Hollow Needle Injection for Composite Fibrous Textures
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Solution Overview
Problem
Existing methods for injecting a loaded suspension into 3D or 2.5D fibrous textures face challenges in achieving homogeneous penetration and are not adaptable to varying geometries, leading to high porosity and increased development and implementation costs due to the 'filter' effect and complex shape of these textures.
Innovation Solution
A method using hollow needles to inject a loaded suspension directly into the core of the fibrous texture, allowing for controlled injection and adaptability to different geometries by adjusting needle position and depth, with the needles having a diameter of 0.4 mm to 0.8 mm and beveled ends for easier penetration, enabling the use of highly loaded suspensions with minimal pressure loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional liquid process methods are used to impregnate 3D or 2.5D fibrous textures, then the suspension can penetrate the texture, but the penetration is non-homogeneous due to the filter effect and long injection duration leading to high porosity
Solution Approach 1:
The injection process is segmented by using multiple hollow needles distributed across the texture surface, each injecting suspension at different locations simultaneously or sequentially. This divides the single non-homogeneous penetration process into multiple localized homogeneous penetration zones, collectively achieving uniform impregnation throughout the 3D or 2.5D texture.
Solution Approach 2:
The invention transitions from surface-level injection to three-dimensional injection by inserting hollow needles through the texture thickness. Suspension is injected at controlled depths within the texture volume rather than relying on surface penetration, enabling homogeneous distribution throughout the thickness and eliminating the filter effect that causes non-uniform impregnation.
2Manufacturing precision
If diluted suspension is used to achieve homogeneous penetration, then the suspension can flow through the texture, but significant development work is required including modeling flows and developing specific tooling for each geometry
Solution Approach 1:
The hollow needle injection system is designed as a universal tool that can adapt to different part geometries by adjusting needle positions, depths, and injection parameters. The same basic apparatus serves multiple functions across various texture types and part shapes, eliminating the need for geometry-specific tooling development while maintaining homogeneous penetration.
Solution Approach 2:
The invention controls penetration homogeneity by adjusting injection parameters such as needle insertion depth, injection pressure, flow rate, and suspension concentration directly at the injection point. These parameter changes enable homogeneous impregnation without requiring diluted suspension or complex flow modeling, simplifying the overall process development.
3Reliability
If highly loaded suspension is used to reduce final porosity, then the particle content increases, but conventional methods cannot achieve homogeneous penetration due to high viscosity and filter effect
Solution Approach 1:
The hollow needles are pre-inserted to specific depths within the texture before injection begins, creating direct pathways to the texture core. This preliminary positioning allows highly loaded suspension to be delivered directly to target zones without relying on surface-level flow that would be blocked by the filter effect, enabling both high loading and homogeneous distribution.
Solution Approach 2:
The hollow needles act as intermediaries that bridge the suspension source and the texture interior. They deliver highly loaded suspension directly into the texture core, bypassing the filter effect that would otherwise prevent homogeneous penetration. The needles mediate between the high-viscosity suspension and the textured structure, enabling effective impregnation.
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 method significantly improves the control and speed of injection, reduces porosity, and allows for the use of highly loaded suspensions with a high filler content, reducing the duration and cost of the injection process while maintaining the texture's architecture, achieving a low macroporosity rate and adaptable geometry compatibility.
Implementation Method 1
the injection of the loaded suspension is carried out by means of at least one hollow needle... so as to inject the loaded suspension at one or more determined depths in the fibrous texture
Data Source
AI summary
A method for injecting a loaded suspension into a fibrous texture having a three-dimensional or multilayer weaving includes the injection of a suspension containing a powder of solid particles into the volume of the fibrous texture. The injection of the loaded suspension is carried out by at least one hollow needle in communication with a loaded suspension supply device, each needle being movable in at least one direction extending between a first face and a second opposite face of the fibrous texture so as to inject the loaded suspension at one or more determined depths in the fibrous texture.