Mobile Inert-Gas Cladding for Turbofan Hard-Surfacing

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Solution Overview

Problem

Existing methods for hard-surfacing metal parts in aircraft turbofans, such as laser cladding, face limitations in protecting curved surfaces over significant distances due to bulky protection enclosures that restrict movement and allow oxidation, especially in parts like titanium, nickel, and cobalt alloys.

Innovation Solution

A portable, non-integral protection tool with a mobile cover and guide rails allows for large translational movement of the nozzle, maintaining an inert gas environment around the metal part to prevent oxidation, using a nozzle that emits a laser or electron beam to heat and deposit powder for hard-surfacing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a protection enclosure with a notch is used to prevent oxidation during laser hard-surfacing, then oxidation protection is improved, but the ability to hard-surface over significant distances deteriorates due to restricted nozzle movement

Engineering Contradiction:

Improveoxidation protectionVSAvoidhard-surfacing distance

Core Design Contradiction:

ReliabilityVSLength of moving object

Solution Approach 1:

The patent makes the protection enclosure dynamic by enabling it to move along with the nozzle during the hard-surfacing process. The enclosure is designed to translate in the same direction as the nozzle, maintaining continuous protection over extended distances. This dynamic configuration allows the enclosure to adapt its position rather than being fixed, thereby resolving the contradiction between maintaining oxidation protection and achieving hard-surfacing over significant distances.

Inventive Principle:

Principle #15Dynamics

2Reliability

If a large chamber is used to provide inert gas protection, then oxidation protection is improved, but cost and implementation time increase

Engineering Contradiction:

Improveoxidation protectionVSAvoidimplementation cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent extracts the protection function from a large chamber configuration and concentrates it into a localized mobile enclosure that moves with the nozzle. Instead of protecting the entire work area with a large chamber, only the immediate vicinity of the laser processing zone is enclosed and protected with inert gas. This extraction principle reduces the amount of inert gas required and eliminates the need for large chamber infrastructure, thereby reducing implementation costs while maintaining effective oxidation protection.

Inventive Principle:

Principle #2Taking out (Extraction)

3Length of moving object

If a mobile cover is used to allow nozzle movement, then hard-surfacing distance is improved, but gas insulation effectiveness deteriorates

Engineering Contradiction:

Improvehard-surfacing distanceVSAvoidinert gas loss

Core Design Contradiction:

Length of moving objectVSLoss of energy

Solution Approach 1:

The patent employs a mobile cover that acts as a flexible sealing element, allowing the protection enclosure to move with the nozzle while maintaining gas tightness. The cover is designed to flex and adapt to the movement, creating a dynamic seal that prevents inert gas escape. This flexible sealing approach maintains insulation effectiveness during motion, resolving the contradiction between achieving hard-surfacing distance and preventing inert gas loss.

Inventive Principle:

Principle #30Flexible shells and thin films

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 efficient hard-surfacing over extended distances without the need for a large chamber, reducing costs and preventing mechanical degradation by effectively preventing oxidation during the process.

Implementation Method 1

a nozzle emitting a laser beam, or an electron beam, which is to heat a powder sprayed on the part for hard-surfacing said metal part

Methodology Applied

Scientific EffectLaser heating: Laser

Implementation Method 2

the inside volume of the notch 105 is emptied of its oxygen by sending a neutral gas, for example argon or helium, through pipes 106 connected to the nozzle 103; the hard-surfacing of the end 102 can thus be carried out without an oxidation phenomenon

Methodology Applied

Scientific EffectOxidation prevention through inert gas atmosphere: Oxidation

Data Source

PatentUS11117215B2Method for hard-surfacing metal parts for aircraft turbofans, and local protection tool for implementing the method

Publication Date: 2021.09.14 SAFRAN AIRCRAFT ENGINES SAS

AI summary

A method for hard-surfacing metal parts for an aircraft turbofan, the method involving the use of a nozzle outputting a laser beam or an electron beam, which is to heat a sprayed powder for hard-surfacing the metal part, the method including positioning the metal part to be hard-surfaced in an enclosure, the top portion of which has an opening; positioning a mobile cover covering the opening of the top portion, the mobile cover having an opening; positioning the nozzle at the opening of the mobile cover; feeding an inert gas into the enclosure; spraying metal powders and emitting the laser or electron beam for hard-surfacing the metal part; moving the nozzle relative to the enclosure along a path for hard-surfacing the metal part, the movement of the nozzle causing the movement of the mobile cover on the top surface of the enclosure.