Composite Ceramic Core Inserts for Airfoil Casting
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Solution Overview
Problem
The existing methods for creating complex ceramic cores for advanced gas turbine engine airfoils with intricate air cooling channels face challenges such as dimensional variability, assembly complexity, and flash formation due to the limitations of tooling design and the need for multiple core pieces, which affect the accuracy and efficiency of airfoil cooling.
Innovation Solution
A method involving the formation of composite core inserts with interlocked fused joints using preformed and in-situ formed fugitive core inserts, eliminating the need for adhesives and reducing flash formation by creating a mechanically interlocked and sealed joint, allowing for more complex core geometries and improved internal feature control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple ceramic core pieces are assembled to achieve complex cooling schemes, then the complexity of cooling features is improved, but dimensional variability and assembly complexity increase
Solution Approach 1:
The core is divided into multiple fugitive insert components that can be separately formed and then assembled. Each insert can be optimized independently while maintaining overall core functionality for complex cooling schemes.
Solution Approach 2:
A core die with integrated locating schemes acts as an intermediary to precisely position and assemble multiple ceramic core pieces. The die ensures proper alignment and reduces dimensional variability during assembly.
2Adaptability or versatility
If multiple fugitive core inserts are assembled in a core die, then complex geometries are achieved, but flash formation and handling scrap increase
Solution Approach 1:
The locating schemes in the core die are designed to not only position inserts but also prevent flash formation by ensuring intimate contact between inserts and the die walls during molding.
Solution Approach 2:
The core die is pre-configured with locating features before inserts are loaded, ensuring proper positioning and preventing flash formation during the molding process.
3Ease of manufacture
If conventional tooling is used to form ceramic cores, then manufacturing simplicity is maintained, but core complexity is limited
Solution Approach 1:
The core is segmented into multiple fugitive inserts that can be formed using conventional tooling methods, then assembled to create complex geometries that would be impossible with single-piece conventional tooling.
Solution Approach 2:
The assembly of multiple inserts in three-dimensional space within the core die enables complex cooling schemes and geometries that cannot be achieved with conventional single-piece tooling approaches.
Data Source
AI summary
A multi-wall ceramic core for casting an airfoil with one or more internal cooling passages is made by preforming at least one fugitive core insert to have a joint-forming surface with a male and/or female joint feature and then forming at least one fugitive core insert in-situ adjacent and integrally connected and fused to the at least one preformed core insert at the joint-forming surface to form an interlocked, fused joint to form a composite core insert that includes features to form internal passage surfaces in the core when the composite core insert is removed. Another aspect involves preforming first and second fugitive core inserts to have respective joint-forming surfaces with respective snap-fittable joint features and assembling the first and second fugitive core inserts to form a composite core insert by snap fitting the snap-fittable joint features together to form an interlocked joint. The composite core insert is placed in a core molding die cavity, and a fluid ceramic material is introduced into the die cavity to form the ceramic core body incorporating the fugitive composite core insert therein.