Laser Oxide Stripping With Adaptive Energy Density Control

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Solution Overview

Problem

Existing methods for removing oxide layers on metal products, such as stainless steel strips, are inefficient, costly, environmentally harmful, and unable to adapt to varying oxide layer thickness and composition on an industrial scale, particularly with changing line speeds.

Innovation Solution

A method and installation using laser stripping with adjustable energy density thresholds determined by analysis laser pulses to effectively remove oxide layers without damaging the metal surface, utilizing a system to detect and adjust energy levels for each section of the moving product.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If chemical pickling is used to remove oxide layers, then oxide removal effectiveness is improved, but environmental pollution and acid consumption increase significantly

Engineering Contradiction:
Improveoxide removal effectivenessVSAvoidenvironmental pollution
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces chemical pickling (chemical system) with laser stripping (optical/thermal system). The laser beam delivers energy to vaporize and eject oxide layers without chemical reactions, eliminating acid consumption and associated environmental pollution while maintaining effective oxide removal.

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

Solution Approach 2:

The patent changes the fundamental parameter of the stripping process from chemical concentration (acid strength) to energy density (laser power per unit area). By controlling laser energy density, the process achieves oxide removal without the harmful chemical byproducts of traditional pickling.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If laser stripping is used with fixed energy density, then process simplicity is improved, but adaptability to varying oxide layer thickness and composition deteriorates

Engineering Contradiction:
Improveprocess simplicityVSAvoidadaptability to varying oxide conditions
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent introduces dynamic adaptability by allowing laser energy density to vary based on real-time detection of oxide layer characteristics. The system transitions from a static fixed-energy approach to a dynamic adaptive approach, where energy parameters are continuously adjusted to match varying oxide thickness and composition across different sections of the metal product.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements a feedback mechanism where the laser system responds to detected oxide conditions by adjusting energy density. This closed-loop control enables the system to adapt to varying oxide layers while maintaining process simplicity through automated parameter adjustment rather than complex manual intervention.

Inventive Principle:
Principle #23Feedback

3Reliability

If high energy density is used for complete oxide removal, then stripping effectiveness is improved, but risk of metal surface damage increases

Engineering Contradiction:
Improvestripping effectivenessVSAvoidsurface damage risk
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent utilizes parameter changes in the oxide layer itself during the stripping process. As the laser energy density vaporizes the oxide, the optical properties of the remaining material change, providing natural feedback that allows precise control of energy input to stop just before damaging the metal substrate.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces mechanical contact-based stripping methods with optical energy delivery. The laser energy can be precisely controlled and stopped at the exact moment oxide removal is complete, avoiding the overshoot and surface damage risks inherent in mechanical or chemical methods that cannot be as precisely controlled.

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

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

Achieves efficient oxide layer removal on an industrial scale with reduced environmental impact, enabling precise control over energy density to ensure complete stripping without surface damage, and allowing for adaptability to varying oxide conditions.

Implementation Method 1

laser stripping by means of at least one stripping laser

Methodology Applied
Scientific EffectLaser: Laser

Implementation Method 2

expulsion of the oxide layer

Methodology Applied
Scientific EffectAblation: Ablation

Data Source

PatentEP4377042B1Method and apparatus for stripping an oxide layer from a metal product
Publication Date: 2025.07.23 APERAM
  • EP4377042B1 patent drawingFigure 1
  • EP4377042B1 patent drawingFigure 2
  • EP4377042B1 patent drawingFigure 3

AI summary

The method comprises determining an energy density threshold of removal of the oxide layer from a section of the product (3), this comprising transmitting, to a segment of the section, analysis pulses of wavelength and of pulse duration equal to those of the stripping lasers (13) to form a stripped region, capturing an image of the segment, determining, on the basis of this image, a dimension representative of the stripped region and evaluating, on the basis of said dimension, the removal energy density threshold; transmitting stripping pulses to the section, the energy density of the stripping pulses being higher than the removal energy density threshold, the stripping laser (13) being controlled such that every point of the section is exposed to an energy density higher than the removal energy density threshold.