Laser Chamfering of Glass Plate Edges Without Annealing Cracks
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for chamfering the edge surfaces of annular glass blanks for magnetic disks using laser beams often result in cracking and reduced production efficiency due to residual stress and delayed fractures.
Innovation Solution
Preheat the glass blank to a specific temperature (Tp) before chamfering, ensuring the temperature difference (Tg−Tp) meets certain criteria based on the glass's transition point (Tg) and thermal expansion coefficient (α), thereby preventing immediate and delayed cracks without the need for annealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the edge of the sheet is preheated to high temperatures and further heated with a laser beam for finishing, then the edge surface can be shaped and residual stress is suppressed, but the glass plate cracks after heating through irradiation with a laser beam and before annealing
Solution Approach 1:
The glass blank is preheated to a specific temperature range (Tg-Tp) ≤ -5.67×10^7·α+840 before laser beam irradiation. This preliminary heating action prepares the glass in an optimal state for subsequent laser processing, preventing thermal shock and crack formation during the high-temperature laser heating phase while enabling proper edge shaping.
Solution Approach 2:
The invention controls the preheating temperature parameter Tp relative to the glass transition point Tg and thermal expansion coefficient α by satisfying the relationship (Tg-Tp) ≤ -5.67×10^7·α+840. This parameter control ensures the glass is in an appropriate thermal state for laser processing without causing cracks, resolving the contradiction between achieving proper edge shaping and preventing crack occurrence.
2Reliability
If annealing is performed after laser beam heating for edge finishing, then residual stress is reduced and crack occurrence is suppressed, but production efficiency decreases
Solution Approach 1:
The glass blank is preheated to a specific temperature range (Tg-Tp) ≤ -5.67×10^7·α+840 before laser beam irradiation. This preliminary heating action prepares the glass in an optimal state for subsequent laser processing, preventing thermal shock and crack formation during the high-temperature laser heating phase while enabling proper edge shaping.
Solution Approach 2:
The invention controls the preheating temperature parameter Tp relative to the glass transition point Tg and thermal expansion coefficient α by satisfying the relationship (Tg-Tp) ≤ -5.67×10^7·α+840. This parameter control ensures the glass is in an appropriate thermal state for laser processing without causing cracks, resolving the contradiction between achieving proper edge shaping and preventing crack occurrence.
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 effectively prevents cracking and delayed fractures, allowing for stable chamfered edges on glass plates, enhancing production efficiency and reducing residual stress.
Implementation Method 1
a step of forming a chamfered surface by irradiating, with a laser beam, the edge surface of a glass blank before being subjected to the chamfering processing
Implementation Method 2
a step of heating the glass blank before irradiation with the laser beam
Data Source
AI summary
In a method for manufacturing a glass plate that includes chamfering processing for chamfering an edge surface of a glass plate, the chamfering processing includes a step of forming a chamfered surface by irradiating the edge surface of the glass plate with a laser beam, and a step of heating the glass plate before the chamfered surface is formed. When a temperature of the glass blank at which the glass blank is heated is Tp [° C.], a glass transition point of the glass blank is Tg [° C.], and an average coefficient of linear thermal expansion of the glass blank is α [1/° C.], (Tg−Tp)≤−5.67×107·α+840 is satisfied.