Laser Welding Gas Flow Stabilization for Spatter and Pore Control
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Solution Overview
Problem
Laser welding processes, especially with fiber-guided systems, face issues such as spatter and pore formation due to varying absorption characteristics, leading to reduced weld quality across different welding speeds.
Innovation Solution
Applying a gas flow that mechanically stresses the molten bath by exerting a non-negligible force, with the gas directed either in or against the feed direction, to stabilize the molten pool and reduce material loss, while adjusting the gas flow's dynamic pressure in relation to the feed rate to optimize weld quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a gas flow is applied to displace ambient air and prevent oxidation, then weld protection is improved, but the weld pool becomes unstable leading to spatter and pore formation
Solution Approach 1:
The patent changes the parameters of the gas flow by directing it at a specific angle (10°-45°) relative to the workpiece surface and positioning it at an optimized distance (0.5-5 mm) from the laser focus. This parameter optimization allows the gas flow to simultaneously protect the weld pool from oxidation while stabilizing the molten bath and reducing spatter and pore formation.
Solution Approach 2:
The gas flow acts as an intermediary between the laser beam and the ambient environment. By introducing this intermediate gas stream at optimized parameters, it mediates the interaction between the laser welding process and atmospheric oxygen, providing protection while simultaneously stabilizing the molten pool through controlled hydrodynamic effects.
2Stability of the object's composition
If the gas flow is directed at a steep angle to mechanically stress the molten bath, then weld pool stability is improved, but oxidation protection may be compromised
Solution Approach 1:
The patent optimizes the gas flow angle parameter within the range of 10°-45° relative to the workpiece surface. This specific angular range creates the right balance: steep enough to mechanically stress and stabilize the molten pool, but not so steep that the gas flow fails to effectively displace ambient air and prevent oxidation.
Solution Approach 2:
The gas flow direction and positioning are dynamically optimized based on the welding conditions. The angle and distance parameters allow the system to adapt the gas flow's mechanical stress effect while maintaining adequate oxidation protection throughout the welding process.
3Object-affected harmful factors
If conventional gas flow parameters are used to minimize weld pool influence, then oxidation protection is maintained, but spatter and pore formation increase
Solution Approach 1:
The patent departs from conventional gas flow parameters by implementing a steeper angle (10°-45°) and optimized distance (0.5-5 mm) from the workpiece surface. These parameter changes transform the gas flow from a passive protective shield into an active stabilizing force that reduces spatter and pore formation while maintaining oxidation protection.
Solution Approach 2:
Instead of minimizing gas flow influence on the weld pool as in conventional approaches, the patent inverts the approach by intentionally applying significant mechanical stress through the gas flow. This inversion of the conventional principle leads to reduced material loss through decreased spatter and pore 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 significantly improves weld seam quality by reducing spatter and pore formation, maintaining stability across a range of welding speeds, and minimizing material loss, contrary to conventional methods where the weld pool is minimally influenced by the gas flow.
Implementation Method 1
a laser beam directed onto a workpiece surface having such a radiation intensity that the workpiece material of the at least one workpiece to be welded is melted in the area of a laser focus
Implementation Method 2
Due to the different absorption characteristics depending on the wavelength
Implementation Method 3
the molten bath is mechanically stressed for stabilization during the welding process by being subjected to a gas flow directed onto the workpiece surface
Data Source
Figure 1~2
Figure 3
AI summary
The invention relates to a method for laser welding workpieces (W), a laser beam (L) directed onto a workpiece surface having such a radiation intensity that the workpiece material of the at least one workpiece (W) to be welded is melted in the region of the laser focus (F), a vapor capillary (D) which is at least partly surrounded by a molten bath (S) forming in the region of the laser focus (F). The laser beam (L) is moved relative to the workpiece surface in a direction of advance (V) in order to produce a weld seam. According to the invention, the molten bath (S) is subjected to mechanical stress by directing a gas stream (G) onto the workpiece surface for the purpose of stabilization during welding. The invention further relates to a device (1) designed for carrying out said method.