolled without developing angled side walls or causing surface defects
2Volume of moving object
If glass thickness is decreased to meet product trends, then thinner glass is achieved, but flexibility increases and handling becomes more difficult
Solution Approach 1:
The Teflon® interleaf serves as a mediator between thin glass ribbon layers, enabling safe handling and rolling of extremely thin glass (0.3 mm or less) by preventing direct contact that would cause stress points and breakage
Solution Approach 2:
The use of a thin, compliant Teflon® film as interleaf allows the system to accommodate the increased flexibility of thin glass while maintaining structural integrity during rolling and handling operations
3Device complexity
If direct surface to surface contact of glass is used in spooled roll, then rolling is simplified, but surface defects create stress points leading to breakage
Solution Approach 1:
The Teflon® interleaf is placed between glass ribbon layers to eliminate direct surface-to-surface contact. This intermediary prevents stress concentration at contact points, thereby preventing crack initiation and maintaining glass integrity throughout the rolling process
Solution Approach 2:
The interleaf material provides beforehand cushioning between glass layers, absorbing and distributing any contact forces before they can create stress points on the glass surface that would lead to breakage
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 allows for the successful rolling of thin glass ribbons with straight side walls, reducing the risk of damage and facilitating handling and unwinding by providing adequate resistance to lateral forces and thickness variations.
Implementation Method 1
choosing an interleaf material with a sufficient coefficient of friction between it and the glass ribbon being wound assists in providing a force to resist that produced by the differential thickness and/or camber
Implementation Method 2
the interlayer should be thickness compliant, or have some give to it when compressed, in order to absorb any thickness differences that may be present in the central portion of the glass ribbon
Data Source
AI summary
A roll (10) of glass ribbon (20), having a thickness of 0.3 mm or less, wherein a thickness compliant material interlayer (40) is wound together with the glass ribbon. The characteristics of the interlayer are chosen to form the roll with minimal lateral offset (9). For example, the static coefficient of friction between the interlayer and the glass ribbon may be greater than or equal to 3.0 (as measured with a vertical force of 0.5 N). Other characteristics may include the width, thickness, and compliance, of the interlayer. There is also disclosed a method of rolling a glass ribbon wherein the roll winding parameters, for example web tension and pressure between the layers of the roll, are chosen to minimize the lateral offset.