Laser Matrix Code Marking for Steel Tube Production Control

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Solution Overview

Problem

Existing methods for identifying and managing steel tubes and pipes, particularly in nuclear power plant applications, face challenges such as difficulty in applying to small-diameter pipes, high labor costs, heat generation during machining, and reduced identification performance due to surface roughness, making it hard to reliably identify and record production information across multiple processes.

Innovation Solution

A production management method involving machining a two-dimensional matrix code on the steel tubes and pipes using a laser beam, which is read automatically with a linear sensor type camera, allowing for efficient identification and recording of production information without causing thermal damage, and incorporating manual reading for specific cases to ensure accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a bar code is stuck to a material-protective sheet or inserted in a steel pipe, then identification management can be carried out, but much labor is spent because production management must be carried out on a pipe basis in all processes

Engineering Contradiction:
Improvelabor consumptionVSAvoidproduction management efficiency
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The patent replaces manual mechanical operations (attaching bar codes, manual inspection, manual data recording) with an automated laser marking system that directly imprints identification codes onto steel pipes. The linear sensor camera automatically reads the codes without human intervention, and the control unit automatically records production information, eliminating the need for manual labor in identification management across all production processes.

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

Solution Approach 2:

The steel pipe itself becomes the carrier of identification information through direct laser marking on its surface, eliminating the need for external tags or labels. The pipe's own surface serves the dual function of structural integrity and information storage, allowing the pipe to 'identify itself' throughout the production process without requiring additional components or manual intervention.

Inventive Principle:
Principle #25Self-service

2Reliability

If markings are performed directly on steel pipe outer surface, then identification is improved, but the marking may disappear

Engineering Contradiction:
Improveidentification reliabilityVSAvoidmarking durability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent transitions from surface-level markings (2D) to multi-dimensional encoding by using matrix codes with multiple layers of information. The identification system incorporates not only visual patterns but also encodes production conditions, timestamps, and quality data in multiple dimensions, making the information more resilient to surface degradation while maintaining readability.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The laser marking is applied early in the production process before any surface treatment or coating operations. By establishing the identification code on the raw steel surface first, the marking becomes part of the base material structure, ensuring it remains intact through subsequent manufacturing steps and maintains durability throughout the product lifecycle.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If imprinting is performed on the inner or outer surface of steel pipe, then identification is improved, but flaws are generated on the steel pipe or imprinting on inner surface of small-diameter pipe is incapable

Engineering Contradiction:
Improveidentification capabilityVSAvoidsteel pipe flaw generation
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces mechanical imprinting processes (which involve physical contact and pressure) with non-contact laser marking technology. The laser beam delivers energy to the steel surface without mechanical force, eliminating the generation of flaws or structural damage while still creating permanent, readable identification marks on both inner and outer surfaces regardless of pipe diameter.

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

4Reliability

If laser beam is applied to form thick lines, then bar code is formed, but thermal attack and chemical change in material are caused

Engineering Contradiction:
Improvecode formationVSAvoidthermal attack and chemical change
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent uses matrix codes instead of traditional bar codes, which require less total laser energy to create the same information density. The optimized laser parameters deliver just enough energy to create clear, readable marks without excessive heating. The linear sensor camera efficiently reads the code with minimal exposure time, reducing the duration of thermal exposure and preventing material degradation.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The patent optimizes laser marking parameters including pulse duration, power density, and scanning speed to minimize thermal input. By adjusting these parameters, the system achieves clear code formation with reduced heat accumulation, preventing thermal attack and chemical changes in the steel material while maintaining code readability and durability.

Inventive Principle:
Principle #35Parameter changes

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 method enables reliable identification and recording of production information on a pipe basis, reducing thermal attacks and increasing productivity by using a two-dimensional matrix code that can be read efficiently across multiple processes, especially suitable for complex production processes like heat exchanger tubes for steam generators.

Implementation Method 1

a matrix code which encodes tube or pipe information is machined in a tube or pipe end by a laser beam

Methodology Applied
Scientific EffectLaser ablation: Laser Ablation

Implementation Method 2

the matrix code is read automatically by a linear sensor type camera

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP2775364B1Steel tube production control method
Publication Date: 2019.10.30 NIPPON STEEL CORPORATION
  • EP2775364B1 patent drawingFigure 1~4
  • EP2775364B1 patent drawingFigure 5~6

AI summary

There is provided a production management method for steel tubes and pipes produced through a plurality of production processes, including: a step of machining a matrix code, which encodes tube or pipe information, in a tube or pipe end by a laser beam so that the central angle of width of the matrix code in a circumferential direction of the tube or pipe is 30° or smaller; and a step of reading the matrix code automatically by using a linear sensor type camera, wherein through reading the matrix code, the production history is managed by identifying and recording the production information and quality information corresponding to each steel tube or pipe for each tube or pipe number, and the tube or pipe information is retrievable as necessary.