Mandrel Fluid Passage for Elastomer Release
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Solution Overview
Problem
Elongated, thin-walled, and reinforced elastomeric parts tend to cling to mandrels due to vacuum, frictional, and constrictive forces, making it difficult to remove them after molding.
Innovation Solution
A mandrel with an elongated body and a passage that allows fluid communication from the internal cavity to the outer surface, preventing uncured elastomer flow, facilitates the release of the elastomeric part by introducing a fluid to intervene between the mandrel and the part, easing its removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If elastomeric parts are molded over a mandrel to achieve the desired shape and structure, then the part can be formed with complex geometry and reinforcement, but the part clings to the mandrel due to vacuum, frictional, and constrictive forces making removal difficult
Solution Approach 1:
A fluid passage system is introduced as an intermediary mechanism between the mandrel and the elastomeric part. The passage allows fluid to be injected into the space between the part and mandrel, acting as a mediator that reduces adhesion forces and enables easy part removal without compromising the molding precision or part structure
Solution Approach 2:
The harmful vacuum and adhesion forces are extracted by introducing fluid through the passage system. The fluid injection removes the vacuum conditions and reduces frictional forces that cause the part to cling to the mandrel, effectively extracting the problematic forces from the system
2Ease of operation
If the mandrel surface is made smooth to facilitate part removal, then the part can be released more easily, but the uncured elastomer may flow through the passage instead of being contained
Solution Approach 1:
The mandrel is designed with different local properties: the passage opening region has specific dimensional characteristics that allow fluid passage while blocking elastomer, and the rest of the surface provides proper molding contact. This local differentiation allows both easy release and proper elastomer containment to occur in different regions of the mandrel
3Loss of substance
If the elastomeric part is made thin-walled to reduce weight and material usage, then the part becomes more efficient, but the part clings more strongly to the mandrel due to increased surface area to volume ratio
Solution Approach 1:
The fluid passage system serves as an intermediary that counteracts the increased adhesion forces on thin-walled parts. By injecting fluid into the part-mandrel interface, the system reduces the effective contact pressure and frictional forces, enabling removal of thin-walled parts that would otherwise cling strongly to the mandrel
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 method allows for the successful release of elongated, thin-walled, and reinforced elastomeric parts from the mandrel under mild conditions, maintaining the part's original structure and preserving the mandrel's molding capability, even for parts exceeding 10 feet in length and reinforced with materials like fiberglass.
Implementation Method 1
flowing the fluid through the internal cavity to cause the fluid to flow out of the passage and intervene between the outer surface of the mandrel and the elastomeric part
Data Source
AI summary
A mandrel configured to facilitate release of an elastomeric part cured thereon may comprise an elongated body having an outer surface, an internal cavity formed in the elongated body, and a passage providing fluid communication between the internal cavity and the outer surface of the body. The passage may be dimensioned so as to permit a flow of a fluid from the internal cavity to the outer surface of the body and to preclude a flow of an uncured elastomer into the passage. The flow of the fluid from the internal cavity to the outer surface may cause the fluid to intervene between the outer surface of the mandrel and the elastomeric part to facilitate the release of the elastomeric part from the mandrel.