Local Repair of Polymeric Erosion Coatings on Fan Blades

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Solution Overview

Problem

Current methods for repairing multi-layered polyurethane erosion coatings on aluminum fan blades in gas turbine engines are limited in their ability to effectively restore erosion protection and corrosion resistance, particularly since they often lack the application of a paint primer and result in slow repair processes.

Innovation Solution

A local repair method involving abrasion of damaged areas down to the aluminum substrate, followed by application of a corrosion-inhibiting paint primer and a filled epoxy paste, which provides faster thickness build rates and enhances erosion protection, facilitating field repairs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a filled epoxy paste is applied without a paint primer in damaged areas, then the repair process can be simplified, but the corrosion resistance and adhesion of the coating system deteriorates

Engineering Contradiction:
Improverepair process complexityVSAvoidcorrosion resistance
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent applies a paint primer to the damaged area before applying the filled epoxy paste. This preliminary action of applying the primer first ensures proper adhesion and corrosion protection, resolving the contradiction by maintaining reliability while still using a simplified repair process that differs from the complete OEM multi-layer system.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If a multi-layer polyurethane erosion coating is applied to protect aluminum fan blades, then erosion and corrosion protection is improved, but the repair capability deteriorates

Engineering Contradiction:
Improveerosion protectionVSAvoidrepair capability
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The patent applies a localized repair coating system only to the damaged areas of the fan blade rather than recoating the entire surface. This local quality approach restores erosion and corrosion protection to specific damaged zones while maintaining the integrity of the undamaged original coating, thereby improving repair capability without compromising overall erosion protection.

Inventive Principle:
Principle #3Local quality

3Manufacturing precision

If abrasion is performed to remove damaged coating down to the aluminum substrate, then the repair quality is improved, but the preparation time increases

Engineering Contradiction:
Improverepair qualityVSAvoidpreparation time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent performs abrasion to remove damaged coating to the aluminum substrate in the damaged areas, which is the necessary level of preparation to ensure proper adhesion and repair quality. This partial action (only where needed) achieves the required repair quality without excessive time consumption that would result from removing all coating from the entire blade surface.

Inventive Principle:
Principle #16Partial or excessive action

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 enables efficient and effective restoration of erosion protection and corrosion resistance on aluminum fan blades, allowing for faster repair processes and improved durability of the coating system.

Implementation Method 1

application of a corrosion-inhibiting paint primer and a filled epoxy paste

Methodology Applied
Scientific EffectCorrosion inhibition:

Implementation Method 2

application of a corrosion-inhibiting paint primer and a filled epoxy paste, which provides faster thickness build rates

Methodology Applied
Scientific EffectCoating deposition: Coatings

Implementation Method 3

abrasion of damaged areas down to the aluminum substrate

Methodology Applied
Scientific EffectAbrasion: Abrasion

Data Source

PatentEP3184180B1Local repair or remanufacture of polymeric erosion coatings
Publication Date: 2020.06.10 RTX CORP
  • EP3184180B1 patent drawingFigure 1
  • EP3184180B1 patent drawingFigure 2~3

AI summary

A method including applying a paint primer onto a substrate and applying a filled epoxy paste to the paint primer to provide erosion and corrosion protection to a substrate.