PVD Surface Treatment Gas Flow to Suppress Steel Sheet Flutter

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Solution Overview

Problem

Grain oriented electrical steel sheets experience coating thickness differences when using the PVD method, leading to flapping and deterioration of magnetic properties such as iron loss, due to uneven coating formation during the surface treatment process.

Innovation Solution

A surface treatment facility is employed where the coating formation-target material is conveyed in a longitudinal direction within a chamber, with a controlled ratio of blowing speed of the coating forming gas to conveyance speed, ranging from 0.4 to 3.0, to prevent flapping and ensure even coating thickness on both surfaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a coating is formed by PVD method on both surfaces of conveyed coating formation-target material, then coating efficiency is improved, but the coating formation-target material may flap and touch interior members causing breakage

Engineering Contradiction:
Improvecoating efficiencyVSAvoidmaterial integrity
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

A blowing mechanism introducing coating forming gas serves as an intermediary to suppress flapping of the coating formation-target material. The gas flow acts as a mediating force that stabilizes the material during conveyance and coating formation, preventing contact with chamber interior members while maintaining the PVD coating process on both surfaces

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If PVD method is used to form coatings on both surfaces, then coating formation speed is improved, but coating thickness difference between surfaces becomes large

Engineering Contradiction:
Improvecoating formation speedVSAvoidcoating thickness uniformity
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The coating forming gas introduced by the blowing mechanism serves as an intermediary that stabilizes the coating formation environment. This gas flow suppresses material flapping and ensures consistent coating thickness on both surfaces by maintaining stable positioning and uniform coating conditions throughout the process

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If coating formation-target material is conveyed in longitudinal direction with both surfaces exposed, then continuous coating production is improved, but flapping occurs causing coating thickness variation

Engineering Contradiction:
Improvecontinuous coating productionVSAvoidcoating thickness consistency
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The coating forming gas acts as a continuous intermediary during the conveyance process, suppressing flapping of the material as it moves through the chamber. This ensures that both surfaces maintain consistent positioning relative to the targets throughout the continuous production process, achieving uniform coating thickness

Inventive Principle:
Principle #24Intermediary (Mediator)

4Strength

If the forsterite coating is removed and steel sheet surface is smoothed, then adhesion of subsequent coating is improved, but the steel sheet surface smoothness deteriorates due to anchoring effect

Engineering Contradiction:
Improvecoating adhesionVSAvoidsurface smoothness
Core Design Contradiction:
StrengthVSShape

Solution Approach 1:

The invention changes the parameters of the coating formation process by using PVD method with controlled gas blowing. This allows coating to be formed on the smoothed surface without requiring forsterite coating removal, maintaining both surface smoothness and achieving adequate adhesion through the PVD process parameters

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 suppresses flapping and achieves even coating thickness, thereby reducing coating thickness differences and improving magnetic properties by maintaining consistent iron loss values.

Implementation Method 1

a coating forming gas is blown on both surface sides of the coating formation-target material in a longitudinal direction

Methodology Applied
Scientific EffectGas flow:

Implementation Method 2

continuously forming coatings by a PVD method on both surfaces of a coating formation-target material conveyed in a longitudinal direction in the chamber

Methodology Applied
Scientific EffectPhysical vapor deposition: Physical Vapour Deposition

Data Source

PatentEP3760759B1Method of using a surface treatment facility
Publication Date: 2024.12.11 JFE STEEL CORP
  • EP3760759B1 patent drawingFigure 1
  • EP3760759B1 patent drawingFigure 2
  • EP3760759B1 patent drawingFigure 3~4

AI summary

Provided is a surface treatment facility in which both surfaces of a material subjected to coating are subjected to continuous film deposition by PVD as the material is conveyed in the longitudinal direction, wherein flutter of the material subjected to coating can be suppressed. This surface treatment facility: has a chamber and continuously deposits a film by PVD on both surfaces of a material subjected to coating as the material is conveyed in the longitudinal direction through the chamber; is further provided with a conveyance mechanism for conveying the material subjected to coating and a blowing mechanism for blowing film-forming gas in the longitudinal direction on both sides of the material subjected to coating present in the chamber; and has an X/Y ratio within a range of 0.4 to 3.0 where X is the film-forming gas blowing speed, where the unit of measurement is m/min, and Y is the conveyance speed of the material subjected to coating, where the unit of measurement is m/min.