An unwinder/splicer combination is a piece of ancillary equipment. So is the rewinder at the other end of a press. These are integral parts of the same machine, but they play a far greater role than serving as simply dumb functionaries in the press room. The entire winding and unwinding process is connected inextricably to the front office, where it has a direct effect on productivity and, therefore, the bottom line of the company.
An MR Series Turret Rewinder from KTI
Unwinds and rewinds are available in an exceptionally wide range of capabilities, as noted on the following pages. Some are simple, others with such complexities as accumulators that allow splices to be made without adjusting the production speed of the press.
Key to the performance of an unwinder, as well as the rewinder at the far end, is tension. It is necessary to keep a constant tension flow throughout the machine. Without that, as rolls on the rewind side fill up and turn slower, the unwind can turn faster.
"A big issue with winders is that customers often don't know the parameters of what they require, or their parameters change after they have ordered a machine," says Rich Herbert, technical sales manager for CTC International, West Caldwell, NJ, USA. "They're not sure of the level of tension they need, but the supplier shouldn't be making that decision for them. There are some standards, some recommended tensions, and it is helpful to become familiar with these."
Web tension is usually specified in pounds per lineal inch. "Measure it," says Herbert. "Use mechanical instruments or load cells. When people don't do that, when we ask them for the information, they often specify numbers that are too wide in range. Sometimes we can go in and help them measure, or the raw material supplier might also be able to provide information.
"They also should determine what winding pattern they need. Constant tension will make a rock-hard roll, and you don't want that with pressure sensitive labels, because you'll get adhesive bleed. With certain films, it's not such an issue, because sometimes these are wound tighter."
CTC All-in-One Offline Glueless Turret Rewinder
Versatile glueless rewinders are among the more popular choices for label converters, and is attracting increasing attention. A glueless turret rewinder uses a tucking mechanism that makes the material cinch up against itself without using glue, according to Herbert. These systems are proprietary by manufacturer, and offer several benefits. "First," he says, "people want environmentally friendly solutions; second, they want the last label off the roll to be 100 percent clean. Those are hard to achieve unless you go glueless. Third, glueless is safer; and fourth, the use of a glueless turret rewinder results in substantial savings: There's no more glue, and electric bills are lower because you're not heating glue any more."
Coreless turret rewinders, which work by tucking around a specially designed shaft, have been available for a while but currently seem to be limited in demand, Herbert notes. "One of the issues with coreless is that the rolls are small and they might move around during shipping and suffer damage."
In the past, turret rewinders were popular for rolls with large label counts, but that is changing. "More people want turrets for low label counts," says Herbert. "Today you see four, eight, 10 feet per roll. These are more on the sticker side of the business, the pretty, decorative products, which tend to be acquired by consumers. The issue here is that you can't get nearly the speed winding a smaller roll than you can with a larger roll. Most of them are not finished on press using a turret, but offline with a rewinder; there's more of an interest in complete offline turrets due to small roll finishing needs (rewind, finish, slitting), and jobs are getting smaller. If the job calls for 40,000 to 50,000 labels, you might want to set that up offline. We recently introduced a completely offline turret just for that type of work."
Converters running pre-printed material have another issue to deal with, says Sherlund. "Once the press stops for a manual splice, there is a significant amount of time that goes into bringing the process back into registration, as well as associated waste. In-register splicers detect registration marks as they pass by a sensor, splice at the register mark, and bring the web back to process line speed. Doing this eliminates the need to manually bring the press back into registration. Depending on the price of the material, the waste associated with bringing the press back into registration is substantially less compared to manual splicing."
CTC International offers a wide range of rewinds and unwinds, and specializes in custom configurations based on client requirements. Typical equipment types include the following:
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. These may be simple plate mounted units or complete unwind stands. They use closed loop feedback to maintain constant tension regardless of the roll diameter.
More sophisticated (and lower tension) unwinds may utilize vector or servo drives to power the material off the unwind shafts. The often have a small linear festoon that provides position feedback to the drives for smooth unwinding.
Automatic splicers (overlap or butt) incorporate the unwind tension control systems described above.
Plate mounted rewinds or rewind roll stands can be vector or servo driven. Sometimes these stands have load cell or dancer feedback to trim the drives. Typically, smaller rolls are wound under constant torque. Larger rolls tend to be wound under some level of taper tension.
Automatic roll changing servo driven turret rewinders for non-stop production of finished product are available with glue as the transfer medium, or glueless start or coreless start. Typically, smaller rolls are wound under constant torque. Larger rolls tend to be wound under some level of taper tension.
Automatic transfer waste matrix winders are used for non-stop waste removal on label presses. These typically use simple drive systems. Tension control is not an issue.
More info: www.ctcintcom
Changing and splicing input rolls can be a significant cause of downtime in a converting process. The process can become especially time consuming when several different materials are used to make a part or label. While many label-related webs come 1000-plus feet per roll, some foams and thick substrates may only come 150 to 300 feet per roll.
A Delta Industrial winding system in action
Delta offers a variety of solutions for such a productivity problem. A lower-cost option would be to incorporate a ready roll and splice table so the changeover can be made with just a quick stop, change, and splice by the operator. More expensive options can include web accumulators and auto-splice modules, which automate splice applications without stopping production.
The company also offers a variety of solutions for managing advanced requirements in unwinding, splicing and rewinding. Each Delta Mod-Tech system can include as few as one or as many as 20 or more unwind and rewind modules. Complete systems can handle the unwinding of full rolls of web, as well as the rewinding (or removal) of waste web, liners, or finished product. Each Delta unwind/rewind spindle is driven by an independent servo motor for maximum control; these are controlled by Delta's touchscreen HMI (human machine interface). The HMI software is able to calculate and monitor roll diameters from start to finish. It offers users flexibility to adjust tension, accumulate material, and make adjustments for a smooth operation. Optional features include transducers and dancers for tension control, accumulators, auto splice mechanisms, and edge guide roll steering.
More info: www.deltamodtech.com
Independent Machine Company
The growth in converting of slitting and computerized traverse winding systems from the traditional slitter/rewinder for most narrow materials used in label and narrow web applications is steadily increasing due to the demand for the traverse wound spool. As manufacturing processes are able to run faster, the converted material that feeds those processes must run continuously with a minimum of splices and downtime. Traverse wound spools provide this capability and can accommodate miles of material in a single package allowing for longer production runs and less operator handling. In addition, the spools are easier to handle during shipping than conventional narrow, large diameter pads or pancakes.
A narrow format winder from Independent Machine
Precise programmable rewind tension at each position, accurate to within 7 grams, is controlled by a closed loop follower drive system through the exclusive IMC Dancer/Tension Controller with a 25:1 tension range. Typically an operator keypad or touchscreen has recipe storage capability for all winding parameters and machine function settings. The integrity of the spool created by proper control of tension and selection of spool settings will ensure the success of the converted material in the unwinding application. The Smartwinder modular concept enables future integration of additional spooling units.
Additionally, IMC has created the Spool-Mate driven spool unwind to provide the same unwinding tension control as the original supply spool for presenting continuous stream of labels into a process.
More info: www.independentusa.com
Kocher + Beck
The newest addition to the portfolio of Kocher + Beck is the UR Precision splice technology system, unveiled in late 2010. The equipment, which features an unwind, splicer and rewind, addresses efficiencies in the printing and converting process with a focus on bottom line improvement.
"Peripheral equipment, such as automatic splicing systems, have to fulfill the same demands as the entire process chain," says Sales Manager Karin Enderle. "Communication of all systems on a higher level contributes in its entity to secure a continuous, well defined predictable efficiency, which can be seen directly on the bottom line. The basic preconditions for the operating efficiency of nonstop winding systems are guaranteed reliability linked with process stability, and of course the typical measurable bottom line impact parameters such as time savings for manual roll change or total elimination of additional start-up waste in a nonstop mode."
The scissor cut transfer unit on Kocher + Beck's UR Precision
Kocher + Beck describes its splicing technology, a scissor cut transfer unit, as the "jewel" of the nonstop winder. "The unit clamps the web instantaneously and cuts it via a scissor cut principle before the actual web transfer happens. The web is then attached to the core with its linear edge. This revolutionary method leads to a controlled web shift and avoids start-up waste at the core by means of zero fold-back. Winding print inside or print outside without having to utilize a turn bar unit prior to the winding process is an additional advantage of this transfer method. Removal of the finished reel does not require floor contact and therefore no contamination of the processed print substrate."
The UR Precision also offers job save and recall function, roll diameter calculation, and what the company describes as power regeneration/energic balance. The systems are "based on a modern and sustainable energy concept and feature servo motors and drives of the latest generation, which are triggered through a can bus system connected to an industrial PC. The drives themselves are linked to a regeneration interconnection. Costly permanent air pressure use being avoid to the greatest possible extent," says Enderle. "The power created from the motor braking energy at the automatic nonstop splicer is not reconverted into heat, but is mainly (up to 80 percent) supplied to the transfer rewinder in order to save energy and to reduce the impact on valuable resources."
More info: www.kocher-beck.com
KTI – Keene Technology Inc.
Utilizing a KTI automatic splicer at the unwind end and a KTI turret rewind at the rewind end of a press can increase production throughput and decrease waste, according to Robin Sherlund. Several models of butt splicers and turret rewinders are available to handle a broad range of rewinding applications.
The ZC Series Butt Splicer has two cantilevered roll positions that will feed a continuous supply of material into the press. Rolls are loaded from the operator side with the use of a roll cart.
The ZG Series Butt Splicer has two shaftless roll positions that will feed the press. Rolls load from the end of the unit, directly off the floor. The benefit is the same as the cantilevered model but it is available in wider web widths.
The PA Series Automatic Splicer is a "perfect fit for laminating applications," says Sherlund. The unit has two roll positions that will supply a secondary web into the process line. In-register splicing capabilities are available on all KTI splicers, she adds.
The MR Series Rewind will continuously wind rolls without stopping for roll removal. The machine is designed with a zero speed transfer system, which means that the web comes to a complete stop at the time of the transfer to a new core. While this is happening, the festoon is taking up the material from the press.
The KR Series Turret Rewind – "The KR is designed as a matched speed rewind, which means that we match the speed of the new core to the speed of the running web when making the transfer," says Sherlund. "Many options are available to make this machine versatile enough to handle a wide range of applications."
More info: www.keenetech.com
Martin Automatic, based in Rockford, IL, USA, specializes in roll management equipment for many segments of the converting industry. Among the newest of its products is the Martin Automatic MBSC splicer, specifically designed for the narrow web market. Combined with an STR rewind, the MBSC provides roll automation for label presses with webs up to 13".
Martin Automatic's MBSC unwind/rewind system
Like the MBS splicer, the MBSC has the same patented rolling-shear splice unit, lift-and-load roll loading from the aisle, automatic roll sidelay for splice alignment and inertia-compensated festoon. The MBSC also will splice automatically on manual push-button initiation; on operator-adjustable, automatic roll diameter calculation; or by tail-grabber initiation as the web separates from the core for minimum waste / maximum material usage.
The STR turret rewind complements the MBSC, and this combination kit is now the standard offering for two major press lines. In the 12 months since launch, Martin has installed more than 16 of these packages of equipment around the world.
More info: www.martinautomatic.com
Retroflex offers lift-from-floor shaftless unwinds and rewinds to suit nearly every narrow to wide web application. The unwind can be center braked, center driven or surface driven. The rewind can be center or surface driven. Both the unwind and rewind feature hydraulically actuated lift arms that bring the core chucks to your roll. The winders eliminate manual lifting of heavy core shafts and concerns over insertion and removal of the core shafts from a roll. The units feature a pre-plumbed on-board hydraulic pump and pre-wired controls. The open/close feature of the chuck arms allow for a variety of roll widths. These unwinds and rewinds can be equipped with tension roll or dancer control of the brake or drive system. Web guiding and slitting is also available.
A Retroflex turret rewinder
Retroflex also offers driven pull rolls, slitting sections, web guiding and roll handling systems that aim to improve the productivity and profitability of the unwind and rewind, Schmidley adds.
More info: www.retroflex.com
Tools & Production
Tools & Production can design and manufacture complete unwind/rewind stands in a range of different configurations. The company offers standard as well as custom designs that can convert printed or unprinted rolls that vary in width from 3" to 60".
Features can include: cantilevered or simply supported pneumatic air shafts; matrix rewinds; differential drive rewinds; vacuum extraction systems (including noise reduction/silencing options); trim removal systems; simple or sophisticated tension control; infeed/outfeed nip rollers; edge guides; vision equipment for inspection and/or registration; print-to punch or diecut registration systems (if required); speeds up to 1,000 feet per minute; conveyors; stackers, and web cleaners.
The company also offers a complete rotary system with print-to-punch registration system. One such machine included a 40" diameter unwind, infeed and outfeed nip rollers, plus punch and die rings and a slitting system.
More info: www.toolsandproduction.com