Laser Surface Heating for Precise Separation of Brittle Materials
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Solution Overview
Problem
Existing methods for processing brittle-hard materials like glass and glass ceramics are inefficient and difficult due to their non-ductile nature, requiring slow ablation or aggressive etching, and often result in quick breakage during machining.
Innovation Solution
A method using a laser beam with a selected wavelength to create temperature gradients on the surface of the workpiece, inducing thermomechanical stresses that allow for precise separation of the material without pre-damage, similar to thermal shock machining.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If ablation is used to create oblique grooves in glass, then material can be removed, but the process is very slow when greater cutting depths are required
Solution Approach 1:
The patent changes the fundamental processing parameter from ablation (slow, sequential material removal) to thermal shock (rapid, controlled fracture). By using a laser beam with wavelength selected for surface absorption and guiding it to create specific temperature gradients, the process achieves fast cutting speeds while maintaining precision through controlled thermomechanical stress that causes clean separation at the desired depth.
Solution Approach 2:
The patent replaces the mechanical ablation process with a thermal field-based approach. Instead of mechanically removing material layer by layer through ablation, the system uses laser-induced temperature gradients to generate thermomechanical stresses that cause controlled fracture and chip removal, dramatically increasing cutting speed while maintaining precision.
2Productivity
If aggressive etching media are used to separate glass, then material can be removed, but the process is slow and requires masking for spatial resolution
Solution Approach 1:
The patent replaces chemical etching with a thermal field approach. By using a laser beam with specific wavelength selection for surface absorption and guiding it to create controlled temperature gradients, the system achieves rapid material separation through thermomechanical stress without requiring aggressive chemicals or complex masking setups. The laser directly defines the separation path through its guided movement.
Solution Approach 2:
The patent introduces temperature gradient as an intermediary mechanism between the laser energy and the glass material. The laser beam creates a temperature gradient that interacts with the material's thermal properties to generate controlled thermomechanical stresses, enabling precise and rapid separation without direct chemical contact or complex masking systems.
3Manufacturing precision
If pre-damage is introduced along the laser beam path, then separation can be achieved, but an additional first step is required making it a two-step process
Solution Approach 1:
The patent extracts the pre-damage step from the processing sequence by using a laser wavelength and guidance system that creates sufficient temperature gradients directly during the separation process. The laser beam with selected wavelength for surface absorption generates the necessary thermomechanical stresses in a single step, eliminating the need for separate pre-damage introduction and achieving both precision and efficiency.
Solution Approach 2:
The patent changes the laser processing parameters, specifically selecting a wavelength that is absorbed at the glass surface and controlling the laser guidance to create appropriate temperature gradients. This parameter optimization enables direct separation without pre-damage, combining the precision of controlled stress with the efficiency of a single-step process.
4Productivity
If brittle materials are machined with mechanical tools, then material can be removed, but the workpiece fractures very quickly due to non-ductile nature
Solution Approach 1:
The patent replaces mechanical tool-based machining with a laser-induced thermal field approach. By selecting a wavelength absorbed at the surface and guiding the laser to create controlled temperature gradients, the system generates thermomechanical stresses that cause clean chip separation without the mechanical contact that triggers unpredictable fracture in brittle materials. This maintains workpiece integrity while enabling efficient material removal.
Solution Approach 2:
The patent changes from mechanical stress application to thermal stress application. By controlling laser parameters (wavelength for surface absorption, guidance path, and power distribution), the system creates controlled temperature gradients that generate predictable thermomechanical stresses, enabling reliable chip removal without the random fracture behavior associated with mechanical machining of brittle materials.
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, accurate, and efficient separation of brittle-hard materials, including those with low thermal expansion coefficients, such as thermally toughened glass, without cracking or requiring additional pre-damage steps, facilitating complex shapes and edge processing.
Implementation Method 1
the wavelength of the laser beam is selected 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 formed in the direction from the surface into the interior of the workpiece
Implementation Method 3
a further temperature gradient is created along the surface between an irradiated area and an adjacent unirradiated area
Implementation Method 4
the two temperature gradients interact in such a way that, due to the thermomechanical stresses caused by the temperature gradients
Implementation Method 5
Rapid, shock-like surface heating generates near-surface stresses that cause a chip, or more generally a portion of the workpiece, to break off
Data Source
Figure 1~2
Figure 3~5
Figure 6
AI summary
A method for the separating processing of brittle materials, in which the surface of a workpiece (1) made of brittle material is irradiated with a laser beam (3), wherein the wavelength of the laser beam (3) is selected such that the light is absorbed at the surface (5) of the workpiece (1), so that the workpiece (1) is heated at the surface (5) and a temperature gradient is formed in the direction from the surface (5) into the interior of the workpiece (1), wherein the laser beam (3) is guided over the surface (5) of the workpiece (1), and wherein a further temperature gradient is created along the surface (5) between an irradiated area (7) and an adjacent unirradiated area (9), wherein the two temperature gradients interact in such a way that, due to the thermomechanical stresses caused by the temperature gradients, the workpiece separates below the surface (5) and a part (11) of the workpiece (1)especially in the form of a chip, which is separated off.