Variable Geometry Ceramic Fiber Composite Production

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Solution Overview

Problem

Current methods for producing ceramic fiber composites, particularly oxide ceramic matrix composites, face challenges in achieving efficient and automated production of complex three-dimensional geometries, with limitations in automation, reproducibility, and material properties due to manual processes and difficulties in infiltration and fiber architecture flexibility.

Innovation Solution

A vacuum-pressure infusion and drying process using a tool with a die and stamp system that allows for precise pressure control and solvent removal, enabling the infiltration and shaping of ceramic fibers with a slip containing ceramic particles and solvents, followed by thermal treatment and repeated infusion steps to achieve uniform infiltration and desired material properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If manual lay-up or hand infiltration processes are used to produce ceramic fiber composites, then flexibility in processing different fiber architectures is maintained, but automation level and production efficiency are severely limited

Engineering Contradiction:
Improveautomation levelVSAvoidfiber architecture flexibility
Core Design Contradiction:
Extent of automationVSAdaptability or versatility

Solution Approach 1:

The patent replaces manual mechanical lay-up processes with an automated vacuum infusion system. The slip is automatically introduced into the mold cavity under vacuum pressure, eliminating the need for manual fiber placement while achieving complete infiltration of complex fiber architectures including 3D preforms, braids, and woven fabrics.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The vacuum infusion apparatus is designed to handle multiple fiber architectures (woven fabrics, braids, 3D preforms, short fibers) through a single automated process. The system uses a universal mold cavity that can accommodate different fiber preform configurations, enabling one process to serve multiple manufacturing needs.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Productivity

If winding process is used to increase automation, then production efficiency improves for simple geometries, but the process cannot be parallelized and scaling to higher quantities remains uneconomical

Engineering Contradiction:
Improveproduction efficiencyVSAvoidprocess scalability
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent divides the production process into independent mold cavities that can be filled simultaneously. Multiple fiber preforms are placed in separate cavities within the same mold assembly, allowing parallel infusion and independent drying. This segmentation enables scaling from single-part to multi-part production without increasing process complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from sequential winding (one-dimensional time progression) to parallel infusion (multi-dimensional spatial processing). Multiple cavities are infused simultaneously through separate slip introduction channels, adding a spatial dimension to production that enables parallel manufacturing and easy scaling to higher quantities.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Ease of manufacture

If vacuum bag infusion process is used without fixed tool, then setup complexity increases and resource efficiency decreases, but the process can handle complex geometries

Engineering Contradiction:
Improvesetup efficiencyVSAvoidgeometric precision
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent introduces a fixed mold cavity as an intermediary between the fiber preform and the vacuum bag. The mold cavity provides a precise geometric framework that guides slip infiltration while the vacuum bag provides the necessary pressure differential. This intermediary structure enables both complex geometry handling and manufacturing precision.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The mold cavity is pre-configured with defined walls and surfaces before fiber placement. This preliminary structuring establishes the exact geometric boundaries and infiltration pathways, ensuring manufacturing precision is built into the process setup rather than achieved through post-processing or complex vacuum bag configuration.

Inventive Principle:
Principle #10Preliminary action

4Manufacturing precision

If infiltration pressure is increased to improve infiltration, then fiber bundle penetration improves, but fiber layer compression increases which can prevent complete infiltration

Engineering Contradiction:
Improveinfiltration completenessVSAvoidfiber layer compression
Core Design Contradiction:
Manufacturing precisionVSStress or pressure

Solution Approach 1:

The patent employs periodic cycling between vacuum infiltration and atmospheric pressure drying phases. During vacuum phases, negative pressure draws slip into fiber bundles; during atmospheric phases, pressure equalizes and allows fiber layer relaxation. This periodic action achieves complete infiltration without sustained high compression that would prevent bundle penetration.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent dynamically changes pressure parameters between vacuum (negative pressure) and atmospheric (positive pressure) states. This parameter cycling allows the system to achieve both high infiltration completeness during vacuum phases and reduced fiber compression during atmospheric phases, resolving the contradiction between infiltration effectiveness and layer compression.

Inventive Principle:
Principle #35Parameter changes

5Strength

If water-based or solvent-based slip systems are used to achieve desired material properties, then ceramic fiber composite performance improves, but complete infiltration becomes difficult and drying time increases

Engineering Contradiction:
Improvecomposite strengthVSAvoiddrying time
Core Design Contradiction:
StrengthVSLoss of time

Solution Approach 1:

The patent combines infiltration and drying into a continuous integrated process within the same mold cavity. Slip infiltration under vacuum is immediately followed by in-situ drying without removing the workpiece from the mold. This continuous action eliminates transfer time and ensures the slip remains in optimal position for drying, reducing total process time while maintaining complete infiltration.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The patent merges the infiltration function and drying function into a single integrated process step. The mold cavity serves dual purposes: as the infiltration chamber during vacuum phases and as the drying chamber during atmospheric phases. This merging eliminates the need for separate infiltration and drying equipment, reducing overall process time while ensuring complete slip penetration before drying begins.

Inventive Principle:
Principle #5Merging (Combining)

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 enables the production of ceramic fiber composites with improved strength, homogeneous porosity, and reduced defects, allowing for cost-effective and high-quality production of complex geometries with increased automation and reproducibility, minimizing manual labor and post-processing needs.

Implementation Method 1

a device for reducing the pressure inside the mold cavity and/or for removing excess water and/or solvent

Methodology Applied
Scientific EffectVacuum: Vacuum

Implementation Method 2

a device for increasing the pressure inside the mold cavity and/or for supplying the slip into the mold cavity

Methodology Applied
Scientific EffectPressure: Pressure Increase

Implementation Method 3

at least one heating device which enables the heating of the cavity

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP4194168B1Method and apparatus for producing variable geometry ceramic fiber composites
Publication Date: 2024.12.04 DEUTSCHES ZENTRUM FÜR LUFT UND RAUMFAHRT E V
  • EP4194168B1 patent drawingFigure 1
  • EP4194168B1 patent drawingFigure 2
  • EP4194168B1 patent drawingFigure 3

AI summary

The present invention relates to a method and a device for producing ceramic fiber composites with variable geometry using a vacuum pressure infusion process.