Laser Machining Head Chromatic Compensation for Accurate Process Sensing
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Solution Overview
Problem
Laser processing heads face challenges in precise process monitoring due to chromatic aberration when adjusting the focal position of the laser beam, especially when using different materials for focusing optics, which affects the accuracy of sensor detection and can lead to defocusing issues, particularly on workpieces with curved surfaces.
Innovation Solution
Incorporating a compensating optics system outside the laser beam path to correct chromatic aberration by using a combination of lenses with different dispersions, allowing for achromatic correction and ensuring accurate monitoring regardless of focal position changes, and using a wide range of materials including crystalline and plastic for the compensating optics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If chromatic aberration is not compensated, then the device complexity is reduced, but the measurement precision of the sensor arrangement deteriorates due to defocusing at different focal positions
Solution Approach 1:
A compensating optics arrangement is introduced as an intermediary optical element between the focusing optics and the sensor arrangement. This compensating optics specifically corrects the chromatic aberration caused by the focusing optics, enabling accurate detection of process light at different focal positions without requiring complete redesign of the entire optical system.
Solution Approach 2:
The compensating optics arrangement changes the optical parameters (focal length, chromatic properties) to compensate for the chromatic aberration. By adjusting the optical parameters of the compensating optics, the system maintains measurement precision across varying focal positions while keeping the overall device complexity manageable.
2Adaptability or versatility
If the focal position is adjusted for workpieces with curved surfaces, then the adaptability to different workpiece geometries is improved, but the chromatic aberration causes defocusing and reduces measurement precision
Solution Approach 1:
The compensating optics acts as a mediator that specifically addresses the chromatic aberration issue when focal position is adjusted. This allows the laser processing head to adapt to curved surfaces by changing focal position while the compensating optics ensures that process light from different wavelengths remains properly focused on the sensor.
Solution Approach 2:
The compensating optics is designed to provide local chromatic correction specifically for the process light detection path. Different regions of the optical system have different functions: the focusing optics handles the laser beam, while the compensating optics specifically addresses the chromatic properties for sensor detection, allowing optimized performance for each function.
3Reliability
If different materials are used for focusing optics, then the laser beam processing capability is improved, but the chromatic aberration increases and affects sensor detection accuracy
Solution Approach 1:
The compensating optics serves as an intermediary that corrects the chromatic aberration introduced by the focusing optics made of specific laser-compatible materials. This allows the use of optimal materials for laser beam processing while compensating for their chromatic properties in the detection path.
Solution Approach 2:
The optical system is segmented into distinct functional sections: the focusing optics section optimized for laser beam processing, and the compensating optics section optimized for chromatic correction of process light. This segmentation allows each section to be optimized for its specific function without compromise.
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 solution enables precise and reliable monitoring of laser machining processes, maintaining accurate detection of process light across different focal positions and orientations, enhancing the reliability and precision of laser processing heads.
Implementation Method 1
compensating optics for correcting a chromatic aberration, caused by the focusing optics, of the laser beam
Implementation Method 2
focusing optics for focusing the laser beam onto the workpiece
Data Source
AI summary
A laser machining head for material processing with a laser includes: a focusing optics for focusing the laser beam; an exit opening for the laser beam; an optical sensor arrangement; a coupling optics for coupling light entering through the exit opening out of the beam path of the laser beam to the sensor arrangement; an optics for adjusting a focal position of the laser beam, which has at least one adjustable optical element for adjusting the focal position of the laser beam; and a compensating optics for correcting a chromatic aberration, caused by the focusing optics, of the light coupled out to the sensor arrangement. The compensating optics are arranged between the coupling optics and the sensor arrangement and are arranged for adjusting a focal position of the light coupled out to the sensor arrangement.