Turbine Blade Tip Casting with Segmented Ceramic Cores
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Solution Overview
Problem
Current methods for casting turbine engine blades with tip pockets and tip shelves face challenges in accurately forming the complex geometries and ensuring effective cooling passageways, particularly in integrating strongback cores with ceramic materials to achieve precise surface casting and efficient cooling systems.
Innovation Solution
The method involves forming a shell using a ceramic casting core assembly, comprising a strongback core and a feedcore, to mold the base and sidewall surfaces of tip pockets and tip shelves, along with adjacent airfoil portions, and overmolding with pattern material to create a cooling passageway system with outlets, enabling precise casting of nickel-based alloys and efficient cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a ceramic core is used to cast tip pockets and tip shelves, then the geometric precision and surface quality of complex tip structures are improved, but the manufacturing complexity and process difficulty increase
Solution Approach 1:
The ceramic core is divided into multiple segments including a tip shelf core, a tip pocket core, and a strongback core. Each segment is separately formed and then assembled together to create the complete core structure. This segmentation allows for easier manufacturing of individual components while achieving the complex overall geometry required for precise tip structure casting.
Solution Approach 2:
The tip shelf core and tip pocket core are nested within or attached to the strongback core structure. The smaller, more complex cores are positioned within the framework of the larger strongback core, allowing all components to be formed and assembled in a coordinated manner that simplifies the overall manufacturing process while maintaining geometric precision.
2Manufacturing precision
If multiple separate cores are used for tip pockets and tip shelves, then the geometric accuracy of each feature is improved, but the assembly complexity and potential misalignment increase
Solution Approach 1:
The tip shelf core, tip pocket core, and strongback core are merged into a single integrated core assembly through attachment. This unified assembly ensures that all tip features are positioned relative to each other with high precision, eliminating alignment issues that would arise from using completely separate cores. The merged structure maintains geometric accuracy while reducing assembly complexity.
Solution Approach 2:
The strongback core serves multiple functions: it provides structural support for the entire core assembly, positions the tip shelf and tip pocket cores relative to each other, and defines the geometry of the airfoil body. This multi-functional design reduces the number of separate components needed while maintaining geometric accuracy across all features.
3Manufacturing precision
If ceramic materials are used for strongback cores, then the surface quality and dimensional accuracy of cast surfaces are improved, but the manufacturing difficulty and cost increase
Solution Approach 1:
The ceramic core manufacturing process is segmented into forming individual core components (tip shelf core, tip pocket core, strongback core) that can be manufactured using optimized processes for each component. This segmentation allows for easier manufacturing of individual ceramic pieces while maintaining the high surface quality and dimensional accuracy required for the final cast product.
Solution Approach 2:
A pattern material or bonding agent serves as an intermediary between the separate ceramic core components during assembly. This intermediary facilitates the joining of ceramic pieces while protecting their surfaces and ensuring precise positioning, thereby reducing manufacturing difficulty without compromising surface quality or dimensional accuracy.
Data Source
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AI summary
A method for casting a blade, the blade with an airfoil having: a tip having at least one of a tip pocket and a tip shelf. Each said at least one of a tip pocket and a tip shelf having a base surface and a sidewall surface. The method includes forming a shell, the forming of the shell including shelling a pattern having at least one ceramic casting core; and casting in the shell, the shell having a first portion formed by the at least one ceramic casting core and a second potion formed by applied shell material. For at least a first tip pocket or tip shelf of the least one of a tip pocket and a tip shelf, the at least one ceramic casting core molds the base surface and the sidewall surface and an adjacent portion of at least one of the pressure side and the suction side spanwise inboard of the base surface.