Needle-Formed Z-Channels in Ceramic Preforms for Uniform Densification

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

In the processing of ceramic matrix composites (CMCs), large voids between adjacent tows of a preform create defects and tortuous pore networks that hinder uniform infiltration and composite properties, necessitating improved methods to form direct pathways for reactant gases.

Innovation Solution

A method involving a stand-alone tooling assembly with aligned fixtures and needles is used to create z-channels in a fibrous preform by heating the preform above the glass transition temperature of a polymer binder, inserting needles through aligned holes, and removing them to leave behind z-channels, facilitating uniform matrix densification.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a woven preform structure is used, then the composite structure is formed, but large voids and tortuous pore networks are created that hinder uniform infiltration

Engineering Contradiction:

Improveuniformity of matrix depositionVSAvoidlarge voids and tortuous pore networks

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The preform is segmented into multiple tow bundles that are arranged in a specific pattern and bonded together. By controlling the spacing and arrangement of these tows, the patent creates a more open, less tortuous pore network that facilitates uniform reactant gas flow and matrix deposition throughout the composite structure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces z-channels that extend through the thickness dimension of the preform, creating direct pathways perpendicular to the traditional in-plane pore network. This dimensional addition allows reactant gases to access interior regions more directly, eliminating tortuous paths and improving deposition uniformity across the composite thickness.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Manufacturing precision

If traditional infiltration methods are used without z-channels, then the processing procedure is simple, but reactant gases follow tortuous pathways leading to uneven deposition

Engineering Contradiction:

Improveuniformity of matrix depositionVSAvoidprocessing procedure complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

Z-channels are formed in the preform before the infiltration process begins. This preliminary action creates predetermined direct pathways for reactant gases, ensuring uniform deposition from the start without requiring complex real-time control or modification of the infiltration process itself.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The z-channels act as intermediary structures that mediate between the external reactant gas source and the interior preform regions. These channels provide a controlled, direct route for gas flow, simplifying the overall infiltration process while achieving uniform matrix deposition that would otherwise require complex process control.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Strength

If large voids exist between adjacent tows, then the preform structure is maintained, but defects are created that are detrimental to composite properties

Engineering Contradiction:

Improvecomposite propertiesVSAvoidlarge voids and defects

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent applies different characteristics to different regions of the preform. Specifically, the spacing and arrangement of tows are optimized locally to create appropriate void spaces that serve as pathways for reactant gases, while maintaining structural integrity in other regions. This local optimization eliminates harmful large voids while preserving necessary structural features.

Inventive Principle:

Principle #3Local 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

The z-channels provide direct pathways for reactant gases, enhancing uniform matrix densification and improving composite properties by reducing defects and ensuring even deposition throughout the preform thickness.

Implementation Method 1

heating the preform mounted in the tooling assembly to a temperature above a glass transition temperature of a polymer binder within the preform to induce a softened state of the polymer binder

Methodology Applied

Scientific EffectGlass transition:

Data Source

PatentUS12552085B2Z-channeling into a preform via needle perforation in a stand-alone tool

Publication Date: 2026.02.17 RTX CORP

AI summary

A method of forming z-channels in a fibrous ceramic preform includes mounting the preform in a tooling assembly, the tooling assembly comprising a first fixture and a second fixture, heating the preform mounted in the tooling assembly to a temperature above a glass transition temperature of a polymer binder within the preform to induce a softened state of the polymer binder, inserting a plurality of needles sequentially through respective first holes in the first fixture, the preform, and respective corresponding second holes in the second fixture, and removing the plurality of needles leaving behind a corresponding plurality of z-channels in the preform.