Gas Turbine Blade Repair Using a Sacrificial Build Platform

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Solution Overview

Problem

The high cost and resource inefficiency of replacing entire bladed discs in gas turbine engines due to damaged blades, particularly those made of critical metals like nickel or titanium, necessitate an improved system and method for repairing damaged blades.

Innovation Solution

A sacrificial build platform is used in conjunction with additive manufacturing to repair damaged blades, ensuring accurate geometry and mechanical properties, while preventing damage to the disc during the repair process by blocking laser strikes and unwanted powder contact, and allowing for layer-by-layer material deposition to create a base structure that can be further processed to restore the blade to OEM specifications.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the entire bladed disc is replaced when a blade is damaged, then the reliability of the engine is maintained, but the cost increases significantly and resources are wasted

Engineering Contradiction:
Improveengine reliabilityVSAvoidmaterial waste
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The invention segments the bladed disc into separable components: the disc and individual blades. This allows the damaged blade to be removed and replaced independently while retaining the intact disc and other functional blades, thereby avoiding the waste of replacing the entire assembly and reducing material loss.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention enables the recovery and reuse of the disc and undamaged blades by discarding only the specific damaged blade. The used blade can be sent for specialized repair or recycling, while the recovered disc and blades continue to serve, significantly reducing material waste and resource consumption.

Inventive Principle:
Principle #34Discarding and recovering

2Reliability

If the entire bladed disc is replaced when a blade is damaged, then the engine reliability is maintained, but the cost increases significantly

Engineering Contradiction:
Improveengine reliabilityVSAvoidcost
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

By segmenting the bladed disc into replaceable individual blades, the invention enables cost-effective maintenance where only the damaged blade needs replacement or repair. This avoids the high cost of replacing the entire expensive disc assembly, significantly reducing energy and resource costs while maintaining engine reliability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention facilitates economical recovery of valuable materials from the disc and undamaged blades. By discarding only the damaged blade and recovering the rest, the system reduces material costs and avoids the expense of replacing the entire bladed disc assembly.

Inventive Principle:
Principle #34Discarding and recovering

3Manufacturing precision

If additive manufacturing is used to repair the blade, then the geometry accuracy and mechanical properties can be restored, but the complexity of the repair process increases

Engineering Contradiction:
Improveblade geometry accuracyVSAvoidrepair process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention applies preliminary action by creating a support structure before the additive manufacturing process. The support structure is designed and positioned in advance to hold the blade segment during material deposition, ensuring geometric accuracy while managing process complexity through pre-planned structural assistance.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The support structure acts as an intermediary element that facilitates the additive manufacturing process. It provides the necessary structural assistance during material deposition, enabling precise geometry restoration without requiring complex real-time control systems or advanced manufacturing equipment.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Ease of repair

If material is deposited during the repair process, then the damaged blade can be restored, but the disc or remaining blade portion may be damaged by laser strikes or powder contact

Engineering Contradiction:
Improveblade restorationVSAvoidlaser and powder damage to disc
Core Design Contradiction:
Ease of repairVSObject-affected harmful factors

Solution Approach 1:

The support structure serves as a protective intermediary between the additive manufacturing process and the disc. It physically blocks laser strikes and powder contact from reaching the disc surface, enabling safe material deposition on the blade without causing harmful effects to the remaining blade portion or disc.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The support structure is designed as a disposable protective element that can be easily removed after serving its protective function. This cheap, temporary structure absorbs the harmful effects of laser and powder during the repair process, protecting the valuable disc while being discarded afterward.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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 system enables efficient repair of damaged blades, meeting OEM requirements for geometry and mechanical properties, reduces material waste, and minimizes additional processing, thereby lowering costs and conserving resources.

Implementation Method 1

A height of the sacrificial build platform is decided such that, an upper portion of the sacrificial build platform that is closer to the stub portion can quickly melt into a melt pool

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 2

The sacrificial build platform may block any laser strikes or unwanted powder contact with the component

Methodology Applied
Scientific EffectLaser absorption: Absorption (EM radiation)

Implementation Method 3

The projections may provide for an interference fitting between the stub portion and the sacrificial build platform, which may eliminate a need of additional fixtures to hold the sacrificial build platform in place

Methodology Applied
Scientific EffectInterference fitting:

Data Source

PatentEP4721911A1System and method for repairing a damaged blade of a gas turbine engine
Publication Date: 2026.04.08 ROLLS ROYCE PLC
  • EP4721911A1 patent drawingFigure 1
  • EP4721911A1 patent drawingFigure 2
  • EP4721911A1 patent drawingFigure 3A~3B

AI summary

A system (100) for repairing a damaged blade (102) of a gas turbine engine (10) includes a sacrificial build platform (106, 106-1, 106-2) configured to be positioned and fused with the damaged blade (102) proximal to at least one stub portion (108, 108-1, 108-2) of the damaged blade (102). The at least one stub portion (108, 108-1, 108-2) protrudes from a root (110) of the damaged blade (102) and defines a deposition surface (112). The sacrificial build platform (106, 106-1, 106-2) includes a base (114) defining a pair of cavities (116a, 116b). The at least one stub portion (108-2) includes a pair of projections (108a, 108b), each cavity (116a, 116b) is configured to receive a corresponding projection (108a, 108b) from the pair of projections (108a, 108b). The system (100) further includes an additive manufacturing system (150) that is configured to deposit material on the base (114) of the sacrificial build platform (106, 106-1, 106-2) and the deposition surface (112) of the at least one stub portion (108, 108-1, 108-2) to form a base structure (118) of a repaired blade (122).