Metallic Casting Core With Tapered Leading Portion
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Solution Overview
Problem
Current investment casting techniques face challenges in manufacturing fine, precisely located cooling passageways for superalloy gas turbine engine components, as they are difficult to manufacture and can be fragile, affecting engine efficiency.
Innovation Solution
A method involving the use of a metallic blank with a tapered leading portion, which is locally thinned and through-cut to fit into a ceramic core, allowing for the creation of investment casting cores with precise features for enhanced cooling passageways, combined with a ceramic core assembly for improved structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If ceramic casting cores are used to form fine cooling passageways, then manufacturing precision is improved, but reliability deteriorates due to fragility
Solution Approach 1:
The patent uses a composite core assembly combining ceramic and refractory metal materials. The ceramic portion provides the fine cooling passageway geometry with high manufacturing precision, while the refractory metal portion provides structural strength and reliability. The two materials are bonded together to form an integrated core that leverages the advantages of both materials.
2Productivity
If fine cooling features are manufactured, then cooling efficiency is improved, but ease of manufacture deteriorates
Solution Approach 1:
The core is divided into separate ceramic and refractory metal portions that can be manufactured independently using optimized processes for each material. The ceramic portion is molded and fired to create precise cooling features, while the refractory metal portion is formed separately and then bonded to the ceramic, making the overall manufacturing process more feasible.
3Reliability
If refractory metal sheet stock is used for metallic cores, then reliability is improved, but manufacturing precision deteriorates for fine features
Solution Approach 1:
Different portions of the core have different material properties optimized for their specific functions. The ceramic portion provides high precision for the fine cooling passageway features, while the refractory metal portion provides structural strength. Each material is used locally where its properties are most beneficial.
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 production of gas turbine engine components with enhanced cooling efficiency by creating precise, robust cooling passageways, maximizing the cooling benefit from a given amount of cooling air while maintaining structural integrity.
Implementation Method 1
the leading portion tapers from a first thickness (T1) of 0.005 to 0.20 inches (0.13 to 0.5 mm) over a taper length (L1) of 0.040 to 0.100 inches (1-2.5 mm) to a second thickness (T2) of 25-75% of the first thickness; through-cutting the blank across the thickness; and inserting the leading portion into a slot in a pre-formed ceramic core
Data Source
Figure 1
Figure 2~2A
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AI summary
A method for manufacturing an investment casting core uses a metallic blank (60) having a thickness between parallel first and second faces less than a width and length transverse thereto. The blank is locally thinned from at least one of the first and second faces (82, 84). The local thinning forms a taper on a leading portion of the RMC. The blank is through-cut across the thickness. The blank is inserted into the leading portion into a slot in a pre-formed ceramic core.