Glass Separation Crack Path Control for Smooth Strong Edges
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Solution Overview
Problem
Existing glass separation methods fail to control the course of cracks accurately, leading to rough separation faces and edges with low strength, making them susceptible to damage and crack propagation.
Innovation Solution
A method involving the formation of tensile and compressive stress zones within the glass material using a line focus to control the crack path, allowing for precise separation without material removal and contamination, and enhancing edge strength and surface smoothness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional separation methods (thermal laser beam separation, mechanical scribing, laser scribing) are used, then separation can be achieved, but the course of cracks cannot be controlled accurately leading to rough separation faces and low edge strength
Solution Approach 1:
The patent applies preliminary action by creating a scratch line on the surface of the glass element before the actual separation process. This scratch line serves as a predefined guide that controls the subsequent crack propagation path. By preparing this initial surface modification beforehand, the method ensures that the crack will follow the desired separation face trajectory, thereby achieving both precise separation face control and high edge strength without uncontrolled crack deviation
Solution Approach 2:
The scratch line acts as an intermediary element between the separation force and the glass material. Instead of applying separation force directly to the glass, the scratch line mediates the process by providing a predetermined path that guides crack propagation. This intermediary structure ensures that the crack follows the intended separation face while maintaining control over the separation process, resolving the contradiction between precision and strength
2Productivity
If laser filamentation method with perforation holes is used, then separation can be achieved, but the roughness value of the separation face increases and tear line can deviate from the desired course
Solution Approach 1:
The patent applies the taking out principle by removing the problematic perforation holes from the process while retaining the beneficial crack propagation control. Instead of creating multiple perforation holes that cause roughness and deviation, the method extracts only the essential function of guiding the crack through a surface scratch line. This eliminates the harmful effects of perforations (roughness, deviation) while maintaining separation efficiency through controlled crack propagation along the scratch line
3Manufacturing precision
If ablation methods are used to remove glass material iteratively, then separation can be achieved, but the process takes a long time and causes large damage zones
Solution Approach 1:
The patent applies mechanics substitution by replacing the iterative ablation process (which removes material step by step) with a crack propagation mechanism. Instead of repeatedly applying energy to remove small amounts of material, the method uses a scratch line to initiate and guide a single crack propagation event that achieves separation in one go. This substitution dramatically reduces processing time while maintaining separation face quality by controlling the crack path through the predefined scratch line rather than relying on multiple ablation passes
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
Enables precise control over the separation face, reducing roughness and increasing edge strength, thus improving the reliability and efficiency of glass separation while maintaining the glass material's integrity.
Implementation Method 1
controlling at least one line focus within the glass body in such a way that at least one tensile stress zone and/or at least two compressive stress zones are formed in the glass material along the separation face
Implementation Method 2
introducing an initial damage to form at least one crack respectively in the glass material in the tensile stress zone and/or between the two compressive stress zones
Data Source
AI summary
The present disclosure relates to a method for at least section-wise separating a glass element into at least two glass sub-elements along a separation face and a glass sub-element which is manufactured and/or can be manufactured in particular by the method according to the disclosure.