Elastomeric Hollow Membrane for Wrinkle-Free Composite Bagging
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Solution Overview
Problem
The existing bagging processes for composite parts are time-consuming, labor-intensive, and result in fiber distortion and mark-offs due to the use of non-elastic materials, especially on complex geometries, and the materials are typically discarded after each cure cycle, adding to the cost.
Innovation Solution
A method and system utilizing an elastomeric hollow membrane that inflates to fit around a composite part on a rigid mandrel, then naturally contracts to compress and cure the composite without forming pleats or wrinkles, allowing for reusability and efficient processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If standard non-elastic bagging materials are used, then the composite part can be compressed for curing, but the bagging material forms pleats and wrinkles that cause fiber distortion and mark-offs on the outer surface
Solution Approach 1:
The patent applies the dynamics principle by using an elastomeric membrane that can dynamically change its state between inflated and deflated. When inflated, the membrane expands to accommodate complex geometries without forming pleats or wrinkles. When deflated, it provides uniform compression for curing. This dynamic behavior eliminates surface defects while maintaining manufacturing feasibility.
Solution Approach 2:
The patent employs parameter changes by altering the physical state of the bagging material through inflation and deflation cycles. By changing the volume and pressure parameters of the elastomeric membrane, the system transitions from a loose state (accommodating complex shapes) to a compressed state (providing uniform curing pressure), thereby preventing fiber distortion and mark-offs.
2Productivity
If non-elastic bagging materials are used, then compression can be applied, but the process becomes time-consuming and labor-intensive
Solution Approach 1:
The patent utilizes pneumatics by employing an inflatable elastomeric membrane that can be rapidly expanded and deflated using air pressure. This pneumatic mechanism replaces manual bagging operations, significantly reducing labor intensity and processing time while maintaining effective compression during curing.
Solution Approach 2:
The patent applies the discarding and recovering principle by making the elastomeric membrane reusable. After each curing cycle, the membrane is deflated and can be easily removed, cleaned, and reused for the next part. This eliminates the need to discard single-use bagging materials, reducing both time and material costs.
3Adaptability or versatility
If pleats are used in the bagging material to conform to complex geometry, then the material can wrap around the part, but wrinkles form during vacuum compression that mark the outer surface
Solution Approach 1:
The elastomeric membrane dynamically adapts to complex geometries when inflated, conforming to the part shape without forming permanent pleats or wrinkles. During the deflated compression phase, the membrane provides smooth, uniform contact with the composite surface, eliminating surface defects while maintaining geometric adaptability.
Solution Approach 2:
By changing the inflation parameter of the membrane, the system achieves two opposing requirements: when inflated, the membrane expands to match complex geometries; when deflated, it provides uniform compression without surface markings. This parameter transition resolves the contradiction between conformability and surface quality.
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 approach reduces labor and processing costs while ensuring high-quality composite parts by eliminating fiber distortion and mark-offs, enabling rapid and efficient bagging and curing of composite parts with minimal material waste.
Implementation Method 1
The hollow membrane can be located within and sealed to the rigid external vessel at or proximate to the two opposing ends of the hollow membrane. The hollow membrane is inflatable from a natural state to an inflated or expanded state via a pressure differential drawing the hollow membrane toward the rigid external vessel.
Implementation Method 2
The hollow membrane can be made of elastomeric material. Releasing the membrane from the inflated state causes it to naturally contract toward its natural state, compressing the composite material.
Implementation Method 3
Heating the composite material to a cure temperature while the composite material is compressed by the membrane.
Data Source
AI summary
A method and system for manufacturing composite parts free of wrinkles and mark-offs from bagging compression. The method can include placing composite material around a rigid mandrel and sealing opposing end of an elastomeric hollow membrane within a rigid external vessel. Then the method can include inflating the hollow membrane from a natural state to an inflated state. In the natural state, the hollow membrane can have a cross-section smaller than the cross section of the rigid mandrel with the composite material thereon. The method can then include inserting the rigid mandrel and the composite material into the membrane while it is in the inflated state, followed by releasing the membrane from the inflated state to naturally contract toward its natural state. Then the method can include heating the composite material to a cure temperature while the composite material is compressed by the membrane.