Casting Internal Features with Retained Insert Member
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Solution Overview
Problem
The complex process of forming internal cooling passages in cast products, such as those for high-temperature gas turbine engines, is hindered by the need for intricate cores that are delicate and require support, leading to unwanted apertures and thermal stresses when removed, which can cause operational issues and component failure.
Innovation Solution
A method involving a core with sections and gaps, where an insert member spanning the gaps remains securely within the cast product, formed of a different material than the core, to support the core sections and maintain internal features like cooling passages without leaving apertures, using a mould with retaining formations to suspend the core and ensure the insert member's retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a core is used to define internal cooling passages, then cooling efficiency is improved, but the core structure becomes delicate and requires support structures that leave unwanted apertures
Solution Approach 1:
The core is divided into multiple separable sections that can be independently positioned and supported. Each section can be supported individually by the mould's retaining formations, eliminating the need for complex support structures like spines that would create unwanted apertures when removed.
Solution Approach 2:
The mould acts as an intermediary structure with retaining formations that directly support the core sections during casting. This eliminates the need for additional support structures (spines) within the core itself, thereby preventing unwanted apertures in the final component.
2Stability of the object's composition
If support structures like spines are added to hold core sections, then core stability is improved, but unwanted apertures are created in the final component
Solution Approach 1:
The support function is extracted from the core structure itself and transferred to the mould's retaining formations. This allows the core to be stable during casting without requiring internal support structures that would leave harmful apertures in the final component.
Solution Approach 2:
The mould serves as an intermediary that provides the necessary support and stability to the core sections during the casting process, eliminating the need for additional support structures within the core that would create unwanted apertures.
3Ease of manufacture
If conventional brazing or welding is used to close exit apertures, then aperture closure is achieved, but thermal stresses and cracking occur
Solution Approach 1:
The invention converts the potential harm of thermal stresses from brazing/welding into a benefit by eliminating the need for these thermal processes entirely. The core design with retained sections provides aperture closure without thermal processing, avoiding cracking and thermal stresses.
Solution Approach 2:
Instead of using thermal processes to close apertures, the invention uses a mechanical copy approach where the core sections themselves are retained in place to define the final aperture configuration, avoiding thermal stresses entirely.
4Manufacturing precision
If intricate cores with thin walls are used to create cooling chambers, then cooling passage complexity is improved, but core strength deteriorates
Solution Approach 1:
The core is segmented into multiple sections that can be independently supported by the mould's retaining formations. This allows intricate geometries with thin walls to be maintained for precise cooling passages while each section is individually supported to prevent collapse during casting.
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 allows for the creation of robust, air-tight internal cooling passages without the need for additional support structures, reducing thermal stresses and machining costs, while ensuring the insert member remains securely in place, enhancing the component's operational efficiency and reliability.
Implementation Method 1
introducing a liquid phase material into the gap between the core bodies in the mould; allowing the liquid phase material to solidify in the gap so as to form a feature of a resulting solid product
Data Source
AI summary
A method of forming a cast product (30) by providing a core (52) having a plurality of sections (54) and one or more gaps (55) there-between. The core further includes an insert member (60) spanning the gap (55) between adjacent sections (54). The core (52) is located within a mold (68) and a liquid phase material is introduced into gap (55) between the core sections. The liquid phase material is solidified in the gap so as to form a cast feature of a resulting solid product and the core sections (54) are removed from the solid product (30) such that the insert member (60) remains securely held within the feature (74).