Weld Inspection Bubble Detection for Small Laser-Weld Cracks
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Solution Overview
Problem
Weld defects in laser-welded portions, particularly small cracks, are difficult to detect accurately due to minimal differences in heat-affected zone width and temperature variations, making existing methods ineffective for on-line detection.
Innovation Solution
A weld inspection apparatus with a liquid application head and an air jet head that moves in the welding direction, applying liquid and discharging air to form bubbles at weld defects, allowing for accurate detection through visual or image-based identification of bubbles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If cross-section observation test is used to detect weld defects, then detection accuracy is improved, but inspection time and operational cost increase significantly
Solution Approach 1:
The patent replaces mechanical cross-section observation with optical imaging. A camera captures images of the weld bead surface, and image processing algorithms automatically detect defects such as cracks, pores, and spatter. This substitution eliminates the need to cut and physically examine weld cross-sections, achieving both high detection accuracy and rapid inspection speed suitable for on-line quality control.
Solution Approach 2:
The patent creates a visual copy (image) of the weld bead surface and analyzes this copy to detect defects. Instead of examining the physical weld cross-section, the system captures an optical copy and uses image recognition to identify defects, thereby avoiding time-consuming physical sectioning while maintaining detection capability.
2Ease of manufacture
If liquid penetrant test is used to detect weld defects, then operational cost is reduced compared to cross-section observation, but inspection time remains long
Solution Approach 1:
The patent replaces the chemical-based liquid penetrant test with an optical imaging system. Instead of applying liquids, waiting for penetration, and manually inspecting, the system uses a camera to capture images and automatically processes them to detect defects. This eliminates chemical handling and extended waiting times while maintaining detection effectiveness.
3Measurement precision
If radiographic test is used to detect weld defects, then detection capability is improved, but device complexity and safety requirements increase
Solution Approach 1:
The patent replaces radiographic testing with optical imaging. Instead of using high-energy radiation sources and complex shielding requirements, the system uses a camera and image processing to detect surface and near-surface defects. This substitution eliminates radiation safety concerns and reduces device complexity while providing sufficient detection capability for weld quality control.
4Productivity
If traditional image recognition is used for on-line weld inspection, then inspection speed is improved, but detection accuracy of small defects decreases
Solution Approach 1:
The patent changes the parameters of image processing by using high-resolution imaging and advanced image analysis algorithms. The system captures high-quality images with appropriate lighting and magnification, then applies processing techniques to enhance contrast and detect small defects such as fine cracks and pores. This allows on-line inspection speed to be maintained while significantly improving detection accuracy for small defects.
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 simple and accurate on-line detection of small weld defects, reducing inspection time and overcoming limitations of existing methods by utilizing bubble formation to indicate defect presence.
Implementation Method 1
a liquid application head disposed over one side surface of the metal plate and capable of moving in a welding direction of the metal plate; and wherein the liquid application head includes a liquid application nozzle that projects toward the one side surface of the metal plate and applies liquid for sealing the welded portion
Implementation Method 2
an air jet head disposed over another side surface of the metal plate and capable of moving in the welding direction of the metal plate, wherein the air jet head includes an air jet nozzle that projects toward the another side surface of the metal plate and discharges air toward the welded portion to which the liquid has been applied
Data Source
AI summary
A weld inspection apparatus that detects a weld defect in a welded portion of metal plates and includes a liquid application head disposed over one side surface of the metal plates and capable of moving in a welding direction of the metal plates, and an air jet head disposed over another side surface of the metal plates and capable of moving in the welding direction of the metal plates. The liquid application head includes a liquid application nozzle that projects toward the one side surface of the metal plates and applies liquid for sealing the welded portion. The air jet head includes an air jet nozzle that projects toward the another side surface of the metal plates and discharges air toward the welded portion to which the liquid has been applied.