Vacuum glass laser welding is a high-precision technique offering numerous advantages. It ensures strong, crack-free welds with minimal impact on glass transparency, making it ideal for applications requiring optical clarity. The non-contact, localized heating process prevents mechanical damage and material deformation, while fast welding speeds boost production efficiency. Suitable for various environments, including vacuum, it prevents oxidation and contamination. The equipment, including high-power lasers, precision motion platforms, and vacuum systems, supports complex shape welding and automation. This technology is widely used in construction, transportation, and electronics for its ability to create high-quality, durable glass joints.

Characteristics and Equipment of Vacuum Glass Laser Welding Technology

I. Characteristics of Vacuum Glass Laser Welding Process

1. High Precision and Quality
   • High Welding Strength: Laser welding achieves high-precision connections with strong, crack-free welds and high optical transparency. The decrease in light transmittance of the glass after welding is less than 4.4%, which hardly affects the optical properties of the glass.
   • No Mechanical Damage: Laser welding is a non-contact process, which means it won’t cause mechanical damage to the glass. It is suitable for processing near heat-sensitive components.
2. Localized Heating
   • Small Heat-Affected Zone: Laser welding focuses the heat on the spot where the laser beam hits. Parts of the workpiece farther away won’t heat up, making it ideal for welding glass that has heat-sensitive structures on or near it.
   • Reduced Material Deformation: With a small heat-affected zone, there is minimal material deformation, eliminating the need for post-processing.
3. Fast Welding
   • High Production Efficiency: Laser welding is fast and efficient. For example, under optimal parameters, the glass welding speed can reach 30 mm/s.
4. Environmental Adaptability
   • Suitable for Various Environments: Laser welding can be performed in vacuum, air, or specific gas environments, and it is not affected by electromagnetic fields.
   • Advantages of Vacuum Environment: Welding in a vacuum environment can prevent oxidation and contamination, further improving welding quality.
5. Reduced Material Deformation
   • No Post-Weld Processing Needed: Due to the small heat-affected zone, there is minimal material deformation, and no additional processing is required after welding.
6. High Flexibility
   • Complex Shape Welding: Laser welding can handle complex shapes and is suitable for various types of glass products.
   • High Degree of Automation: Laser welding equipment can be equipped with advanced automated control systems to achieve high-precision welding path control.

II. Equipment for Vacuum Glass Laser Welding

1. Vacuum Glass Laser Welding Platform
   • Worktable: Used to fix and support glass workpieces to ensure the stability of the welding process.
   • Conveyor Belts: Upper and lower conveyor belts are used for the loading and unloading of glass, improving production efficiency.
   • Vacuum Pump: Provides a vacuum environment to prevent oxidation and contamination.
   • Rails and Slides: Used to precisely control the position and movement of the laser welding head.
   • Laser Welding Head: Emits the laser beam to achieve glass welding.
   • Unloading Rack and Support Plate: Used for the unloading of glass after welding to ensure that the welded glass does not deform due to gravity.
2. Laser Source
   • Type: Typically uses high-power ultrashort pulse (USP) lasers, such as picosecond or femtosecond lasers.
   • Wavelength: The wavelength is generally in the range of IR to 1um, which is suitable for glass material absorption.
   • Power: The laser power is selected according to welding requirements to ensure welding quality and efficiency.
3. Welding Fixture
   • Custom-Designed Fixture: Adjusts the vacuum suction to tightly contact the glass sheets, ensuring good contact between the glass sheets during the welding process.
   • Adjustability: The fixture can be adjusted according to different sizes and shapes of glass to meet various welding needs.
4. Optical System
   • Focusing Lens: Focuses the laser beam onto the welding spot of the glass to ensure high concentration of laser energy.
   • High Numerical Aperture (NA) Objective Lens: Used to precisely control the focus point of the laser to improve welding accuracy.
5. Motion Platform
   • 2D or 3D Precision Motion Platform: Used to precisely control the position and welding path of the glass to ensure high-precision welding.
   • Automated Control: Equipped with advanced automated control systems to achieve high-precision welding path control.
6. Vacuum System
   • Vacuum Environment: Provides a vacuum environment during the welding process to prevent oxidation and contamination.
   • Vacuum Pump: Maintains the vacuum environment to ensure the stability of the welding process.

III. Detailed Comparison Table of Vacuum Glass Laser Welding Process and Equipment

Detailed Explanations

1. Welding Principle

• Laser Energy Absorption: Laser welding uses a high-energy-density laser beam as the heat source. When the laser energy is absorbed by the glass, the glass material rapidly heats up and melts.
• Surface Tension Effect: Adjacent glass pieces merge together under the influence of surface tension and laser pressure. After cooling, a strong welding joint is formed.
• Advantages of Vacuum Environment: Welding in a vacuum environment can prevent oxidation and contamination, further improving welding quality.

2. Welding Process

• Vacuum Environment Preparation: The welding process is usually carried out in a vacuum environment to reduce gas interference and improve welding quality.
• Laser Beam Focusing: The laser beam is focused onto the welding spot of the glass through the optical system. The welding quality is ensured by precisely controlling the laser power, pulse frequency, and scanning speed.
• Welding Path Control: The position and welding path of the glass are precisely controlled by the motion platform to ensure high-precision welding.

3. Equipment Composition

• Vacuum Glass Laser Welding Platform: Composed of a worktable, upper and lower conveyor belts, vacuum pump, rails, slides, laser welding head, unloading rack, and support plate, it is used to achieve vacuum glass welding.
• Laser Source: Typically uses high-power ultrashort pulse (USP) lasers, such as picosecond or femtosecond lasers, with a wavelength generally in the range of IR to 1um.
• Welding Fixture: Custom-designed fixtures adjust the vacuum suction to tightly contact the glass sheets, ensuring good contact between the glass sheets during the welding process.
• Optical System: Includes focusing lenses and high numerical aperture (NA) objective lenses to focus the laser beam onto the welding spot of the glass.
• Motion Platform: 2D or 3D precision motion platforms are used to precisely control the position and welding path of the glass.
• Vacuum System: Provides a vacuum environment during the welding process to prevent oxidation and contamination.

4. Application Fields

• Construction: Used in the manufacturing of vacuum glass windows and doors to improve their thermal and sound insulation properties.
• Transportation: Used for welding glass components in automobiles, trains, and other means of transportation to ensure the strength and optical properties of the glass.
• Electronics: Used in the manufacturing of electronic tubes, sensor packaging, and other applications to ensure the high precision and quality of glass components.