Laser Welding Focus Correction via Return-Light Scan Direction
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Solution Overview
Problem
Existing laser welding systems face accuracy issues in controlling the focusing of laser light when applying it obliquely to a workpiece, as the defocusing accuracy varies with the scanning direction of the laser light.
Innovation Solution
A method and system that apply laser light obliquely to a workpiece, determine a correction value for defocus based on return light intensity, and adjust the defocus to zero during scanning, improving focusing accuracy by scanning in a direction approaching the emission point when defocus reaches zero.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If laser light for inspection is applied obliquely to a workpiece and scanned, then it is possible to inspect defocusing in laser welding apparatuses with fixed-point scanning capability, but the accuracy of focusing control becomes insufficient depending on the scanning direction
Solution Approach 1:
The patent applies dynamic control by changing the scanning direction of the laser light for inspection to always approach the emission point, rather than using a fixed scanning direction. This dynamic adjustment ensures that the laser light consistently travels toward the emission point regardless of the scanning position, thereby maintaining high measurement precision in focusing control while adapting to the fixed-point scanning apparatus configuration.
2Area of stationary object
If laser light for inspection is scanned in various directions, then coverage of the workpiece surface is improved, but the amount of change in return light intensity decreases reducing inspection accuracy
Solution Approach 1:
The patent introduces asymmetry in the scanning direction by always directing the laser light to approach the emission point, rather than using symmetric or arbitrary scanning directions. This asymmetric scanning approach creates a consistent relationship between the scanning direction and the emission point, which maximizes the amount of change in return light intensity and thereby improves measurement precision while still covering the workpiece surface.
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
Enhances the accuracy of laser light focusing control by increasing the change in return light intensity, allowing for precise welding.
Implementation Method 1
the defocusing of the laser light is inspected based on the intensity of reflected light of the laser light for inspection
Data Source
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AI summary
A welding method according to the present disclosure includes a step of applying laser light (L1) for inspection obliquely to a workpiece (W) while changing an amount of defocus, a step of determining a correction value for the amount of defocus based on intensity of return light (L2) of the laser light (L1) for inspection, and a step of welding the workpiece (W) by applying laser light for welding to the workpiece (W) so that the amount of defocus corrected by the correction value becomes zero. In the welding method, the laser light (L1) for inspection is scanned in a direction approaching an emission point at a timing at which the amount of defocus becomes zero. As a result, a welding method, a welding system (100), and a correction method capable of improving the accuracy of the control of the focusing of laser light for welding are provided.