Smart Memory Polymer Mandrel for Complex Aircraft Engine Parts
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Solution Overview
Problem
Current manufacturing processes for aircraft engine parts, particularly fluid delivery tubes and ducts with complex geometries, face challenges such as high tooling costs, difficulty in removing mandrels, and the need for new tooling with design changes, especially when using non-destructive methods that allow for reconfiguration and reuse.
Innovation Solution
A method utilizing shape memory polymer (SMP) tooling with low-temperature metal deposition, where the SMP mandrel is deformed to replicate the target part's geometry, coated with conductive metal, and electroplated, allowing for easy removal and reuse by heating above the SMP's glass transition temperature, enabling the fabrication of complex 3-D geometries with transitioning cross-sections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a rigid cure tool/mandrel is used for fabricating non-metal parts with complex geometry, then the part can be formed with precise geometry, but the mandrel removal becomes difficult, costly, and time consuming
Solution Approach 1:
The patent applies parameter changes by utilizing the temperature-dependent properties of shape memory polymers. The mandrel is heated above its glass transition temperature to become soft and compliant during part formation, then cooled to become rigid for easy removal. This temperature parameter change allows the same mandrel to provide both precise geometry during forming and easy removal afterward, resolving the contradiction between manufacturing precision and removal time.
Solution Approach 2:
The patent employs phase transitions of the shape memory polymer mandrel between its rubbery state (above glass transition temperature) and glassy state (below glass transition temperature). During part formation, the mandrel is in the rubbery phase allowing deformation and conforming to the mold. After part formation, cooling transitions it to the glassy phase where it becomes rigid and can be easily removed. This phase transition mechanism enables both precise geometry formation and easy mandrel removal.
2Ease of operation
If a segmented mandrel is used for removal after curing, then the mandrel can be removed and disassembled in sections, but the installation and removal process becomes expensive and time consuming
Solution Approach 1:
The patent uses parameter changes by controlling the temperature of the shape memory polymer mandrel. By heating the mandrel above its glass transition temperature, it becomes soft and can be easily deformed and removed from the cured part without segmentation. This temperature-dependent property change eliminates the need for complex segmented designs while reducing both installation and removal time and cost.
3Manufacturing precision
If conventional metal deposition is used on SMP tooling, then metal parts can be formed, but the process requires high temperature that may deform the SMP mandrel
Solution Approach 1:
The patent replaces conventional high-temperature mechanical metal deposition processes with electrochemical deposition (electroforming). This substitution allows metal to be deposited at low temperatures that do not deform the SMP mandrel, while still achieving precise metal part geometry. The electrochemical process uses electrical current to deposit metal ions onto the SMP mandrel surface, forming a precise metal replica without requiring high temperatures.
Solution Approach 2:
The patent applies parameter changes by controlling the deposition temperature well below the glass transition temperature of the SMP mandrel. This temperature parameter control ensures the mandrel remains in its rigid glassy state during metal deposition, maintaining its shape and precision while allowing low-temperature electrochemical metal formation. The temperature parameter is carefully managed to prevent mandrel deformation while enabling complete metal part formation.
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 reduces tooling costs, allows for reconfiguration, and minimizes thermal deformation, enabling the efficient production of complex aircraft engine parts with reusable SMP tooling, facilitating the creation of thinner, lighter assemblies and reducing manufacturing complexity.
Implementation Method 1
The SMP will hold its deformed shape indefinitely until heated above its Tg again; whereat the SMP returns to its pre-formed ('remembered') state
Implementation Method 2
applying voltage to electrochemically deposit metal onto a surface of the tooling
Data Source
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AI summary
A manufacturing process for making aircraft engine parts 100 utilizes reusable reconfigurable smart memory polymer mandrel tooling 320, low temperature metal deposition 420, and composite part lay-up with resin coated conformable braided carbon fiber sleeves, to fabricate both metal internal engine parts and non-metal external parts for turbine engines.