Cryogenic Preform Cutting for RTM Composite Manufacturing
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Solution Overview
Problem
The existing RTM process for fabricating aerospace parts, particularly fan blades, faces challenges in cutting flexible and deformable fibrous preforms due to resistance and deformation, making manipulation and positioning in injection molds difficult.
Innovation Solution
A device and method utilizing cryogenic freezing to harden fibrous preforms, allowing for precise cutting and handling, involving a die with a template for outer edge cutting and a pressurized water jet cutting system, with cryogenic freezing stiffening the fibers and solidifying a substrate liquid for retention and positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional cutting tools are used to cut the preform, then cutting operation can be performed, but the operation is difficult due to resistance from carbon strands and deformation of the preform
Solution Approach 1:
The patent applies cryogenic freezing to change the temperature parameter of the preform, transforming it from a flexible state to a rigid state. This parameter change enables easy cutting operation by eliminating the resistance and deformation issues associated with conventional cutting tools on flexible preforms.
Solution Approach 2:
The patent utilizes phase transition of water (liquid to solid) through cryogenic freezing to harden the preform. The freezing process transforms the physical state of the preform, making it rigid and easy to manipulate and cut, thereby resolving the cutting difficulty problem.
2Ease of operation
If the preform is cut on a cutting frame, then cutting can be effected, but the preform must be extracted and transferred to the injection mould which is difficult due to deformation
Solution Approach 1:
The patent applies cryogenic freezing as a preliminary action before cutting and transfer operations. By freezing the preform beforehand, it becomes rigid and stable, eliminating deformation during subsequent manipulation and transfer to the injection mold, thereby enabling easy operation.
Solution Approach 2:
The patent changes the temperature parameter of the preform through cryogenic freezing, transforming it from a flexible state prone to deformation to a rigid state that maintains its shape. This parameter change ensures stability during transfer and enables easy manipulation without deformation.
3Productivity
If the preform is left flexible after weaving, then the weaving process is complete, but the preform deforms under its own weight and is difficult to position in the mold
Solution Approach 1:
The patent utilizes phase transition of water through cryogenic freezing to transform the preform from a flexible state (after weaving) to a rigid state. This phase change provides stability during positioning in the mold while maintaining productivity of the weaving process.
Solution Approach 2:
The patent changes the temperature parameter of the preform through cryogenic freezing, transforming it from a flexible state that deforms under its own weight to a rigid state that maintains stability during positioning, thereby resolving the stability issue without affecting weaving productivity.
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 easy manipulation and precise cutting of fibrous preforms, ensuring correct positioning and reducing deformation during transfer to the injection mold, improving the efficiency and accuracy of the RTM process.
Implementation Method 1
the device includes means for hardening said preform by cryogenic freezing
Implementation Method 2
Hardening is advantageously generated by solidifying a liquid forming a substrate for said preform
Implementation Method 3
The cutting means advantageously consist in a system for cutting using a jet of liquid sprayed under pressure
Implementation Method 4
a pressurized water jet cutting system
Data Source
AI summary
A device for cutting a fibrous preform, for production of a part made of a composite material by injection of resin under vacuum. The device includes a die for receiving the preform, on which a template of outer edges of the part is referenced, a mechanism cutting outer edges of the preform according to the template, and a mechanism for cooling the preform that is suitable for solidifying a liquid forming a substrate for the preform.