Peel-off Device Idler Configuration for Thin Polymer Film Unwinding
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Solution Overview
Problem
High-speed unwinding of thin polymer films for products like diapers or sanitary napkins often results in web blocking due to interlocking and adhesion issues, leading to tension changes, wrinkle formation, and potential web breakage, which disrupts production.
Innovation Solution
A peel-off device with a base and a linear guiding system that includes two idlers offset from each other, where the first idler maintains constant contact with the roll surface to maximize peel force and the second idler provides restraining action, ensuring a meandering path and minimizing layout space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single idler is used to support the web during unwinding, then the device complexity is reduced, but web blocking occurs due to insufficient peel force and tension control
Solution Approach 1:
The single idler is divided into two separate idlers (first idler and second idler) that work in sequence. The first idler applies peel force to separate the web from the roll surface, while the second idler provides tension control and restraining action. This segmentation allows each idler to perform a specific function that collectively prevents web blocking more effectively than a single idler could.
2Productivity
If high tension forces are applied to drive the stock roll at high speed, then productivity is improved, but web breakage occurs due to excessive tension
Solution Approach 1:
The two idlers act as intermediary elements between the driven rolls and the stock roll. Instead of applying high tension forces directly to the stock roll, the idlers provide a gradual peeling action that reduces peak tension forces. The first idler creates a controlled separation point, and the second idler manages the web tension, thereby protecting the web from breakage while enabling high-speed operation.
3Force
If the first idler is kept in permanent contact with the roll surface, then peel force is maximized, but the contact force requirements increase device complexity
Solution Approach 1:
The first idler is designed to be dynamically positioned against the roll surface, maintaining permanent contact through a controlled mechanism (such as a spring-loaded or pneumatic actuator). This dynamic contact ensures consistent peel force is applied as the web unwinds, adapting to variations in roll diameter and web tension while maximizing the peeling action without requiring overly complex fixed contact arrangements.
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 device reliably prevents web blocking by maintaining constant peel force and tension, reducing the risk of web breakage and allowing for continuous high-speed unwinding with minimal disruption to production.
Implementation Method 1
a first one of the idlers is pushed towards the roll so that a contact force is maintained between the first idler and the surface of the roll while the web is peeled off the roll
Data Source
Figure 1
Figure 2
AI summary
Peel off device (4) for unwinding a web of material (2) from a stock roll (1), especially for high speed unwinding a web of a thin polymer film or the like, comprising a base (5) associated to the roll (1), a linear guiding device (6) mounted on the base (5), an idler support (7) linearly guided on the base (5) in a direction towards the roll (1), and a pair of idlers (9, 10) for the web (2) to be unwound. The idlers (9, 10) are mounted offset with respect to each other on the idler support (7) to provide for a meandering path of the web between the idlers (9, 10). The axes of rotation (A9, A10) of the idlers (9, 10) are parallel to the bearing axis (A3) of the roll (1). The the first idler (9) is pushed towards the roll to maintain a contact force (F) between the first idler (9) and the surface of the roll (1) while the web (2) is peeled off the roll (1).