Laser Weld Monitoring Using Beam-Spot Luminance Defect Detection
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Solution Overview
Problem
Current laser welding machines lack real-time capability to detect and identify various welding defects during the welding of sheet metals, which can lead to suboptimal welding outcomes.
Innovation Solution
A laser welding machine equipped with a camera and an image analysis device that captures and analyzes the welding area, setting an analysis window with a reference point at the beam spot center to extract specific regions of interest based on luminance patterns, allowing for real-time determination of welding defects such as underfill, unconnected joints, insufficient penetration, edge displacement, and other defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If real-time welding defect detection is implemented, then welding quality is improved, but device complexity increases
Solution Approach 1:
The patent divides the welding area into multiple analysis windows, each focusing on specific regions where different defect types may occur. This segmentation allows the system to detect multiple defect types simultaneously using simple luminance comparisons in each region, rather than requiring a single complex analysis system.
Solution Approach 2:
The patent applies different analysis methods to different regions of the welding area. Specifically, it compares luminance values in predetermined regions (such as the weld bead region, molten pool region, and surrounding areas) to detect specific defect types. This localized approach enables simple region-specific detection logic to identify multiple defect types without requiring complex global analysis.
2Measurement precision
If multiple welding defect types are detected, then measurement precision is improved, but difficulty of detecting and measuring increases
Solution Approach 1:
The patent segments the detection task by dividing the welding area into multiple analysis windows, each dedicated to detecting specific defect types. This allows the system to apply simple luminance comparison methods in each region independently, achieving precise multi-type defect detection without requiring complex integrated analysis.
Solution Approach 2:
The patent changes the detection parameter from complex structural analysis to simple luminance value comparison in predetermined regions. By monitoring luminance changes in specific areas (such as comparing the luminance of the weld bead region with the surrounding region), the system can precisely detect multiple defect types using straightforward parameter thresholds.
3Productivity
If real-time defect determination is performed, then productivity is improved, but device complexity increases
Solution Approach 1:
The patent performs preliminary actions by pre-defining analysis windows and luminance comparison regions based on expected defect locations and characteristics. This preliminary setup enables real-time defect detection during welding without requiring complex real-time decision-making, as the comparison criteria are already established beforehand.
Solution Approach 2:
The patent simplifies real-time monitoring by changing from complex defect analysis to simple luminance value comparison. The system continuously monitors luminance parameters in predetermined regions and compares them against threshold values, enabling rapid real-time defect determination with minimal computational complexity.
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
Enables real-time detection and identification of welding defects, ensuring proper welding quality by determining the specific type of defect that has occurred, thereby improving the overall welding process.
Implementation Method 1
a camera (11) that captures a predetermined range including a beam spot of a laser beam (5) irradiated on the sheet metals (W1, W2)
Data Source
AI summary
A camera captures a predetermined range including a beam spot of a laser beam irradiated on the first and second sheet metals to be welded. An image analysis device determines whether a welding defect has occurred, based on an image signal obtained by capturing the first and second sheet metals. The image analysis device sets an analysis window in a frame of the image signal, and a center of the beam spot is located at a reference point set in the analysis window. A region extractor extracts pixels of a region of interest whose position is set with reference to the reference point corresponding to a welding defect of a determination target, among pixels included in the analysis window. A welding defect determination unit determines whether the welding defect of the determination target has occurred, based on luminance in the region of interest.