Composite Tool Vacuum Integrity via Elastomeric Barrier
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Solution Overview
Problem
Composite tools used in vacuum bag processing for composite parts often experience through-the-tool leaks due to thermal cycling or handling, leading to inconsistent part quality and reliability issues, with temporary repairs not being durable and affecting dimensional accuracy.
Innovation Solution
A composite tool with a multi-ply laminate structure incorporating an integral air-impermeable membrane barrier layer, sandwiched between first and second sets of composite plies, and an edge breather groove to prevent air leaks, using flexible materials like rubber, nylon, or silicone to maintain vacuum integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If composite tools are used for vacuum bag processing, then manufacturing cost is reduced and weight is decreased, but through-the-tool leaks occur due to thermal cycling or impact damage
Solution Approach 1:
The tool incorporates a hybrid laminate structure combining composite plies with an elastomeric barrier layer. This composite construction maintains the lightweight and cost advantages of composite materials while adding vacuum integrity through the elastomeric layer that resists permeation and prevents through-the-tool leaks.
Solution Approach 2:
An elastomeric barrier layer (thin film) is integrated within the composite laminate structure. This flexible elastomeric layer conforms to the tool geometry and provides a continuous vacuum barrier that prevents air permeation through the composite tool, even when cracks occur in the composite plies.
2Reliability
If temporary repairs are applied to composite tools, then leakages are reduced, but dimensional accuracy of cured parts is affected and durability is compromised
Solution Approach 1:
The vacuum barrier function is built into the tool structure during manufacturing by integrating the elastomeric barrier layer within the composite laminate. This preliminary incorporation eliminates the need for temporary field repairs, ensuring consistent dimensional accuracy and long-term durability without compromising part quality.
3Duration of action of moving object
If composite tools undergo thermal cycling, then service operation is enabled, but through-the-tool leaks develop over time
Solution Approach 1:
The tool structure incorporates an elastomeric barrier layer with distinct material properties (flexibility, permeation resistance) that complement the composite plies. This parameter differentiation allows the elastomeric layer to maintain vacuum integrity during thermal cycling, compensating for composite material expansion and contraction without developing leaks.
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
The solution effectively reduces through-the-tool leaks, ensuring consistent part quality, improving strength and integrity, and reducing material and labor costs by providing a durable and reliable vacuum seal that withstands repeated thermal cycling.
Implementation Method 1
a membrane that is flexible and that is impervious to air in order to prevent through-the-tool leaks and maintain a vacuum seal
Implementation Method 2
The vacuum bag is evacuated in order to compress the layup against the tool and thereby consolidate and/or form the layup
Data Source
Figure 1~2
Figure 2A~3
Figure 4~6
AI summary
A composite tool (10) for vacuum bag processing composite parts comprises a plurality of laminated composite plies(12,14), including a facesheet (14) adapted to have a composite part placed thereon. A gas impermeable barrier layer (16)sandwiched between the composite plies prevents air leaks through the tool.