Slit Web Strand Separation via Stretchable Surface
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Solution Overview
Problem
Current methods for slitting films during continuous web processes do not effectively separate strands of slit webs with intact bridging regions, limiting the ability to create mechanical fasteners with enhanced breathability, flexibility, and performance.
Innovation Solution
A method involving running a slit web or polymeric netting over a stretchable surface that stretches in the cross-machine direction, using rotating diverging disks with a stretchable surface, to separate strands and increase the width of the material, allowing for the creation of mechanical fasteners with unique properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the slit web is fed over a stretchable surface in the machine direction while the surface stretches in the cross-machine direction, then the strands are separated and breathability is improved, but the device complexity increases
Solution Approach 1:
A stretchable surface acts as an intermediary between the slit web and the separation mechanism. The surface temporarily holds the web during stretching, allowing strands to separate while maintaining control over the process. This mediator enables strand separation without requiring direct mechanical manipulation of each strand.
Solution Approach 2:
The stretchable surface changes its physical parameters (area, shape) during the process. By stretching the surface in the cross-machine direction while feeding the web in the machine direction, the surface creates the necessary conditions for strand separation. The parameter change from a static to a dynamic stretching surface enables the separation function.
2Ease of operation
If multiple strands are separated to create openings, then flexibility and comfort are improved, but the strength of the mechanical fastener decreases
Solution Approach 1:
The mechanical fastener is designed with non-uniform structure where different regions have different properties. Some areas have separated strands creating openings for flexibility, while other areas maintain intact bridging regions for strength. This local variation in quality allows the fastener to exhibit both flexibility and strength in different locations.
Solution Approach 2:
The mechanical fastener functions as a composite structure combining separated strand regions and intact bridging regions. This composite approach allows the material to exhibit multiple properties simultaneously - flexibility from separated areas and strength from connected areas - resolving the contradiction between these opposing requirements.
3Area of stationary object
If the web is stretched in the cross-machine direction during feeding, then the width is increased and breathability is improved, but the manufacturing precision may be compromised
Solution Approach 1:
The stretchable surface is prepared and positioned before the web is fed onto it. The surface is already in the correct stretched configuration, which predetermined the final width and geometry of the separated web. This preliminary preparation ensures that when the web is fed and stretched, the manufacturing precision is maintained through the pre-established geometry.
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 creation of mechanical fasteners with increased breathability and flexibility, providing improved comfort and performance by resisting shifting forces, while minimizing material waste and reducing costs.
Implementation Method 1
the stretchable surface is stretching in the cross-machine direction
Implementation Method 2
The traction between the slit web and the stretchable surface during the stretching at least partially separates at least some of the multiple strands
Data Source
Figure 1A
Figure 1B~1C
Figure 2A~2B
AI summary
A method of separating strands of a slit web is disclosed. The method includes providing a slit web having a length in a machine direction and running the slit web in the machine direction onto a stretchable surface. The slit web includes multiple strands provided by a plurality of slits extending in a first direction not parallel to a cross-machine direction. The slit web is in contact with the stretchable surface for a path length in the machine direction, and for at least a portion of the path length, the stretchable surface is stretching in the cross-machine direction. The traction between the slit web and the stretchable surface during the stretching at least partially separates at least some of the multiple strands of the slit web in a second direction transverse to the first direction. A method of increasing a width of a polymeric netting is also disclosed.