Layered Ceramic Core for Turbine Cooling Passages
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Solution Overview
Problem
Existing investment casting processes are inadequate for producing components with complex, convoluted internal passageways, such as advanced gas turbine blades, as they struggle to accurately replicate the intricate three-dimensional cooling schemes required by modern aerospace and power industries.
Innovation Solution
A layering process is employed to construct a three-dimensional ceramic core mold from stacked layers of fugitive material, allowing for the creation of convoluted passageways by defining void areas in each layer, which are then stacked to form a detailed three-dimensional structure, eliminating the need for wax molds and ceramic dipping processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional investment casting with ceramic cores is used, then components with simple interior passages can be produced, but components with complex convoluted interior passageways cannot be produced with sufficient precision
Solution Approach 1:
The ceramic core is constructed by segmenting it into multiple thin layers of fugitive material, each layer being formed separately and then stacked together. This segmentation allows each layer to be precisely formed with the correct void pattern, and when stacked, they create the complete complex three-dimensional passageway structure with high fidelity throughout the entire core.
Solution Approach 2:
The invention transitions from forming complex three-dimensional passageways directly to forming them through stacked two-dimensional layers. Each layer captures a two-dimensional cross-section of the passageway, and stacking multiple layers builds up the complete three-dimensional structure, enabling precise control of complex geometries that would be difficult to achieve with traditional single-step core formation.
2Adaptability or versatility
If traditional wax mold and ceramic dipping processes are used, then simple cooling passages can be formed, but convoluted three-dimensional cooling schemes cannot be produced
Solution Approach 1:
The invention extracts and eliminates the wax mold and ceramic dipping steps from the traditional investment casting process. Instead, fugitive material layers are directly formed in the desired shape and stacked to create the ceramic core, simplifying the manufacturing process while enabling greater versatility in producing complex cooling passage geometries.
Solution Approach 2:
The fugitive material layers are prepared in advance with the precise void patterns required for the complex cooling passages before assembly. This preliminary formation of each layer with the correct geometry allows the complete complex passageway structure to be achieved through stacking, rather than requiring complex molding and dipping operations during the casting process.
3Manufacturing precision
If ceramic cores with complex geometries are attempted using prior art methods, then the manufacturing process becomes prohibitively complex, but with the layering process, complex geometries can be achieved with improved manufacturability
Solution Approach 1:
By segmenting the ceramic core into multiple thin layers, each layer can be efficiently formed using standardized processes and then quickly assembled by stacking. This segmentation maintains high profile fidelity in the interior passages while improving productivity through modular construction and parallel processing of individual layers.
Data Source
AI summary
A method of casting a component (42) having convoluted interior passageways (44). A desired three dimensional structure corresponding to a later-formed metal alloy component is formed by stacking a plurality of sheets (18, 20) of a fugitive material. The sheets contain void areas (22) corresponding to a desired interior passageway in the metal alloy component. A ceramic slurry material is cast into the three dimensional structure to form either a ceramic core (34) or a complete ceramic casting vessel (38). If just a ceramic core is formed, a wax pattern is formed around the ceramic core and an exterior ceramic shell (38) is formed around the wax pattern by a dipping process prior to the removal of the fugitive material and wax. An alloy component having the desired interior passageway is cast into the casting vessel after the fugitive material is removed.