Sectorized Ring Mold for Composite Back-Draft Unmolding
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Solution Overview
Problem
The challenge in fabricating composite material components for aviation parts, such as fan casings, lies in unmolding parts with internal cavities that have back-draft configurations, where the narrowing passage prevents the upstream drum from being withdrawn, making conventional RTM injection tooling ineffective.
Innovation Solution
Incorporating a sectorized ring with at least three mutually touching inserts, including a 'keystone' insert, and a conical drum that creates natural draft within the internal cavity, allowing for the upstream drum to be withdrawn and facilitating the unmolding of parts with back-draft configurations without increasing mold weight or complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional RTM injection tooling with a rigid mold is used to fabricate a fan casing with an internal cavity having back-draft configuration, then the manufacturing precision and mechanical properties of the composite material part are maintained, but the unmolding process becomes impossible when the passage narrows at the upstream end, preventing withdrawal of the upstream drum
Solution Approach 1:
The rigid mold is divided into multiple detachable segments: an upstream drum, a downstream drum, and a sectorized ring with keystone inserts. This segmentation allows each component to be removed independently, solving the unmolding problem for back-draft configurations where a single rigid mold cannot be withdrawn
Solution Approach 2:
The mold transitions from a completely rigid structure to a dynamic system where the sectorized ring can be detached and repositioned during the unmolding process. The keystone inserts enable controlled separation and reassembly, allowing the mold to adapt its configuration during different stages of the manufacturing cycle
2Ease of operation
If the upstream drum is designed to be completely removable for easy unmolding, then the ease of operation is improved, but the mold structure becomes more complex and may require additional components that increase device complexity
Solution Approach 1:
The sectorized ring is divided into multiple inserts including keystone elements that can be independently positioned and removed. This segmentation allows the upstream drum to be withdrawn while using simple, modular components rather than complex mechanisms
Solution Approach 2:
Instead of making the entire upstream drum removable, the invention keeps the drum structure simple and removable while adding the sectorized ring with keystone inserts to the fixed mold portion. This inverts the approach by making the supporting structure adaptable rather than the drum itself complex
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
Enables the successful unmolding of composite material parts with internal cavities having back-draft configurations by recreating natural draft, allowing for efficient removal of the final part without significant modifications to the mold or increased weight, while maintaining mechanical properties and dimensional stability.
Implementation Method 1
a conical drum that is secured to said inside surface of said sectorized ring to support it and that is withdrawn, once separated from said sectorized ring, relying on said natural draft created by said inside surface of said sectorized ring
Data Source
AI summary
An injection tooling is configured to inject a polymer resin into a fiber preform for fabricating a part in the form of a body of revolution out of composite material, the part having an internal cavity with back-draft. In order to enable the part to be unmolded after the polymer resin has been injected and polymerized, the tooling includes, arranged at least in the internal cavity, firstly a sectorized ring made up of at least three mutually touching inserts including one forming a keystone, the ring having an outside surface that matches the internal cavity with back-draft and an inside surface that presents natural draft, and secondly a conical drum secured to the inside surface of the sectorized ring to support it and that is withdrawn, once separated from the sectorized ring, relying on the natural draft created by the inside surface of the sectorized ring.