Laser Cutting Feedback Control for Real-Time Dross Monitoring

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Solution Overview

Problem

Laser treatment machines face challenges in achieving optimal productivity and quality in cutting and piercing processes due to static optimization of parameters, which can result in suboptimal conditions, and existing monitoring methods fail to provide reliable continuous feedback on dross formation.

Innovation Solution

A laser treatment method and machine equipped with a control unit and monitoring device that continuously acquires images of the processing zone, analyzes characteristic parameters, and adjusts process parameters in real-time to control the quality of cutting or piercing, allowing for the tolerable presence and quantity of dross to be managed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If processing parameters are optimized statically through simulations or measurements to maximize productivity, then productivity is improved, but treatment quality may become suboptimal under varying conditions

Engineering Contradiction:
Improveprocessing productivityVSAvoidtreatment quality
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent implements dynamic adjustment of processing parameters during laser treatment by continuously monitoring dross formation and modifying laser power, gas pressure, or cutting speed in real-time. This transforms the static parameter optimization into a dynamic control system that adapts to changing process conditions, maintaining both high productivity and consistent treatment quality throughout the workpiece processing.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent introduces a feedback control mechanism where dross formation is continuously monitored during the laser treatment process and this information is used to adjust processing parameters. The feedback loop compares actual dross levels with target values and automatically modifies laser parameters to maintain optimal quality, resolving the contradiction between productivity and quality by enabling adaptive control.

Inventive Principle:
Principle #23Feedback

2Manufacturing precision

If processing parameters are set to obtain maximum achievable quality (absence of dross), then treatment quality is improved, but productivity is reduced

Engineering Contradiction:
Improvetreatment qualityVSAvoidproductivity
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent employs parameter changes by dynamically adjusting laser power, gas pressure, and cutting speed based on real-time dross monitoring. Instead of using fixed conservative parameters that ensure quality but reduce productivity, the system continuously modifies parameters to maintain optimal quality while maximizing productivity, allowing higher speeds and powers when conditions permit.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system transitions from static parameter settings to dynamic parameter adjustment, where processing parameters are continuously optimized during treatment based on actual dross formation. This enables the system to operate at higher productivity levels while maintaining quality by adapting parameters to actual process conditions rather than using fixed conservative settings.

Inventive Principle:
Principle #15Dynamics

3Loss of information

If photodiodes are used to monitor the treatment process, then some process information is obtained, but reliable information on dross formation cannot be obtained

Engineering Contradiction:
Improveprocess informationVSAvoiddross detection accuracy
Core Design Contradiction:
Loss of informationVSMeasurement precision

Solution Approach 1:

The patent replaces photodiode-based optical monitoring with a different detection approach that uses sensors capable of reliably detecting dross formation. This substitution enables accurate measurement of dross characteristics by using detection technology specifically suited for identifying dross presence and quantity, overcoming the limitations of photodiodes which cannot provide reliable dross information.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces an intermediary detection system that indirectly measures dross formation through characteristics that correlate with dross presence. Rather than directly observing dross with inadequate photodiodes, the system uses intermediate measurements (such as optical properties, acoustic signals, or other process parameters) that provide reliable information about dross formation, enabling accurate monitoring without direct dross observation.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 enables continuous monitoring and control of cutting or piercing quality, optimizing productivity while maintaining desired quality levels, and allows for the determination of non-discrete dross presence, improving the accuracy and flexibility of the process.

Implementation Method 1

an emission source 4 of a laser beam 5 configured to emit the laser beam 5

Methodology Applied
Scientific EffectLaser heating: Laser

Implementation Method 2

directing the laser beam 5 onto the work piece 2 at a working zone 7 in order to execute the cutting and/or piercing

Methodology Applied
Scientific EffectLaser ablation: Laser Ablation

Data Source

PatentEP3838471B1Laser treatment method
Publication Date: 2024.06.19 ADIGE SPA
  • EP3838471B1 patent drawingFigure 1~2c
  • EP3838471B1 patent drawingFigure 3~4

AI summary

A laser treatment method of a metallic work piece (2) comprising at least the steps of a) directing a laser beam (5) onto the work piece (2) at a working zone (7) of the working piece (2) in order to execute a cutting and/or piercing; b) executing a relative movement between the laser beam (5) and the work piece (2) at a determined velocity; c) acquiring a plurality of acquired images (9) of the working zone (7); d) determining a time course of at least one characteristic parameter from the acquired images (9); e) calculating at least one statistical parameter from the time course of the characteristic parameter; f) establishing a quality value from the statistical parameter; and g) controlling one or more process parameters, in particular at least an intensity of the laser beam (5) and/or a laser frequency of the laser beam (5) and/or a position of the focus of the laser beam (5) and/or the determined velocity and/or a gas jet and/or a gas pressure of the gas jet, in function of the quality value.