Laser Machining Camera Alignment via Wavelength-Selective Mirror
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Solution Overview
Problem
Existing laser machining systems face challenges in reliably imaging the laser beam on the workpiece, particularly at the outlet nozzle, and are prone to complex structures susceptible to pollution, with manual adjustments and external detection methods failing to accurately register lateral beam displacements.
Innovation Solution
A laser machining apparatus with a wavelength-selective mirror and an imaging camera positioned inside the processing head, allowing for automatic beam control and alignment relative to the outlet nozzle, using image data to adjust the mirror and ensure precise beam positioning in the XY plane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a camera is positioned outside the laser processing head for beam detection, then the structure is simpler, but lateral position displacements of the laser spots at the workpiece cannot be registered
Solution Approach 1:
The camera is repositioned from an external location to an internal position within the laser processing head, changing the spatial dimension of detection. This allows the camera to capture images at the actual workpiece location, enabling accurate registration of lateral beam displacements while maintaining structural simplicity through integrated design
2Measurement precision
If detectors are used for laser beam detection, then beam position can be measured, but the structure becomes complex and susceptible to pollution
Solution Approach 1:
Instead of using complex detectors to directly measure the laser beam, the system uses a camera to capture images of the laser spot on the workpiece. The camera records visual information (copy) of the beam position, which is then processed to determine lateral displacements. This approach simplifies the detection system while maintaining measurement capability and reducing susceptibility to pollution
3Ease of operation
If manual beam adjustment is used, then the system is simpler to operate, but automation and optimal workpiece machining cannot be ensured
Solution Approach 1:
The system implements automatic feedback control by continuously capturing images of the laser spot position with the camera, processing these images to determine lateral displacements, and automatically adjusting the beam position based on the measured deviations. This closed-loop feedback mechanism ensures automation and optimal machining quality while maintaining ease of operation through automatic control
4Device complexity
If the camera optical path overlaps with the laser beam path, then compact design is achieved, but the mirror must be wavelength selective to separate laser and visible light
Solution Approach 1:
The mirror is designed with wavelength-selective properties, being reflective for the laser wavelength while transparent for visible light wavelengths. This local differentiation of optical properties allows the same mirror surface to serve dual functions: deflecting the laser beam to the workpiece while permitting visible light to pass through to the camera for imaging
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 setup enables accurate determination and correction of the laser beam position on the workpiece, preventing poor quality processing and ensuring high-quality cuts by decoupling the laser beam from visible light, allowing for real-time tracking and monitoring of the beam and nozzle conditions.
Implementation Method 1
a wavelength-selective mirror (8) which is reflective for a laser beam (3) in the laser beam path (7) and is transparent to at least one wavelength region of the visible spectrum
Implementation Method 2
wavelength-selective mirror (8) which is reflective for the laser beam (3) and is transparent to at least one wavelength region of the visible spectrum
Implementation Method 3
an imaging camera (10), wherein an optical path (11) of the camera is directed from the inside to the outlet nozzle (5)
Data Source
AI summary
The invention relates to a laser processing device (1) for processing a workpiece (2) with a laser beam (3), in particular a laser cutting machine, comprising a laser processing head (4) with a laser exit nozzle (5), a laser beam path (7) defined within the laser processing head (4), a mirror (8) arranged in the laser beam path (7) for deflecting the laser beam (3) onto the exit nozzle (5), a drive (9) for moving the mirror (8), and an imaging camera (10), wherein the camera beam path (11) is directed from the inside onto the exit nozzle (5), wherein the camera (10) is communicatively connected to an image data evaluation device (12) and the drive (9) of the mirror (8) is communicatively connected to a control device (13), wherein the control device (13) is configuredin order to automatically control the drive (9) of the mirror (8) depending on the evaluation unit (12) of the image data recorded by the camera (10), thereby achieving a predetermined, in particular centered, alignment of the laser beam (3) in relation to the exit nozzle (5).