Laser Welding Head Alignment for Accurate Vapor Capillary Depth
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Solution Overview
Problem
Existing laser processing systems face challenges in accurately measuring the depth of the vapor capillary during laser welding due to variations in geometric properties and position, leading to inaccuracies in welding depth measurement, especially in complex weld geometries and over time, as the position of the optical measuring beam can drift or become misaligned.
Innovation Solution
Incorporating an image acquisition unit to capture images of the workpiece surface, including the vapor capillary and the measuring spot, allowing for real-time adjustment and alignment of the optical measuring beam to ensure accurate measurement of the vapor capillary depth without interrupting the welding process, using a camera or digital camera that can detect thermal radiation or visible light to enhance contrast and determine the position of the measuring spot relative to the vapor capillary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an optical measuring beam is used to measure the depth of the vapor capillary, then the measurement can be performed contactlessly, but the position of the measuring beam may drift or become misaligned over time, leading to measurement inaccuracies
Solution Approach 1:
The system captures images of the workpiece surface including the vapor capillary and measuring spot position, processes these images to determine the actual position of the vapor capillary, and uses this information to adjust and realign the measuring beam position. This closed-loop feedback mechanism continuously corrects drift and maintains measurement accuracy over time
Solution Approach 2:
The patent replaces manual or mechanical alignment adjustment mechanisms with an automated optical system that uses image capture and processing to detect vapor capillary position and automatically reposition the measuring beam, eliminating the need for physical realignment operations
2Measurement precision
If the position of the optical measuring beam is adjusted to follow the vapor capillary position, then measurement accuracy is maintained, but additional complexity is introduced to the system
Solution Approach 1:
The system uses a single imaging device that serves multiple functions: capturing the vapor capillary position, determining the measuring spot position, and providing feedback for beam realignment. This multi-functional approach avoids adding separate alignment systems and reduces overall complexity
Solution Approach 2:
The patent introduces an image processing step as an intermediary between the optical measuring system and the control system. The processed image data serves as a mediator that translates visual information into positional corrections, simplifying the control logic while maintaining measurement precision
3Ease of operation
If the measuring beam position is fixed, then the system is simpler to operate, but the position of the vapor capillary may shift during processing, leading to measurement errors
Solution Approach 1:
The system transitions from a static measuring beam position to a dynamic position that can be automatically adjusted based on real-time detection of the vapor capillary position. The measuring beam position changes dynamically to track the vapor capillary, maintaining measurement accuracy while the system remains automated and easy to operate
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 continuous and reliable measurement of the vapor capillary depth, ensuring accurate welding depth control and improved processing quality by maintaining the correct alignment of the measuring beam with the vapor capillary, even in complex geometries and over extended periods, without the need for additional optical devices.
Implementation Method 1
The depth of the vapor capillary is typically measured contactlessly using spectral interferometric distance measurement or optical distance measurement using optical coherence tomography (OCT)
Implementation Method 2
The depth of the vapor capillary is typically measured contactlessly using spectral interferometric distance measurement
Implementation Method 3
using a camera or digital camera that can detect thermal radiation or visible light to enhance contrast and determine the position of the measuring spot relative to the vapor capillary
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
The invention relates to a laser machining system, in particular a laser welding system, for machining a workpiece by means of a laser beam, comprising: a laser machining head for radiating the laser beam onto a workpiece surface to generate a vapour capillary; an optical measuring device for measuring distance by means of an optical measuring beam; an image capturing unit which is designed to capture an image of a region of the workpiece surface which includes the vapour capillary and a measuring spot generated by radiating the optical measuring beam; wherein the laser machining system is designed to determine the position of the measuring spot and the position of the vapour capillary on the basis of the captured image. The invention further relates to a method for machining a workpiece by means of a laser beam, comprising the steps of: radiating the laser beam onto a workpiece surface to generate a vapour capillary; radiating an optical measuring beam onto the workpiece surface to measure the depth of the vapour capillary; capturing an image of a region of the workpiece surface which includes the vapour capillary and a measuring spot generated by radiating the optical measuring beam; determining the position of the measuring spot and the position of the vapour capillary on the basis of the captured image.