Laser Welding Quality Determination via High-Speed Camera Analysis
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Solution Overview
Problem
Conventional methods for determining laser welding quality are unable to provide real-time assessment, making it difficult to diagnose defects and predict shearing strength and fracture mode during high-speed, high-precision laser welding.
Innovation Solution
A method and apparatus that utilize a high-speed camera to acquire images of the welding section and analyze parameters such as spatter count per unit length, area of high-luminance region, and keyhole detection frequency, comparing these to reference values to determine welding quality in real-time, allowing for in-process quality control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional molten pool visualization apparatus is used to photograph the molten pool frame by frame, then the molten pool can be observed, but the welding quality cannot be determined quickly because observation is only possible after welding is finished
Solution Approach 1:
The patent applies preliminary action by establishing reference tables of parameter values (spatter count, high-luminance region area, keyhole detection frequency) that correspond to different welding quality levels before actual welding occurs. During welding, real-time capture of these parameters and immediate comparison with pre-established reference tables enables instant quality determination without waiting for welding completion, thus resolving the time loss contradiction.
2Loss of information
If conventional molten pool visualization apparatus is used, then the molten pool can be photographed, but it is difficult to diagnose welding defects and predict shearing strength and fracture mode because only the state of welding can be observed
Solution Approach 1:
The patent applies universality by designing an inspection system that performs multiple functions using the same core components. The high-speed camera and image analysis system simultaneously capture welding state, diagnose defects (pits, burn-through), and predict mechanical properties (shearing strength, fracture mode) by analyzing multiple parameters against comprehensive reference tables. This multi-functional approach prevents information loss without proportionally increasing device complexity.
Solution Approach 2:
The patent introduces parameter analysis (spatter count, high-luminance region area, keyhole detection frequency) as an intermediary between direct observation and defect diagnosis. These intermediate parameters serve as indicators that bridge the gap between visual welding state and underlying quality issues, enabling indirect detection of defects and prediction of mechanical properties without requiring direct observation of the final welded joint.
3Productivity
If high-speed camera is used to capture welding images in real-time, then welding quality can be determined during the process, but the system complexity increases
Solution Approach 1:
The patent replaces complex mechanical quality control systems with an optical-based image analysis system. Instead of using mechanical sensors or complex physical measurement devices, the invention uses a high-speed camera to capture welding images and processes them through image analysis algorithms. This substitution achieves real-time quality control (improving productivity) while keeping the apparatus relatively simple, as the core component is a standard high-speed camera rather than complex mechanical measurement equipment.
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 determination of welding quality, differentiation between defects like pits and burn-through, and prediction of tensile shearing strength and fracture mode, facilitating high-speed, high-precision quality control.
Implementation Method 1
an image of the welding section and a region surrounding the welding section is acquired by using a high-speed camera
Implementation Method 2
laser welding being performed using laser light from a CO2 laser or YAG laser
Data Source
AI summary
Welding quality of a welding section W welded by laser welding is determined by acquiring an image of the welding section W and its surrounding region by means of a high-speed camera 11, analyzing, as parameters, the number of spatters P per unit length and the area of a high-luminance region in the acquired image by means of an analyzer 12, and comparing the analyzed parameters with respective comparison tables created beforehand, to determine the welding quality of the welding section Wa. Information on the welding quality of the welding section W is displayed on a monitor 13. Not only the laser welding quality of the welding section can be determined but also in-process shearing strength prediction as well as in-process fracture mode prediction can be performed, thus enabling quality control matching high-speed and high-precision laser welding.