Curved Bulletproof Glazing Bending Process
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Solution Overview
Problem
The production of curved bulletproof glazing with multiple brittle materials is hindered by the conflict between achieving high surface quality and accurate fit, leading to a narrow process window, especially when dealing with different viscosity materials like glass and glass ceramics, resulting in thicker lamination films and increased overall thickness.
Innovation Solution
A novel approach involving higher bending viscosities for relatively higher viscosity glasses, combined with long holding times and temperature gradients, allows for bending stacks with good surface quality and thin lamination films, using sacrificial plates and sequential bending to manage viscosity differences and achieve complex geometries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional bending processes are used with lower viscosity materials, then easier manufacturing is achieved, but surface quality deteriorates and pane fit accuracy is poor
Solution Approach 1:
The patent changes the viscosity parameter of the glass material by selecting specific glass compositions (such as borosilicate glasses) that maintain higher viscosity at bending temperatures. This parameter change allows the glass to retain sufficient structural integrity during bending while still enabling formability, thereby achieving both ease of manufacture and high manufacturing precision simultaneously
Solution Approach 2:
The patent applies preliminary actions by carefully controlling the heating process to reach optimal bending temperatures before forming, and by using separating agents in advance to prevent unwanted adhesion between panes. These preliminary preparations ensure that when bending occurs, the glass maintains the right viscosity characteristics for both ease of forming and precision surface quality
2Manufacturing precision
If thicker lamination films are used to compensate for poor surface quality, then manufacturing tolerance is increased, but overall composite thickness increases
Solution Approach 1:
By changing the material parameter (viscosity) to higher values, the patent achieves better surface quality and pane fit accuracy inherently, which eliminates the need to compensate with thicker lamination films. This directly prevents increase in overall composite thickness while maintaining manufacturing precision
Solution Approach 2:
The patent uses thin lamination films (less than 2.54mm, preferably less than 1.27mm) as intermediaries that can effectively bond high-quality, precisely-fitted panes together. These thin films serve as adequate mediators when surface quality is high, preventing the need for thicker compensatory films
3Reliability
If multiple brittle materials with different viscosities are used to achieve high bullet resistance, then bulletproof performance is improved, but manufacturing complexity increases due to narrow process window
Solution Approach 1:
The patent applies local quality by assigning different glass types with specific viscosity characteristics to different positions or functions within the composite structure. Each material layer is optimized for its local requirement, allowing the use of multiple brittle materials for high bullet resistance while managing viscosity differences through localized material selection
Solution Approach 2:
The patent manages the narrow process window by carefully selecting glass compositions whose viscosity-temperature characteristics are compatible with each other. By changing and optimizing the viscosity parameters of different glass types to be sufficiently close, the patent enables joint bending of multiple brittle materials without excessive manufacturing complexity
4Reliability
If higher bullet resistance is achieved through increased material thickness, then protection level is improved, but interior volume loss increases
Solution Approach 1:
The patent uses composite materials consisting of multiple thin glass and glass ceramic panes laminated together to achieve high bullet resistance (Stanag Level 2 and above). This composite structure provides the required protection level while keeping the total thickness under 65mm, thereby minimizing interior volume loss compared to using single thick panes
Solution Approach 2:
The patent changes the thickness parameter of individual panes to optimized values (typically 3-10mm each) and uses multiple layers to achieve the required bullet resistance. This parameter optimization allows high protection levels with reduced overall thickness, preserving vehicle interior volume
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 method enables the production of curved bulletproof composites with high surface quality and low weight per unit area, achieving Stanag Level 2 protection with total thicknesses under 60mm and thin lamination films, while maintaining optical clarity and structural integrity.
Implementation Method 1
heating to a temperature at which the panes move together under their own gravity bend into the bending shape. The bending temperature is usually around 625°C for soda-lime glass, which corresponds to a viscosity of around 10^10.25
Implementation Method 2
heating to a temperature at which the panes move together under their own gravity bend into the bending shape
Implementation Method 3
heating to a temperature at which the panes move together under their own gravity bend into the bending shape
Implementation Method 4
laminated together using foil or synthetic resins
Data Source
Figure 1a~1c
Figure 2a~2d
Figure 2e~2g
AI summary
Laminated, transparent pane set made of brittle materials and laminating films, wherein the brittle materials are various glasses, special glasses, glass ceramics, transparent ceramics and crystalline materials, methods for manufacturing and bending these pane sets and their use as bulletproof, shatterproof and impact-resistant glazing with low weight per unit area.