Laser Machining Head Distance Sensing Using OCT Reference Reflections
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Capacitive distance measurement methods in laser processing systems are prone to errors due to lateral sensitivity issues, particularly when cutting or welding, as they can be influenced by the proximity of the nozzle to other components and the geometry of the workpiece, leading to unstable machining processes.
Innovation Solution
A laser processing system with a processing head that uses optical coherence tomography to determine the distance between the processing head and the workpiece by directing a measuring beam onto a reflective reference and the workpiece, allowing for precise and error-free distance measurement through multiple reflections, which can also account for an offset between the reference and the processing head.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If capacitive measuring method is used for distance measurement, then the measurement can be implemented, but the measurement precision deteriorates due to lateral sensitivity and interference from surrounding components
Solution Approach 1:
The patent replaces the capacitive measuring method with an optical coherence tomography (OCT) based optical measuring method. The OCT system uses optical beams to measure distance, eliminating the lateral sensitivity issues and magnetic field interference that plague capacitive sensors. The optical measuring beam travels through the processing head along with the laser beam and reflects off the workpiece surface to provide accurate distance measurements without being affected by surrounding components.
Solution Approach 2:
The patent introduces an optical coherence tomography system as an intermediary measurement device. The OCT system uses reference beams and measuring beams that interact with the workpiece surface to determine distance. This intermediary optical system provides a clean measurement path that is not influenced by the electromagnetic environment or lateral sensitivity issues of direct capacitive sensing.
2Measurement precision
If the optical measuring beam is directed coaxially with the laser beam, then the distance measurement accuracy is improved, but the device complexity increases
Solution Approach 1:
The patent merges the optical measuring beam path with the laser beam path by directing both beams through the same processing head and focusing optics. The OCT system's measuring beam is combined with the laser processing beam, allowing both functions to share common optical components such as the focusing lens and delivery fiber. This integration reduces overall system complexity while maintaining measurement accuracy.
Solution Approach 2:
The processing head is designed to serve multiple functions: it delivers both the laser processing beam and the optical measuring beam to the workpiece. The focusing optics and beam delivery system are configured to handle both beams simultaneously, making the system universal in its capability to perform both material processing and precise distance measurement through the same aperture and optical path.
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 stable and accurate distance control during laser processing, minimizing errors and maintaining a constant distance between the processing head and the workpiece, thereby enhancing the stability and precision of machining processes.
Implementation Method 1
a measuring device (in particular an optical coherence tomograph) is configured to direct a measuring beam onto the aperture and the at least one reflective reference
Implementation Method 2
determine a distance between the processing head and the workpiece on the basis of a first reflection of the optical measuring beam from the at least one reflective reference and at least a second reflection of the optical measuring beam from the workpiece
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
The invention relates to a machining head (101) for a laser machining system (100), which is designed for machining a workpiece (1) using a laser beam (10). The machining head (101) comprises a housing (210) having an opening (212) for allowing the laser beam (10) to pass out of the machining head (101), at least one reflective reference area (214) on the housing (210), and a measuring device (120) which is designed to direct an optical measuring beam (13) onto the opening (212) and the at least one reflective reference area (214), wherein the measuring device (120) is also designed to determine a distance (d1) between the end section (216) and the workpiece (1) based on a first reflection (A) of the optical measuring beam (13) from the at least one reflective reference area (214) and a second reflection (B) of the optical measuring beam (13) from the workpiece (1).