Laser Chip Separation of Brittle-Hard Materials by Thermal Gradients
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Solution Overview
Problem
Existing methods for processing brittle-hard materials like glass and glass ceramics are slow, require aggressive chemicals, and lack spatial resolution, making them inefficient and difficult to implement.
Innovation Solution
A method using a laser beam with a chosen wavelength to create temperature gradients that induce thermomechanical stresses, allowing the material to separate and form chips or chamfers without preliminary damage, utilizing CO2 or CO lasers for efficient heating and separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional mechanical tools are used to cut brittle-hard materials, then material separation can be achieved, but the processing speed is slow and the workpiece breaks rapidly due to brittle nature
Solution Approach 1:
The patent replaces mechanical cutting tools with a laser beam that induces thermomechanical stresses through rapid heating and cooling cycles. This substitution eliminates direct mechanical contact that causes brittle materials to break rapidly, while achieving faster processing speeds through controlled thermal shock that separates material in chip form.
Solution Approach 2:
The patent changes the physical state and temperature parameters of the brittle-hard material by applying cyclic thermal loading. The laser beam rapidly heats and cools the material surface, creating temperature gradients that induce thermomechanical stresses, transforming the material's mechanical response from brittle fracture to controlled chip separation.
2Manufacturing precision
If ablation is used to create oblique gutters in glass, then chamfering can be achieved, but the process is very slow for greater cutting depths
Solution Approach 1:
The patent employs periodic action by applying cyclic thermal loading through the laser beam. The rapid heating and cooling cycles create repeated thermomechanical stress cycles that progressively separate material in chip form, achieving both precise chamfering and faster processing compared to continuous ablation methods.
Solution Approach 2:
The patent utilizes phase transitions through rapid thermal cycling. The laser beam induces quick heating that temporarily changes the material's thermal state, followed by rapid cooling, creating phase transitions that generate thermomechanical stresses for efficient material separation while maintaining precision.
3Manufacturing precision
If etching media are used for glass etching, then surface modification can be achieved, but aggressive chemicals are required and the process is slow without spatial resolution
Solution Approach 1:
The patent replaces chemical etching media with a laser-based thermomechanical process. This substitution eliminates the need for aggressive chemicals while achieving superior spatial resolution through the laser's focused energy delivery and rapid processing speed through controlled thermal shock.
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 rapid, precise, and efficient processing of brittle-hard materials, including low-expansion glasses and thermally prestressed glasses, by forming chips or chamfers with high precision and speed, suitable for various surface treatments.
Implementation Method 1
the wavelength of the laser beam is chosen such that the light is absorbed at the surface of the workpiece, so that the workpiece is heated at the surface
Implementation Method 2
a temperature gradient is created in the direction from the surface to the interior of the workpiece
Implementation Method 3
a further temperature gradient is formed along the surface between an irradiated region and an adjacent non-irradiated region
Implementation Method 4
due to the thermomechanical stresses caused by the temperature gradients
Implementation Method 5
The rapid, shock-like surface heating produces near-surface stresses that lead to the splitting off of a chip
Implementation Method 6
the workpiece separates below the surface and a portion of the workpiece is severed, in particular in the form of a chip
Data Source
AI summary
A method for the separative processing of brittle-hard materials is provided. The method includes irradiating a surface of a workpiece made of brittle-hard material with a laser beam having a wavelength sufficient so that light of the laser beam is absorbed at the surface and so that the workpiece is heated to create a first temperature gradient in a direction from the surface to an interior of the workpiece; guiding the laser beam over the surface along an irradiated region; forming a second temperature gradient along the surface between the irradiated region and a non-irradiated region adjacent the irradiated region, the first and second temperature gradients interacting in such a way that, on account of thermomechanical stresses, the workpiece is separated below the surface with a portion of the workpiece being severed in the form of a chip.