Laser Marking Quality Control via Real-Time Power Feedback
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Solution Overview
Problem
Current methods for applying identification codes using laser cutting machines result in poor quality due to low repeatability of traversing movements, power fluctuations, and inaccurate contouring, leading to unreliable marking and increased processing time, especially when using high-power lasers.
Innovation Solution
Operating the laser in a pulsed manner with power between 10% and 60% of the maximum, regulating power and pulse duration in real-time based on quality feedback, and using material-specific parameter sets to ensure consistent quality and accuracy of the engraving process, particularly for two-dimensional array codes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If laser cutting machines with high-power lasers (>1 kW) are used for engraving identification codes, then the need for additional engraving devices is eliminated, but the quality of engraving deteriorates due to power fluctuations and poor control in the low-power range
Solution Approach 1:
The system dynamically adjusts laser parameters (power, pulse duration, frequency) in real-time during the engraving process based on feedback from quality monitoring, enabling high-power lasers to operate effectively in the lower power range required for precise engraving
Solution Approach 2:
A quality monitoring system continuously monitors the engraving process and provides feedback to the control unit, which automatically adjusts laser parameters to maintain consistent engraving quality despite power fluctuations inherent in high-power laser operation
2Productivity
If the laser is operated at high power for cutting, then cutting efficiency is improved, but the laser spot size increases and contours become blurred when used for engraving
Solution Approach 1:
The laser operates in pulsed mode with carefully controlled pulse durations and frequencies, delivering energy in discrete bursts that prevent excessive heat diffusion and maintain sharp contours while still achieving efficient material removal
Solution Approach 2:
The system changes multiple laser parameters simultaneously (power reduction to 10-60% of maximum, pulse duration adjustment, frequency modification) to optimize the laser output for precise engraving while maintaining the ability to perform cutting when needed
3Productivity
If fast traversing movements are used for engraving, then processing time is reduced, but repeatability of movements deteriorates due to mass acceleration of the cutting bridge
Solution Approach 1:
The system uses dynamic parameter adjustment during the engraving process, adapting laser power and pulse characteristics in real-time to compensate for variations in movement speed and acceleration, ensuring consistent quality even during fast traversing movements
Solution Approach 2:
The quality monitoring system detects variations in engraving quality caused by movement inconsistencies and provides feedback that triggers automatic parameter adjustments, compensating for the poor repeatability of fast traversing movements
4Adaptability or versatility
If frequent direction changes are made for applying identification codes, then code complexity is increased, but processing time increases due to reduced travel speed
Solution Approach 1:
The pulsed laser operation with optimized pulse frequency and duration allows the system to maintain high engraving quality even during frequent direction changes and pauses, minimizing the impact on processing time while supporting complex code patterns
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 allows for high-quality, reliable identification code engraving on high-energy laser sources, reducing processing time and minimizing errors, with improved accuracy and readability of the markings across various materials.
Implementation Method 1
a laser processing unit at least for changing at least the surface of the workpiece
Implementation Method 2
laser processing unit at least for changing at least the surface of the workpiece
Data Source
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AI summary
This application relates to a method and a device for applying a permanent marking (1) to a workpiece by modifying at least the surface of the workpiece. For this purpose, a pattern is engraved into the surface of the workpiece using a pulsed laser beam, the quality of the engraving is automatically determined, and the laser beam is modified depending on the determined quality. The laser processing unit is operated with an output power between 10% and 60% of its maximum power. Based on the determination of a value characterizing the quality of the engraving, at least one of the parameters of the laser processing unit—power and pulse duration—is controlled in real time such that the characterizing value is kept essentially constant.