Liquid Nitrogen Blasting for Aluminum Fan Blade Coating Removal

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Solution Overview

Problem

The existing methods for removing coatings from aircraft fan blades, such as plastic media blasting, are time-consuming, prone to human error, and can damage the substrate, leading to stock loss and inefficiency.

Innovation Solution

A method using liquid nitrogen blasting to lift and peel off coatings from the substrate, employing a nozzle that discharges liquid nitrogen at high pressure to remove airfoil and tip coatings in an automated and controlled manner, ensuring zero substrate erosion and quick processing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If plastic media blasting is used to remove coatings, then coating removal is achieved, but the substrate is eroded and damaged

Engineering Contradiction:

Improvecoating removal qualityVSAvoidsubstrate erosion and damage

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the mechanical abrasion of plastic media blasting with a thermal field (liquid nitrogen spray) to achieve coating removal. The liquid nitrogen causes thermal shock and contraction that lifts and peels the coating away without mechanical contact, thereby eliminating substrate erosion while maintaining effective coating removal.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the physical state and temperature parameters by using liquid nitrogen at extremely low temperatures. This thermal parameter change causes the coating to contract and lift from the substrate, enabling non-contact removal that preserves the substrate integrity while achieving complete coating elimination.

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If manual plastic media blasting is used, then coating removal is achieved, but the process is time consuming and prone to human error

Engineering Contradiction:

Improvecoating removal completenessVSAvoidprocessing time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The liquid nitrogen spray system operates autonomously to remove coatings without human intervention. The thermal field automatically lifts and peels the coating as the nozzle traverses the blade, eliminating manual operations and reducing processing time while ensuring consistent, error-free removal.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent implements continuous coating removal by traversing the liquid nitrogen nozzle along the blade surface without interruption. This continuous thermal action eliminates the stop-start nature of manual blasting, significantly reducing processing time while maintaining complete coating removal throughout the entire blade surface.

Inventive Principle:

Principle #20Continuity of useful action

3Productivity

If automated liquid nitrogen blasting is used, then processing speed and automation are improved, but equipment complexity increases

Engineering Contradiction:

Improveprocessing speedVSAvoidblasting system complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent uses a liquid nitrogen delivery system with nozzles that can be traversed along the blade. This pneumatic/hydraulic delivery mechanism enables automated, high-speed coating removal while maintaining relatively simple equipment architecture compared to other automated blasting systems, achieving high productivity with controlled complexity.

Inventive Principle:

Principle #29Pneumatics and hydraulics

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 rapid, automated, and error-free removal of coatings with zero substrate loss, significantly reducing processing time and improving the reliability of the coating removal process.

Implementation Method 1

discharging liquid nitrogen through a nozzle onto the blade at a coating to cause lifting of the coating from a substrate of the blade

Methodology Applied

Scientific EffectThermal shock: Thermal Shock

Implementation Method 2

discharging liquid nitrogen through a nozzle onto the blade at a coating to cause lifting of the coating from a substrate of the blade

Methodology Applied

Scientific EffectContraction: Thermal Contraction

Implementation Method 3

traversing the nozzle along the blade to cause peeling of the coating off of the substrate of the blade as the nozzle traverses the blade

Methodology Applied

Scientific EffectThermal stress: Thermal Shock

Data Source

PatentUS11814983B2Method to strip coatings off of an aluminum alloy fan blade

Publication Date: 2023.11.14 RTX CORP

AI summary

A method for stripping a coating off of a blade includes discharging liquid nitrogen through a nozzle onto the blade at a coating to cause lifting of the coating from a substrate of the blade and traversing the nozzle along the blade to cause peeling of the coating off of the substrate of the blade as the nozzle traverses the blade.