Eccentric Laser Welding for Uniform Weld Depth in Rotating Workpieces
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Solution Overview
Problem
Laser welding of metal workpieces often results in fluctuating weld depth and strength along the weld seam due to the unstable end of the vapor capillary formed during the process.
Innovation Solution
The laser beam is directed eccentrically offset from the axial center of the workpieces, causing the intermediate section of the vapor capillary to determine the weld seam root, rather than the unstable end, resulting in a more stable and constant weld depth and strength. This is achieved by rotating the workpieces around their axis while maintaining a stationary laser source, ensuring the laser beam penetrates deeply into the material and avoids contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the laser beam is directed radially onto the workpiece surface during conventional laser welding, then the welding process can be performed with a simple setup, but the weld depth fluctuates and the weld strength varies along the weld seam due to the unstable vapor capillary end
Solution Approach 1:
The laser beam is directed onto the workpiece surface at an eccentric position rather than at the center, creating an asymmetric configuration. This asymmetric laser beam positioning relative to the rotating workpiece allows the stable intermediate section of the vapor capillary to determine the weld root, eliminating the instability caused by the fluctuating capillary end and achieving uniform weld depth along the entire weld seam.
2Strength
If the laser beam penetrates deeply into the workpiece material to achieve sufficient welding depth, then the weld strength increases, but process pores are more likely to form within the weld root in critical areas
Solution Approach 1:
The invention extracts or removes the harmful element (unstable vapor capillary end) from the weld root formation process. By positioning the laser beam eccentrically, the weld root is determined by the stable intermediate section of the vapor capillary rather than its unstable end, which is prone to causing process pores. This separation of functions allows deep penetration and high weld strength while eliminating pore formation in critical areas.
3Length of stationary object
If the laser beam is positioned to create a vapor capillary for deep penetration welding, then the welding depth increases, but the end of the vapor capillary becomes unstable and determines the weld root course, leading to variable weld quality
Solution Approach 1:
The invention changes the spatial dimension of laser beam positioning from radial (conventional) to eccentric (offset from center). This dimensional change in beam positioning allows the stable intermediate section of the vapor capillary to determine the weld root instead of the unstable end, achieving both deep penetration and stable weld root formation simultaneously.
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 method achieves a uniform welding depth and high strength along the weld seam, minimizing process pores within critical areas and maintaining a consistent weld seam course, thereby enhancing the overall quality of the laser welding process.
Implementation Method 1
a laser beam is directed with its beam direction onto a surface in the contact area of the workpieces to be joined together
Implementation Method 2
the material located in the area of influence of the laser beam melts on the outer surface due to the absorption of laser radiation
Implementation Method 3
a vapor capillary forms in the melt
Implementation Method 4
the workpieces rotate about their axis of symmetry during the irradiation
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
In a method for laser welding workpieces, a laser beam (12) is directed with its beam direction towards a surface in the contact region of the workpieces (10) to be connected to one another during a relative movement of the laser beam (12) in relation to the workpieces (10). According to the invention, when the workpieces (10) are placed against one another along one of their axes, the laser beam (12) is directed towards the surface with the beam direction eccentrically offset to the axial centre (11) of the workpieces (10).