Vacuum Laser Welding for Deep, Low-Porosity Aerospace Joints
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Solution Overview
Problem
Existing laser beam welding (LBW) processes face challenges in achieving deep welds due to laser beam scattering caused by metal vapor and plasma, leading to porous welds and reduced weld quality, especially when welding aerospace parts.
Innovation Solution
The implementation of a laser beam welding system that operates in a vacuum environment, allowing the optical head and part support to be dynamically positioned relative to each other, maintaining a fixed focal distance, and using a low or medium vacuum to reduce laser beam scattering and enhance weld stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If laser beam welding is performed at atmospheric pressure, then the process is simpler and can be carried out at atmospheric pressure, but laser beam scattering occurs due to metal vapor and plasma causing porous welds and reduced weld quality
Solution Approach 1:
The patent applies vacuum environment (inert atmosphere principle) to eliminate metal vapor and plasma interference. By operating the laser beam welding process under vacuum conditions, the scattering of laser energy is prevented, ensuring deep, clean welds without porosity while maintaining process feasibility through integrated vacuum chamber design
2Length of stationary object
If electron beam welding is used to achieve deep welds, then weld depth is improved, but heavy radiation shielding is required due to X-radiation generation
Solution Approach 1:
The patent replaces electron beam welding with laser beam welding under vacuum. This substitution eliminates X-radiation generation while maintaining the capability to achieve deep welds through keyhole formation, thereby removing the need for heavy radiation shielding and associated safety infrastructure
Solution Approach 2:
By using vacuum environment with laser beam welding, the patent achieves deep weld penetration without generating harmful X-radiation. The vacuum prevents metal vapor scattering and allows sustained keyhole formation at high power densities, delivering EBW-level weld depths without radiation shielding requirements
3Length of stationary object
If high power density laser beam is used to achieve deep welds, then weld depth is improved, but metal vapor and plasma cloud forms causing laser energy scattering
Solution Approach 1:
The patent employs vacuum environment to eliminate metal vapor and plasma formation during high power density laser beam welding. By removing atmospheric gases, the vacuum prevents scattering of laser energy by metal vapor clouds, allowing sustained deep weld penetration with efficient energy utilization and no porosity formation
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 approach improves weld quality by reducing scattering, increasing weld depth, and enhancing the strength and consistency of welds, while also reducing system complexity and cost compared to electron beam welding (EBW).
Implementation Method 1
LBW utilizes a laser beam which provides a concentrated heat source that melts and fuses the parts together
Implementation Method 2
LBW is typically carried out at atmospheric pressure. However, it can be difficult to achieve deep welds using LBW
Implementation Method 3
the energy from the laser beam 102 heats the workpiece and causes a keyhole 104 to form in the workpiece
Implementation Method 4
A molten metal pool 106 can surround the keyhole 104
Data Source
AI summary
Systems and methods for laser beam welding in a vacuum and for controlling laser beam welding processes, such as for use in manufacturing aerospace parts, are described herein. In some embodiments, a laser beam welding system can include an optical head movably positioned within a vacuum chamber. The optical head can be configured to direct a laser beam toward a part positioned within the vacuum chamber to melt and fuse the part.