Blind Hole Formation in Composite Tank Walls Using Soluble Tooling
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Solution Overview
Problem
Existing methods for creating blind holes in composite fluid vessels, such as those used in aircraft potable water systems, face challenges in achieving a reliable seal and clean removal of soluble tooling, especially when using soluble or collapsible tooling.
Innovation Solution
A method involving a soluble tool with mating parts, a composite material with a central opening, and a spacer that cures within the composite material to form a blind hole, allowing for the removal of the soluble tool and creation of a blind hole without the need for a boss or post-manufacturing machining.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a boss is used to create a hole in the wall shared by sections, then the hole can be maintained open through curing, but the tool must seal on both mating parts and come out cleanly, which is difficult with soluble or collapsible tooling
Solution Approach 1:
The patent extracts the sealing function from the soluble tool itself by introducing a separate boss component. The boss is inserted into the soluble tool's central opening and maintains the hole open during curing, while the soluble tool material is washed away afterward, leaving the boss in place as the permanent sealing element.
Solution Approach 2:
The boss acts as an intermediary element between the soluble tool and the final product. It temporarily occupies the space needed for the hole during manufacturing, then remains as a functional component that seals against the mating tool parts while allowing the soluble material to be removed.
2Manufacturing precision
If machining a hole post-manufacturing is performed, then a clean blind hole can be created, but the cost becomes prohibitive
Solution Approach 1:
The patent performs the hole creation action during the manufacturing process itself by designing the tool and boss configuration to form the blind hole as the composite cures. This preliminary action eliminates the need for subsequent machining operations, reducing both cost and manufacturing steps while maintaining hole quality.
3Ease of manufacture
If soluble tooling is used, then the tool can be removed after curing, but it is difficult to create a boss that seals well and comes out cleanly
Solution Approach 1:
The patent separates the sealing function from the soluble tool by introducing a dedicated boss component. The boss remains in place to provide sealing, while the soluble tool material is extracted through washing, solving the conflict between tool removability and seal quality.
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 efficient creation of blind holes during the manufacturing process of multi-section tanks, ensuring a reliable seal and reducing costs associated with post-manufacturing machining.
Implementation Method 1
washing out the soluble tool to form a blind hole between mating sections of the tank
Implementation Method 2
curing the composite material and the spacer around the soluble tool
Data Source
AI summary
A method of making a blind hole in a wall of a multi-section tank during manufacture includes inserting a thin, flexible composite spacer ring in a hole in a composite material between mating parts of a soluble tool. The composite spacer ring is cured to the composite material during curing and maintains the hole between sections of the tank once completed.