Laser Welding Uniform Penetration via Preheating
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Solution Overview
Problem
Existing laser welding methods face challenges in achieving uniform penetration depth during the welding of two workpieces, leading to instability in the welded part due to temperature differences between the initiation and termination points, requiring complex output control of the welding laser beam.
Innovation Solution
A method involving preliminary heating of the entire welding path with a heating laser beam, followed by continuous irradiation with both the heating and welding laser beams, allowing the welding process to maintain a heated state without complex output control, thereby reducing temperature differences and enhancing penetration depth uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If scanning is performed with a welding laser beam along a closed loop welding path, then the workpieces can be welded together, but the penetration depth becomes non-uniform due to heat accumulation at the unwelded part
Solution Approach 1:
The patent applies preliminary heating to the entire welding path before welding begins. By pre-heating the workpieces along the entire closed loop welding path, the temperature distribution is equalized beforehand, preventing heat accumulation differences during welding and ensuring uniform penetration depth throughout the weld.
Solution Approach 2:
The patent maintains continuous heating along the entire welding path throughout the welding process. This continuous thermal action ensures that the workpieces remain at a consistent elevated temperature throughout welding, preventing localized heat accumulation and maintaining uniform melting and penetration characteristics along the entire weld path.
2Manufacturing precision
If the laser beam output is adjusted to achieve uniform penetration depth, then the welded part stability improves, but the control system complexity increases
Solution Approach 1:
The patent changes the thermal parameter of the workpieces by applying preliminary and continuous heating, raising the baseline temperature of the entire welding path. This parameter change in the workpiece temperature state eliminates the need for complex real-time output modulation of the welding laser, as the uniform thermal state naturally produces uniform penetration depth.
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 ensures a more uniform penetration depth of the welded part without complex output control, reducing temperature differences and improving the stability of the welded joint.
Implementation Method 1
irradiating the entire welding path with a heating laser beam
Implementation Method 2
the entire welding path is irradiated with the heating laser beam... the entire welding path of the workpieces is heated
Implementation Method 3
performing scanning with a welding laser beam along the welding path... the two workpieces can be welded to each other
Implementation Method 4
heat input from the laser beam to the workpieces results in heat transfer
Data Source
AI summary
A laser welding method includes preliminarily heating an entire welding path by irradiating the entire welding path with a heating laser beam for a first predetermined time, the welding path being closed loop-shaped and formed at a boundary between two workpieces as welding objects, and performing scanning with a welding laser beam along the welding path while continuously performing the irradiation with the heating laser beam after the preliminary heating and terminating the irradiation with the welding laser beam after the welding laser beam goes around the welding path.