Thin Glass Cutting with Oblique Gas Jet and Gap Control
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Solution Overview
Problem
The existing laser fusing methods for cutting thin glass sheets with thicknesses of 500 µm or less face issues such as defective shaping of cut end surfaces, breakage due to improper gap management between fused end surfaces, and the challenge of effectively removing molten glass portions, leading to operational inefficiencies and product quality deterioration.
Innovation Solution
A cutting method involving the precise management of the gap between fused end surfaces using a laser beam with a defocused state and assist gases, where the assist gas is jetted obliquely to prevent the cutting portion from hanging and efficiently remove molten glass, ensuring a convex curved surface and reducing the risk of adhesion, thereby enhancing the quality and operability of the cutting process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a laser beam is used to fuse and cut glass sheets, then cutting capability is improved, but cracks are liable to be formed in cut surfaces leading to glass sheet breakage
Solution Approach 1:
The patent introduces a multi-stage gas jet system as an intermediary between the laser beam and glass sheet. The pre-heating gas jet (oblique direction) and main cutting gas jet (vertical direction) work together to control the thermal process and molten glass removal, preventing direct thermal stress concentration that causes cracks while maintaining cutting effectiveness.
Solution Approach 2:
The patent changes the physical parameters of the cutting process by controlling gas jet directions, temperatures, and flow rates. The pre-heating gas jet raises the glass temperature before laser irradiation, reducing thermal shock. The main cutting gas jet removes molten glass at controlled rates, preventing crack formation while maintaining cutting capability.
2Productivity
If a center assist gas is jetted vertically downward to blow off melts, then cutting efficiency is improved, but dross adheres to the glass sheet deteriorating product quality
Solution Approach 1:
The patent segments the gas jet function into two independent systems: a pre-heating gas jet for efficient melting and a main cutting gas jet for controlled dross removal. This segmentation allows each gas jet to be optimized for its specific function, maintaining cutting efficiency while preventing dross adhesion.
Solution Approach 2:
The patent introduces an oblique dimension to the gas jet direction. The pre-heating gas jet is jetted obliquely downward at a specific angle, creating a three-dimensional gas flow pattern that efficiently removes molten glass while directing dross away from the glass sheet surface, thereby improving product quality.
3Manufacturing precision
If the laser beam is focused to a micro spot for precise cutting, then cutting precision is improved, but the cutting portion hangs causing defective shaping
Solution Approach 1:
The patent applies preliminary action by jetting a pre-heating gas obliquely onto the glass sheet before laser irradiation. This pre-heating softens the glass surface and reduces its melting point, allowing the focused laser beam to cut precisely without causing the molten glass to hang or deform.
4Reliability
If thin flat glass is cut by fusing, then a gap must be secured between fused end surfaces to prevent breakage, but excessive gap creates shape defects and requires more material removal
Solution Approach 1:
The patent changes the physical state parameters of the glass by pre-heating it with an oblique gas jet before laser cutting. This controlled heating allows the glass to be softened to an optimal viscosity range, enabling precise gap control (0.1-2.0 times glass thickness) that prevents breakage while minimizing material removal and maintaining shape integrity.
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
This method effectively maintains the shape of fused end surfaces, prevents breakage, and improves the operational efficiency and quality of cut surfaces by ensuring a satisfactory gap between fused ends and efficient removal of molten glass, resulting in higher product yields and reduced defects.
Implementation Method 1
laser fusing for cutting a cutting portion of the glass sheet by melting the cutting portion by using irradiation heat generated by radiating a laser beam
Implementation Method 2
melting the cutting portion by using irradiation heat generated by radiating a laser beam
Implementation Method 3
a center assist gas jetted together with the laser beam substantially vertically downward from just above the cutting portion
Data Source
Figure 1~2
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AI summary
Provided is a cutting method for a glass sheet, comprising radiating a laser beam to a cutting portion (C) of a glass sheet (G) having a thickness of 500 µm or less to fuse the glass sheet (G), wherein a narrowest gap between fused end surfaces (Ga1 and Gb1) of the glass sheet (G), which face each other in the cutting portion (C), is managed to satisfy a relationship of 0.1≤b/a≤2, where "a" is a thickness of the glass sheet (G) and "b" is the narrowest gap.