Silicone Elastomer Intensifier for CMC Resin Molding
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Solution Overview
Problem
Ceramic Matrix Composite (CMC) pre-ceramic polymer resins are prone to gaseous compound release during processing, leading to voids and porosity in the laminate, which are challenging to suppress in liquid infusion processes like Resin Transfer Molding (RTM), affecting the quality of the cured laminate.
Innovation Solution
A silicone elastomer intensifier with a high coefficient of thermal expansion is used within the RTM tool to apply pressure and suppress void formation by expanding thermally, ensuring uniform consolidation and wet-out of the fiber preform, using pressures from 50 psi to 800 psi, and encapsulating the fibrous sheet and pre-ceramic polymer resin between the intensifier and a cover plate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If pre-ceramic polymer resin is processed using conventional RTM, then the resin can be molded into the fiber preform, but void formation and porosity occur due to gaseous compound release
Solution Approach 1:
The intensifier applies preliminary counter-pressure to the pre-ceramic polymer resin before and during the release of gaseous compounds. This preliminary anti-action prevents void formation by opposing the harmful gas release, maintaining resin pressure above atmospheric pressure throughout the curing process, and eliminating the pressure differential that would otherwise cause porosity in the cured laminate
Solution Approach 2:
The intensifier dynamically adjusts the pressure parameter of the pre-ceramic polymer resin during processing. By maintaining elevated pressure (counter-pressure) throughout the curing cycle, the system changes the pressure parameter from conventional atmospheric or low-pressure RTM conditions to high-pressure conditions, preventing gas bubble expansion and void formation while the resin cures
2Manufacturing precision
If pressure is applied during RTM to suppress voids, then void formation is reduced, but the complexity of the molding system increases
Solution Approach 1:
The intensifier is nested within the existing RTM tooling structure, fitting into the mold cavity alongside the fiber preform. This nested configuration allows the intensifier to deliver high pressure directly to the resin without requiring external pressure generation equipment, thereby reducing overall system complexity while achieving superior void suppression
Solution Approach 2:
The intensifier is a self-contained device that generates its own counter-pressure independently of the external RTM processing equipment. It requires no additional pumps, pressure vessels, or control systems beyond its own internal mechanism, making the system self-sufficient and avoiding the complexity that would arise from integrating external pressure application systems
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 effectively minimizes void formation and porosity in the laminate, achieving less than 2% volume void content, ensuring a dense and defect-free composite material suitable for high-performance applications.
Implementation Method 1
a silicone elastomer (or functionally equivalent) intensifier inside the closed RTM tool to provide additional pressure during processing, thereby suppressing void formation within the laminate and providing uniform consolidation pressure
Implementation Method 2
the thermal energy subsystem is configured to heat the intensifier
Data Source
Figure 1
AI summary
A process for manufacturing a ceramic matrix composite component comprises inserting at least one fibrous sheet (18) into a resin transfer molding system (10). The process further includes wetting the at least one fibrous sheet (18) with a pre-ceramic polymer resin (28). The process further includes applying a pressure to the at least one fibrous sheet (18) and pre-ceramic polymer resin (28) with an intensifier (30) responsive to thermal expansion and curing the pre-ceramic polymer resin (28).