Brush Roll Torque Monitoring for Electrical Steel Groove Depth

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Solution Overview

Problem

Existing methods for forming grooves on electrical steel sheets using laser beams are prone to forming shallow grooves due to beam output decreases or focal point shifts, which can reduce the iron loss reduction rate of the steel sheets.

Innovation Solution

A groove depth monitoring system that utilizes a torque acquisition unit to measure rotational torque from a polishing brush roll and a groove depth determination unit to determine if the groove depth is sufficient, supplemented by spatter amount monitoring to ensure accurate groove depth assessment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If beam output decreases or focal point shifts during groove formation, then the groove becomes shallow, but detecting this condition is difficult using only spatter monitoring

Engineering Contradiction:
Improvegroove depthVSAvoiddetection accuracy
Core Design Contradiction:
Manufacturing precisionVSMeasurement precision

Solution Approach 1:

The patent introduces a polishing brush roll as an intermediary element that contacts the groove surface after formation. The brush roll's rotational torque serves as a mediator to indirectly measure groove depth, overcoming the limitation of direct spatter monitoring which cannot reliably detect shallow grooves caused by beam output decrease or focus shifts.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the optical/spatter-based detection system with a mechanical torque measurement system. By measuring the rotational torque of the polishing brush roll as it contacts the groove, the system achieves more reliable detection of groove depth variations that spatter monitoring cannot detect.

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

2Device complexity

If only spatter amount monitoring is used to detect groove depth, then the monitoring system is simple, but shallow grooves due to beam output decrease cannot be reliably detected

Engineering Contradiction:
Improvemonitoring system complexityVSAvoiddetection reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent merges two monitoring approaches: spatter amount monitoring and polishing brush roll torque monitoring. By combining these methods, the system maintains operational simplicity while significantly improving detection reliability for shallow grooves that would be missed by spatter monitoring alone.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system establishes a feedback mechanism where the rotational torque of the polishing brush roll is continuously monitored and used to detect groove depth variations. This feedback loop enables real-time detection of beam output issues and focus shifts, allowing for timely corrective actions.

Inventive Principle:
Principle #23Feedback

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

The system effectively detects and prevents shallow grooves by monitoring rotational torque and spatter amounts, ensuring the grooves meet a reference depth, thereby maintaining the iron loss reduction efficiency of the electrical steel sheets.

Implementation Method 1

a polishing brush roll that removes deposits adhering to the front surface of the steel sheet on which the groove is formed by the beam

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

a polishing brush roll that removes deposits adhering to the front surface of the steel sheet on which the groove is formed by the beam

Methodology Applied
Scientific EffectAbrasion: Abrasion

Implementation Method 3

a groove is formed by irradiating a front surface of the grain-oriented electrical steel sheet with a laser beam

Methodology Applied
Scientific EffectLaser ablation: Laser Ablation

Implementation Method 4

a groove is formed by irradiating a front surface of the grain-oriented electrical steel sheet with a laser beam

Methodology Applied
Scientific EffectAblation: Ablation

Data Source

PatentEP4678328A1Groove-depth monitoring system, electrical steel sheet manufacturing apparatus, groove depth monitoring method, and groove depth monitoring program
Publication Date: 2026.01.14 NIPPON STEEL CORPORATION
  • EP4678328A1 patent drawingFigure 1
  • EP4678328A1 patent drawingFigure 2
  • EP4678328A1 patent drawingFigure 3

AI summary

A groove depth monitoring system includes: a torque acquisition unit that acquires a rotational torque generated when removing deposits adhering to a front surface of a steel sheet on which a groove is formed by a beam by a polishing brush roll; and a groove depth determination unit that determines whether or not a depth of the groove formed on the front surface of the steel sheet is equal to or larger than a reference value based on the rotational torque acquired by the torque acquisition unit and a predetermined reference rotational torque.