Rapid Tooling for Gas Turbine Casting via Conductive Coating

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Solution Overview

Problem

The traditional manufacturing process for tooling used in investment casting, such as for gas turbine engine parts, is time-consuming, typically taking 8 to 28 weeks, which hinders the rapid production of complex geometries like internal cooling passages in airfoils and vanes.

Innovation Solution

A rapid manufacturing method utilizing stereolithography (SLA) or selective laser sintering (SLS) processes to create tooling from polymeric materials, followed by smoothing and coating with conductive metallic materials, allowing for the rapid production of casting articles in hours or days.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional manufacturing processes (milling, high speed machining, EDM) are used to manufacture tooling, then manufacturing precision and durability are improved, but lead time increases to 8-28 weeks

Engineering Contradiction:
Improvetooling durabilityVSAvoidlead time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

A preliminary rapid prototype tooling is manufactured using stereolithography or selective laser sintering to enable immediate casting article production. This preliminary tooling allows the casting process to begin before the final precision tooling is complete, significantly reducing overall lead time while maintaining product quality

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The tooling manufacturing process is segmented into two distinct phases: rapid prototype tooling manufacturing (using additive processes) and final precision tooling manufacturing (using traditional subtractive processes). This segmentation allows parallel execution of both processes, with the rapid prototype enabling immediate production while the precision tooling is being fabricated

Inventive Principle:
Principle #1Segmentation

2Strength

If traditional manufacturing processes are used, then tooling conductivity and strength are improved, but manufacturing speed decreases to hours or days

Engineering Contradiction:
Improvetooling strengthVSAvoidmanufacturing speed
Core Design Contradiction:
StrengthVSProductivity

Solution Approach 1:

The rapid prototype tooling uses composite construction combining polymeric material (from stereolithography or selective laser sintering) with metallic coating layers. This composite structure provides sufficient strength for rapid prototyping while the metallic coating restores electrical conductivity and thermal properties needed for the casting process

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The tooling material properties are changed through coating application - transforming the polymeric rapid prototype into a conductive, thermally stable tooling piece. The coating process modifies surface parameters (conductivity, hardness, thermal resistance) to match the requirements of the casting process without requiring bulk material changes

Inventive Principle:
Principle #35Parameter changes

3Loss of time

If rapid manufacturing processes (stereolithography, selective laser sintering) are used, then lead time is reduced to hours or days, but manufacturing precision and surface quality worsen

Engineering Contradiction:
Improvelead timeVSAvoidsurface quality
Core Design Contradiction:
Loss of timeVSManufacturing precision

Solution Approach 1:

Traditional mechanical finishing processes (milling, machining, grinding) are replaced with coating application processes. The coating is deposited onto the rapid prototype surface, providing the required precision and surface quality without requiring extensive post-processing of the additive manufactured part

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The metallic coating acts as an intermediary layer between the rapid prototype and the casting article. This coating layer provides the necessary surface quality, dimensional accuracy, and functional properties (conductivity, thermal resistance) that the polymeric rapid prototype cannot provide alone, while requiring minimal post-processing

Inventive Principle:
Principle #24Intermediary (Mediator)

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 significantly reduces the lead time for manufacturing tooling, enabling the rapid production of complex casting articles with improved durability and conductivity, thus facilitating faster development of gas turbine engine components.

Implementation Method 1

The tooling is formed in a rapid manufacturing process from a polymeric material. In one example, the rapid manufacturing process is a stereolithography process.

Methodology Applied
Scientific EffectPhotopolymerisation: Photopolymerisation

Implementation Method 2

The rapid manufacturing method utilizing stereolithography (SLA) or selective laser sintering (SLS) processes to create tooling from polymeric materials

Methodology Applied
Scientific EffectSelective laser sintering: Selective Laser Sintering

Implementation Method 3

followed by smoothing and coating with conductive metallic materials

Methodology Applied
Scientific EffectPhysical vapor deposition: Physical Vapour Deposition

Data Source

PatentEP2551092B1Rapid manufacturing method for casting a gas turbine engine part
Publication Date: 2014.10.22 UNITED TECH CORP
  • EP2551092B1 patent drawingFigure 1
  • EP2551092B1 patent drawingFigure 2
  • EP2551092B1 patent drawingFigure 3~4

AI summary

A rapid manufacturing method includes forming tooling (32) in a rapid manufacturing process. The tooling (32) is coated with a conductive material (44).