Bladder Fixture Assembly for Diffusion-Bonded Titanium Fan Blades

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Solution Overview

Problem

The manufacturing of large hollow titanium fan blades for gas turbine engines is time-consuming and costly due to the complexity of achieving the required airfoil shape and structural integrity, especially when using diffusion bonding and subsequent expansion processes.

Innovation Solution

A fixture assembly with a bladder assembly, including a face sheet and an 'S' shaped bellows, is used to pressurize the cover into the blade body, allowing for efficient shaping and bonding of the fan blade, reducing the need for complex and costly processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If traditional diffusion bonding and hot forming processes are used to manufacture hollow titanium fan blades, then structural integrity and airfoil shape are achieved, but manufacturing time and cost increase significantly

Engineering Contradiction:

Improvestructural integrityVSAvoidmanufacturing time

Core Design Contradiction:

StrengthVSLoss of time

Solution Approach 1:

The blade body and cover are pre-formed with diffusion bonding surfaces and machined cavities before assembly. The fixture assembly is pre-configured with heating elements and pressure application mechanisms to enable direct diffusion bonding during assembly, eliminating separate bonding and forming steps.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent combines multiple manufacturing operations into a single integrated process. The fixture assembly simultaneously performs heating, pressure application, and shape formation during the diffusion bonding process, merging bonding and hot forming into one step rather than sequential operations.

Inventive Principle:

Principle #5Merging (Combining)

2Shape

If complex diffusion bonding and hot forming processes are used, then proper airfoil shape is achieved, but process complexity and cost increase

Engineering Contradiction:

Improveairfoil configurationVSAvoidprocess complexity

Core Design Contradiction:

ShapeVSDevice complexity

Solution Approach 1:

The fixture assembly applies pressure and heat locally at the diffusion bonding interfaces between the blade body and cover. The heating elements are positioned specifically at bonding surfaces, and pressure is applied through contact points at the interface, concentrating energy where needed rather than requiring complex global control.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The fixture assembly acts as an intermediary device that simplifies the bonding process. It provides controlled heating and pressure application through straightforward mechanical and thermal fields, mediating between the raw components and the desired bonded structure without requiring complex process control systems.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Volume of moving object

If traditional multi-step manufacturing processes are used, then hollow structure with collapsed walls is achieved, but subsequent expansion and twisting steps are required

Engineering Contradiction:

Improvehollow structureVSAvoidmanufacturing efficiency

Core Design Contradiction:

Volume of moving objectVSProductivity

Solution Approach 1:

The blade body and cover are pre-formed with the correct hollow geometry and airfoil shape before assembly. The cavities are machined to final dimensions, and the components are designed to bond in their final configuration, eliminating the need for post-bonding expansion and twisting operations.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces complex mechanical expansion and twisting operations with a simplified diffusion bonding process. Instead of bonding collapsed hollow structures and then mechanically expanding them, the components are bonded in their final expanded configuration using controlled heating and pressure in the fixture assembly.

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

This method enables the cost-effective and efficient production of structurally sound, hollow titanium fan blades with reduced processing time and environmental impact, eliminating the need for multiple time-consuming and costly steps in traditional manufacturing processes.

Implementation Method 1

deploying a bladder assembly within the fixture to press the cover into the blade body

Methodology Applied

Scientific EffectPressure: Pressure Increase

Implementation Method 2

a heating element positioned to heat the blade body and the cover to a diffusion bonding temperature

Methodology Applied

Scientific EffectHeating: Heating

Implementation Method 3

a vacuum port in communication with the interior of the fixture to remove air from the fixture

Methodology Applied

Scientific EffectVacuum: Vacuum

Implementation Method 4

heating the blade body and the cover to a diffusion bonding temperature

Methodology Applied

Scientific EffectDiffusion bonding: Diffusion Welding

Data Source

PatentUS11346362B2Processes and tooling associated with diffusion bonding

Publication Date: 2022.05.31 RTX CORP

AI summary

A fixture assembly including a first fixture portion; a second fixture portion that interfaces with the first fixture portion; and a bladder assembly mounted to the second fixture portion to face the first fixture portion. A method of manufacturing a fan blade includes inserting a blade body and a cover into a fixture; and deploying a bladder assembly within the fixture to press the cover into the blade body.