Machinery maker Windmöller & Hölscher KG (W&H) unveiled three advancements in blown film extrusion equipment technology in June during a two-day, in-house expo at its Lengerich, Germany, headquarters. The company, which operates as Windmoeller & Hoelscher Corp., Lincoln, R.I., in the U.S., reported 1,000 visitors from 51 countries attended the event, held every three years.
The equipment advances focus on reducing changeover time and ratcheting up process enhancements that expand the capability of W&H's blown film machinery, says Andrew Wheeler, president of the company's North American operations.
TURBOCLEAN
W&H premiered Turboclean, a new automatic purging system for the Varex II line that is designed to reduce resin changeover times from 30 minutes or longer to two minutes. The specially designed closed-loop pneumatic system purges material from the hardware components of a line.
The dramatic reduction in changeover time is possible due to a combination of an intelligent-control algorithm added to the operating software of the machine control with automatic pneumatic cleaning of gravimetric and vacuum conveyors. The machine operator needs only to switch a suction pipe from one resin container to another.
Some of the requirements of the resin changeover system include outfitting the gravimetric and loading system with the pneumatics as well as additional sensors, and uploading the program to the machine software. Turboclean is designed to work with vacuum loaders from Mann+Hummel GmbH, Ludwigsburg, Germany, says Wheeler.
The automatic changeover system is an alternative to conventional approaches "where the operator would clean out each equipment component manually, one at a time," Wheeler says. "A three-layer lamination film line would have roughly 15 components to clean, taking two minutes each. A nine-layer line could have 35 components and would take well over an hour to clean. With Turboclean, even a nine-layer system can be cleaned in two minutes."
Turboclean cleans all of the system components simultaneously rather than one by one. The software halts the drawing of material into the equipment, and the material is drained at high speed into catch bins underneath the gravimetric hoppers. This action ensures that virgin materials remain unmixed.
Turboclean generates pressurized air that is blown through the system to remove residual pellets. New material is then introduced into the blown film system. At the expo, Turboclean performed changeovers of three-layer lamination films of different colors.
EXTENDING FILM-STRETCHER'S PERFORMANCE
W&H also demonstrated an updated version of its film-stretching technology, MDO, which stands for machine direction orientation. It was demonstrated inline, although it also is available as a stand-alone unit.
The Optifil P automation module continuously stretches films produced on W&H's blown film or cast-film lines in the machine direction, which creates films with unique properties and reduces film thickness.
The company says the system minimizes potential film issues associated with stretching, such as neck-in due to stretching, and keeps film thickness uniform while reducing trimming requirements.
The MDO was used in a demonstration that produced a thin, multilayer breathable backsheet diaper film. Stretching the mineral- filled film separates the polymer matrix from the filler particles, resulting in a network of microscopic pores that allow gases to pass through while keeping liquids in.
Like Turboclean, the MDO works with the Varex II blown film extrusion system, which was introduced in 2013 following three years of development, says Wheeler. The Varex II line can be designed to produce films with up to 11 layers with working widths up to 11 feet, 10 inches. It can be configured with W&H's Maxicone die, the Arctis dual-lip air-ring system, the Optifil automatic gauge profile control system and ProControl TS machine operator console. The Varex II system can be set up with 2- to 5-inch diameter extruders and 5- to 35-inch diameter blown film dies, says Wheeler.
ADJUSTABLE CALIBRATION FOR
WATER-QUENCHED FILM LINE
W&H also premiered a flexibility enhancement to the Aquacage film calibration system, for use with its Aquarex modular water-cooled blown film line.
The Aquarex line is configured upside down in comparison to an air-cooled blown film in that the extruders are atop the tower and the film is blown down rather than up. The bubble is cooled as it passes through the Aquacage water calibration system. Water is removed from the film, then the dry film is wound.
The rapid cooling that water provides keeps the crystallinity of the film low, maintaining its amorphous structure. Water-quenched films achieve high clarity and gloss, good sealability and puncture resistance, says Lennart Ederleh, technical sales director, extrusion equipment. The film possesses favorable thermoforming properties compared to other blown and cast film. The line is designed to produce high-barrier films for medical packaging.
The Aquarex line produces a wide range of films; however, its flexibility has been limited by the use of single-size calibrators that required changeout when a film-width change was required.
Aquacage has been updated as an adjustable water calibrator, and W&H claims it is the first of its type in the world. Aquacage automatically adjusts the bubble diameter, similar to a bubble cage with conventional air-blown film lines.
The system eliminates the need to physically switch out calibrators to change the film diameter, widening the application range of the Aquarex product line.
Wheeler does not disclose how the patented technology adjusts the calibrator, but says that the system handles up to a 20-inch layflat width. W&H used Aquacage on an Aquarex system at its event to produce a high-barrier thermoforming film.
Mikell Knights, senior correspondent
Contact:
Windmoeller & Hoelscher Corp., 401-333-2770, www.whcorp.com
