Metallic Substrate Coating with Powder and Autodepositable Layers

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Solution Overview

Problem

Existing coating methods for metallic machine components face challenges in providing comprehensive protection against corrosion and ultraviolet degradation, particularly in edges and recessed areas, while also being cost-effective, as multiple layer coating processes are costly and prone to weathering issues.

Innovation Solution

A method involving the application of a powder coating composition to the majority of a metallic substrate's surface, combined with an autodepositable coating composition on less than the majority of the surface, specifically targeting discontinuous areas to enhance coverage and durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If powder coating composition is applied to metallic substrate, then corrosion and weathering protection is improved, but coverage on edges and recessed areas deteriorates

Engineering Contradiction:

Improvecorrosion protectionVSAvoidedge coverage

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The coating process is segmented into two distinct stages: first applying powder coating to majority surfaces, then applying autodepositable coating to edges and recessed areas. This segmentation allows each coating method to optimize its performance for specific surface types, resolving the coverage deficiency on edges while maintaining the corrosion protection benefits of powder coating on flat surfaces.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different coating compositions are applied to different locations on the substrate. Powder coating is applied to majority surfaces where it provides excellent corrosion protection, while autodepositable coating is specifically applied to edges and recessed areas where it provides superior coverage. This local quality approach ensures optimal performance in each specific location.

Inventive Principle:

Principle #3Local quality

2Reliability

If multiple layer coating process is applied, then coverage and durability are improved, but cost increases

Engineering Contradiction:

Improvecoating durabilityVSAvoidprocess cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

Instead of applying multiple layers of the same coating composition throughout, the invention applies autodepositable coating partially - only to edges and recessed areas that require enhanced coverage. This partial action approach maintains the durability benefits of multi-layer coating where needed while significantly reducing material costs and process complexity compared to full multi-layer application.

Inventive Principle:

Principle #16Partial or excessive action

3Manufacturing precision

If emulsified liquid coating composition is applied to improve edge coverage, then edge coverage is improved, but weathering resistance deteriorates

Engineering Contradiction:

Improveedge coverageVSAvoidweathering resistance

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The invention applies emulsified liquid coating composition locally only to edges and recessed areas rather than uniformly across the entire substrate. This localized application provides the edge coverage benefits of liquid coating while limiting exposure to areas where weathering resistance is critical, thereby resolving the contradiction between edge coverage and weathering resistance.

Inventive Principle:

Principle #3Local quality

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 approach provides a robust, cost-effective coating solution that enhances corrosion and weathering resistance, reducing the need for extensive autodepositable coating application and maintaining process stability, thereby lowering maintenance costs.

Implementation Method 1

it is known that powder coating compositions, typically applied using an electrostatic spraying method

Methodology Applied

Scientific EffectElectrostatic deposition: Electrostatic Deposition

Implementation Method 2

applying an autodepositable coating composition to less than the majority of the surface of the metallic substrate

Methodology Applied

Scientific EffectAutodeposition: Electrochemiluminescence

Data Source

PatentUS8313823B2Method for coating a metallic substrate with a powder coating composition and an autodepositable coating composition

Publication Date: 2012.11.20 CATERPILLAR INC

AI summary

A method for coating a metallic substrate includes applying a powder coating composition to a majority of a surface of the metallic substrate, and applying an autodepositable coating composition to less than the majority of the surface of the metallic substrate. According to a preferred embodiment, the powder coating composition is applied to at least one continuous surface of the metallic substrate, while the autodepositable coating composition is applied to at least one discontinuous surface, such as an edge, of the metallic substrate.