Flexible Membrane Impregnation for Ceramic Composite Parts
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Solution Overview
Problem
Current methods for manufacturing ceramic matrix composite (CMC) parts face challenges in controlling fiber volume ratio and achieving uniform sedimentation of ceramic particles, particularly for large-sized and thin parts, leading to issues with sizing tolerances and inhomogeneous deposition.
Innovation Solution
A method involving a mold with an impregnation chamber and a flexible membrane, where a compression fluid is injected to apply pressure on the membrane, and a slip with ceramic particles is injected at a lower pressure, with the pressure difference maintained to control fiber volume and sedimentation, using a control unit to regulate pressures and ensure uniform deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rigid counter mold is used for injection molding, then the mold structure provides stable support, but manufacturing precision deteriorates for large-sized and thin parts due to extremely fine sizing tolerance requirements
Solution Approach 1:
The patent replaces the rigid counter mold with a flexible membrane that can deform to accommodate the shape of large-sized and thin parts. The membrane is supported by a rigid backing plate, combining the flexibility needed for complex geometries with the structural support required for stability. This eliminates the need for extremely fine sizing tolerances in the mold structure while maintaining manufacturing precision.
2Productivity
If pressure is applied to the flexible membrane to cause slip penetration, then the impregnation process is accelerated, but fiber volume rate control deteriorates due to difficulty in controlling the compression force
Solution Approach 1:
The patent incorporates a control system that uses feedback from pressure sensors to regulate the compression force applied to the flexible membrane. The control unit adjusts the hydraulic or pneumatic pressure in real-time to maintain the desired fiber volume rate, preventing both over-compression and under-compression of the preform during the impregnation process.
Solution Approach 2:
The patent replaces direct mechanical compression with a fluid-based compression system using hydraulic or pneumatic pressure. This substitution allows for more precise and controllable application of force through fluid pressure regulation, enabling better control of fiber volume rate while maintaining high impregnation speeds.
3Productivity
If high injection pressure is used for slip injection, then the impregnation process is faster, but deposition uniformity deteriorates due to inhomogeneous distribution of ceramic particles
Solution Approach 1:
The patent uses a dual-pressure injection system where a first fluid injection device applies hydraulic or pneumatic pressure to accelerate the slip through the preform, while a second fluid injection device applies a lower counter-pressure to prevent excessive force. This pneumatic-hydraulic control system enables fast injection while maintaining uniform particle distribution by preventing slip stagnation and ensuring homogeneous penetration throughout the preform.
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 better control of fiber volume ratio and improved sedimentation of ceramic particles, resulting in a more homogeneous and accurately manufactured CMC part, particularly suitable for parts with small thickness and large surface areas like turbomachine casings.
Implementation Method 1
injection of a compression fluid into the compaction chamber so as to apply a first pressure on the membrane
Implementation Method 2
the slip loaded with ceramic particles is injected into the cavity separating the mold and its counter-mold in which the preform is located, in order to cross the preform by applying a pressure gradient
Implementation Method 3
injection of a slip comprising ceramic particles into the impregnation chamber with a second pressure... improved sedimentation of the slip particles within the fibrous reinforcement
Data Source
Figure 1A~1B
Figure 2~3B
Figure 4
AI summary
The invention relates to a method for producing a part made from a composite material, comprising the following steps: arranging a fibrous preform (3) in a mould (2) including an impregnation chamber (21) which comprises, in the lower part thereof, a filter, with a first surface of the preform (3) resting on the filter, the impregnation chamber (21) being closed by a flexible membrane (23) placed opposite a second surface of the preform (3), said membrane (23) separating the impregnation chamber (21) from a compaction chamber (22). The invention is characterised in that the method further comprises the following steps: injecting a compression fluid into the compaction chamber (22) so as to apply a first pressure on the membrane (23); and injecting a slurry comprising ceramic particles into the impregnation chamber (21) with a second pressure, while continuing to inject the compression fluid, the second pressure for slurry injection being lower than the first pressure on the membrane (23).