Back to Basics
An update on cores, shafts, and chucks technology.
CORES, SHAFTS, AND chucks can easily be compared to "all the little people" of the film industry. From light technicians to make-up artists to set designers, the work of the people behind the scenes makes a big impact on a movie's turnout. Likewise, despite the seemingly harmlessness of cores, shafts, and chucks, their performance is very important to the outcome of every print job.
Core knowledge
Cores provide the backbones for many substrates and tapes. While there may appear not to be much difference between company offerings, there are.
Double E. Co. (West Bridgewater, Mass.) offers its Dura-Light® fiberglass composite cores. Lightweight and strong, Dura-Light cores can be reused indefinitely. They withstand high tension and won't crush, nor will they tear out regardless of torque magnitude. Dura-Light cores are available in diameters up to 48˝ and in lengths up to 32´.
Sonoco (Hartsville, S.C.) produces cores made of fiber, plastic, and composite materials, and are designed to meet customer needs in a wide range of markets, including the film market. Its high-performance film cores series, The Millennium Series™, is designed with a range of surface qualities and characteristics engineered to minimize surface markings, and improve winding and unwinding. Sonoco takes note that for many types of films and foils, there is a strong correlation between the surface of the core and the amount of scrap generated.
Bayland, Inc. & Southwest Quality, Inc. (Manvel, Texas) have a variety of extruded cores to offer in any diameter, from 1/2˝ through 6˝. Their featured material for precision film cores is high-impact polystyrene (HIPS), but their cores also come in HDPE, PP, polycarbonate, ABS, and engineering-grade resins.
The dish on shafts
Unlike the heavy shafts of the past, today's offerings are designed with press operators in mind. "A persistent need among our customers is to reduce the weight of air shafts to address operator safety, reduce the number of lawsuits, address the needs of women in the workplace, and as a means to decrease changeover time," said Courtney Donaldson, director of marketing at Goldenrod Corp. (Prospect, Conn.).
Goldenrod offers one of the lightest 3-inch air shafts on the market. The Goldenrod 1260-LF weighs less than 0.25 lbs. per inch assembled, meaning even a 60-inch body shaft weighs under 20 lbs. The external multiple bladder shaft is easy to maintain and takes but minutes to change, thanks to its unique design: all the bladders are accessible from the outside of the shafts. The 1260-LF also has removable leaf expanders that will not distort thin-walled cores.
Tidland Corp. (Camas, Wash.), too, has concentrated their efforts on producing a lightweight shaft that will make handling easier and reduce operator injury. Tidland invented the airshaft in 1951, said Kasey Stratton, media manager for Maxcess International—Tidland's parent company—and has been improving shaft technology ever since. The company's newest addition is the External Element GX Air Shaft, an ultra-light, low-cost shaft designed for light to medium duty applications. Available in 3 to 6˝ core sizes, the GX features a fail-safe multi-circuit air system that ensures that a loss of air in one element will not affect the expansion and performance of the other elements. If needed, expanding elements can be changed without removing the GX from the machine.
Concentrating on a lightweight shaft that can run at high speeds with a minimum of vibration and deflection, Double E. Co. has introduced an ultra-high precision, high-speed carbon fiber composite air shaft. Its lightness stems from its carbon fiber composite make up, which features excellent strength-to-weight and stiffness-to-weight ratios. Among its many attributes, the air shaft has a high critical speed and can run at faster line speeds.
Converter Accessory Corp. (CAC, Wind Gap, Pa.) also offers shaft technology designed for speedy changeovers. CAC has been designing web handling equipment for converters of paper, film, foil, nonwovens, and textiles for nearly 30 years. Now, CAC is offering its newly engineered sleeve-based core adapting option available with the company's production-proven COR-LOK® air shaft technology. The sleeve-based option allows rapid changeovers between rolls with differing core diameters ranging from 3 to 18˝. According to CAC's Engineering Manager Jeff Damour, the new feature is especially effective in label production and other narrow-web operations.
Adding to its extensive line of expanding shafts and chucks, Convertech, Inc. (Wharton, N.J.) recently introduced a lightweight, cost-effective, large diameter through shaft, as well as a small diameter shaft designed for smaller presses and slitters. Available in steel, aluminum, or carbon fiber, the through shaft incorporates advanced technologies that make the equipment lighter than conventional shafts, and includes coiled hoses and fittings for single-point inflation. The small diameter shaft runs in diameters from 7/16 to 2˝, and can accommodate virtually any size web.
Chucks update
From safety to shaftless, chuck technology is advancing with the rest of today's press equipment.
Boschert, LLC (Mobile, Ala.) introduced the VT Style replaceable insert for use with its safety chuck. The efficient design creates longer lasting concentricity between the safety chuck and roll shaft by separating the two forces of wear that breakdown the seat of the chuck, explained Bob Banks Jr., Boschert manager. The VT-7 features a roll shaft journal made of a round part with a square part. The round part accepts the load-bearing footprint of the roll shaft and the square part transmits torque through the safety chuck to the roll shaft. As a result, torque is separated from the load-bearing footprint of the roll shaft, preventing wear to the roll shaft journal. This allows the shaft to remain almost as precise as new throughout the life of the VT-7 replaceable insert.
Converters have available a core-friendly shaftless chuck from Tidland. The company has launched the first in the new Raptor Series of its shaftless winding products. The new 3˝ Tidland Air Powered Lug Chuck was designed for high-speed printing, laminating, sheeting applications on unwind flying or zero-speed splicers, and other shaftless unwind/rewind applications. Featuring a toolless removable adapter that changes from 3 to 6˝ cores in less than 5 seconds, easy maintenance, lugs that don't stick, and a wide footprint, the air powered lug chuck reduces downtime and the risk of injury, and increases productivity. With the new chuck, converters can improve splice reliability, increase operating speeds, and save time and money with repeated use of cores without damage to core ends.
In addition to its release of new shaft technology, Convertech has introduced pneumatic step chucks. The new technology frees operators to run two different core diameters without any adapters or changing of the chucks. The pneumatic step chucks come in sizes that range from 70 mm to 12˝.
Double E. Co.'s DF-2000® torque-activated core chuck has new slide-on adapters, making changeover from one core size to another quick and easy. The DF-2000 uses rollers which travel up and down bi-directional ramps for expansion and retraction of its jaws. The rolling mechanism decreases friction and eliminates the need for lubrication. The DF-2000 also features smooth gripping jaws, and is available in sizes from 2.75˝ and up, as well as in single, quick-disconnect, step, and through-shaft models.
by: Kate Sharon
