Laser Welding Beam Switching for Gap-Aware Penetration Measurement
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Solution Overview
Problem
Laser welding devices face challenges in accurately measuring the depth of penetration when welding overlapping workpieces, particularly due to gaps between them, leading to incorrect measurements and potential melt-through issues.
Innovation Solution
The device emits a measurement beam with a different wavelength than the laser beam, allowing it to switch between measuring at the keyhole position and the weld bead position, determining the gap between workpieces, and adjusting welding conditions to prevent insufficient penetration and melt-through.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the measurement beam is emitted coaxially with the laser beam to measure keyhole depth, then the depth of penetration can be measured, but the measurement becomes inaccurate when gaps exist between overlapping workpieces
Solution Approach 1:
The measurement process is segmented into two distinct positions: keyhole position measurement and weld bead position measurement. By separating these measurements and comparing them, the system can detect gaps between workpieces and correct depth measurements accordingly
Solution Approach 2:
The system uses feedback from weld bead depth measurements to correct keyhole depth measurements. When a gap is detected through comparison, the measurement value is corrected by subtracting the gap amount, ensuring accurate penetration depth assessment
2Productivity
If the laser beam irradiates overlapping workpieces with gaps, then welding can proceed, but melt-through may occur due to insufficient penetration depth control
Solution Approach 1:
The system performs preliminary detection of gaps between workpieces before completing the welding process. By measuring both keyhole and weld bead positions and detecting gaps in advance, the system can prevent melt-through issues before they occur
Solution Approach 2:
Real-time feedback from dual-position measurements allows the system to monitor penetration depth accuracy during welding. When gaps are detected, the system can adjust welding parameters or alert operators to maintain consistent weld quality
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 configuration enables accurate measurement of the keyhole depth and determination of workpiece state, preventing melt-through and ensuring sufficient bonding strength by adjusting laser output and welding conditions based on gap measurements.
Implementation Method 1
the measurement beam is reflected from the bottom of the keyhole and received by an optical interferometer via a beam splitter. Since the optical interferometer can measure the optical path length of the measurement beam
Data Source
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AI summary
A laser welding device is configured to switch an irradiation position of a measurement beam S between a position of a keyhole 37 coaxial with the optical axis of a laser beam L and a position of a weld bead 38 behind the center of an optical axis of the laser beam L in a welding direction. The laser welding device determines whether there is a gap between an upper metal plate 31 and a lower metal plate 32 based on a measured value of a recess depth measured at the position of the weld bead 38.