Curved Glass Viscosity Control for Shape Accuracy
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Solution Overview
Problem
The challenge lies in achieving a balance between shape accuracy and surface quality in glass shaping, where high shape accuracy in low viscosity ranges leads to poor surface quality, and high surface quality in high viscosity ranges results in cracking due to excessive bending stress.
Innovation Solution
The solution involves creating a difference between bulk and local viscosities by mixing particles into the amorphous portions of glass, maintaining a specific viscosity range and crystallinity, which suppresses cracking during shaping and enhances both shape accuracy and surface quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If glass is shaped in a low viscosity range to increase shape accuracy, then shape accuracy is improved, but surface quality deteriorates
Solution Approach 1:
The patent changes the viscosity parameter by controlling temperature and composition to achieve optimal shaping conditions. Specifically, it maintains bulk viscosity in the range of 10^11.4 to 10^12.7 dPa·s while creating a viscosity difference between bulk and local regions through compositional control, resolving the contradiction between shape accuracy and surface quality
Solution Approach 2:
The patent applies local quality by creating a viscosity difference between bulk glass and local regions. By controlling the viscosity difference log η - log η0 to be between 0.1 and 1.5, the glass exhibits different flow characteristics in different regions, allowing high shape accuracy in the bulk while maintaining surface quality through controlled local viscosity behavior
2Object-generated harmful factors
If glass is shaped in a high viscosity range to enhance surface quality, then surface quality is improved, but cracking occurs due to excessive bending stress
Solution Approach 1:
The patent optimizes the viscosity parameter by controlling it within a specific range (log η = 11.4 to 12.7) and managing the viscosity difference parameter (log η - log η0 = 0.1 to 1.5). This parameter control allows the glass to have sufficient viscosity for surface quality while maintaining enough flexibility to prevent cracking under bending stress
Solution Approach 2:
The patent introduces dynamic control of viscosity through temperature management and compositional design. The glass composition is formulated to provide appropriate viscosity characteristics at shaping temperature, enabling the material to dynamically adapt its flow behavior to prevent cracking while achieving high surface quality
3Strength
If particles are mixed into amorphous portions to create viscosity difference and suppress cracking, then cracking resistance is improved, but glass composition complexity increases
Solution Approach 1:
The patent creates a composite glass structure by mixing particles into the amorphous portions. This composite approach generates the desired viscosity difference (log η - log η0 between 0.1 and 1.5) that suppresses cracking during shaping, while the particle distribution and size are controlled to manage composition complexity
Solution Approach 2:
The patent applies local quality by strategically placing particles within the amorphous portions to create localized viscosity variations. This approach improves cracking resistance through controlled local viscosity differences while avoiding uniform complexity throughout the entire glass composition
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 effectively reduces bending stress and improves shape accuracy and surface quality by maintaining a controlled viscosity difference, allowing for the production of glass with a curved shape that is both precise and crack-resistant.
Implementation Method 1
produce a difference between bulk material viscosity and local viscosity by mixing particles into amorphous portions of glass
Implementation Method 2
softening the glass sheet by heating it to its softening temperature or higher
Implementation Method 3
cause it to deform by its own weight so as to conform to the shape of the molding die
Data Source
AI summary
The present invention relates to a glass in which: the glass is a crystallized glass; the glass has a difference log η−log η0 (dPa·s) between a logarithm log η (dPa·s) of bulk viscosity η (dPa·s) and a logarithm log η0 (dPa·s) of local viscosity η0 (dPa·s) of larger than 0 and 1.8 or smaller, in a temperature range in which the logarithm log η0 (dPa·s) of the bulk viscosity η (dPa·s) is 11.4 or larger and 12.7 or smaller.