Vacuum Laser Welding for Deep, Low-Porosity Aerospace Joints
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Solution Overview
Problem
Current laser beam welding (LBW) processes face challenges in achieving deep welds due to laser beam scattering caused by metal vapors and plasma, leading to porous welds and reduced weld depth, especially when attempting to weld aerospace parts which require high strength and minimal additional material.
Innovation Solution
Implementing a vacuum-based LBW system where the optical head and part support are dynamically positioned within a vacuum chamber to maintain a predetermined focal distance, reducing laser beam scattering and enhancing weld quality by operating at reduced ambient pressure, which can be as low as a rough vacuum, thus eliminating the need for a hard vacuum.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If laser beam welding is performed at atmospheric pressure to enable concentrated heat source melting and fusion, then ease of operation is improved, but manufacturing precision deteriorates due to laser beam scattering from metal vapors and plasma
Solution Approach 1:
The patent applies vacuum environment (inert atmosphere principle) to eliminate metal vapors and plasma that cause laser beam scattering. By operating in vacuum, the laser beam maintains its concentration and precision throughout the weld depth, resolving the contradiction between ease of operation at atmospheric pressure and manufacturing precision degraded by beam scattering.
2Manufacturing precision
If electron beam welding is used to achieve deep welds with high strength, then manufacturing precision is improved, but device complexity increases due to hard vacuum requirements and radiation shielding
Solution Approach 1:
The patent changes the pressure parameter from hard vacuum (electron beam welding) to rough vacuum (laser beam welding). This parameter change allows using laser technology instead of electron beam technology, achieving deep welds with simpler equipment that doesn't require heavy radiation shielding while maintaining manufacturing precision.
3Manufacturing precision
If laser power is increased to achieve greater weld depth, then manufacturing precision is improved, but loss of energy increases due to secondary scattering effects from metal vapors
Solution Approach 1:
By operating in vacuum environment, the patent eliminates metal vapors that cause secondary scattering. This allows laser energy to penetrate deeper into the workpiece without being scattered by vapors, improving weld depth while reducing energy loss compared to atmospheric pressure welding.
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 reduces weld defects, improves weldability, and increases weld depth and strength by minimizing scattering and maintaining keyhole stability, while also simplifying the system and reducing operational costs compared to conventional electron beam welding systems.
Implementation Method 1
LBW utilizes a laser beam which provides a concentrated heat source that melts and fuses the parts together
Implementation Method 2
a beam of high-velocity electrons is applied to the parts to be joined until the parts melt and flow together as the kinetic energy of the electrons is transformed into heat upon impact
Implementation Method 3
Implementing a vacuum-based LBW system where the optical head and part support are dynamically positioned within a vacuum chamber
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.