Fluidized-Bed Coating Method for Thin Film Formation

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Solution Overview

Problem

Conventional fluidized-bed coating methods face difficulties in forming thin, continuous coating films due to high particle diameter of powder coating materials, leading to surface unevenness and discontinuous sections, which are unsuitable for applications requiring precise coating on small workpieces.

Innovation Solution

A fluidized-bed coating method involving a workpiece immersed in a powder coating material with a controlled air flow rate between 5-20 mm/min and a floating ratio of 5-20%, and a temperature range from the softening temperature to the melting temperature of the powder, ensuring a dense and continuous thin film formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional fluidized-bed coating method is used with high particle diameter powder coating material, then coating process is simple, but coating film becomes uneven and discontinuous

Engineering Contradiction:

Improvecoating film continuityVSAvoidcoating process complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent changes the particle diameter parameter of the powder coating material from conventional large sizes to specifically 1 μm to 10 μm, and adjusts the air flow rate to 5-20 mm/min and floating ratio to 5-20%, transforming the coating result from uneven and discontinuous to continuous and uniform thin film

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses smaller particle diameter powder (1-10 μm) which is finer than conventional materials, allowing the powder to better conform to the workpiece surface and form continuous coating even at thin film thickness of 20-50 μm

Inventive Principle:

Principle #16Partial or excessive action

2Manufacturing precision

If air flow rate is not controlled within 5-20 mm/min, then fluidized-bed operation is easier, but thin continuous coating film cannot be formed

Engineering Contradiction:

Improvecoating film thickness controlVSAvoidair flow rate control

Core Design Contradiction:

Manufacturing precisionVSEase of operation

Solution Approach 1:

The patent establishes a specific air flow rate parameter range of 5-20 mm/min, which controls the fluidization state to achieve optimal balance between powder suspension and deposition, enabling formation of continuous thin coating films with thickness of 20-50 μm

Inventive Principle:

Principle #35Parameter changes

3Manufacturing precision

If floating ratio is not maintained at 5-20%, then fluidized-bed operation is simpler, but coating uniformity deteriorates

Engineering Contradiction:

Improvecoating film uniformityVSAvoidfloating ratio control

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent defines a specific floating ratio parameter range of 5-20%, which controls the proportion of powder particles suspended in the fluidized bed, ensuring uniform distribution and continuous coating formation while maintaining operational feasibility

Inventive Principle:

Principle #35Parameter changes

4Manufacturing precision

If workpiece temperature is outside softening to melting temperature range of powder, then heating process is simpler, but powder adhesion and film formation are insufficient

Engineering Contradiction:

Improvepowder adhesionVSAvoidworkpiece temperature control

Core Design Contradiction:

Manufacturing precisionVSTemperature

Solution Approach 1:

The patent utilizes the phase transition of the powder coating material from solid to softened state by controlling workpiece temperature within the softening to melting temperature range, enabling the powder to adhere to the workpiece surface and form continuous thin film coating during the coating process

Inventive Principle:

Principle #36Phase transitions

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 achieves a continuous thin film coating with a thickness of 20-50 μm, enhancing coating efficiency and precision, suitable for small workpieces and applications requiring advanced features.

Implementation Method 1

air is introduced from a bottom of the fluidized-bed vessel at an average air flow rate of 5 mm/min or higher and 20 mm/min or lower per unit area of the bottom so that a floating ratio of the powder coating material is 5% or higher and 20% or lower

Methodology Applied

Scientific EffectFluidisation: Fluidisation

Implementation Method 2

the workpiece having a temperature higher than or equal to a softening temperature of the powder coating material and lower than or equal to a melting temperature of the powder coating material

Methodology Applied

Scientific EffectSoftening:

Implementation Method 3

heating the powder coating material attached to the workpiece

Methodology Applied

Scientific EffectMelting: Melting

Data Source

PatentUS11794208B2Fluidized-bed coating method and fluidized-bed coating apparatus

Publication Date: 2023.10.24 FUJIFILM BUSINESS INNOVATION CORP

AI summary

A fluidized-bed coating method includes: immersing at least part of a workpiece in a powder coating material contained in a fluidized-bed vessel while air is introduced from a bottom of the fluidized-bed vessel at an average air flow rate of 5 mm/min or higher and 20 mm/min or lower per unit area of the bottom so that a floating ratio of the powder coating material is 5% or higher and 20% or lower, the workpiece having a temperature higher than or equal to a softening temperature of the powder coating material and lower than or equal to a melting temperature of the powder coating material; taking the workpiece out of the powder coating material; and heating the powder coating material attached to the workpiece.