Refractory Metal Core Bending for Turbine Cooling Passages
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Solution Overview
Problem
Existing investment casting methods for gas turbine engine components, such as combustor panels, face challenges in efficiently creating complex internal cooling passages using fragile ceramic cores and expensive hard tooling, which limits the geometric complexity and increases costs.
Innovation Solution
The method involves using a refractory metal stock investment casting core, cut from a sheet and bent to conform to the desired cooling passage shape, eliminating the need for ceramic cores and complex forming processes, and integrating cooling features through machining or other techniques before or after bending, allowing for simpler and cost-effective production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If ceramic cores are used to form internal cooling passages, then the passages can be created in investment casting, but the cores are fragile and limit geometric complexity
Solution Approach 1:
The patent changes the material parameter of the core from ceramic to refractory metal, fundamentally altering the mechanical properties. This material substitution transforms the core from a fragile component limited in geometric complexity to a robust component capable of withstanding complex geometries and handling during the investment casting process while maintaining manufacturing precision for internal passages.
2Manufacturing precision
If complex forming processes are used to create cooling passages, then geometric precision is improved, but manufacturing cost increases
Solution Approach 1:
The patent segments the core formation process into simpler steps: cutting the refractory metal stock to basic dimensions and then bending it to the desired shape. This segmentation avoids complex forming processes while achieving the required geometric precision for cooling passages, thereby reducing manufacturing complexity and cost.
Solution Approach 2:
The patent changes the material parameters of the core to refractory metal, which possesses superior formability compared to ceramic materials. This parameter change enables the use of simple cutting and bending operations instead of complex forming processes, maintaining geometric precision while significantly easing manufacturing.
3Manufacturing precision
If hard tooling is used for precision forming, then manufacturing precision is improved, but equipment cost increases
Solution Approach 1:
The patent changes the core material parameter to refractory metal, which inherently provides the necessary dimensional stability and precision without requiring expensive hard tooling. The material properties of refractory metal allow for accurate cutting and bending operations using simpler, less costly equipment while maintaining the required manufacturing precision for gas turbine components.
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 enables the efficient and cost-effective fabrication of combustor panels with complex internal cooling features, reducing the reliance on fragile ceramic cores and expensive tooling, while maintaining the structural integrity and geometric precision required for gas turbine components.
Implementation Method 1
the stock investment casting core is bent to thereby form the production investment casting core
Data Source
Figure 1A~1C
Figure 1D~3
Figure 2
AI summary
An investment casting method includes providing a stock investment casting core (40), bending the stock investment casting core (40) to thereby form a production investment casting core (40) that conforms to a design cooling passage shape, and casting an alloy around the production investment casting core (40) to form a cast article.