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Dual Unwinding for higher winding capacity

Why store spools in two positions? Why pause production when changing the parent roll? Why not a winder with two unwind stands instead? Valmet’s Dual Unwind is an exceptionally fast way to make a parent roll change at the winder. You’ll end up with more production and higher winder capacity.

New thinking at the finishing area

Almost a decade ago, Valmet launched a revolutionary winding equipment that would significantly increase capacity. The first one was delivered to Propapier. After this first start-up, almost 30 Dual Unwind solutions have been sold already to increase winding capacity. Dual Unwinding makes it possible to get rid of additional reel spool storages at the winder. There is no need to pause the production due to parent roll change as earlier. The Dual Unwind sequence is fully optimized and independent of a crane.

Old type of finishing area

Old type of finishing area 

New type of finishing area with Dual Unwind

New type of finishing area with Dual Unwind

With Dual Unwind, you’ll get:

  • One-minute parent roll change
  • 15-30 % more capacity for winders
  • For winder modernizations and new winders

With conventional parent roll change solutions, fast manual changes are 5-6 minutes. However, typical measured parent roll change times in the industry are in average some 9-12 minutes. With this in mind, a one-minute parent roll change with Dual Unwind is very fast. This alone leads into big savings with the capacity increase at winder. Depending on the winder, the capacity gain can be 15-30 %, even up to 40 %.

The movements of parent rolls are arranged to happen simultaneously with the set changes, which is a robust solution to ensure there are no compromises to the roll structure and quality during winding. The second unwind stand is designed only for unwinding the last set from the parent roll. This allows the primary unwind stand to receive a new, prepared parent roll during winding.

The dual unwind can delivered with two different splicing technologies, a conventional flying splice or a butt-joint splice, BJS, which will prepare a sellable splice.

Butt-joint splicing

Butt-joint splicing

BJS delivers:

  • High-quality splices that run through the printing press
  • Excellent splicing quality and reliability
  • Suitable for all paper/board grades
  • Automatic tail threading from parent roll to slitter section
  • Unwinding from above and under