Laser Welding Keyhole Depth Tracking With Image Feedback
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Solution Overview
Problem
Current laser machining systems face challenges in accurately and continuously measuring the depth of the vapor capillary during laser welding due to variations in process parameters and potential inaccuracies, such as drift in deflection units, leading to incorrect positioning of the optical measuring beam and unreliable welding depth information.
Innovation Solution
Incorporating an image acquisition unit to capture images of the vapor capillary and the measuring beam's point of incidence, allowing for real-time adjustment and positioning of the measuring beam to ensure accurate and continuous depth measurement of the vapor capillary, eliminating the need for additional optical devices and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an optical coherence tomograph is used to measure the depth of the vapor capillary, then measurement capability is provided, but positioning accuracy deteriorates due to drift in deflection units and variations in process parameters
Solution Approach 1:
The system uses an image acquisition device to continuously capture images of the vapor capillary and determining device to calculate its position and depth. This feedback loop allows real-time tracking and adjustment of the measuring beam position, compensating for drift in deflection units and ensuring accurate measurement throughout the welding process
Solution Approach 2:
The image acquisition device serves multiple functions: it captures images for vapor capillary positioning, enables depth measurement, and provides continuous monitoring. This multi-functional approach eliminates the need for separate positioning systems and reduces overall system complexity while maintaining measurement reliability
2Measurement precision
If the optical measuring beam is used to measure vapor capillary depth, then depth information is obtained, but continuous monitoring is compromised due to interruptions in measurement
Solution Approach 1:
The image acquisition device operates continuously throughout the welding process, capturing images at regular intervals. This continuous imaging enables uninterrupted monitoring of vapor capillary depth, eliminating measurement gaps and providing real-time data for the entire welding duration
Solution Approach 2:
The system determines the position and depth of the vapor capillary in advance by analyzing images captured during the welding process. This preliminary determination allows the system to prepare for the next measurement cycle and ensures continuous monitoring without interruptions
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 enables reliable, continuous, and real-time measurement of the vapor capillary depth, improving processing quality by ensuring the measuring beam is always correctly positioned, thus enhancing the accuracy and efficiency of laser welding.
Implementation Method 1
The depth of the vapor capillary is typically measured contactlessly using spectral interferometric distance measurement or optical distance measurement by means of optical coherence tomography (OCT)
Implementation Method 2
When the laser beam is projected onto the workpiece to be machined, the material of the workpiece, for example metal, is heated so intensely by the laser power in an irradiation region that it changes into a vaporous state or a plasma state
Implementation Method 3
the material of the workpiece, for example metal, is heated so intensely by the laser power in an irradiation region that it changes into a vaporous state
Data Source
AI summary
A laser machining system, or laser welding system, for machining a workpiece includes: a laser machining head for directing a laser beam onto a workpiece to produce a vapor capillary; an optical measuring device using an optical measuring beam; an image acquisition unit to capture an image of a region of the workpiece surface containing the vapor capillary and a measuring spot produced by irradiation with the measuring beam. The system determines positions of the measuring spot and vapor capillary based on the image. A method includes: directing the laser beam onto a workpiece surface to produce a vapor capillary; directing an optical measuring beam onto the surface to measure a depth of the vapor capillary; capturing an image of a region containing the vapor capillary and a measuring spot from the optical measuring beam; and determining, based on the captured image, position of the measuring spot and vapor capillary.