Laser Welding Gap Bridging Detection via Intensity Profile Analysis
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Solution Overview
Problem
Current methods for monitoring laser welding of transparent workpieces, such as glass, require laborious manual inspection to assess gap bridging and weld quality, which is inefficient and not real-time.
Innovation Solution
Evaluating the intensity profile of process radiation emitted during laser welding, specifically the depth, duration, and renewed increase in intensity, to determine if a gap between workpieces is bridged, allowing for real-time quality assessment during the process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual inspection with microscope is used to assess gap bridging and weld quality, then measurement precision can be achieved, but productivity is reduced due to laborious and time-consuming inspection process
Solution Approach 1:
The patent replaces manual mechanical inspection with automated optical detection. A photodetector records the temporal intensity profile of process radiation emitted during laser welding, and automated evaluation determines gap bridging status based on intensity decrease features, eliminating the need for manual microscope inspection while maintaining detection accuracy
Solution Approach 2:
The patent creates an optical copy of the weld zone characteristics through process radiation detection. The temporal intensity profile serves as a signature that replicates the physical state of the welding process, allowing indirect assessment of gap bridging without direct physical measurement of the weld seam
2Measurement precision
If transverse microsections are used to examine gap position and size, then measurement precision is improved, but loss of time increases due to complex post-processing examination
Solution Approach 1:
The patent performs the measurement action during the welding process itself rather than after completion. The photodetector continuously monitors process radiation intensity throughout welding, capturing gap bridging information in real-time, so no post-welding sectioning or examination time is required
Solution Approach 2:
The patent maintains continuous monitoring of the welding process through uninterrupted detection of process radiation intensity. The photodetector operates throughout the entire welding sequence, providing continuous data stream that captures the complete welding history including gap bridging events, eliminating discontinuous post-processing examination
3Reliability
If strength measurements are performed to assess weld quality, then reliability of quality assessment is improved, but productivity decreases due to additional testing steps
Solution Approach 1:
The patent implements real-time feedback during the welding process by continuously monitoring process radiation intensity and immediately evaluating gap bridging status. The system provides instantaneous quality assessment information that can influence subsequent welding parameters or trigger alerts, eliminating the need for separate post-weld strength testing
Solution Approach 2:
The patent uses process radiation intensity as an intermediary parameter to indirectly assess weld quality and gap bridging status. Instead of directly measuring mechanical strength properties, the system monitors the optical signature of the welding process, which serves as a reliable proxy for weld quality without requiring physical strength tests
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 immediate identification of gap bridging and weld quality, reducing the need for manual inspection and enabling industrial-scale quality control during processing.
Implementation Method 1
an intensity of process radiation emitted by the melting volume is detected
Data Source
AI summary
A method for monitoring a laser welding process for welding two workpieces using a laser wavelength, in which a pulsed laser beam is directed into the workpieces so as to melt a melting volume in a region of an interface of the two workpieces in order to produce a weld seam, and in which an intensity of a process radiation emitted by the melting volume is detected. According to the method for monitoring the lase welding process, in a first step, a detected intensity profile is evaluated with regard to at least one of the following features: (i) a depth of an intensity decrease, (ii) a duration of an intensity decrease, and (iii) a renewed increase in intensity after an intensity decrease. In a second step it is determined whether or not a gap between the two workpieces was bridged during the laser welding process based on the evaluation.