Coreless Paper Roll Winding with Low-Tension Spindle Extraction
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Solution Overview
Problem
Existing rewinding machines face issues with complex expandable spindles that are prone to breakage and excessive stress, limiting the reuse of spindles in subsequent cycles.
Innovation Solution
A method involving a controlled initial winding tension lower than the steady state tension to reduce friction between the web and spindle, allowing for the use of rigid plastic tubes that can be reused multiple times without deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If expandable spindles are used to enable spindle removal after winding, then the spindles can be extracted from the log, but the structure becomes complex and the spindles are prone to breakage
Solution Approach 1:
The solution separates the spindle removal function from the winding function. The spindle remains rigid and simple during winding, then a separate extraction device performs the removal operation after winding is complete, avoiding the need for complex expandable spindle structures
Solution Approach 2:
An extraction device acts as an intermediary mechanism between the wound log and the spindle. This external extraction device applies controlled forces to remove the spindle without requiring the spindle itself to have complex removable features
2Ease of operation
If deformable elastic spindles are used to enable extraction through elastic reduction, then the spindles can be removed from the coil, but excessive stress is applied to the spindles causing breakage risk
Solution Approach 1:
Instead of making the spindle deformable to achieve extraction, the invention inverts the approach: the spindle remains rigid and strong, while an external extraction device provides the necessary forces for removal. This reverses which component undergoes deformation or stress
Solution Approach 2:
The extraction device is designed to apply controlled, gradual forces during spindle removal, cushioning against sudden stress peaks that would cause breakage. The system prepares for extraction by controlling web tension and friction throughout the winding process
3Manufacturing precision
If high winding tension is applied during steady state winding, then the web is properly wound on the spindle, but the friction between web and spindle increases making extraction difficult
Solution Approach 1:
The winding process uses periodic variation in tension: high tension during steady-state winding to ensure quality, then reduction of tension before extraction to minimize friction. This periodic change in operational parameters optimizes both winding quality and extraction ease
Solution Approach 2:
The system changes the web tension parameter throughout the process: maintaining high tension during winding for quality, then reducing tension before extraction. This parameter change reduces the friction force between web and spindle, making extraction easier without compromising winding quality
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 enables easy removal of spindles without harmful traction, ensuring they remain rigid and reusable, reducing spindle damage and extending their lifespan.
Implementation Method 1
the friction between the web and the external surface of the spindle is less than a predetermined value and consequently the corresponding axial force required to pull the spindle out of the inside of the roll
Data Source
AI summary
A method and apparatus for the production of coreless paper rolls, including a winding phase on a central spindle of a paper web carried out by a main reel, until the formation of a wound paper roll, a phase of extraction from the wound roll of the spindle by application of a relative axial extraction force between the roll and the spindle, where the winding phase includes a first winding phase of a number of web revolutions on the central spindle performed at a first winding tension that is lower than the next winding tension.