Molten Pool Inspection via Multi-Region Light Intensity Ratio
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Solution Overview
Problem
Existing laser beam welding quality determination systems face challenges in accurately evaluating welding quality, especially in remote welding scenarios where the laser torch is far from the workpieces, leading to decreased detection accuracy of poor welding conditions due to weak electrical signals and temperature fluctuations.
Innovation Solution
A welded portion inspection apparatus that radiates a welding laser beam along a set locus on the workpieces, receiving reflected light, vapor light, and thermal radiation, and inspecting the welding state based on the intensity ratio between two regions within the molten pool, allowing for precise evaluation even in remote welding scenarios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the laser torch is positioned far from the workpieces to perform remote welding, then the welding process can be performed on spaced workpieces, but the electrical signals from received laser reflection light and welding light become weak, decreasing determination accuracy of poor welding
Solution Approach 1:
The patent divides the molten pool into multiple regions (first region, second region, third region) and performs separate light reception and signal processing for each region. This segmentation allows the system to capture spatial distribution information of the molten pool, enabling accurate welding quality determination even when the laser torch is positioned far from the workpieces.
Solution Approach 2:
The patent transitions from single-point light reception to multi-regional light reception by scanning different regions of the molten pool. This dimensional expansion from point to area measurement enhances the signal information available for welding quality determination, compensating for the signal weakness caused by remote welding.
2Adaptability or versatility
If the workpiece temperature fluctuates largely during laser beam welding, then the welding process can adapt to varying conditions, but the electrical signals from received laser reflection light and welding light change according to temperature, further decreasing determination accuracy of poor welding
Solution Approach 1:
The patent implements a feedback mechanism where light reception signals from multiple molten pool regions are continuously monitored and used to determine welding quality. The system adjusts its evaluation based on the actual signal patterns observed in different regions, enabling accurate poor welding detection despite temperature fluctuations during the welding process.
Solution Approach 2:
The patent utilizes changes in light reception signal parameters (intensity, distribution pattern across different regions) as indicators of welding quality. By monitoring how these parameters change across multiple regions of the molten pool, the system can distinguish between normal temperature variations and actual welding defects.
3Device complexity
If single-point light reception is used to simplify the inspection system, then the device complexity is reduced, but the ability to minutely inspect welding state in remote welding conditions deteriorates
Solution Approach 1:
The patent employs a dynamic light reception approach where the light reception unit scans multiple regions of the molten pool during the welding process. This dynamic multi-regional scanning capability provides comprehensive welding state information without requiring an overly complex static multi-point reception system, achieving a balance between device complexity and inspection precision.
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 accurate and minute inspection of welding states by normalizing signal intensity variations caused by temperature changes and distance, effectively detecting poor welding conditions with improved reliability.
Implementation Method 1
a light-receiving portion that receives a returned light beam including at least one of reflection light of the welding laser beam or the inspection laser beam radiated by the radiation portion, the reflection light being reflected from the molten pool of the workpieces
Implementation Method 2
vapor light caused due to melting and evaporation of the workpieces
Implementation Method 3
thermal radiation light emitted from the molten pool of the workpieces
Data Source
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AI summary
A welding laser beam (LI) is radiated along welding loci (C11, C12) set in workpieces (W1, W2), or an inspection laser beam (L5) is radiated along scanning loci (C51, C52) set in a molten pool (Y1) of the workpieces that are molten by radiation of the welding laser beam, a returned light beam (L2) including reflection light from the molten pool, vapor light caused due to melting and evaporation of the workpieces, and thermal radiation light emitted from the molten pool is received, and a welding state of a welded portion of the workpieces is inspected based oh an intensity of a returned light beam received in a first region inside the molten pool which is relatively close to a given point and an intensity of a returned light beam received in a second region inside the molten pool which is relatively spaced from the given point.