Weld Joint Butt Position Detection Using Offset Sensor Geometry
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Solution Overview
Problem
Existing butt position detecting methods for weld joints are inefficient, requiring extensive time, complex installations, and limited design flexibility, and struggle with accuracy in recessed areas due to scattered and random light reflections.
Innovation Solution
A method and device using a two-dimensional displacement sensor that irradiates the butt portion with light, positioned offset from the butt portion and inclined at a specific angle relative to the sensor's direction, to minimize scattered light interference and clearly detect the butt position between joint surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If light emitters are arranged on both member sides and lighting is changed over to achieve high edge clarity, then measurement precision is improved, but detection time increases and productivity decreases
Solution Approach 1:
The patent divides the light source into multiple emitters positioned at different locations (one on each member side) and selectively activates only the necessary emitter based on the workpiece configuration. This segmentation allows achieving high measurement precision through optimized lighting angles without requiring both emitters to be active simultaneously, thus reducing detection time and improving productivity.
Solution Approach 2:
Instead of always using both light emitters or changing lighting conditions extensively, the patent applies partial action by selecting only the appropriate light emitter for the current measurement situation. This reduces the detection process time while maintaining sufficient edge clarity for accurate butt position detection.
2Measurement precision
If light emitters are installed on both member sides perpendicular to the weld line, then measurement precision is improved, but device complexity and installation complexity increase
Solution Approach 1:
The patent adopts an asymmetric arrangement where light emitters are positioned on both member sides but not necessarily in symmetric locations. The emitter on the first member side is positioned differently from the emitter on the second member side, optimized for their respective geometries. This asymmetric configuration achieves accurate butt position detection while simplifying the overall device structure and installation process compared to rigid symmetric arrangements.
Solution Approach 2:
Each light emitter is positioned and oriented according to the local geometric characteristics of its respective member side. The lighting conditions are optimized locally for each position rather than applying a uniform symmetric arrangement, which simplifies installation while maintaining high measurement precision for the specific butt joint configuration being measured.
3Measurement precision
If a mechanism moves in the image taking optical axis direction by predetermined step amount, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces the mechanical stepping mechanism with an optical solution using multiple fixed light emitters positioned at different angles and locations. Instead of moving a single sensor mechanically to capture surface shape at different positions, the system uses strategically positioned light sources to illuminate different facets of the butt joint simultaneously or selectively, eliminating the need for complex mechanical movement mechanisms and reducing both device complexity and cost while maintaining measurement precision.
4Measurement precision
If light is irradiated at recess at butt position, then butt position detection is attempted, but scattered and random reflection occur making edge portion measurement difficult
Solution Approach 1:
The patent addresses the scattered light problem by positioning light emitters and receivers at specific local locations and angles relative to the recessed butt portion. The lighting geometry is optimized locally for each emitter-receiver pair to illuminate the recessed area at angles that minimize scatter and maximize the clarity of reflected light carrying edge information, thereby maintaining measurement precision despite the challenging recessed geometry.
Solution Approach 2:
The patent uses asymmetric positioning of light emitters and receivers relative to the recessed butt portion. Rather than symmetric illumination that would cause equal scattered light in all directions, the asymmetric arrangement directs light at specific angles that favor specular reflection toward the receiver while minimizing scatter, improving edge portion measurement capability in recessed areas.
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
This approach allows for accurate detection of the butt position while reducing costs and enhancing design freedom, enabling high-quality weld joints by correcting the welding position based on precise measurements.
Implementation Method 1
irradiating the butt portion with irradiation light of a two-dimensional displacement sensor
Data Source
AI summary
A butt position detecting method for a weld joint, when an arrangement direction of a first member and a second member is defined as a first direction, and a direction that is perpendicular to the first direction is defined as a second direction, the first member has a corner portion and a chamfer portion, and a two-dimensional displacement sensor is arranged at a position offset from the butt portion toward the first member side in the first direction, and such that an angle θs at which the second direction and an optical axis direction of irradiation light of the two-dimensional displacement sensor intersect with each other and an angle θa at which the second direction and a formation direction of the chamfer portion of the first member intersect with each other satisfy a condition expression: 0°<θs<θa.