Paper Machine Winding Basics

Key Questions

The following key questions are answered in this module:

What are the TNTs of winding?
The structure of finished roll sets is largely dependent on three winding variables - sheet tension, nip load, and winding torque. These are often referred to as the TNTs of winding - Tension, Nip and Torque.

Why are there spreading devices both before and after the slitters on a winder?
Spreading devices straighten the sheet before the slitters to ensure good quality cuts and then keep the slit sections separate as they enter the winding section. They help prevent the sheet from weaving back and forth between adjacent rolls in the roll set.

Where is sheet tension controlled on a typical two-drum winder?
During winding, the sheet is tensioned by the driven drums in the winding section and a mechanical brake or regenerative brake motor in the unwind section. The braking force is used to control sheet tension.

What is the difference between wound-in-tension and residual tension?
Wound-in-tension is the amount of tension present in the sheet as it is being wound. Once a roll set has been built, the wound-in-tension converts to residual tension. Residual tension is usually positive in the outermost layers of the roll, and negative or negligible in the center and middle.

Why do winders run at such high speeds?
Because there is usually one winder per machine and a winder may only run 50% of the time (due to parent reel changes, slitter adjustments, maintenance, blade changes, and repairs), a winder must run at least twice as fast as the paper machine in order to keep up with production.

Sample Video Transcript

Below is a transcript of the video sample provided for this module:

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