Quality Factor Estimation Using Physics-Guided Feature Importance

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Solution Overview

Problem

Existing methods for predicting quality defects in manufacturing processes can generate mathematical models with local regions that contradict the physical mechanism of defect occurrence, leading to inaccurate estimation of quality factors.

Innovation Solution

A method and apparatus that utilize quality and operating data to generate models with feature importance determination, identify major operating variables for quality defects, and adjust operating conditions based on high-accuracy predictions, using machine learning and probabilistic evaluation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the number of splits in the operating variable space is increased to improve model accuracy, then the model error decreases, but local regions that contradict the physical mechanism of defect occurrence are generated

Engineering Contradiction:
Improvemodel accuracyVSAvoidconsistency with physical mechanism
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent changes the parameter used for determining split points from purely data-driven clustering or manual setting to physics-driven parameter selection. By using parameters that reflect the actual physical mechanism of defect occurrence, the method ensures that increased model accuracy does not come at the cost of physical consistency. This resolves the contradiction by transforming the split determination criterion to align with physical reality while maintaining high accuracy.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces physics-based knowledge as an intermediary between the data-driven model and the physical mechanism. This intermediary guides the splitting process to ensure that while the model achieves high accuracy through multiple splits, the resulting local regions remain consistent with the underlying physical mechanisms. The physics knowledge acts as a mediator that reconciles the conflicting requirements of accuracy and physical consistency.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If clustering methods or manual setting are used to determine split points, then the mathematical model can be constructed, but the selected operating variables may contradict the physical mechanism of defect occurrence

Engineering Contradiction:
Improvemodel construction feasibilityVSAvoidphysical mechanism consistency
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent fundamentally changes the parameter selection criterion from convenience-based (clustering/manual) to physics-based. By selecting split points based on parameters that represent the actual physical mechanisms of defect occurrence, the method ensures that the constructed model is not only easy to build but also physically meaningful. This resolves the contradiction by making physics consistency the foundation of model construction rather than an afterthought.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent performs preliminary action by incorporating physics-based knowledge before the actual model construction and splitting process. By pre-establishing the physical mechanisms and selecting split points based on these mechanisms in advance, the method ensures that subsequent model construction automatically maintains physical consistency. This preliminary physics-based preparation prevents contradictions from arising during model construction.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4715722A1Quality factor estimation method, operation condition change method, model generation method, quality factor estimation device, and operation condition change device
Publication Date: 2026.03.25 JFE STEEL CORP
  • EP4715722A1 patent drawingFigure 1
  • EP4715722A1 patent drawingFigure 2
  • EP4715722A1 patent drawingFigure 3

AI summary

A method of estimating quality factors includes a step of acquiring quality data indicating a quality of a product with respect to normal quality and m types of quality defects, m being two or more, a step of acquiring operating data of a manufacturing process, a step of creating quality evaluation data for each of the m types of quality defects, a step of acquiring m types of models generated using the quality evaluation data and determining a feature importance indicating the magnitude of contribution of an operating variable for each of the m types of models, and a step of identifying the operating variable that is estimated to be a major factor for at least one of the m types of quality defects by comparing the feature importance of the m types of models.