Removable Composite Core for Complex Investment Casting Passages
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Solution Overview
Problem
Investment casting is limited by the difficulty in designing and removing complex ceramic cores without affecting the molded part, restricting its application to components with intricate passages.
Innovation Solution
A composite core is developed, comprising a core element and a deformable structural element with a rigid shell, where the structural element is coated with a slurry that hardens into a brittle shell, allowing for controlled deformation and easy removal by applying forces to break the shell, facilitating the creation of complex passages in investment casting molds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If ceramic cores are used in controlled solidification investment casting, then tight tolerances and controlled solidification are achieved, but the ceramic cores are difficult to remove or destroy without affecting the molded part
Solution Approach 1:
The core is divided into two functional segments: an inner rigid ceramic core element that defines the passage geometry and maintains precision, and an outer deformable structural element with a rigid shell that facilitates removal. The deformable element can be compressed or twisted to break the shell and collapse the structure, allowing easy extraction of the rigid core element without damaging the molded part.
Solution Approach 2:
The structural element's physical state is changed from rigid to deformable through material selection and design, allowing it to be collapsed or compressed during removal. The rigid shell provides structural integrity during molding, then can be broken by applying force to the deformable element, changing the core's parameters from stable to removable.
2Adaptability or versatility
If complex passages are required in the molded part, then design flexibility is improved, but the process is severely restricted due to core removal difficulties
Solution Approach 1:
By separating the core into a permanent rigid ceramic element and a temporary deformable structural element, the system enables complex passage designs while maintaining high productivity. The rigid core can be precisely formed for complex geometries, while the deformable outer element enables rapid removal through collapse or compression, avoiding time-consuming manual extraction processes.
Solution Approach 2:
The deformable structural element with rigid shell is designed to be discarded or easily removed after serving its purpose of forming the passage. The rigid ceramic core element is recovered and reused for subsequent molding operations, while the deformable element is replaced, enabling continuous high-speed production of parts with complex passages.
3Stability of the object's composition
If a rigid shell is formed about the structural element, then the core maintains its shape during molding, but the shell must be broken during removal which requires additional force application
Solution Approach 1:
The core structure transitions from a static rigid configuration during molding to a dynamic deformable state during removal. The deformable structural element with rigid shell maintains shape stability under molding conditions, then can be dynamically collapsed or compressed by applying force to exposed portions, converting the removal process from a high-force static extraction to a controlled dynamic collapse.
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 solution enables the production of complex cored passages, expanding the applicability of controlled solidification investment casting, reducing scrap rates and production cycle time, and enhancing microstructure quality through automated processes.
Implementation Method 1
The slurry is cured to form a rigid shell element
Implementation Method 2
The structural element is configured to deform when a force is applied to the structural element. The shell element is configured to break when the structural element deforms.
Data Source
AI summary
A composite core for forming a passage in an investment casting mold is provided including a core element. A generally hollow structural element is positioned about an exterior of the core element. The structural element is configured to deform when a force is applied to the structural element. A rigid shell element is integrally formed about the structural element. The shell element is configured to break when the structural element deforms.