Open Gap Film Roll Core Reduces Stress Impressions
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Solution Overview
Problem
The existing cut transfer process for winding polymeric films onto cores results in core impressions due to stress disparities, leading to defects and waste in the initial layers of wound web material.
Innovation Solution
An open gap film roll core with a compliant layer and a longitudinal gap is used, where the starting end of the web is adhered to the compliant layer, allowing the subsequent layers to compress and minimize stress, reducing core impressions by positioning the web edge within the gap.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a cut transfer process with adhesive tape is used to attach the starting end of the web to the core, then the web can be wound onto the core to form rolls, but the leading edge of the web overlaps with subsequent layers causing stress disparity and core impressions
Solution Approach 1:
The core is segmented into multiple circumferential sections with gaps between adhesive tape segments. This segmentation allows the web leading edge to be positioned in a gap rather than overlapped by adhesive tape, eliminating stress concentration and core impressions while maintaining effective web attachment and winding capability
Solution Approach 2:
The adhesive tape is extracted from continuous coverage and repositioned to leave gaps. By removing adhesive tape from certain circumferential positions and creating gaps, the web leading edge can be placed in these gap regions, preventing the overlap and stress disparity that causes core impressions
2Reliability
If adhesive tape is used to attach the web to the core, then the web can be secured for winding, but core impressions are created on initial layers resulting in wasted product
Solution Approach 1:
The adhesive tape is divided into multiple circumferential segments with gaps between them. This segmentation strategy maintains sufficient web attachment security through the distributed adhesive segments while creating gap regions where the web leading edge can be positioned without causing core impressions, thereby reducing wasted film product
Solution Approach 2:
Gaps are introduced as intermediary spaces between adhesive tape segments. These gaps serve as mediator regions that accommodate the web leading edge, allowing the web to be securely attached by the adhesive segments while preventing the web edge from creating stress concentrations that lead to core impressions and product waste
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 solution significantly reduces core impressions and associated waste by minimizing stress on adjacent layers, improving the yield of web processing lines.
Implementation Method 1
the subsequent layers to compress and minimize stress
Implementation Method 2
a compliant layer disposed on the outer surface
Data Source
AI summary
The disclosure generally relates to a film roll core used for winding a polymeric film around, an apparatus for winding the polymeric film on the film roll core, a process of winding the polymeric film on the film roll core, and a rolled film on the film roll core. The disclosure more particularly relates to an open gap film roll core that is capable of reducing defects in wound films.