Composite Magnetic Sheet Production via Dry Mixing and Pressure Shaping

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Solution Overview

Problem

Conventional methods for producing magnetic sheets for coil parts face challenges such as prolonged production time, high costs, and limited magnetic permeability due to residual voids and low filling ratios of magnetic substance powders, which are exacerbated by the use of solvents in wet mixing processes.

Innovation Solution

A composite magnetic sheet production method involving dry mixing of magnetic substance powders with polytetrafluoroethylene (PTFE) powders, followed by pressure shaping to create a high-density network structure, allowing for improved filling ratios and reduced voids, thereby enhancing magnetic permeability and mechanical strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If wet mixing of magnetic substance powders with binder and organic solvent is used to form coating film, then the magnetic sheet can be produced with binding properties, but the production time is prolonged and cost is raised due to essential sintering process

Engineering Contradiction:
Improvebinding propertyVSAvoidproduction time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The invention extracts and eliminates the organic solvent from the conventional wet mixing process. By using only inorganic binder without organic solvent, the drying process becomes unnecessary, thereby removing the sintering step and significantly reducing production time while maintaining binding properties through the inorganic binder's adhesive characteristics.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention changes the chemical composition parameters by replacing organic solvent-based binders with inorganic binder. This parameter change allows the coating film to be formed without organic solvent, eliminating the need for high-temperature sintering and reducing production time while preserving binding functionality.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If wet mixing with organic solvent is used to form coating film, then the magnetic sheet can be produced with flexibility and bonding property, but residual voids are generated by evaporation of solvent which reduces effective filling ratio and magnetic permeability

Engineering Contradiction:
Improvebonding propertyVSAvoideffective filling ratio
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The invention extracts and removes the organic solvent from the mixing process entirely. By using inorganic binder without organic solvent, there is no solvent evaporation to create voids. This eliminates the source of residual voids and maintains high effective filling ratio of magnetic substance powders while preserving bonding properties through the inorganic binder.

Inventive Principle:
Principle #2Taking out (Extraction)

3Manufacturing precision

If metal based magnetic substance powders are used to increase filling ratio, then magnetic permeability can be improved, but the amount of resin and solvent must be reduced which increases vulnerability of magnetic sheet

Engineering Contradiction:
Improvemagnetic permeabilityVSAvoidvulnerability
Core Design Contradiction:
Manufacturing precisionVSStrength

Solution Approach 1:

The invention changes the binder composition parameters by using inorganic binder without organic solvent. This allows achieving high magnetic permeability with metal based magnetic substance powders while maintaining sheet strength through the inorganic binder's binding properties, eliminating the need to compromise on vulnerability.

Inventive Principle:
Principle #35Parameter changes

4Ease of manufacture

If conventional wet mixing process with drying is used, then coating film can be formed with binder and magnetic substance powders, but the production process becomes complex and costly

Engineering Contradiction:
Improvecoating film formationVSAvoidproduction process
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The invention extracts and eliminates the organic solvent and drying process from the conventional manufacturing method. By using only inorganic binder, the coating film can be formed directly without drying or sintering steps, significantly simplifying the production process and reducing equipment complexity while maintaining ease of manufacture.

Inventive Principle:
Principle #2Taking out (Extraction)

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 the production of magnetic sheets with high magnetic permeability and strength at a lower cost, while simplifying the process and improving heat and humidity resistance, by eliminating solvent-related voids and increasing the filling ratio of magnetic substance powders.

Implementation Method 1

pressure shaping to create a high-density network structure

Methodology Applied
Scientific EffectPressure shaping: Compression

Implementation Method 2

dry mixing of magnetic substance powders with polytetrafluoroethylene (PTFE) powders

Methodology Applied
Scientific EffectDry mixing:

Implementation Method 3

pressure shaping to create a high-density network structure, allowing for improved filling ratios and reduced voids

Methodology Applied
Scientific EffectPressure shaping: Compression

Data Source

PatentEP1818950B1Production method of a composite magnetic sheet
Publication Date: 2012.08.29 SUMIDA CORP
  • EP1818950B1 patent drawingFigure 1A~2
  • EP1818950B1 patent drawingFigure 3
  • EP1818950B1 patent drawingFigure 4

AI summary

The present invention provides a composite magnetic sheet having a high magnetic permeability, to be produced easily at a low cost. The composite magnetic sheet includes magnetic substance powders and polytetrafluoroethylene powders.