Hollow Composite Mandrel Removal via Segmented Protective Membrane
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Solution Overview
Problem
Existing methods for forming complex hollow composite parts face challenges in mandrel removal, as shrinking mandrels get trapped and glass bead blasting can damage the inner surfaces, necessitating an improved method for manufacturing complex monolithic composite parts.
Innovation Solution
A method involving forming a mandrel with a hollow tunnel, placing a protective membrane, inserting tube-like impermeable membranes, and using a vacuum to compress the composite material, followed by curing and breaking up the mandrel for removal, while protecting the inner surfaces with a segmented protective membrane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If glass bead blasting is used to remove foam mandrels, then the mandrel can be removed from complex hollow composite parts, but the inner surfaces of the composite part are damaged
Solution Approach 1:
A protective membrane is introduced as an intermediary layer between the composite material and the mandrel. This membrane allows the mandrel to be removed via glass bead blasting while protecting the composite inner surfaces from damage. The membrane acts as a sacrificial barrier that absorbs the impact of the blasting process.
Solution Approach 2:
The protective membrane is divided into multiple segments that can be separately removed after mandrel extraction. This segmentation allows for easy removal of the protective layers without damaging the composite part, enabling complete mandrel removal while preserving the composite structure.
2Ease of manufacture
If shrinking mandrels are used for basic geometry parts, then the mandrel can be removed after curing, but the mandrel becomes trapped in complex hollow composite parts
Solution Approach 1:
The protective membrane is segmented into multiple removable sections that can be peeled away from the composite part after mandrel removal. This segmentation enables the membrane to be completely extracted without damaging the complex geometry of the composite structure.
Solution Approach 2:
The protective membrane serves as an intermediary between the mandrel and the composite material, allowing for easy mandrel removal while maintaining the integrity of complex composite geometries. The membrane facilitates mandrel extraction without requiring the mandrel to shrink or the composite to be damaged.
3Manufacturing precision
If compression pressure is applied on outer surfaces of composite part, then the composite material is consolidated, but proper consolidation is not consistently achieved
Solution Approach 1:
The protective membrane acts as an intermediary that distributes compression pressure more evenly across the composite structure. This intermediate layer helps achieve consistent consolidation by preventing localized stress concentrations and ensuring uniform pressure application during the curing process.
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 allows for the successful formation and removal of complex hollow composite parts without damaging the inner surfaces, enabling the production of parts with complex geometries like hollow grids and lattice structures.
Implementation Method 1
Air may then be removed from between the internal and external impermeable membranes, compressing the mandrel toward the composite material and the composite material toward the mandrel
Data Source
AI summary
A system and method for forming a hollow, complex, monolithic composite part. Composite material may be placed around the mandrel, then an internal impermeable membrane may be placed into and/or through tunnels formed in the mandrel. Next, an external impermeable membrane may be placed around the composite material and sealed against itself and the internal impermeable membrane such that the mandrel and the composite material are both contained in an airtight manner between the internal and external impermeable membranes. Air may then be removed from within the sealed impermeable membranes, compressing the impermeable membranes against the mandrel and/or the composite material. The consolidated composite material may be hardened to form the composite part. Finally, the impermeable membrane may be removed from around the hollow composite part and from within the mandrel, followed by removal of the mandrel from within the composite part by breaking it up into smaller pieces.