Remote Laser Welding Detection via Reflected Light Intensity
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Solution Overview
Problem
In remote laser beam welding, it is challenging to accurately detect the beginning and end of a welding point due to the multi-step process involving laser beam irradiation, making it difficult to distinguish the start and finish based solely on the turning on/off of the laser beam.
Innovation Solution
A laser beam welding apparatus and method that includes a head for irradiating a workpiece with a laser beam, an optical system for focusing and scanning, and a controller that determines the start and end of a welding point by analyzing the intensity and duration of reflected light, specifically differentiating between laser beam and plasma reflections using set-intensity and set-time thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multi-step laser beam irradiation is performed for remote laser beam welding, then welding flexibility and coverage are improved, but the ability to detect the beginning and end of welding points deteriorates
Solution Approach 1:
The patent introduces a protective film as an intermediary substance between the laser beam and the workpiece surface. This film modifies the reflected light characteristics during welding, enabling the detection system to distinguish between different welding states (beginning, middle, end) through changes in light reflection patterns, thereby resolving the detection difficulty caused by multi-step irradiation
Solution Approach 2:
The patent utilizes changes in the optical properties (analogous to color changes) of the workpiece surface and protective film during the welding process. By monitoring variations in reflected light intensity and characteristics across different welding stages, the system can accurately identify welding point boundaries despite the complex multi-step irradiation sequence
2Device complexity
If laser beam turning on/off is used to detect welding points, then the detection method is simple, but the detection accuracy deteriorates in remote laser beam welding
Solution Approach 1:
The patent implements a feedback mechanism where the detection system continuously monitors reflected light characteristics and provides real-time information about welding state to the control system. This feedback loop enables accurate identification of welding point beginning and end by analyzing changes in light reflection, transforming the simple on/off detection into a precision measurement system
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 detection of the beginning and end of a welding point even in remote laser beam welding, improving the precision of the welding process by utilizing intensity and time thresholds for reflected light analysis.
Implementation Method 1
an optical receiver which receives a reflected light of the laser beam from the workpiece
Data Source
AI summary
Provided is a laser beam welding apparatus capable of correctly detecting the beginning and the end of one welding point even in remote laser beam welding. The laser beam welding apparatus includes a head which irradiates a workpiece with a laser beam, an optical receiver which receives a reflected light of the laser beam from the workpiece, and a controller. The optical receiver receives only a laser beam and a plasma of the reflected light. The controller determines that one welding point begins when a time during which intensity of the reflected light is larger than or equal to a second set-intensity is longer than or equal to a first set-time, and determines that the one welding point ends when a time during which the intensity of the reflected light is smaller than or equal to a first set-intensity is longer than or equal to a second set-time.