Continuous Galvanizing Line Scheduling for Coil Transition Quality

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Solution Overview

Problem

Existing methods for scheduling production on continuous galvanizing lines face challenges in maintaining product quality and productivity due to variations in steel strip characteristics, leading to defects, scrap, and line stoppages, while existing software fails to effectively manage transitions between coils.

Innovation Solution

A method and device for scheduling galvanized coil production that evaluates the impact of coil transitions on product quality by adjusting process parameters and allocating weighting factors, considering line constraints, to optimize the production schedule and minimize defects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If manual scheduling based on operator expertise is used, then operational flexibility is maintained, but transition coils must be regularly inserted which decreases line productivity

Engineering Contradiction:

Improveoperational flexibilityVSAvoidline productivity

Core Design Contradiction:

Ease of operationVSProductivity

Solution Approach 1:

The scheduling system automatically generates optimized coil sequences by evaluating transitions between consecutive coils based on multiple product variables, eliminating the need for manual intervention and transition coils while maintaining operational flexibility

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system dynamically adjusts scheduling parameters by evaluating multiple product variables (width, thickness, zinc coating weight, etc.) and their transitions, optimizing the coil sequence to minimize quality issues without requiring transition coils

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If commercial software with arbitrary penalty/bonus approach is used to smooth transitions, then some transitions are optimized, but the approach is not adapted to variations in product mix and cannot simultaneously optimize multiple product variables

Engineering Contradiction:

Improvetransition qualityVSAvoidadaptability to product mix variations

Core Design Contradiction:

Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The system evaluates multiple product variables (width, thickness, zinc coating weight, grade, etc.) simultaneously with dynamically adjusted weighting factors that adapt to variations in product mix, replacing the arbitrary penalty/bonus approach with a versatile optimization framework

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The weighting factors for different product variables are dynamically adjusted based on the specific product mix and production conditions, allowing the system to adapt to variations in product requirements and optimize transitions accordingly

Inventive Principle:

Principle #15Dynamics

3Manufacturing precision

If process parameters are regularly adapted to match steel strip features, then technical specifications are reached, but transition time causes strip to be out of specifications leading to scrap

Engineering Contradiction:

Improvetechnical specifications complianceVSAvoidscrap

Core Design Contradiction:

Manufacturing precisionVSLoss of substance

Solution Approach 1:

The system pre-evaluates all possible coil transitions and selects sequences that minimize parameter changes, allowing process parameters to be adjusted more gradually and reducing the length of strip out of specification during transitions

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system optimizes the sequence of coils to minimize changes in product variables between consecutive coils, enabling smoother parameter adjustments and reducing scrap during transitions

Inventive Principle:

Principle #35Parameter changes

4Adaptability or versatility

If coils of very different grades are processed consecutively, then production variety is achieved, but welding difficulties and strip breaks occur

Engineering Contradiction:

Improveproduction varietyVSAvoidstrip break occurrence

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The system evaluates compatibility between consecutive coils based on grade differences and other product variables, selecting sequences that minimize welding difficulties and strip break risks while maintaining production variety

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The scheduling system acts as an intermediary that selects appropriate transition coils between coils of different grades, preventing direct incompatible transitions that would cause welding difficulties or strip breaks

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS12371769B2Method for scheduling production on a continuous galvanizing line

Publication Date: 2025.07.29 ARCELORMITTAL SA

AI summary

A method for setting the production schedule of a multiplicity of galvanized coils of metallic strip on a continuous galvanizing line is provided, the method including the steps of evaluating, for each possible combination of two uncoated coils, the impact of the transition from the first uncoated coil to the second uncoated coil on the quality of the galvanized coils, allocating to each possible combination of uncoated coils a weighting factor which depends on the results of the previous step and which takes into account the line constraints, computing the results of the previous step by calculating, for a number of possible schedules of the multiplicity of uncoated coils, a score which depends on the sum of the weighting factors attributed to the combinations of uncoated coils involved in the given schedule and by selecting the schedule with the optimal score.