The document discusses requirements for a good paper rewinder machine. It notes that rewinders are used to rewind defect rolls, make splices, slit rolls into narrower widths, and change roll dimensions. An effective rewinder should have large diameter drums like the main winder to produce high quality rolls at high capacity. It should also allow for fast accelerations and decelerations as well as automatic trim changes for multiple roll widths. The document provides contact information for Pekka Komulainen of Pele Oy if a rewinder with a trim width of 2500mm is needed.

1. Pele Oy
Rewinder Requirements
August 2018
Pekka.Komulainen@clarinet.fi

2. Pele Oy
Winder and rewinder
◼ First winding happens on paper
machine reel.
◼ Second winding is on the main winder
for smaller rolls.
◼ Some part of the production is normally
handled on the rewinder.
◼ Reasons for rewinding can be:
• Rewinding defect rolls
• Making splices and removing faults
• Slitting narrower rolls
• Changing roll diameter or core
dimensions
◼ If you need a good rewinder of trim
width 2500 mm please contact me:
◼ Pekka.Komulainen@clarinet.fi
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Paper
machine
Winder
Rewinder

3. Pele Oy
Roll quality and rewinder
◼ Drum diameters of a two-drum winder have big effect on roll quality and
winder capacity. Rewinder drums should have same diameter as the
main winder.
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Good rewinder – large
diameter drums (850 mm)
Common rewinder – small
diameter drums (500 mm)

4. Pele Oy
Effect of speed changes
◼ On a rewinder there are more accelerations and decelerations than on the
main winder. These have effect on the roll structure. In practice
deceleration always hardens the roll and acceleration loosens.
◼ During deceleration roll weight will be more on the front drum and the nip
there can be too hard causing roll defects.
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Picture: David Roisum

5. Pele Oy
Effect of splicing on roll structure
◼ Rolls having winder splices are never as
good as normal rolls.
◼ If the splice is made because of web break
in the previous winding, the winder must be
decelerated before the splice, which
increases web tension.
◼ During the splicing the web can be loose,
which decreases roll hardness.
◼ After the splice winder is accelerated,
which reduces roll hardness.
◼ On top of this loose part nip effect is higher
and roll hardness is increased again.
◼ When drum diameter is higher, nip effect is
smaller. This is one reason that rewinder
drum diameter should be high.
Roll hardness
Roll diameter
Splice
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Picture: Pekka Komulainen

6. Pele Oy
Requirements of good rewinder
◼ Good rewinder should have the following similar
properties as main winder to make same roll quality with
high capacity:
• Large diameter drums for good roll quality and smooth
high capacity winding
• Electric unwind for fast acceleration and deceleration
• Automatic trim change in case of several roll widths
• Accurate double spreader for efficient separation of
narrow rolls
◼ If you need a good rewinder of trim width 2500 mm please
contact me: Pekka.Komulainen@clarinet.fi
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