Glass Separation Perforation Using Hot Laser Defects and Cooling
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Solution Overview
Problem
Existing methods for separating glass elements, particularly after hot forming processes, face challenges with misalignment of edge surfaces and high, scattered fracture forces due to temperature-dependent filamentation processes.
Innovation Solution
The method involves introducing filament-shaped defects using an ultrashort pulse laser at elevated temperatures, followed by rapid cooling to create a temperature gradient, reducing the breaking force required for separation by inducing mechanical stress at the defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If glass elements are separated after hot forming processes at elevated temperatures, then the glass can be processed in its formed state, but the filamentation process generates high and scattered fracture forces due to temperature-dependent material properties
Solution Approach 1:
The patent applies preliminary action by introducing filament-shaped defects into the glass element during the hot forming process itself, rather than after cooling. The laser creates these defects while the glass is at elevated temperature, and the defects are then activated during cooling to enable separation. This preliminary defect introduction allows the glass to be separated reliably after forming without requiring high fracture forces during the separation step.
Solution Approach 2:
The patent exploits parameter changes by utilizing the temperature-dependent properties of glass during the hot forming process. The laser parameters (wavelength, pulse duration, power) are optimized for interaction with glass at elevated temperatures to create filament-shaped defects. The subsequent cooling process then activates these defects to enable separation at lower, more controlled fracture forces.
2Productivity
If filamentation is performed at high temperatures to enable inline production, then productivity increases, but the degree of material damage is lower and breaking forces are significantly higher with greater scatter
Solution Approach 1:
The laser introduces filament-shaped defects during the hot forming process itself, performing the fracture preparation action preliminarily while the glass is still hot and formable. This allows inline production without requiring a separate cooling and re-processing step, maintaining high productivity while preparing the glass for later separation at controlled conditions.
Solution Approach 2:
The laser creates localized filament-shaped defects with specific spatial and structural characteristics along the desired separation line. These defects have a particular quality (filament shape with specific dimensions and distribution) that is optimized for activation during subsequent cooling, enabling controlled separation while maintaining overall glass integrity during processing.
3Strength
If the glass is cooled rapidly to activate the filamentation defects, then the breaking force decreases and separation becomes easier, but a temperature gradient must be carefully controlled to induce appropriate mechanical stress
Solution Approach 1:
The patent utilizes the phase transition of glass from a hot, formable state to a cooler, more rigid state. During this cooling phase transition, the previously introduced filament-shaped defects are activated as the glass matrix contracts and develops mechanical stress. The controlled cooling rate manages the temperature gradient to ensure proper defect activation without causing thermal shock or unwanted stress patterns.
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 significantly reduces fracture forces and narrows the statistical distribution of breaking forces, enhancing the reliability and control of glass separation.
Implementation Method 1
a perforation line is inserted into a glass element during or after a hot processing process at an elevated temperature by inserting filament-shaped defects spaced apart along a predetermined course of the perforation line into the glass element with a pulsed laser beam of an ultrashort pulse laser
Implementation Method 2
the laser beam line creates an induced absorption within the material and the induced absorption creates a defect line at a temperature above the annealing or tempering temperature of the glass along the laser beam line within the glass
Implementation Method 3
the glass element is cooled with a cooling fluid in such a way that a temperature gradient is created which induces a mechanical stress at the filament-shaped defects, thereby reducing the breaking force required to separate the glass element along the perforation line
Implementation Method 4
a temperature gradient is created which induces a mechanical stress at the filament-shaped defects
Data Source
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AI summary
The invention is based on the objective of making the separation of glass elements following a hot process easier and more reliable.A method for processing glass elements (1) is provided in which a perforation line (3) for separating the glass element (1) is inserted into a glass element (1) during or after a hot processing process at an elevated temperature of at least 100 °C, by inserting filament-shaped defects (9) spaced apart along the predetermined course of the perforation line (3) with a pulsed laser beam (5) of an ultrashort pulse laser (7), and wherein, during or after the insertion of the filament-shaped defects (9), the glass element (1) is cooled in such a way that a temperature gradient is created which induces a mechanical stress at the filament-shaped defects (9), thereby reducing the breaking force required to separate the glass element (1) along the perforation line (3).