Airfoil Cluster Coating via Segmentation and Diffusion Brazing

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Solution Overview

Problem

Applying durability coatings to airfoil clusters in gas turbine engines, particularly those with endwall contouring and serpentine passages, is challenging due to limited access between airfoils, which complicates the coating process.

Innovation Solution

A method involving the attachment of register blocks for precise alignment, splitting the airfoil cluster using wire EDM, applying coatings to separated portions, and rejoining via diffusion brazing to maintain the engine's performance features.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If airfoil clusters are cast with endwall contouring and serpentine passages to enhance engine performance, then engine performance is improved, but applying durability coatings becomes difficult due to limited access between airfoils

Engineering Contradiction:

Improveengine performanceVSAvoidcoating application difficulty

Core Design Contradiction:

ProductivityVSEase of manufacture

Solution Approach 1:

The airfoil cluster is divided into multiple individual airfoils that can be separated from the cluster. This segmentation allows coating equipment to access and apply durability coatings to each airfoil surface, including previously inaccessible areas between airfoils, while maintaining the performance-enhancing features of endwall contouring and serpentine passages

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Durability coatings are applied to airfoils before they are assembled into the cluster configuration. This preliminary coating action ensures that all surfaces, including those that would be inaccessible in the final cluster assembly, receive proper coating coverage

Inventive Principle:

Principle #10Preliminary action

2Ease of manufacture

If airfoil clusters are used to reduce costs, then manufacturing cost is reduced, but applying durability coatings after casting becomes difficult

Engineering Contradiction:

Improvemanufacturing costVSAvoidcoating application difficulty

Core Design Contradiction:

Ease of manufactureVSEase of repair

Solution Approach 1:

The airfoil cluster is segmented into individual airfoils that can be independently removed and coated. This approach maintains the cost advantage of cluster casting while enabling complete coating coverage by accessing each airfoil separately after extraction from the cluster

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Durability coatings are applied to airfoils before cluster assembly, ensuring that the cost-effective cluster approach is maintained while achieving complete coating coverage on all surfaces that would otherwise be inaccessible

Inventive Principle:

Principle #10Preliminary action

3Ease of operation

If airfoils are separated from the cluster for coating, then coating access is improved, but alignment precision must be maintained upon reassembly

Engineering Contradiction:

Improvecoating accessVSAvoidalignment precision

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

Register blocks are introduced as intermediary components during the disassembly and reassembly process. These register blocks provide precise alignment references that ensure airfoils are repositioned accurately in their original locations within the cluster, maintaining manufacturing precision while enabling coating access

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

Traditional mechanical alignment methods are replaced with a systematic approach using register blocks that provide automated alignment guidance. This substitution ensures consistent alignment precision during reassembly while facilitating the coating operation

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

Enables effective application of durability coatings while preserving the structural integrity and performance-enhancing features of airfoil clusters, ensuring consistent alignment and unimpeded airflow.

Implementation Method 1

separating the portions from one another using a wire electrical discharge machining (EDM) machine

Methodology Applied

Scientific EffectElectrical discharge machining: Electrical Discharge Machining

Implementation Method 2

rejoining the portions together using a diffusion brazing process

Methodology Applied

Scientific EffectDiffusion brazing: Diffusion Welding

Data Source

PatentEP2969363B1Method for working an airfoil cluster

Publication Date: 2020.11.04 RTX CORP

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AI summary

A method for working an airfoil cluster is disclosed. The method may include attaching a first datum to a first portion of the airfoil cluster and a second datum to a second portion of the airfoil cluster; adding material to at least one of the first portion and the second portion; and joining the first portion to the second portion, the first and second datums substantially aligned in a common plane spaced away from the first and second portions.