Co-molding Fluid Pressure Demolding for Footwear Soles
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Solution Overview
Problem
The complexity of mold designs in co-molding processes for articles like footwear soles increases the difficulty in removing the co-molded article, especially due to protuberances and undercuts, requiring excessive force and making the process inefficient.
Innovation Solution
A method involving a two-piece mold with a first element and a second element, where the second element forms a chamber under pressure, conforming to the mold surfaces and affixing the first element, reducing contact with protuberances and facilitating easier removal by minimizing contact with mold surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the mold design includes protuberances and undercuts to ensure proper registration and tight holding of elements, then the registration precision and holding stability are improved, but the difficulty of article removal from the mold increases significantly
Solution Approach 1:
The mold is divided into two separable portions: a first mold portion that forms the exterior surface and a second mold portion that forms the interior surface and receives the fluid. This segmentation allows the mold to be opened and the article to be removed without requiring complex extraction mechanisms, while still maintaining tight holding during the molding process through the fluid pressure system.
Solution Approach 2:
A fluid communication system is integrated into the second mold portion, allowing fluid to be introduced into a chamber formed by the mold portions. The fluid pressure ensures tight holding of the first element against the mold surfaces during molding, while the ability to release and equalize pressure facilitates easy article removal without damaging the mold.
2Manufacturing precision
If the mold design incorporates features to ensure tight holding of elements for proper registration, then the manufacturing precision is improved, but the force required for article removal increases
Solution Approach 1:
The fluid communication system allows controlled application of fluid pressure to hold elements tightly during molding, then controlled release of pressure to facilitate removal. This hydraulic control enables precise management of holding force during molding and minimal removal force during ejection, resolving the contradiction between tight holding and easy removal.
Solution Approach 2:
The mold transitions from a static tight-holding state during molding to a dynamic release state during removal. The fluid pressure system dynamically adjusts the holding force, maintaining high force during molding and reducing it during removal, allowing the same mold structure to serve both functions effectively.
3Manufacturing precision
If the mold is designed as a single rigid structure to ensure proper formation of the article, then the manufacturing precision is improved, but the ease of article removal decreases due to undercuts
Solution Approach 1:
The rigid mold structure is segmented into two separable portions that can be moved relative to each other. This allows the mold to maintain rigidity and precision during the molding process, then open to allow article removal, effectively combining the benefits of a rigid single-structure mold with the removal capabilities of a multi-piece mold.
Solution Approach 2:
The mold portions are designed to move in a direction that allows the article to be removed without requiring complex extraction from undercuts. By separating the mold into portions that can move relative to each other, the design adds a dimensional aspect to removal that bypasses the undercut problem while maintaining precision 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 method simplifies the co-molding process by reducing the force required for demolding and ensuring the co-molded article can be easily extracted without damaging the mold, enhancing the efficiency of the manufacturing process.
Implementation Method 1
Fluid under pressure is introduced into the second element to conform the second element to the mold surfaces and affix the first element to the second element
Data Source
AI summary
The disclosure is directed to a method for co-molding. A first element has a top surface, an edge, and a protuberance with a base extending down from the top surface. A second element has an edge, an upper surface, and a lower surface.The mold includes a first mold portion defining a co-molding upper surface, and a second mold portion defining a co-molding mold cavity. The first element is placed into the second mold portion with the protuberance base in contact with the second mold portion. The second element is placed on top of the first element. The mold is closed, thereby producing the second element as a chamber.Fluid under pressure introduced into the chamber forces the second element to conform to the shape of the mold, thereby to affix the first element to the second element. Energy is applied to the mold to co-mold the elements together.