CVI Tooling Hole Geometry for Uniform CMC Infiltration

Solution Overview

Problem

Existing tooling for ceramic matrix composite (CMC) parts with complex shapes experiences uneven infiltration of vaporous precursors, leading to variations in deposition rate and IFC thickness, which affects mechanical behavior and durability.

Innovation Solution

The development of tooling fixtures with conical, directional, and branching holes that increase hole concentration and diameter on the inner surface, facilitating even and tailored deposition of reactant gases.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If uniform hole dimensions are used in tooling, then manufacturing simplicity is maintained, but infiltration uniformity deteriorates for complexly-shaped preforms

Engineering Contradiction:

Improvetooling manufacturing simplicityVSAvoidinfiltration uniformity

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies local quality by varying the hole dimensions (diameter, angle, concentration) at different locations within the tooling fixture. Specifically, holes are designed with different diameters at different depths, and the hole concentration varies across the tooling surface to match the complex geometry of the preform, ensuring uniform reactant gas distribution throughout the entire preform volume.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent implements parameter changes by modifying multiple hole parameters simultaneously: diameter (varying from inlet to outlet), concentration (number of holes per unit area at different locations), and angular orientation. These parameter variations are systematically designed to compensate for the complex shape of the preform and achieve uniform infiltration across all regions.

Inventive Principle:

Principle #35Parameter changes

2Device complexity

If simple uniform holes are used in tooling, then device complexity is reduced, but deposition rate uniformity deteriorates

Engineering Contradiction:

Improvetooling hole structureVSAvoiddeposition rate uniformity

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The patent applies local quality by varying the hole dimensions (diameter, angle, concentration) at different locations within the tooling fixture. Specifically, holes are designed with different diameters at different depths, and the hole concentration varies across the tooling surface to match the complex geometry of the preform, ensuring uniform reactant gas distribution throughout the entire preform volume.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent transitions from two-dimensional hole patterns to three-dimensional hole structures by varying hole diameter along the depth dimension and introducing angular orientations. This dimensional enhancement allows the tooling to address the complex three-dimensional geometry of the preform, achieving uniform deposition rates throughout the volume rather than just on the surface.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Ease of manufacture

If uniform hole concentration is used throughout tooling, then manufacturing process is simplified, but IFC thickness consistency deteriorates

Engineering Contradiction:

Improvetooling manufacturing processVSAvoidIFC thickness consistency

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies local quality by varying the hole dimensions (diameter, angle, concentration) at different locations within the tooling fixture. Specifically, holes are designed with different diameters at different depths, and the hole concentration varies across the tooling surface to match the complex geometry of the preform, ensuring uniform reactant gas distribution throughout the entire preform volume.

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

Enhances uniformity of reactant gas distribution, ensuring consistent IFC thickness and improved mechanical properties of CMC parts.

Implementation Method 1

Chemical vapor infiltration (CVI)... vaporous precursors to infiltrate the preform for the deposition of a ceramic matrix

Methodology Applied

Scientific EffectChemical Vapour Deposition: Chemical Vapour Deposition

Data Source

PatentUS12503759B2Chemical vapor infiltration tooling hole modification for optimizing infiltration in ceramic matrix composites

Publication Date: 2025.12.23 RTX CORP

AI summary

A tooling fixture suitable for use in infiltrating a fibrous preform with a reactant gas includes an outer surface and opposing inner surface defining a thickness therebetween, and a plurality of holes extending through the thickness. Each hole of the plurality of holes includes an inlet at the outer surface, the inlet configured to receive a flow of the reactant gas, an outlet at the inner surface, a transition point between the inlet and the outlet, and an angled segment extending from the transition point to the outlet. Each hole of the plurality of holes has a first diameter at the inlet and a second diameter at the outlet, and the second diameter is greater than the first diameter.