CMC Airfoil Mandrel Kickback for Easier Removal
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Solution Overview
Problem
The removal of mandrels from complex-shaped gas turbine engine airfoils formed using ceramic matrix composites (CMCs) is challenging due to the intricate designs, which complicates the process of forming and densifying the CMC components.
Innovation Solution
A mandrel with radially spaced ends is used to form a CMC yarn shear tube, followed by the addition of CMC fabric layers, and a filler material is inserted to facilitate mandrel removal after densification by ensuring the mandrel ends are not aligned with the final airfoil shape, allowing for easier extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the mandrel shape closely tracks the desired final airfoil shape to ensure manufacturing precision, then the manufacturing precision is improved, but the ease of removing the mandrel deteriorates
Solution Approach 1:
The mandrel is segmented into two distinct parts: a core mandrel that defines the airfoil shape and an end portion that extends beyond the airfoil contours. This segmentation allows the core mandrel to provide precise shape definition while the extended end portion facilitates easy removal by protruding through the fabric layers during the forming process
Solution Approach 2:
The extended end portion of the mandrel acts as an intermediary extraction feature. It provides a grip point or protrusion that extends through the fabric layers, serving as a mediator that enables removal of the core mandrel without directly pulling on the tightly fitted airfoil-shaped portion
2Manufacturing precision
If the mandrel shape closely tracks the desired final airfoil shape to ensure proper CMC layer formation, then the manufacturing precision is improved, but the device complexity increases
Solution Approach 1:
The mandrel is divided into a core functional portion that defines the airfoil geometry and a separate extended end portion that aids removal. This segmentation adds minimal structural complexity while providing the dual functionality of precise shape definition and easy extraction
Solution Approach 2:
The mandrel is designed as a disposable forming tool that is removed after use. The extended end portion is specifically designed to facilitate this single-use removal process, accepting that the mandrel will be discarded after one forming cycle rather than designed for repeated use
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 efficient removal of the mandrel from the densified CMC airfoil components, simplifying the manufacturing process and ensuring the integrity of the complex airfoil shape.
Implementation Method 1
The CMC materials are then densified
Data Source
AI summary
CMC yarn is formed on the outer surface of a mandrel, generally tracking the shape of the mandrel outer shape. CMC fabric layers are formed outwardly of the shear tube to form a desired shape of a final airfoil leading edge. The mandrel, and the shear tube are provided with a shape at at least one of the mandrel radially inner and outer ends to be spaced from the desired final shape of the airfoil leading edge at a corresponding one of a fabric radially inner and outer ends. A filler material is inserted into a space between the corresponding one of a fabric radially inner end and a fabric radially outer end of the fabric layers.