Laser Surface Tempering of Glass for Higher Fracture Stress
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Solution Overview
Problem
Conventional glass tempering methods face limitations in enhancing mechanical properties and reducing defects, particularly due to issues with mechanical stresses and uniformity in thermal treatment processes.
Innovation Solution
A method involving laser treatment of vitreous materials at specific temperature ranges, with a CO2 laser emitting a focused beam that scans the surface in a back-and-forth motion, creating a molten layer that improves mechanical strength and reduces defects, while maintaining a robust finish against mechanical aggression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional thermal tempering is used to improve mechanical strength, then fracture stress increases, but manufacturing complexity and energy consumption increase due to high-temperature furnaces and forced cooling systems
Solution Approach 1:
The patent replaces the conventional mechanical thermal tempering system (furnace with forced cooling) with a laser-based system. The laser beam directly induces compressive stresses on the glass surface through localized heating and rapid cooling, eliminating the need for complex thermal tempering equipment while achieving comparable or superior strength enhancement.
Solution Approach 2:
The laser treatment applies thermal energy locally to specific regions of the glass surface rather than heating the entire piece uniformly. This localized heating creates compressive stresses precisely where needed, improving manufacturing efficiency and reducing overall process complexity compared to global thermal tempering.
2Strength
If conventional thermal tempering is used to improve mechanical strength, then fracture stress increases, but energy consumption increases due to high-temperature heating and forced cooling
Solution Approach 1:
The laser system consumes significantly less energy than conventional thermal tempering furnaces. The laser beam delivers concentrated energy only to the surface layer being treated, avoiding the massive energy input required to heat entire glass pieces to high temperatures and then rapidly cool them with forced air systems.
Solution Approach 2:
By concentrating energy delivery to only the necessary surface region, the laser process avoids the wasteful global heating of entire glass pieces. This localized energy application dramatically reduces overall energy consumption while achieving the same strengthening effect.
3Manufacturing precision
If laser treatment is used to reduce surface defects and improve strength, then manufacturing precision improves, but device complexity increases due to laser scanning systems
Solution Approach 1:
The patent replaces complex mechanical scanning systems with a stationary laser source and moving glass substrate. The glass piece is conveyed through the laser beam path, eliminating the need for precision laser positioning mechanisms while maintaining treatment accuracy. This approach achieves comparable manufacturing precision with reduced device complexity.
4Strength
If conventional thermal tempering is used to improve mechanical strength, then fracture stress increases, but production speed decreases due to prolonged heating and cooling cycles
Solution Approach 1:
The laser treatment process dramatically reduces production time compared to conventional thermal tempering. The laser can treat glass surfaces continuously at high speed, eliminating the prolonged heating and forced cooling cycles required by traditional furnaces, thereby significantly increasing production throughput.
Solution Approach 2:
The laser system enables continuous treatment of glass surfaces as they are conveyed through the processing area, rather than requiring batch-by-batch heating and cooling cycles. This continuous operation mode maintains high production speed while consistently applying the strengthening treatment.
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
The method significantly enhances the mechanical properties of glass, such as fracture stress values, and reduces defects, allowing for improved cutting performance and controlled stress distribution without fracturing, while maintaining a natural appearance.
Implementation Method 1
the material is irradiated with a laser which can emit in the mid-IR range of the electromagnetic spectrum... This process can generate a thin layer of molten material on the irradiated surface of the glass
Implementation Method 2
This process can generate a thin layer of molten material on the irradiated surface of the glass
Implementation Method 3
the material is irradiated with a laser which can emit in the mid-IR range of the electromagnetic spectrum
Data Source
AI summary
Vitreous material treatment uses a piece of vitreous material having two opposite faces and a laser emission beam source. The vitreous material is heated, and a laser beam radiated on one of the faces of the vitreous material to scan following a line surpassing the opposite edges of the face of the vitreous material while the vitreous material oscillates along a path. The scan is performed while the vitreous material is heated. The vitreous material is cooled. The laser beam scan follows a line surpassing the opposite edges of the face. The scan performed oscillating between a first point and a second point.