Plasma Protection Fixture for Stable Laser Weld Penetration
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Solution Overview
Problem
In laser welding, the metal vapor plume interferes with the laser beam, leading to reduced weld penetration depth and inconsistency due to the disturbance of hot weld plasma by secondary gas systems, which affects the stability of the keyhole and the quality of the weld.
Innovation Solution
A plasma protection fixture is used to surround the weld area, with a height defined based on the laser beam power, to inhibit the flow of gas from disturbing the weld plasma, combined with a secondary gas system directing a laminar flow to blow away the plume, ensuring consistent laser energy and penetration depth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a secondary gas system is used to remove the plume, then the laser beam interference is reduced, but the weld plasma is disturbed leading to reduced weld penetration depth and consistency
Solution Approach 1:
The gas flow path is segmented into two distinct zones: a primary gas flow path for plume removal positioned above the workpiece, and a secondary gas flow path for plasma protection positioned at the weld location. This segmentation allows independent control of plume management and plasma stabilization, resolving the contradiction between removing plume interference and maintaining weld consistency
Solution Approach 2:
Different gas flow characteristics are applied to different locations: a stronger gas flow is directed at the plume above the workpiece to remove interference, while a gentler gas flow is directed at the weld plasma to maintain stability. This local differentiation of gas flow quality enables simultaneous plume removal and plasma protection, addressing the contradiction between harmful plume effects and the need for consistent weld penetration
2Illumination intensity
If the plume is removed to ensure laser beam quality, then laser attenuation is reduced, but the keyhole stability and weld penetration depth are reduced
Solution Approach 1:
A dual-path gas delivery system acts as an intermediary between the plume removal need and the plasma protection need. The system uses separate gas flow paths with different characteristics to mediate between these conflicting requirements, allowing plume removal while maintaining plasma stability and keyhole integrity
Solution Approach 2:
The gas flow rates and directions are dynamically adjusted to match the welding conditions. The system can adapt the primary gas flow for plume removal and the secondary gas flow for plasma protection in real-time, enabling optimal balance between laser beam quality and keyhole stability under varying welding parameters
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 configuration maintains the stability of the keyhole and improves weld penetration depth and consistency by protecting the weld plasma from gas interference, resulting in higher quality welds with reduced spatter and contamination.
Implementation Method 1
a laser welder configured to emit a laser beam at a power to form a weld to join the first workpiece and the second workpiece
Implementation Method 2
a secondary gas system configured to direct a flow of a gas over the surface of at least the first workpiece
Data Source
AI summary
A laser welding system for joining a first workpiece to a second workpiece includes a laser welder configured to emit a laser beam at a power to form a weld to join the first workpiece and the second workpiece at a weld location. The laser welding system includes a plasma protection fixture coupled to a surface of at least the first workpiece. The plasma protection fixture defines an opening configured to receive the laser beam. The opening has a perimeter that surrounds and is spaced apart from the weld. The plasma protection fixture has a height above the surface of at least the first workpiece about the perimeter of the opening that is defined based on the power of the laser beam.