Multi-Piece Mandrel for CMC Airfoil Extraction Without Damage
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Solution Overview
Problem
The removal of mandrels from ceramic matrix composite (CMC) airfoils presents challenges due to complex designs, especially when the mandrel is integrated within the airfoil structure, making it difficult to separate without damaging the CMC components.
Innovation Solution
A mandrel body composed of at least two interfitting parts is used, allowing for separate removal after the airfoil formation, with features like bowed profiles, grooves, twists, and chamfered edges to facilitate easy extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single-piece mandrel is used to form the airfoil structure, then the mandrel provides structural support during manufacturing, but the mandrel becomes difficult to remove from complex airfoil designs
Solution Approach 1:
The mandrel is divided into multiple separate pieces that can be independently removed from the airfoil structure. This segmentation allows each mandrel piece to be extracted through different access paths, solving the removal difficulty caused by complex airfoil geometries while maintaining the mandrel's structural support function during manufacturing.
2Manufacturing precision
If the mandrel is integrated within the airfoil structure, then the mandrel provides precise shape definition, but the mandrel cannot be easily separated without damaging the CMC components
Solution Approach 1:
Dividing the mandrel into multiple pieces reduces the risk of damage to CMC components during removal. Each smaller mandrel piece can be extracted with less force and through more manageable paths, eliminating the need for destructive separation methods that would compromise the integrity of the ceramic matrix composite airfoil structure.
Solution Approach 2:
Release agents or coatings applied to the mandrel surface act as intermediaries between the mandrel and CMC yarns. These intermediaries prevent bonding between the mandrel and the ceramic matrix composite materials, allowing the segmented mandrel pieces to be removed cleanly without damaging the airfoil structure.
3Productivity
If the mandrel is designed as a single solid piece, then the mandrel maintains structural integrity, but the mandrel removal process becomes time-consuming and complex
Solution Approach 1:
The mandrel is segmented into multiple removable pieces with simplified individual structures. This segmentation enables parallel removal operations and eliminates the need for complex disassembly procedures, significantly reducing the mandrel removal time and improving overall manufacturing productivity despite the increased mandrel design complexity.
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
Enables efficient and damage-free removal of the mandrel from CMC airfoils, simplifying the manufacturing process and maintaining the integrity of the airfoil structure.
Implementation Method 1
a first of the two mandrel parts has a bowed profile such that a central portion is spaced closer to a second of the two mandrel parts then are upper and lower areas of the first mandrel part
Implementation Method 2
the mandrel shape further has a twist along a radial length of the at least two mandrel parts. the mandrel body has grooves on an outer surface to facilitate the movement of gas during a densification process of the CMC yarns and fabric layers
Data Source
AI summary
A mandrel includes a mandrel body upon which to build ceramic matrix composite (“CMC”) yarns to provide a shear tube for building up an airfoil from CMC fabric layers. The mandrel body formed of at least two mandrel parts interfitting to define a desired shape for the shear tube, and such that after formation of the airfoil the at least two parts of the mandrel body can be separately removed from the shear tube in order to facilitate removal. A method is also disclosed.