Stretchable Vacuum Bag Breather for Composite Radii
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Solution Overview
Problem
Vacuum bag processing of composite laminate parts with contoured surfaces faces challenges such as bridging issues due to difficulty in conforming breathers to inside radii, leading to reduced compaction pressure and increased labor and material costs, as well as the need for labor-intensive pleat formation in bag materials.
Innovation Solution
A stretchable vacuum bag assembly with a one-piece stretchable breather that can be easily deployed and fitted over parts, allowing the breather to stretch and conform to surface features like inside radii, eliminating the need for multiple breather pieces and reducing bridging by covering all areas with breather material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional rigid breathers are used, then they are easy to manufacture and install, but they cannot conform to inside radii causing bridging and reduced compaction pressure
Solution Approach 1:
The breather is made from stretchable material that can elongate to conform to complex surface geometries including inside radii. The material's elastic properties enable it to adapt to contoured surfaces while maintaining structural integrity and breathability functionality.
Solution Approach 2:
The breather is constructed as a flexible, thin-walled structure that can bend and conform to complex part geometries. This flexible construction allows the breather to wrap around inside radii and contoured surfaces without bridging, while still providing the necessary ventilation function.
2Reliability
If multiple piece breathers are used to cover contoured areas, then bridging is reduced, but labor time and material scrap increase
Solution Approach 1:
Multiple separate breather pieces are merged into a single integrated stretchable breather component. This unified structure eliminates the need for cutting, fitting, and sealing multiple pieces together, reducing labor time and material waste while maintaining effective breathing coverage across contoured surfaces.
3Ease of manufacture
If breather material is avoided in contoured areas, then labor and material costs are reduced, but air and volatile escape is limited
Solution Approach 1:
The breather material's physical properties are changed to be stretchable and conformable, enabling it to effectively cover contoured areas including inside radii. This allows the breather to maintain contact with complex surfaces while providing adequate breathing pathways for air and volatile escape.
4Stress or pressure
If hand-formed pleats are created in the vacuum bag, then compaction pressure is maintained in radius areas, but labor time and precision requirements increase
Solution Approach 1:
The stretchable breather assembly performs the function of manual pleat formation automatically. As the breather stretches to conform to the part geometry, it naturally creates the necessary accommodations for inside radii without requiring operator intervention to form pleats, thereby maintaining compaction pressure while simplifying the bagging operation.
5Adaptability or versatility
If a one-piece stretchable breather is used, then bridging is eliminated and conformability is improved, but the breather material must be highly elastic and stretchable
Solution Approach 1:
The breather is constructed from composite or engineered materials that combine stretchability with breathability. The material composition is designed to provide both the necessary elastic properties for conforming to contoured surfaces and the porous structure required for effective air and volatile escape.
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 solution significantly reduces bagging time, labor costs, and material scrap by allowing the breather to stretch and conform to complex geometries, ensuring consistent pressure distribution and eliminating gaps under the vacuum bag.
Implementation Method 1
a stretchable breather that is substantially coextensive with the vacuum bag. The use of a one-piece breather allows all areas of the part to be covered with breather material, thus eliminating the need for cutting and hand placement of individual breather elements. When autoclave and vacuum bag pressure are applied along with heat during curing, the breather stretches and conforms to surface features of the part, such as inside radii.
Implementation Method 2
Composite laminate parts may be cured using autoclave or out-of-autoclave processes. These processes typically employ a combination of heat and pressure applied by a vacuum bag to compact and consolidate the part.
Implementation Method 3
a vacuum bag assembly that is capable of conforming to surface contours, such as an inside radius of a part, and which may be quickly and easily installed
Data Source
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AI summary
A vacuum bag assembly (40) is used to process the composite part. The vacuum bag assembly (40) includes a stretchable vacuum bag (42) attached to a stretchable breather (44).