Laser Beam Weaving for Uniform Weld Bead Formation
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Solution Overview
Problem
Conventional laser welding methods face challenges in forming an excellent weld bead due to thermal imbalance and insufficient heat input at the end portions of the weaving trajectory, especially in butt welding and lap welding, where gaps are likely to form.
Innovation Solution
A laser welding method and device that applies a laser beam to a workpiece while weaving in two directions, with varying amplitudes at the end portions of the trajectory to enhance heat input and balance thermal distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the laser beam is caused to weave in a predetermined direction with uniform amplitude, then the welding speed is improved, but thermal imbalance occurs at the end portions of the weaving trajectory resulting in poor weld bead formation
Solution Approach 1:
The patent applies different weaving amplitudes to different portions of the welding trajectory. Specifically, the weaving amplitude at the end portions of the trajectory is made smaller than the amplitude at the intermediate portions. This local differentiation compensates for the excessive heat diffusion at end portions, ensuring uniform heat input and consistent weld bead quality throughout the entire welding path.
Solution Approach 2:
The patent dynamically adjusts the weaving amplitude based on the position along the welding trajectory. By making the weaving amplitude variable rather than constant, the system adapts to the changing thermal conditions at different portions of the trajectory, particularly compensating for the heat loss at end portions to maintain consistent welding quality.
2Productivity
If the spot diameter of the laser beam is reduced for high-speed scanning welding, then the welding speed is improved, but the laser beam penetrates through gaps in butt welding resulting in insufficient metal melting
Solution Approach 1:
The patent employs periodic weaving motion of the laser beam during welding. This periodic oscillation of the beam position increases the effective heat input to the material by repeatedly passing energy through the same region, ensuring sufficient metal melting and gap filling capability even when using a smaller spot diameter for high-speed 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
The method and device enable the formation of a weld bead with a smooth and uniform shape by increasing heat input at the end portions, addressing thermal imbalances and ensuring sufficient metal melting to fill gaps.
Implementation Method 1
laser welding can perform high-speed and high-quality welding because a laser beam, which is applied to a workpiece serving as an object to be welded, has high power density
Implementation Method 2
heat diffusion from a molten portion of the workpiece to the surrounding portion
Implementation Method 3
amount of metal melted by the laser beam may not be sufficient to fill the gap
Data Source
AI summary
A laser welding method includes a welding step of applying a laser beam to a surface of a workpiece while the laser beam is caused to advance in an X-direction and scanning with the laser beam is simultaneously performed in a Y-direction intersecting the X-direction. The welding step includes a first weaving step of causing the laser beam to weave in the Y-direction with first amplitude (A1), and a second weaving step of causing the laser beam to weave with a predetermined amplitude smaller than first amplitude (A1) at both end portions of a weaving trajectory drawn by the laser beam in the first weaving step.