Laser Piercing Control Using Process Radiation Feedback
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
During laser processing of metal workpieces, spontaneous material removal can lead to contamination and damage of machines, and existing methods struggle to balance processing speed with quality, as excessive energy application causes undesirable material removal processes.
Innovation Solution
The method involves detecting process radiation intensity and gradient changes during pulse pauses in a laser processing operation, comparing these against threshold values, and adjusting laser or processing parameters to control and prevent spontaneous material removal, including the use of auxiliary gas jets to manage the process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the laser processing time is shortened to increase productivity, then the processing speed is improved, but the quality of the perforated hole deteriorates due to excessive energy application causing spontaneous material removal
Solution Approach 1:
The patent implements a feedback control system that continuously monitors process radiation intensity during laser processing. When the radiation intensity exceeds a predetermined threshold, indicating spontaneous material removal, the system automatically adjusts laser parameters (power, pulse duration, frequency) to prevent further damage while maintaining acceptable processing speed. This closed-loop control resolves the contradiction by dynamically balancing productivity and quality based on real-time process conditions.
Solution Approach 2:
The system dynamically adjusts laser processing parameters based on detected process conditions. By making the processing parameters variable rather than fixed, the system can optimize for speed when conditions are favorable and switch to quality-preserving modes when spontaneous material removal is detected, thus resolving the static contradiction between speed and quality requirements.
2Productivity
If higher laser energy is applied to maintain processing speed, then the productivity is improved, but spontaneous material removal processes occur causing contamination and damage to machine components
Solution Approach 1:
The monitoring system detects spontaneous material removal through process radiation analysis and provides feedback to the control system. When harmful material removal is detected, the system reduces laser energy application or adjusts processing parameters to eliminate the harmful effect while minimizing impact on overall productivity. This feedback mechanism prevents the escalation of harmful effects that would otherwise occur with sustained high energy application.
Solution Approach 2:
The system uses the radiation emitted during spontaneous material removal (which is normally harmful) as a detection signal. By monitoring this process radiation, the system can detect the onset of harmful material removal processes and take corrective action. The harmful radiation becomes a useful diagnostic tool that enables preventive control, converting a harmful effect into a beneficial monitoring mechanism.
3Manufacturing precision
If the laser processing time is extended to prevent spontaneous material removal, then the quality is improved, but the productivity decreases
Solution Approach 1:
The feedback control system enables quality maintenance without extended processing time by dynamically adjusting parameters in response to real-time conditions. When spontaneous material removal is detected, the system modifies laser parameters to prevent quality degradation, eliminating the need for conservative extended processing times. This allows the system to maintain high quality standards while preserving productivity through intelligent, responsive control rather than brute-force time extension.
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 effectively detects and mitigates spontaneous material removal, allowing for controlled and efficient piercing or cutting operations with improved productivity and reduced machine damage, while maintaining hole quality.
Implementation Method 1
focusing a pulsed laser beam onto a processing location on a workpiece
Implementation Method 2
detecting process radiation emitted from the processing location
Data Source
AI summary
The disclosure relates to methods and systems for piercing, drilling, or cutting metal workpieces in a laser processing operation. The methods include focusing a pulsed laser beam onto a processing location on a workpiece; detecting process radiation emitted from the processing location; determining an intensity of the process radiation at a plurality of temporally sequential times during pulse pauses; determining an intensity gradient of the process radiation; comparing the intensity gradient with a gradient threshold value; and detecting a spontaneous material removal on the workpiece when the number of times the gradient threshold value has been exceeded is above a predetermined limit value. When a spontaneous material removal is detected, the system changes one or both of a laser parameter and a processing parameter of the laser processing operation. The disclosure also relates to processing machines for carrying out the methods.