Aztech Converting Systems offers standard modular unwind and rewind systems.
"Without that control, those materials may stretch by a factor of two at the unwind, and that can create issues trying to feed material into the machine at constant speeds."
Kocher+Beck offers the UR Precision winding system, which features a servo driven integrated isolation dancer on the unwind that compensates for the time of acceleration required for a new roll of material.
Unwind technology developed during Telstar Engineering's 22 years has become one of the most important ingredients in the company's success.
Retroflex unwinds and rewinds are available for web widths from just a few inches to well over 120" at speeds over 3,500 fpm."
"The routine task of changing rolls at the unwind and rewind stand on rollfed applications can hold the key to extra production gained or lost." says Robin Sherlund, marketing manager at KTI--Keene Technology Inc, South Beloit, IL, USA.
Without that, as rolls on the rewind side fill up and turn slower, the unwind can turn faster.
Basic mechanical unwind tension controls using pneumatics or springs to balance the force of a rotating dancer or rotary web festoon against some type of brake on the unwind shaft.
CTC is one of several manufacturers that supply unwind and splicing equipment to the narrow web industry.
CTC International offers these two types of unwind as well.
We measure the amount of tension in the supply or take-up web, then modulate the amount of torque to the unwind brake or the rewind clutch, so that the amount of tension on the web is constant from beginning to end," Kirtz says.
"If you put drag on the unwind and let it go, the top surface of the material will have more tension than the web, and it causes curl after the lamination is made."