Ceramic Core Setter Posts for Precise Airfoil Wall Spacing
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Solution Overview
Problem
Maintaining relative spacing of ceramic core segments during firing is challenging, leading to variability in wall thickness and tolerance issues in multi-wall castings, particularly in airfoil components of gas turbine engines.
Innovation Solution
A core setter with protruding posts and optional bumpers maintains a predetermined minimum separation between core legs, ensuring precise positioning and spacing during firing, which is achieved by using setter posts with specific dimensions and configurations to support and space the core legs effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple separate core pieces are stacked to form multi-wall castings, then complex passageway structures can be achieved, but maintaining relative spacing between core segments becomes difficult leading to tolerance issues and wall thickness variability
Solution Approach 1:
The patent introduces core ties as intermediary elements that connect adjacent core segments together. These core ties act as mediators to maintain fixed relative spacing between the core pieces, preventing movement and ensuring consistent wall thickness during the casting process. The core ties are positioned between core segments and extend to contact both segments, creating a rigid connection that eliminates tolerance accumulation.
2Adaptability or versatility
If multiple separate core pieces are used for multi-wall castings, then complex airfoil internal structures can be formed, but positioning accuracy and registration between pieces deteriorates during firing
Solution Approach 1:
The patent divides the complex core structure into multiple separable core segments that can be manufactured and positioned independently. Each segment represents a portion of the overall passageway system, allowing for modular assembly. The segmentation enables complex internal structures to be built from simpler components while maintaining positioning accuracy through the use of core ties and setter posts.
Solution Approach 2:
The core ties serve as intermediary connection elements between adjacent core segments. These ties maintain precise relative positioning of the segments during assembly and firing, ensuring that the registered positions of multiple core pieces remain consistent. The core ties prevent any relative movement or drift that would otherwise occur during the firing process.
3Ease of manufacture
If traditional firing methods without specialized positioning structures are used, then the firing process is simpler, but core segments move relative to each other causing increased variability in casting dimensions
Solution Approach 1:
The patent implements preliminary positioning actions by pre-configuring the setter with posts at specific locations and pre-attaching core ties to core segments before firing. This preliminary arrangement ensures that when the core assembly is placed in the setter, the relative positions of all segments are already established and locked in place. The setter posts contact the core ties to maintain these predetermined positions throughout the firing process, preventing any dimensional variability.
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
The solution ensures precise registry and consistent wall thicknesses in cast airfoil components, enhancing manufacturing consistency and reducing scrappage by maintaining core segment alignment throughout the casting process.
Implementation Method 1
placing the core in a setter, the setter having a plurality of protruding setter posts between second legs of the core and with distal ends supporting first legs of the core; and firing the core in the setter to harden the core. During the firing, the setter posts maintain a predetermined minimum separation between the first legs and the second legs.
Implementation Method 2
firing the core in the setter to harden the core
Data Source
Figure 1
Figure 1A~3
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AI summary
A method for firing a ceramic core (100) includes: placing the core (100) in a setter, the setter having a plurality of protruding setter posts (30) between second legs (114A-F) of the core (100) and with distal ends (36) supporting first legs (112A-H) of the core (100); and firing the core (100) in the setter to harden the core. During the firing, the setter posts (30) maintain a predetermined minimum separation between the first legs (112A-H) and the second legs (114A-F). A core setter for firing a core (100) later used to cast an airfoil element (600) and a method of using this core setter are also claimed.