All wound up

Winders currently have the unenviable task of not only keeping pace with rising throughput levels for blown- and cast-film lines but also handling increasingly technical webs.

“The winder is the last machine part in the extrusion process,” explains Ingo Putsch, technical sales director for extrusion equipment at Windmöller & Hölscher (W&H; Lengerich, Germany), “and therefore it is a very important part. If the winding is not O.K., you destroy the film.” Putsch adds that W&H, which supplies winding and extrusion equipment, is seeing films increasingly complex in properties, including stiffer, thinner, and stickier webs. “The demands on the winding technology are increasing,” Putsch says, “and new developments or different winders are necessary for special applications.”

Davis-Standard (D-S; Pawcatuck, CT), which, in addition to film-extrusion equipment, supplies center or turret and surface winders, feels it has stayed a step ahead of increasing film demands. “D-S has been staying ahead of the curve as the film thicknesses have been reduced and line speeds have increased to maintain the same pounds-per-hour throughput,” explains Rick Keller, VP of sales for D-S Converting Systems. In general terms, Keller says D-S’s winders are rated to 2200 ft/min in cast film and 600 ft/min in blown film. For higher-speed applications, the company has integrated roll handling and re-coring.

Earlier this year, D-S introduced a 64-inch (1625-mm) Model 1450 dual-turret winder with dual-direction auto transfer and a servodriven horizontal lay-on carriage for precise lay-on pressure and gap winding (see MPW Product Watch, February 2007, for initial report).

Keller, and Michael Perrigo, D-S blown-film technical director, said the core drives for that unit are AC vector drives and that other position movements of winder components are handled with servodrives to boost accuracy and repeatability.

D-S supplies blown-film winders capable of handling 60-inch-diameter rolls, with a variety of custom configurations available, including large outer-diameter rolls as well as small contractor-size and consumer rolls.

MDO expands

D-S also provides machine-direction orientation (MDO) units for barrier, breathable hygienic, and stretch films, with easy thread up, and has been joined by many other suppliers hoping to exploit the technology’s ability to bolster film properties.

Extruder and winder supplier Hosokawa Alpine (Augsburg, Germany) provides its own MDO technology, using orientation to enhance stiffness, gloss, haze, and barrier in films. The Alpine Machine Direction Orienter features shaftless rewind that can accommodate three- or six-inch cores and orient films with a maximum lay-flat width of 78.75 inches (2m). Servodrives are used for the 11 processing rollers, enhancing speed control and overall accuracy. The orientation ratio is infinitely adjustable from 1:1 to 10:1.

Kiefel (Worms, Germany), which supplies winding equipment through subsidiary Wintech and was acquired earlier this year by Brückner (Siegsdorf, Germany), launched its monoaxial Kirion stretching technology in November 2001, according to the firm. Since then, customer concerns remain the same: Is the wound film free of wrinkles; how is roll winding accomplished; are waste levels kept low; and can multiple reels be created when winding?

To allay such concerns, Kiefel offers modular construction to customize the machine, as well as web-tension control, through constant lay-on pressure as well as inline slitting for multiple reels. The company also offers PerfectCut to create fold-free web separation when changing rolls. The company figures, in spite of some additional waste caused by added edge trimming, that cost savings still amount to more than 8% at throughputs of 600 kg/hr.

Webex (Neenah, WI) also promises tension isolation and web control with its Isoten vacuum rolls. The company acquired the Isoten vacuum-roll product line from Coating and Converting Resources Inc. (CCR; Sussex, WI), including its full product line of vacuum-tension rolls, vacuum chill rolls, and vacuum belts, in April 2007. Depending on the application, the rolls offer a variety of coatings including tungsten carbide plasma release, polymer compounds, stainless steel mesh screen, felt, and rotary-gravure seamless for magnetic media or optically clear films. The rolls come in diameters from 12-160 inches with web-wrap angles from 30-180°. The vacuum belts can be stretched length-wise to increase sustainable tension and feature an adjustable-width vacuum-zone option for varying web widths.

Contact information

Alpine Hosokawawww.halpine.com

Davis-Standardwww.davis-standard.com

Kiefelwww.kiefel.de

Webexwww.webexinc.com

Windmöller & Hölscherwww.wuhlengerich.de