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Air Care

Dec 1, 2006 12:00 AM


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Phil Sutton often suffered from a major pain in the neck, but it didn’t come from sleeping on too soft a pillow. It wasn’t his managers or colleagues, either; his employer, Cedar Graphics, Inc., has been a five-time winner of the Master Printers of America’s “Best Workplaces in America.”

Sutton’s pain was due to static electricity that caused a host of production problems in his company’s pressroom and bindery areas.

Static screw-ups
One of the Midwest’s largest sheetfed printers with 130 employees, Hiawatha, IA-based Cedar Graphics prides itself on providing high levels of service, quality and value to its customers. Cedar Graphics prints a wide range of projects ranging from advertising flyers to college recruitment materials, calendars, catalogs and annual reports.

As pressroom manager, Sutton battled with static electricity that jammed his six presses 30 to 40 times a day, interrupting production workflow, reducing throughput, wasting paper and causing expensive downtime. “That sort of waste and downtime isn’t the way we do things,” Sutton says. Especially frustrating was the fact the problems were both seasonal (mostly during colder months) and sporadic.

Static cling caused double-sheeting of papers and paperboard, which wasted paper, jammed presses and stopped work for cleanup. Problems were most severe in the bindery and finishing areas, where operations sometimes slowed to less than one-third their normal rate. Static cling also caused uneven jogging, making it virtually impossible to get a consistent edge.

Humidity hang-ups
Although static electricity was the most severe problem dogging Sutton, it was far from the only one. Dimensional stability was another pain in the neck when low relative humidity (RH) in the warehouse and on the shop floor caused paper to shrink, warp and wrinkle. Sometimes there were feeding problems and more press stops. There were registration problems, both in printing and die cutting. And too-dry paper frequently cracked or broke during scoring, folding and cutting, releasing dust into the air and contributing more stock to the waste stream.

Cedar Graphics’ problems weren’t unique. Similar production problems caused by dry air are common in many parts of the country where temperatures drop sharply in fall and winter, and heating systems are kept busy 24/7 providing warm air to keep employees comfortable.

Heating air dries it out, and RH often drops to troublesome levels, sometimes to less than 10 percent. Troubles typically kick in when RH drops to less than 30 percent. Ideal humidity for printing and finishing ranges from 45 percent to 55 percent RH at 70°F.

Despite its dry air problems, Cedar Graphics had better humidity control than many printing plants. A previously installed electric steam humidification system provided a small measure of control. RH levels sometimes dropped into the low 20s. According to Sutton, the system’s capacity was inadequate for the job.

“The way our steam humidifiers delivered moisture was inconsistent,” Sutton says. “Some areas were too dry, while nearby areas were too wet. Our bindery manager refused to use the system most of the time because excess water droplets were rusting equipment and drips were ruining stock.”

To make things worse, energy costs for electricity were very high and the steam system required constant, expensive service. According to Sutton, “Our area’s water quality is poor, with high lime content. We couldn’t use reverse osmosis (RO) water with our system, so sludge and hard lime built up quickly in the nozzles and steam heads.”

After analyzing and researching the issues, Sutton determined that solving his static electricity and dimensional stability problems would require more consistent humidity control at a much higher RH range (45 percent to 50 percent).

Meet ML
Sutton’s research convinced him that a high-pressure humidification system would provide increased capacity and greater consistency. He also learned that a high-pressure system would require far less maintenance and would sharply reduce energy costs.

“High-pressure is inherently more energy-efficient,” Sutton says, “because it generates cool mist. Using electricity to heat water into steam is inherently inefficient and typically the most expensive way to put moisture into the air. Steam systems also generate more maintenance, because evaporating water at high temperatures leaves more deposits in nozzles and steam cores.”

At Graph Expo, Sutton met Pierre Husson of Husson Inc., exclusive North American distributor for ML System, a Danish-based world leader in high-pressure humidification that offers a wide range of models for different problems.

After reviewing a number of high-pressure systems, Sutton reduced the field to two companies. “All the high-pressure systems had significantly lower energy costs and required less time and money for maintenance,” he says, “but not all were equal in the amount of energy and maintenance savings. There were large differences in installation costs and the cost and convenience of adding to or reconfiguring the system.”

Sutton’s decision to select an engineered system from ML System was based on several factors:

  • The ML system had more capacity than the job required, providing capacity now and for future expansion.
  • It would require less maintenance time and cost, even when compared to other high-pressure systems.
  • Installation of the ML system, using flexible hydraulic hose, would be significantly easier and less expensive than a hard-plumbed system with stainless steel piping.
  • Use of hydraulic hose would make it easier to move or reconfigure the system in the future.
  • RO water was standard with the system, which would reduce or eliminate sludge or hard lime buildup.
  • There would be major energy savings compared to the electric steam system.
Sutton’s ROI analysis revealed that the ML system would pay for itself in less than two years. “After that, choosing ML wasn’t really difficult,” says Sutton.

Hasta la vista, static and humidity
Husson installed a new, engineered ML system in Cedar Graphics’ 60,000-sq.-ft. printing plant, including paper storage, pressroom, bindery and finishing areas. The system included ten of ML’s high-capacity Princess 2 humidifiers, equally divided between two zones. Humidity meters throughout the zones are linked to a remote programmable controller that reads results and controls the mist units.

Sutton explains, “Each zone has a set point at 45 percent RH. If RH drops below that level, the PC starts the Princess units, generating a cool, fine mist until the target RH is regained. The difference was apparent right away. Static electricity ceased to be a problem in a day or two. The paper feed problems, paper jams and trip-offs just disappeared. So did the jogger problems, including the paper jams and the haystacking. The bindery became more than 50 percent more efficient overnight.”

Issues related to paper shrinkage and curling also disappeared. With paper now the right size and more pliable, there were no more problems gripping the paper and none with printing or die cutting.

Sutton says his ML system has lived up to all his expectations. “It’s nice to have a system with capacity, consistency and reliability. The integral fan and small droplets of the Princess 2 units provide uniform coverage throughout.” He says there have been few operating problems and only anticipated routine maintenance has been required. And as expected, energy costs have been about 70 percent lower than with the electric steam system.

Cedar Graphics’ continued growth and resulting new equipment (a new KBA Rapida 105 six-color sheetfed press and a KBA Rapida 105 10-color, 5/5 perfector) have meant pressroom expansion and the need to expand the humidification system. Sutton says his first stop in shopping for that expansion will be ML System and Husson Inc.

For more information, see www.hussoninc.com.



Humidity—it’s all relative
Humidity is the amount of water vapor in the air. Relative humidity (RH) is a phrase many use but few truly understand. RH refers to the amount of water vapor actually in the air divided by the amount of water vapor the air can hold. In the winter months, air typically is drier (or less humid) and static charges tend to build. To avoid these shocking developments in the pressroom and bindery, consider some of the humidification and anti-static options found in AMERICAN PRINTER’s October 2005 issue. In “Beware of dry air” (pg. 44), you’ll find products from American Moistening, Ionix Technologies, DRAABE, Prisco, Simco, Takk, Meech Static Eliminators, Tantec and more!