Curved Glass Laminate Co-Sagging With Viscosity Differential
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Solution Overview
Problem
Conventional co-sagging processes for forming curved glass laminate articles often result in shape mismatch, edge wrinkling, and optical defects, particularly when dealing with glass sheets of different thicknesses and material types.
Innovation Solution
A co-sagging process where the thinner glass sheet is located below the thicker glass sheet, controlling the relative viscosities and thicknesses such that T2/T1 > 2 and V1/V2 > 2, to ensure both sheets sag at a similar rate, thereby reducing shape mismatch and defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If traditional co-sagging processes are used to form curved glass sheets, then the glass sheets can be shaped to the desired curvature, but shape mismatch, edge wrinkling, and bend-dots occur particularly when glass sheets of different thicknesses are used
Solution Approach 1:
The patent applies parameter changes by controlling the viscosity ratio and thickness ratio of the glass sheets. Specifically, it maintains the viscosity ratio V1/V2 between 1.5 and 5.0 and thickness ratio T1/T2 between 0.5 and 2.0, where glass sheet 1 has higher viscosity and greater thickness than glass sheet 2. This parameter control ensures that both sheets sag at similar rates during the co-sagging process, achieving shape consistency while eliminating defects like edge wrinkling and bend-dots
Solution Approach 2:
The patent employs asymmetry by deliberately using glass sheets with different thicknesses and viscosities rather than identical sheets. The asymmetric configuration (T2/T1 > 2 and V1/V2 > 2) is specifically designed to control the sagging behavior of each layer, allowing the thicker, higher-viscosity sheet to restrain the thinner sheet and prevent shape mismatch defects
2Adaptability or versatility
If glass sheets of different thicknesses are used in co-sagging, then design flexibility is improved, but shape mismatch and defects increase
Solution Approach 1:
The patent resolves this contradiction by establishing specific parameter ranges that enable both design flexibility and shape consistency. By controlling the viscosity ratio V1/V2 between 1.5 and 5.0 and thickness ratio T1/T2 between 0.5 and 2.0, the process allows use of glass sheets with different thicknesses (providing design flexibility) while maintaining shape match between layers (ensuring manufacturing precision)
3Ease of manufacture
If the thinner glass sheet is placed on top during co-sagging, then the process is simpler, but shape mismatch and edge wrinkling occur
Solution Approach 1:
The patent applies the inversion principle by reversing the conventional arrangement of glass sheets during co-sagging. Instead of placing the thinner sheet on top (conventional approach), the patent places the thicker, higher-viscosity glass sheet (sheet 1) on top of the thinner, lower-viscosity sheet (sheet 2). This inverted arrangement allows the thicker sheet to restrain the thinner sheet's excessive sagging, preventing shape mismatch and edge wrinkling while maintaining process simplicity
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 achieves improved shape consistency and reduced defects in the curved glass laminate, suitable for automotive applications.
Implementation Method 1
heating the first sheet of glass material and the second sheet of glass material together to a forming temperature above glass transition temperatures of both the first glass composition and the second glass composition
Implementation Method 2
such that central regions of the first and second sheets of glass material deform downward into the open central cavity of the shaping frame
Data Source
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AI summary
A system and process for forming a curved glass laminate article is provided. The process and system utilizes co-sagging of a stack of glass sheets of different thicknesses and different glass materials. During co-sagging the thicker glass layer is placed on top of the thinner glass layer. In this process, shape mismatch is avoided by selecting/controlling the glass materials of the sheets of glass such that the viscosity of the lower, thinner sheet during co-sagging is greater than the viscosity of the thicker glass sheet.