Jet Engine Heat Shield Panel Threaded Stud Manufacturing

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Solution Overview

Problem

The manufacturing of heat shield panels for gas turbine engines is complicated by the need for integral cast threads, which leads to casting difficulties and quality issues such as porosity, stray grains, and dimensional conformance problems, resulting in higher costs and process complexities.

Innovation Solution

A method of manufacturing heat shield panels and threaded studs separately, where the studs are formed using a mold with a negative cavity and a helix grain selector, and the panels are formed using a wax pattern and ceramic casting, allowing for improved thread alignment and integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If integral cast threads are used in heat shield panels, then thread alignment and integrity are improved, but casting difficulties and quality issues such as porosity, stray grains, and dimensional conformance problems increase

Engineering Contradiction:
Improvethread alignment and integrityVSAvoidcasting process complexity
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The invention divides the heat shield panel into separate components: the panel body is cast without threads, and threaded studs are manufactured separately and then attached to the panel. This segmentation eliminates the casting difficulties associated with integral threads while maintaining the required thread alignment and integrity through separate precision manufacturing of the studs followed by controlled attachment.

Inventive Principle:
Principle #1Segmentation

2Strength

If heat shield panels are manufactured with integral cast threads, then structural integrity is improved, but manufacturing costs and process complexity increase

Engineering Contradiction:
Improvestructural integrityVSAvoidmanufacturing process complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The heat shield panel assembly is segmented into the panel body and threaded studs as separate manufacturable components. The panel is cast without threads, and studs are manufactured separately using appropriate processes, then attached to maintain structural integrity while simplifying the overall manufacturing process and reducing costs.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The threaded studs are prepared in advance through separate manufacturing processes optimized for thread formation, then attached to the cast panel body. This preliminary preparation of threads independently allows for better quality control and simplifies the main casting process.

Inventive Principle:
Principle #10Preliminary action

3Ease of manufacture

If separate formation of heat shield panels and threaded studs is used, then manufacturing simplicity and cost reduction are improved, but assembly complexity increases

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidassembly process complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The design segments the panel and studs into separate manufacturable parts that are then assembled through controlled attachment processes such as welding, threading, or mechanical fastening. This segmentation simplifies manufacturing of each component while the assembly process is managed through standardized attachment procedures.

Inventive Principle:
Principle #1Segmentation

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 approach simplifies the manufacturing process, enhances thread alignment and integrity, and reduces costs by allowing for the separate formation and assembly of heat shield panels and threaded studs, improving the overall quality and efficiency of the heat shield assembly.

Implementation Method 1

heating the mold containing a negative cavity of the threaded stud to a first temperature... cooling metal within the helix grain selector using the cooling platform... slowly lowering the mold into a cooling source

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

cooling metal within the helix grain selector using the cooling platform starting from the cooling platform and moving towards the mold

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 3

allowing metal in the negative cavity of the threaded stud and the helix grain selector to reach a selected equilibrium temperature

Methodology Applied
Scientific EffectThermal equilibrium:

Implementation Method 4

slowly lowering the mold into a cooling source to allow solidification of metal within the negative cavity of the threaded stud from a bottom of the mold to the top of the mold

Methodology Applied
Scientific EffectSolidification: Freezing

Data Source

PatentEP3453972B1Method to produce jet engine combustor heat shield panels assembly
Publication Date: 2021.09.01 RTX CORP
  • EP3453972B1 patent drawingFigure 1
  • EP3453972B1 patent drawingFigure 2
  • EP3453972B1 patent drawingFigure 3

AI summary

A method of manufacturing a heat shield panel assembly (401) is provided. The method comprising: forming a heat shield panel, wherein the heat shield panel comprises one or more orifices (440); and forming each of one or more threaded studs (332) through operations comprising: injecting melted wax (864) into a negative cavity (866) of a threaded stud; allowing the wax to solidify to form a positive pattern (868) of the threaded stud; removing the positive pattern of the threaded stud from the negative cavity of the threaded stud; coating the positive pattern of the threaded stud with a ceramic (870); melting the positive pattern of the threaded stud away from the ceramic, the ceramic having a second cavity (872) forming a second negative cavity (874) of the threaded stud; pouring melted metal (876) into the second cavity (874); allowing metal in the second cavity to solidify to form the threaded stud; and removing the ceramic from the threaded stud.