Machinable Coating for Ceramic Matrix Composite Geometric Correction

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Solution Overview

Problem

Manufacturing methods for ceramic matrix composite articles, such as chemical vapor infiltration and melt infiltration, often leave behind manufacturing artifacts like dents, depressions, or protrusions that are difficult to correct without damaging the composite, especially when strict geometric requirements are involved.

Innovation Solution

Applying a machinable coating to the manufactured ceramic matrix composite article, which can be made of materials like rare earth silicates, yttria-stabilized zirconia, or mullite, and machining it to correct the manufacturing artifacts using techniques like grinding or milling to achieve the desired geometry without compromising the article's integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If chemical vapor infiltration or melt infiltration is used to manufacture ceramic matrix composite articles, then cost-effective manufacturing is achieved, but manufacturing artifacts such as dents, depressions, or protrusions are left behind that are difficult to correct

Engineering Contradiction:
Improvemanufacturing cost-effectivenessVSAvoidgeometric accuracy
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

A machinable coating layer is applied as an intermediary between the manufactured ceramic matrix composite article and the final geometric requirements. This coating serves as a mediating layer that can be machined to correct surface artifacts without damaging the underlying composite structure, thus resolving the contradiction between cost-effective manufacturing and geometric precision

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The solution segments the correction process into two distinct stages: first, applying a machinable coating layer that can accommodate surface artifacts; second, machining this coating layer to achieve the desired geometric precision. This segmentation allows the underlying composite structure to remain intact while the coating layer handles the geometric corrections

Inventive Principle:
Principle #1Segmentation

2Manufacturing precision

If traditional machining is attempted directly on the ceramic matrix composite article to correct manufacturing artifacts, then geometric precision may be improved, but the mechanical integrity of the composite material is compromised

Engineering Contradiction:
Improvegeometric accuracyVSAvoidmechanical integrity
Core Design Contradiction:
Manufacturing precisionVSStrength

Solution Approach 1:

The machinable coating acts as a protective intermediary layer that absorbs the machining operations. By machining the coating rather than the composite itself, the mechanical integrity of the composite is preserved while still achieving the required geometric precision through coating removal or modification

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The solution changes the material parameter being machined from the composite material itself to a separate machinable coating layer. This parameter change allows machining operations to be performed without compromising the mechanical properties of the underlying composite structure

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4385968A1Article and method of making a ceramic matrix composite article
Publication Date: 2024.06.19 RTX CORP
  • EP4385968A1 patent drawingFigure 1
  • EP4385968A1 patent drawingFigure 2A~3
  • EP4385968A1 patent drawing

AI summary

A method of correcting a manufactured article (102) includes applying a machinable coating (106) to a manufactured ceramic matrix composite article (102) with a manufacturing artifact (104) and machining the machinable coating (106) to provide a desired geometry. A method of correcting a manufactured article (102) and a corrected article (100) are also disclosed.