Cores, Shafts, and Chucks in a Digital World
Package printing is moving in the direction of digital, but what impact will digital printing and functions have on the building blocks of material control? Industry insiders offer their opinions.
THE WORD "DIGITAL" is fast becoming commonplace in the package-printing industry. From fully digital presses to digitalized finishing processes and prepress functions, there's something digital about nearly every part of package printing.
Within this digital realm, some elements of the printing process haven't gone hi-tech, including cores, shafts, and chucks, right? It's not a cut-and-dry issue, according to experts.
Some industry insiders, like Larry Taitel, owner of Convertech, don't think cores, shafts, and chucks are affected at all.
"No, the role of cores, shafts, and chucks remains the same," he said. "Any web-fed operation needs to firmly hold and control the rolls at the unwind, rewind, laminating, and matrix locations. Digital technology is changing job set up and run sizes, not eliminating web-fed operations."
Mike Flannigan, regional sales representative, Tidland Corp.—a manufacturer of air shafts—agrees. He said, "I don't see a significant impact on air shaft design or implementation as a consequence of digital printing modulaties."
Of course, there's another side to this viewpoint. But while other experts think cores, shafts, and chucks are impacted by this digital revolution, they say it has more do with how the equipment is manufactured than how the digital functions affect them on-press.
"In all web processes, continuous roll quality is an important part of web stability, production quality, and end-product quality," said Jeff Damour, engineering manager, Converter Accessory Corp. (CAC). "Shafts and cores are similar to a building's foundation. If the foundation is poorly constructed—not level or out of square—the entire building suffers. As the building goes up, the impact of the defects increase. The same is true with rolls. If the core or shaft is of poor quality, the roll may be defective.
"As printing and converting become more digital, the role of air shafts becomes more important. The precision tuning of processes made possible by digital controls allows printers and converters to run at higher speeds and deliver higher quality finished products. Higher speeds place greater stress on the roll and on the shaft's ability to hold securely to the core."
A well-made core, shaft, or chuck will better handle the advances that are coming with digital printing processes and functions, which doesn't necessarily mean these pieces of equipment have to be digitally-savvy. However, there are aspects to this technology that are already slightly digitally inclined, said Robert Banks, Jr., manager, Boschert LLC.
"In my opinion, digital input probably has more play in the manufacturing of the chucks, cores, and shafts," he said. "In the case of shafts and cores, they are steel pieces with movable parts which require little information return during operation. I guess in the case of pneumatic shafts and cores there could be an LED internal pressure indicator.
"Pneumatic Safety Chucks already have proximity sensors available to indicate that the unit is closed, open, or at the loading position, in order to service automatic loading and unloading operations," he added.
For the latest in core, shaft, and chuck technology, read on:
Boschert VT-7 insert design prevents wear, provides longer life
Boschert LLC
www.boschertllc.com
Patented by Boschert, LLC, the highly efficient VT Style VT-7 replaceable insert design allows the concentricity between the safety chuck and roll shaft to remain almost as precise as new throughout the life of the unit. The VT-7 features a roll shaft journal made of a round part with a square part, where 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. Thus, the torque (square part) of the operation is separated from the load-bearing footprint of the roll shaft (round part).
This style of replaceable insert is easily retrofitted into existing Boschert safety chucks that have VT inserts by simply unbolting the existing insert and installing the new round/square style. The VT-7's highly efficient design provides longer life between roll shaft journal changes and replaceable insert changes, more precise quality control of the web during the life of the insert, and fewer quality problems associated with high-speed runs.
New generation of COR-LOK® airshaft and chuck technology
Converter Accessory Corp. (CAC)
www.handleyourweb.com
CAC introduces a new generation of COR-LOK® airshafts and chuck systems. The new COR-LOK® airshafts and chucks feature a freshly engineered tubing (bladder) design contoured to match the geometry of the company's unique, spiraled shaft body. Compared to previous designs, the economical new contoured tubing allows increased gripping power, a longer tubing life, and exceptionally easy replacement. The new COR-LOK® airshaft and chuck systems also offer several air valve options intended to match virtually any plant requirements. To fully inflate, they require only 90 to 120 psi.
Conventional designs feature bladders specifically designed for each airshaft or chuck and are sometimes difficult to replace in a timely manner. COR-LOK® tubing, however, is unique in that it can be quickly and easily sized, on site, to match any CAC airshaft or chuck. Tubing lengths can be ordered in advance and stocked, thus minimizing downtime, even in plants where a large diversity of airshafts and chuck sizes exists. To facilitate easy changeovers, the tubing is mechanically fixed, rather than vulcanized, to the air valve.
All COR-LOK® airshafts and chucks offer exceptional gripping power over the full core length; feature a unique, wear-resistant aluminum leaf locking system, and ensure core protection and damage free operation. They are lightweight and carefully designed for easy, safe operation.
Shaft eliminates winding issues and perfects precision roll control
Convertech
www.convertech.com
Based on customer needs, Convertech's Differential Rewind Shaft design eliminates side-to-side core movement, core slip, and core dust. An advanced internal slip design means cores are locked firmly, allowing precision tension control for different size cores on the same Differential Rewind Shaft.
Ease of loading and unloading has increased this shaft's capacity to improve productivity and uptime. Independent roll locks move freely when the shaft pressure is released and allow cores to slide quickly on and off the shaft. By eliminating cones, spacers, and other time-consuming loading and unloading procedures, this Differential Rewind Shaft is easier to use than other Differential Rewind Shafts.
Convertech's advanced design ensures reduced downtime and increased production. By running multiple width rolls on the same Differential Rewind Shaft, converters can decrease the number of times a shaft needs to be loaded and unloaded. The Differential Rewind Shaft can also eliminate costly shaft changes and will ensure time-sensitive jobs are completed with less effort and in less time. Differential Rewind Shafts are available in 3˝ and 6˝ diameters in both wide and narrow web lengths.
Rugged core chucks set precedent for reliability and gripping strength
Convertech
www.convertech.com
Simplicity of core chuck design and rugged, all-metal construction means reliability and ease of use. Precision-machined parts ensure positive, instant core chuck lock up and release, reducing damage to cores and reduction of personnel injuries in the workplace.
Because all parts are carefully manufactured and tested, Convertech's core chucks provide expansion and retraction to a firm and consistent diameter. Convertech core chucks provide a firm grip with wide-footprint lugs. These chucks can provide high-torque pressure without damaging the inside of the core or the core ends. While eliminating excessive core damage, Convertech's core chucks can dramatically reduce operating costs and substantially increase production with repeated use of cores.
These core chucks reduce workplace injuries with easy unloading. Easy roll removal is maintained with consistent and firm retraction of chuck lugs, keeping the lugs from sticking in the core. Instead of operators forcing rolls off the chucks these core chucks release the core easily and allow rolls to be unloaded with minimal operator effort.
High-speed applications for carbon fiber shafts
Double E Co.
www.doubleeusa.com
The Double E Company has developed and refined its expertise in carbon fiber filament winding and advanced design to produce ultra-high-speed shafts for a variety of applications. These applications all have one thing in common—they all require their shafts to be able to run at extremely high speeds, and with a minimum of vibration and deflection.
For many years, Double E has used carbon fiber as a shaft housing material in the paper, film, and foil converting industries. Traditionally, companies turned to carbon fiber shafts as a means of reducing the weight that their operators were required to lift. Today, there is constant pressure to extend the benefits of carbon fiber, to push the envelope as to what composites can do. Often, machine builders call upon shaft manufacturers to help them to achieve greater line speeds by reducing deflection and vibration. To this end, Double E has developed an ultra-high-precision, high-speed air shaft capable of sustaining increased line speeds without hitting critical speed.
The most significant advantages of carbon fiber composites relate to their superior "strength-to-weight" and "stiffness-to-weight" ratios, combined with extraordinary fatigue life. With few exceptions, any shaft currently made of steel, aluminum, or even titanium, can be made in carbon fiber to enhance performance.
Lightweight carbon fiber Pultrusion shafts
Goldenrod Corp.
www.goldenrodcorporation.com
Goldenrod is continually improving its patented Model 1260-LDC Lightweight Carbon Fiber Pultrusion shafts to handle higher loads and run at ever faster speeds. Bundles of 92-million-modulus fibers are wetted with epoxy and pulled through voids in the aluminum bodies; when the epoxy hardens, the fibers become set at 0° for a true composite unibody construction that has a resulting modulus stiffer than steel. There are no cuts or slots
milled through the carbon that create weak stress points; the carbon is internal and completely surrounded and protected by metal.
Like all Goldenrod Multiple Bladder shafts, the bladders can be replaced in 10 minutes. They offer two designs in 3˝ diameters (the ultralight weighs only 0.36 lbs. per inch of assembled body), plus 4˝, 5˝, 6˝, and 6.75˝ diameter bodies.
Carbon fiber winding air shafts for exacting applications
Nim-Cor, Inc.
www.nim-cor.com
As the demand for increased productivity grows, line speeds are increasing and reel weights are getting heavier. These increases make significant design demands on the winding air shaft, which has to turn at higher speeds, carry the heavier loads, and endure the severely increasing stresses caused by emergency stops. Additionally, machinery designers are continually striving to improve reel handling by introducing turret units or by quick-release drive and bearing systems. These improvements too introduce further strains to the winding shaft.
Nim-Cor is striving to develop innovative ways of meeting these demanding requirements, with a chief focus on making better use of the carbon fiber option. Composite materials bring a wide range of benefits to every application. The material is much lighter than steel and lighter even than aluminum. Reduced weight means that the shafts are easier to lift and to handle, significantly reducing the risk of injury to converters' employees.
Strength and stiffness are key factors on every application. Steel is much stronger and stiffer than aluminum and, until recently, it was also stronger and stiffer than composite material. However, with the new ultra-high-modulus fibers, composite material that is stronger and stiffer than steel can now be produced. Another noteworthy feature of composite material vs. steel is its vibration-dampening capability. This can be an exceptional plus, especially when high speeds are involved.
In the early days, Nim-Cor, together with DuPont, the company's fiber tube manufacturer, worked to refine the selection of carbon fibers—including the supra high fiber—to optimize tube properties. This has resulted in tubes having a stiffness equivalent to or better than steel. This fiber provides an even stiffer tube, but while it does not have the strength of the ultra high fiber, it costs less. More recently, Nim-Cor purchased the production plant and now makes its own tubes in-house, enabling it to offer the same quality product at a reduced cost.
Tidland expands offering of ergonomic shafts and chucks
Tidland
www.tidland.com
Improve overall roll quality, increase operator job satisfaction, and reduce workers' compensation claims with the latest lightweight air shafts from Tidland. The newest 4˝ and 5˝ GX shafts round out Tidland's full-line of ergonomic solutions, which now includes aluminum extrusion and carbon fiber shafts in 3˝, 4˝, 5˝ and 6˝ sizes, and the 6˝ Force5 air chuck.
To facilitate the need for faster changeover, integrating shafts and chucks that are lightweight and easy to maintain into digital printing processes will reduce the time needed for set up between runs and routine maintenance. Tidland's Ultra-lightweight GX shafts have been re-engineered to provide the necessary strength for wide webs at a dramatically reduced weight (because of wider web width, strength is still key).
by Kate Sharon
Associate Editor
