Laser Processing Head Focus Compensation via Camera Feedback
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Solution Overview
Problem
Laser processing heads face challenges in maintaining a consistent focus position due to heating effects, which can lead to suboptimal processing results during material processing, as the optical properties of the lens system change, affecting the beam profile and focal point position.
Innovation Solution
A laser processing head with an imaging sensor unit and a camera that adjusts the focus position using a correction factor calculated from image sharpness, temperature sensors, and radiation intensity, employing a self-learning mechanism to maintain the optimal focus position relative to the workpiece, and utilizing HDR imaging for improved visualization of the processing area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If laser radiation is focused by a lens system during material processing, then the processing precision is improved, but the lens system is heated by laser light causing change in optical properties and focus position
Solution Approach 1:
The patent implements a feedback mechanism where a camera monitors the processing area and detects changes in focus position caused by lens heating. The system calculates a correction factor based on image sharpness analysis and automatically adjusts the lens position to compensate for thermal drift, thereby maintaining consistent focus precision despite temperature increases in the lens system
Solution Approach 2:
The patent replaces direct mechanical temperature control of the lens system with an optical-mechanical substitution approach. Instead of mechanically cooling or stabilizing the lens, the system uses optical monitoring (camera-based image analysis) to detect focus shifts and translates these into mechanical adjustments of the lens position, substituting thermal management with optical feedback and mechanical compensation
2Manufacturing precision
If the focus position is adjusted to compensate for lens heating, then the processing quality is maintained, but additional monitoring and control systems are required
Solution Approach 1:
The patent applies multi-functionality by using the same optical path for both laser processing and monitoring purposes. The camera system shares the optical train with the laser beam, allowing the monitoring system to utilize existing optical components rather than requiring separate dedicated monitoring optics, thereby reducing overall system complexity while maintaining processing quality
Solution Approach 2:
The system implements self-service through automatic focus compensation. The camera continuously monitors image sharpness, automatically calculates the correction factor, and triggers lens position adjustments without requiring external intervention or complex manual calibration procedures, simplifying operation while maintaining high processing quality
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 ensures a consistent and optimal focus position, enhancing the quality of laser processing results by automatically adjusting the focus based on real-time data and learned empirical values, thereby maintaining the desired processing outcome.
Implementation Method 1
laser radiation is focused by means of a lens system
Implementation Method 2
detection of process emissions, that is to say, in particular, of electromagnetic radiation from the interaction zone between laser beam and workpiece, by means of photodiodes, other photosensors or imaging sensor technology
Data Source
AI summary
The invention relates to a laser machining head (100) for machining a workpiece by means of a working laser beam (108), with a camera (102) with an imaging lens system (116) arranged in front of said camera in the beam path for observing a machining region of the workpiece that is being machined by means of the working laser beam (108), with a focusing lens system (114) for focusing the working laser beam (108) on the workpiece surface (104) or on a position defined in relation to the workpiece surface (104), and with an evaluation unit (122) which is designed to calculate a corrective adjusting displacement (ΔZos, ΔZB) by means of an adjusting displacement (ΔdKL) of the imaging lens system (116) in the direction of the optical axis in order to refocus the camera image when there is a shift in the focal point of the focusing lens system (114), which corrective adjustment displacement compensates a shift in the focal point of the focusing lens system (114) in relation to the workpiece surface (104) or with respect to a position defined in relation to the workpiece surface (104).