Touch Fastener Selvedges for Mold Conformity
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Solution Overview
Problem
In the molding process of seat foam buns, existing touch fastener products face challenges with fouling by liquid foamable compositions, which can lead to undesirable variations in foam density and manufacturing costs due to the need for additional protective measures.
Innovation Solution
A touch fastener product with a base having flexible selvedges and a magnetically attractable material, allowing the fastener to conform to the mold surface and prevent foam intrusion, while also being designed for easy recycling and improved adhesion to the foam bun.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If rigid base structure is used for touch fastener, then structural strength is improved, but ability to conform to mold surface deteriorates
Solution Approach 1:
The base is divided into two distinct regions: a central portion with higher stiffness for structural strength and selvedges with lower stiffness for conformability. This segmentation allows each region to perform its specialized function independently, resolving the contradiction between strength and adaptability.
Solution Approach 2:
Different regions of the base are given different mechanical properties - the central portion maintains higher stiffness while the selvedges have reduced stiffness. This local differentiation enables the fastener to simultaneously achieve structural integrity and surface conformity without compromising either property.
2Reliability
If additional protective materials are added to prevent foam fouling, then reliability is improved, but device complexity increases
Solution Approach 1:
The selvedges serve multiple functions simultaneously: they provide structural support as part of the base, enable surface conformity through their flexibility, and create sealing contact with the mold to prevent foam fouling. This multi-functionality eliminates the need for separate protective components, maintaining reliability while avoiding increased complexity.
Solution Approach 2:
The selvedges inherently perform the protective sealing function through their own structural properties and positioning, without requiring additional protective materials or components. The base structure serves itself by using its flexible edges to create the necessary seal against foam intrusion.
3Adaptability or versatility
If selvedges are made more flexible to conform to mold, then adaptability is improved, but structural strength deteriorates
Solution Approach 1:
The base is segmented into a strong central portion and flexible selvedges, allowing the flexible edges to conform to the mold surface while the strong central region maintains structural integrity. Each segment is optimized for its specific function without compromising the other.
Solution Approach 2:
The mechanical properties are locally optimized - the selvedges have reduced stiffness for flexibility and conformity, while the central portion maintains higher stiffness for strength. This local quality differentiation resolves the contradiction between flexibility and strength.
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 solution reduces manufacturing costs by eliminating the need for additional protective materials, enhances adhesion to the foam bun, and minimizes foam density variations by allowing smooth resin flow and improved stress distribution.
Implementation Method 1
a magnetically attractable material secured to an upper face of the base... as the base of the fastener product is drawn against the mold surface by magnetic attraction of the magnetically attractable material
Data Source
AI summary
Touch fasteners for use as mold inserts in molding seat foam buns include a sheet-form base a magnetically attractable material disposed on the upper face of the sheet-form base, and a film cover covering the magnetically attractable material wherein maximum slope angle of the film cover, is less than about 75° as measured from the upper surface of the sheet form base to the outside surface of the cover. The magnetically attractable material is a strand of frangible composite constructed to be readily segmented with the seat foam bun during recycling.