Segmented Ceramic Core Setter for Thermal Expansion Matching

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Solution Overview

Problem

Current die setting apparatuses for ceramic cores face challenges in accommodating the complex shapes and varying thicknesses of turbine airfoil ceramic cores, which can lead to breakage during firing due to mismatched thermal expansion coefficients between the setters and the cores, and the need for a balance between preventing deformation and maintaining dimensional accuracy.

Innovation Solution

A die setting apparatus comprising multiple setter pieces with thermal expansion and contraction materials, allowing for adjustable gaps that match the ceramic core's thermal expansion and contraction, and bearing elements for relative movement, ensuring secure abutment and maintaining dimensional accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the setter is made restrictive to prevent deformation, then manufacturing precision is improved, but the ceramic core breaks due to thermal expansion mismatch

Engineering Contradiction:
Improvedimensional accuracyVSAvoidbreakage risk
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The setter is divided into multiple segments that can move relative to each other, allowing the setter to adapt to thermal expansion of the ceramic core while maintaining dimensional accuracy. The segmented structure enables controlled movement to accommodate expansion forces.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The setter incorporates materials with different thermal expansion coefficients to match the ceramic core, and uses adjustable gaps that change dimension with temperature. This allows the setter to maintain appropriate clearance during thermal cycling while providing support.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the setter is made loose to accommodate thermal expansion, then reliability is improved, but manufacturing precision deteriorates

Engineering Contradiction:
Improvebreakage riskVSAvoiddimensional accuracy
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The setter transitions from a static rigid structure to a dynamic system with movable segments and adjustable gaps. This allows the setter to adapt its constraints in real-time during thermal cycling, providing support when needed and clearance when expansion occurs.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent introduces intermediary elements such as bearing surfaces and thermal expansion compensation materials between the setter and ceramic core. These intermediaries facilitate controlled movement while maintaining positional accuracy.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Device complexity

If a one-piece setter structure is used, then device complexity is reduced, but adaptability to varying core shapes deteriorates

Engineering Contradiction:
Improvesetter structureVSAvoidaccommodation of varying thickness
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The setter is divided into multiple segments that can move relative to each other, allowing the setter to adapt to thermal expansion of the ceramic core while maintaining dimensional accuracy. The segmented structure enables controlled movement to accommodate expansion forces.

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

Enables the production of ceramic cores with significant taper and varying thickness by accommodating thermal changes, reducing the risk of breakage and maintaining dimensional accuracy during the firing process.

Implementation Method 1

Each of the one or more first and second gaps is oriented to thermally expand or contract in correspondence with the thermal expansion or contraction of the ceramic core during a firing process thereof

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

The thermal expansion material is disposed within the one or more of the one or more first and second gaps, and the thermal contraction material is disposed at an exterior of the one or more of the one or more first and second gaps

Methodology Applied
Scientific EffectThermal contraction: Thermal Contraction

Data Source

PatentEP3725484B1Ceramic core setter
Publication Date: 2023.05.31 RTX CORP
  • EP3725484B1 patent drawingFigure 1
  • EP3725484B1 patent drawingFigure 2~3
  • EP3725484B1 patent drawingFigure 4~5

AI summary

A die setting apparatus (401; 901) for a ceramic core (402; 902) is provided. The die setting apparatus includes a first setter (410; 910) abuttable with a first side (403; 903) of the ceramic core and a second setter (420; 920) abuttable with a second side (404; 904) of the ceramic core opposite the first side. At least one of the first and second setters includes two or more pieces (411, 421; 911, 921) respectively arranged to form one or more gaps (412, 422; 912, 922). Each of the one or more gaps is oriented to thermally adjust in correspondence with thermal changes of the ceramic core during a firing process thereof.