Walking Beam Coating for Rare-Earth Magnets

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Solution Overview

Problem

Existing methods for coating rare earth permanent magnets with rare earth compounds result in inefficient slurry consumption and mechanical issues due to sticking and deposition, leading to coating defects and increased costs.

Innovation Solution

A production method and device using a walking beam system to coat sintered magnet bodies with a slurry containing rare earth compounds, where the magnet bodies are transported on a fixed beam with moving beams, allowing for continuous coating and drying while preventing contact between magnet bodies, reducing slurry wastage and mechanical troubles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a net conveyor transport system is used to continuously transport sintered magnet bodies through slurry coating, then productivity is improved, but coating defects occur due to contact between magnet bodies and mechanical troubles arise from slurry sticking and deposit

Engineering Contradiction:

Improvecontinuous coating capabilityVSAvoidcoating uniformity

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The conveyor system is segmented into multiple independent magnet body holding portions (first, second, third, and fourth holding portions) arranged along the transport path. Each holding portion independently supports a magnet body, preventing contact between adjacent magnet bodies during coating, thereby maintaining coating uniformity while enabling continuous transport and improving productivity.

Inventive Principle:

Principle #1Segmentation

2Productivity

If dip coating is used to coat sintered magnet bodies with slurry, then coating efficiency is improved, but slurry is carried out of the coating bath causing wasteful consumption

Engineering Contradiction:

Improvecoating efficiencyVSAvoidslurry consumption

Core Design Contradiction:

ProductivityVSLoss of substance

Solution Approach 1:

The excess slurry is extracted and removed from the coating system by positioning the magnet body holding portions to allow slurry to drain back into the coating bath after coating. The holding portions are designed to release excess slurry, preventing it from being carried out of the coating bath, thereby reducing slurry consumption while maintaining efficient dip coating operations.

Inventive Principle:

Principle #2Taking out (Extraction)

3Productivity

If net conveyor is used for continuous transport, then productivity is improved, but mechanical troubles occur due to sticking and deposit of slurry on the conveyor

Engineering Contradiction:

Improvecontinuous transport capabilityVSAvoidmechanical system stability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The traditional net conveyor mechanical system is replaced with a holding portion system that uses magnetic or gravitational fields to support and transport magnet bodies. This substitution eliminates the mechanical components that are prone to slurry sticking and deposit, thereby maintaining continuous transport capability while improving mechanical system reliability and reducing maintenance requirements.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 method ensures uniform coating, minimizes slurry consumption, and prevents mechanical issues, allowing for efficient production of rare earth magnets with improved magnetic properties by using a walking beam system that stabilizes magnet body movement during coating and drying.

Implementation Method 1

subjecting the resulting sintered magnet bodies to heat treatment to cause absorption of one or more rare earth elements into the sintered magnet bodies

Methodology Applied

Scientific EffectAbsorption: Absorption (physical)

Implementation Method 2

absorption and diffusion of one or more rare earth elements into the sintered magnet bodies

Methodology Applied

Scientific EffectDiffusion: Diffusion

Implementation Method 3

drying the resulting sintered magnet bodies to coat surfaces of the sintered magnet bodies with the powder

Methodology Applied

Scientific EffectEvaporation: Evaporation

Data Source

PatentUS10790076B2Method for producing rare-earth magnets, and rare-earth-compound application device

Publication Date: 2020.09.29 SHIN ETSU CHEMICAL CO LTD

AI summary

A fixed beam 2 along which magnet-body holding sections 22 are consecutively provided is disposed so as to pass through a slurry 1. Sintered magnet bodies m placed in the magnet-body holding sections 22 by movable beams 3 are conveyed by repeating an operation in which the sintered magnet bodies m are moved to the following magnet-body holding sections 22. While being conveyed, the sintered magnet bodies m are passed through the slurry 1 to apply the slurry thereto, and are subsequently dried to remove a solvent in the slurry and affix a powder in the slurry thereto, and, as a result, the powder is continuously applied to the plurality of sintered magnet bodies. Accordingly, a rare-earth-compound powder can be uniformly applied to the surfaces of the sintered magnet bodies, and the amount of the slurry taken from a coating tank can be reduced to effectively decrease wasteful consumption.