Laser-Marked Rotor Core Codes With Stable Contrast on Metal Surfaces

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Solution Overview

Problem

The readability of two-dimensional codes on metal products is compromised due to surface irregularities such as rolling marks and uneven gloss, leading to inconsistent code recognition when scanned.

Innovation Solution

A method involving the formation of a base region and a black marking on the metal surface using laser beams, where the base region is scanned in one direction and the black marking in a different direction, enhancing contrast and readability by ensuring consistent light reflection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a two-dimensional code is formed on a metal surface with rolling marks or surface treatment, then the identification function is achieved, but the readability of the code deteriorates due to irregular light reflection and gloss

Engineering Contradiction:
Improveidentification functionVSAvoidreadability of code
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The invention applies different surface treatments to different regions: the mark region receives laser irradiation to create a matte finish with consistent light reflection, while the base region maintains its original surface characteristics. This local differentiation ensures that the mark region provides stable optical properties for code reading regardless of the overall surface condition of the metal product.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The laser irradiation process is applied in advance to the mark region to pre-establish a surface with consistent light reflection characteristics. This preliminary treatment counteracts the harmful effects of rolling marks and surface gloss before the code reading process occurs, ensuring reliable readability.

Inventive Principle:
Principle #9Preliminary anti-action

2Shape

If the metal surface undergoes surface treatment to improve appearance, then the gloss and evenness of the surface is improved, but the consistency of light reflection deteriorates causing variable code readability

Engineering Contradiction:
Improvesurface evennessVSAvoidcode readability consistency
Core Design Contradiction:
ShapeVSMeasurement precision

Solution Approach 1:

The invention creates a localized matte finish in the mark region through laser irradiation, which has different optical properties from the treated base region. This local quality difference ensures that the mark region's light reflection characteristics are dominated by the laser-induced surface structure rather than the overall surface treatment, providing consistent readability.

Inventive Principle:
Principle #3Local quality

3Loss of information

If laser irradiation is applied to form marks on a metal surface, then the identification code is created, but the contrast and readability deteriorate when the surface has rolling marks or uneven gloss

Engineering Contradiction:
Improveidentification code formationVSAvoidcode contrast and readability
Core Design Contradiction:
Loss of informationVSMeasurement precision

Solution Approach 1:

The laser irradiation creates a localized surface modification in the mark region that produces a matte finish with uniform light scattering properties. This local quality change ensures high contrast between the mark and base regions, and the consistent optical properties of the mark region ensure readable code recognition regardless of the overall surface condition.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention converts the potential harm of surface irregularities into a benefit by creating a mark region with deliberately engineered optical properties. The laser-induced matte surface in the mark region provides consistent light reflection that actually improves readability by eliminating the problematic specular reflection from glossy surfaces.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 significantly improves the readability of the identification code by enhancing the contrast between the black marking and the base region, allowing successful code recognition from various angles and reducing the impact of surface irregularities.

Implementation Method 1

forming a black marking having a predetermined pattern by repeating the process of irradiating a surface of a metal member with a laser beam to oxidize metal

Methodology Applied
Scientific EffectLaser oxidation: Photo-oxidation

Implementation Method 2

first recesses and second recesses formed by laser irradiation, wherein the second recesses have a different light reflection density from the first recesses

Methodology Applied
Scientific EffectLaser heating: Heating

Data Source

PatentEP3610980B1Method for manufacturing metal product, and metal product
Publication Date: 2024.09.25 MITSUI HIGH TEC INC
  • EP3610980B1 patent drawingFigure 1
  • EP3610980B1 patent drawingFigure 2
  • EP3610980B1 patent drawingFigure 3

AI summary

The present disclosure provides a method of manufacturing a metal product and a metal product with enhanced readability of an identification code. A method of manufacturing a stacked rotor core 1 includes forming a base region 12 on a surface 2b of a stack 2 by repeatedly scanning along a predetermined first direction while irradiating the surface 2b of the stack 2 with a base laser beam over multiple rows, and forming a black marking 14 that is formed by oxidizing the surface 2b of the stack 2, by repeatedly scanning along a predetermined second direction while irradiating the surface 2b of the stack 2 with a marking laser beam over multiple rows. The second direction is different from the first direction. An identification code 10 having a predetermined pattern comprises a combination of the base region 12 and the black marking 14.