Deep Bore Patch Welding for Aircraft Engine Defect Repair

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Solution Overview

Problem

Traditional repair techniques are inadequate for addressing defects in hard-to-reach locations within aircraft engine bores, often leading to the scrapping of otherwise repairable parts due to limited access for tools.

Innovation Solution

A method involving defect detection, geometry measurement, preparation of a complementary patch, and directed welding using an electron beam or laser welding process to repair defects within aircraft engine bores, ensuring minimal heat input and precise geometry restoration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of repair

If traditional repair techniques are used for defects in hard-to-reach bore locations, then the part must be scrapped, but this results in loss of valuable components and production delays

Engineering Contradiction:
Improverepairability of deep bore defectsVSAvoidloss of valuable engine components
Core Design Contradiction:
Ease of repairVSLoss of substance

Solution Approach 1:

The patent replaces traditional mechanical repair tools with a welding beam (electron beam or laser) that can be directed through the bore from outside the part. This allows welding material to be deposited at the defect location without requiring physical access to the defect with mechanical tools, enabling repair of deep bore defects that were previously unserviceable

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent uses the bore itself as an intermediary pathway to deliver the welding beam to the defect location. By directing the welding beam through the bore from outside the part, the system uses the existing geometry of the bore as a conduit to reach otherwise inaccessible defect locations deep within the part

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of repair

If welding is performed to repair deep bore defects, then the defect can be filled, but heat input may affect surrounding areas and cause additional damage

Engineering Contradiction:
Improveability to fill and repair defectsVSAvoidheat-affected zone damage
Core Design Contradiction:
Ease of repairVSObject-affected harmful factors

Solution Approach 1:

The patent uses electron beam welding or laser welding instead of traditional arc welding. These processes concentrate thermal energy into a highly focused beam that can be precisely controlled and directed through the bore, minimizing heat input to surrounding areas while still providing sufficient energy to melt and fuse the welding material to the part

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The welding beam provides localized heating only at the specific defect location where material needs to be deposited. The energy is concentrated precisely where needed to melt the welding material and fuse it to the part, while the surrounding areas remain relatively cool and unaffected by the welding process

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 method allows for the effective repair of defects in hard-to-reach bore locations, reducing the need for part scrapping and minimizing heat-affected zones, thereby extending the life of aircraft engine components and reducing production delays.

Implementation Method 1

directing a welding beam from outside the bore, through the bore and onto the patch to weld the patch to the bore

Methodology Applied
Scientific EffectElectron beam welding: Electron Beam

Implementation Method 2

directing a welding beam from outside the bore, through the bore and onto the patch to weld the patch to the bore

Methodology Applied
Scientific EffectLaser welding: Laser Beam Welding

Implementation Method 3

a first crystallization zone with a metallurgical crystal structure indicative of a melted material of a defect patch

Methodology Applied
Scientific EffectMelting and crystallization: Melting

Implementation Method 4

a second crystallization zone with a metallurgical crystal structure indicative of a heat effected zone

Methodology Applied
Scientific EffectHeat treatment: Heat Treatment

Data Source

PatentEP4414123A1Repairs for defects in bores
Publication Date: 2024.08.14 PRATT & WHITNEY CANADA CORP
  • EP4414123A1 patent drawingFigure 1
  • EP4414123A1 patent drawingFigure 2A~2B
  • EP4414123A1 patent drawingFigure 3

AI summary

A method of repair for a metallic part of an aircraft engine (100) includes detecting a defect (134) inside a bore (122) of the metallic part wherein the defect (134) represents a departure from an intended geometry of the bore (122), the bore (122) having a diameter and defining a longitudinal axis (A), and wherein the defect (134) is located within the bore (122) at a depth (D) of at least greater than one diameter along the longitudinal axis (A). The method also includes measuring a geometry of the defect (134), preparing a patch (146) with a complementary geometry to fill the geometry of the defect (134), placing the patch (146) in the bore (122) with the complementary geometry of the patch (146) seated against the geometry of the defect (134), directing a welding beam (144) from outside the bore (122), through the bore (122) and onto the patch (146) to weld the patch (146) to the bore (122), and removing a portion of the patch (146) to provide the intended geometry for the bore (122).