Segmented Ceramic Core Setter for Thermal Expansion During Firing

Solution Overview

Problem

Current turbine airfoil ceramic cores with complex shapes and varying thicknesses are prone to breakage during firing due to mismatched thermal expansion coefficients between the ceramic cores and the setters, which complicates dimensional accuracy and production.

Innovation Solution

A die setting apparatus with multiple pieces and thermal expansion/contraction materials matching the ceramic core's coefficient of thermal expansion, allowing for adjustable gaps and surfaces to accommodate thermal changes, ensuring secure holding and maintaining dimensional accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

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

Engineering Contradiction:

Improvedimensional accuracyVSAvoidcore integrity

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The setter is divided into multiple segments that can move independently relative to each other. This segmentation allows the setter to accommodate thermal expansion of the ceramic core while maintaining overall dimensional control, resolving the contradiction between restrictiveness and core integrity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The setter transitions from a static, rigid structure to a dynamic, adaptable structure. The segments are designed to move dynamically in response to thermal changes, allowing the setter to adjust its constraints based on the thermal state of the ceramic core, thus preventing breakage while maintaining accuracy.

Inventive Principle:

Principle #15Dynamics

2Reliability

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

Engineering Contradiction:

Improvecore integrityVSAvoiddimensional accuracy

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

By segmenting the setter structure, each segment can move independently to accommodate thermal expansion, providing the necessary looseness to prevent breakage while the collective arrangement of segments maintains overall dimensional control through guided movement paths.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The segmented structure acts as an intermediary between the rigid requirements for dimensional accuracy and the flexible needs for thermal accommodation. The segments provide a medium that translates thermal movement into controlled adjustments, preventing direct contact stresses that would cause breakage.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Device complexity

If one-piece setters are used for simplicity, then device complexity is reduced, but adaptability to thermal changes deteriorates

Engineering Contradiction:

Improvesetter structureVSAvoidthermal adjustment capability

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The setter is divided into multiple segments that can move independently relative to each other. This segmentation allows the setter to accommodate thermal expansion of the ceramic core while maintaining overall dimensional control, resolving the contradiction between restrictiveness and core integrity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The setter transitions from a static, rigid structure to a dynamic, adaptable structure. The segments are designed to move dynamically in response to thermal changes, allowing the setter to adjust its constraints based on the thermal state of the ceramic core, thus preventing breakage while maintaining accuracy.

Inventive Principle:

Principle #15Dynamics

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 curvature by allowing for thermal expansion and contraction, reducing breakage and maintaining dimensional accuracy during the firing process.

Implementation Method 1

at least one of a thermal expansion material disposable to drive a thermal expansion of one or more of the one or more gaps and a thermal contraction material disposable to drive a thermal contraction of one or more of the one or more gaps

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

at least one of a thermal expansion material disposable to drive a thermal expansion of one or more of the one or more gaps and a thermal contraction material disposable to drive a thermal contraction of one or more of the one or more gaps

Methodology Applied

Scientific EffectThermal contraction: Thermal Contraction

Data Source

PatentUS11014140B2Ceramic core setter

Publication Date: 2021.05.25 RTX CORP

AI summary

A die setting apparatus for a ceramic core is provided. The die setting apparatus includes a first setter abuttable with a first side of the ceramic core and a second setter abuttable with a second side of the ceramic core opposite the first side. At least one of the first and second setters includes two or more pieces respectively arranged to form one or more gaps. 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.