Aggregate Mandrels for Composite Part Production
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Solution Overview
Problem
The production of composite parts, particularly mandrels for aerospace applications, is hindered by the complexity and cost of existing tooling methods, which often require labor-intensive and time-consuming processes, and result in damaged composite structures due to the removal of mandrels made from materials like plaster and eutectic salts, which also generate environmentally unfriendly waste.
Innovation Solution
A method involving a fluidized aggregate/binder mixture, treated with kinetic energy to behave like a semi-fluid, is injected into a mold, allowing for rapid formation and curing of mandrels, which can be removed before full cure, and reused, reducing environmental impact and production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If plaster mandrels are used for composite structure fabrication, then the mandrel can be easily formed by pouring into a mold, but the mandrel requires significant curing time and must be removed by mechanical agitation which damages the composite structure
Solution Approach 1:
The patent changes the material parameters by using a slurry composition with specific solid content (30-70% by weight) and viscosity characteristics that enable rapid setting. The slurry contains reactive components that undergo fast chemical reaction upon mixing, reducing curing time from hours to minutes while maintaining ease of pouring and formation.
Solution Approach 2:
The mandrel uses a composite slurry material comprising multiple components including reactive powders, binders, and additives in specific ratios. This composite formulation provides both ease of processing (pourability) and rapid setting properties, resolving the contradiction between manufacturability and time consumption.
2Ease of operation
If eutectic salts are used for mandrel fabrication, then the mandrel can be removed by dissolution, but the removal process produces corrosive environmentally unfriendly waste streams
Solution Approach 1:
The patent employs a disposable mandrel made from a biodegradable or environmentally benign slurry material that sets rapidly and can be easily removed without producing harmful waste. The mandrel is designed for single-use, eliminating the need for complex removal processes and avoiding corrosive waste streams associated with eutectic salts.
Solution Approach 2:
The patent converts the potential harm of mandrel removal into a benefit by using a material that dissolves or decomposes harmlessly in the environment. The slurry composition is designed to break down into non-toxic components, turning the removal process from a source of pollution into an environmentally friendly operation.
3Strength
If conventional mandrel materials are used, then the mandrel provides structural support during composite curing, but the mandrel removal process is labor-intensive and time-consuming
Solution Approach 1:
The patent modifies the strength parameters of the mandrel material by controlling the slurry composition and setting conditions. The mandrel achieves sufficient structural strength quickly through rapid chemical setting, enabling it to support the composite structure during curing. The controlled strength development allows for faster production cycles without compromising structural integrity.
4Ease of manufacture
If plaster mandrels are used, then the mandrel can be easily formed, but the mandrel must be discarded as waste after mechanical removal
Solution Approach 1:
The patent implements a system where the mandrel material is either recovered and reused or disposed of in an environmentally friendly manner. The slurry composition is designed to allow for material recovery through processes such as crushing and re-slurrying, reducing waste and improving sustainability while maintaining ease of formation.
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 enables the rapid, cost-effective, and environmentally benign production of high-quality mandrels for complex shapes, facilitating mass production of composite structures with reduced damage and waste, while allowing for the reclamation of mandrel materials.
Implementation Method 1
The mixture is transformed into a fluidized state by application of kinetic energy to the mixture. Kinetic energy is imparted into a non liquid mandrel material, such as a binder/aggregate mixture, through a carrier fluid (most commonly a gaseous fluid such as air or nitrogen), by which the solids are able to be displaced as a semi fluid.
Data Source
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AI summary
A method for forming a composite structure, using a mandrel that is later removed from the composite structure, involves production of a mandrel by depositing a particulate mixture, including an aggregate and a binder, into a mold and removing the mandrel from the mold. The mandrel may be treated while still in the mold by heating, curing with an agent, microwave energy, or by some combination thereof. Once finished, the mandrel can be used in manufacturing polymer and/or composite components. The mandrel can also be include materials that can be easily removed from the finished composite structure by water, shakeout, chemically dissolving, or by some combination thereof.