Weld Seam Depth Measurement Using OCT Keyhole Sensing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current commercial systems lack the capability to directly measure the depth of a weld seam during laser welding, relying on destructive testing methods that are costly and time-consuming, and do not provide real-time feedback on welding penetration depth, leading to potential strength issues or visible welds.
Innovation Solution
A device utilizing a collimator module with adjustable settings for focal position and beam widening, combined with optical coherence tomography, to accurately measure the keyhole depth by superimposing measuring light with the processing beam and analyzing the reflected light for precise depth determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If destructive testing methods (micrograph production) are used to determine welding penetration depth, then measurement accuracy is improved, but productivity is worsened due to time-consuming and costly procedures
Solution Approach 1:
The patent replaces destructive mechanical testing (cutting, mounting, micrograph production) with an optical measurement system that uses light to non-contactively measure keyhole depth during welding, thereby maintaining measurement accuracy while eliminating time-consuming destructive procedures
Solution Approach 2:
The measurement system utilizes the welding process itself (the keyhole formation and light reflection properties) to provide measurement information, eliminating the need for separate testing operations and enabling real-time feedback during production
2Loss of information
If no real-time measurement system is used, then device complexity is reduced, but loss of information occurs regarding welding penetration depth
Solution Approach 1:
The patent integrates the measurement system into the existing welding setup by using the welding laser itself as part of the measurement apparatus and sharing optical components, thereby reducing overall system complexity while enabling real-time depth information acquisition
Solution Approach 2:
The patent uses light reflection from the keyhole as an intermediary to convey depth information without requiring direct physical measurement, allowing information extraction through optical means that add minimal system complexity
3Manufacturing precision
If keyhole depth is not monitored in real time, then ease of operation is improved, but manufacturing precision is worsened due to inability to correct penetration depth variations
Solution Approach 1:
The patent implements real-time feedback by continuously measuring keyhole depth during welding and providing this information to operators or control systems, enabling immediate detection and correction of penetration depth variations to maintain manufacturing precision
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 real-time measurement of welding penetration depth, reducing material waste and allowing for continuous process adjustments, thereby improving weld quality and reducing the risk of inadequate or excessive penetration.
Implementation Method 1
a collimator module (21) having at least one collimation lens (29) for collimating a measuring light beam (23)
Implementation Method 2
for imaging the measuring light beam reflected back from a workpiece to be processed on an exit/entry surface of the optical waveguide (20)
Implementation Method 3
a focusing lens (25) for jointly focusing the measuring light beam (23) and the processing beam (10) on the workpiece (40) and for collimating the reflected measuring light beam
Implementation Method 4
for collimating the reflected measuring light beam
Implementation Method 5
an analysis unit (15) for determining the depth of a weld seam, into which the measuring light reflected back from the workpiece is guided with the superimposed reflected light from the reference arm (18)
Data Source
AI summary
A device for measuring the depth of a weld seam in real time during the welding or joining of a workpiece by means of radiation, including: its measuring light source, the light of which is coupled by a beam splitter into a reference arm and a measuring arm; a collimator module having at least one collimation lens for collimating a measuring light beam, which is fed to the collimator module via an optical waveguide in the measuring arm, and for imaging the measuring light beam, which is reflected from a workpiece to be processed, on an exit/entry surface of the optical waveguide; a coupling element for coupling the measuring light beam into the beam path of a processing beam; a focusing lens for the joint focusing of the measuring light beam and the processing beam on the workpiece and for the collimating of the reflected measuring light beam; and an analysis unit for determining the depth of a weld seam, into which the measuring light reflected from the workpiece is guided with the superimposed, reflected light from the reference arm. The collimator module includes a device for setting the axial focal position of the measuring light beam, and for setting the lateral focal position of the measuring light beam, and a field lens, which is arranged between the exit/entry surface of the optical waveguide and the collimation lens and defines the beam widening of the measuring light beam and therefore the focus diameter of the measuring light beam.