Higher, farther, faster. Like the Olympic ideal, converting customers want to push the boundaries of efficiency and print quality. For most converters, there are never enough hours in the day. Every customer wants his order processed and run at top speed, including drying/curing. Whether the inks and coatings are waterborne or solvent-based, there's never-ending pressure to get each order ready for shipment ASAP.

Suppliers of drying and curing systems are deftly combining the latest technology with concern for environmental laws and safety regulations to bring converters faster, more efficient drying and curing at reasonable cost. We asked some equipment suppliers about the type of drying and curing problems they've solved, and also asked them to preview where the technology is headed in the next few years. Here's a compilation of their answers.

Most drying/curing equipment suppliers agree that today's tight capital-equipment market favors systems that are flexible, versatile or interchangeable. However, that's about all they agree on. As UV and EB curing slug it out for market share with traditional convection air and infrared drying, suppliers of all major types of systems are striving to make their processes efficient and cost-effective.

"The lifespan of many of today's new coated and laminated products can increasingly be expected to be shorter than the equipment used to produce them, either because of the introduction of new, replacement products or because of the ever-changing business climate," says Richard McCarthy, vice president of New Era Converting Machinery, Hawthorne, N.J. "For this reason, new installations of web dryers and curing ovens must be designed to be both flexible and changeable."

Many suppliers tackle that challenge through various levels of equipment customization. "A dryer configuration that works great for one application may be terrible for another," says Bill Scullion, manager of pre-sales engineering for MEGTEC Systems, DePere, Wis. "The days of a 'one size fits all' dryer design are over." He cites versatile nozzle designs, even including interchangeable or reconfigurable versions, as an example of built-in flexibility.

Optimizing the drying/curing process for the converter obviously can't be left to chance, and a few suppliers have made the investment in pilot plants where formal trials using various coatings and drying/curing techniques can be conducted.

"We rely on a combination of computer modeling, pilot lab trials, and experience to accomplish [optimization of the process]," says MEGTEC's Scullion. "Investment in a pilot lab allows us to maintain up-to-date knowledge and experience in a wide range of processes. We've developed an extensive inventory of nozzle designs with a wide range of performance characteristics."

"Oftentimes, the solution to a particular customer's problem lies solely in our experience with a similar product," says New Era's McCarthy. "This is generally the case when the customer wishes to produce a variation on a commodity product. However, for new products, or products that are changing to different substrates or coating solutions, the best technological tool available to us is our pilot coating line."

Once again, flexibility and customization emerge as attributes converters ask for when specifying new dryers. "There is a continuous movement away from roll support dryers to flotation dryers," says Matthew Litzler, president of C.A. Litzler Co., Inc., Cleveland. "Flotation dryers offer significant benefits to customers for higher speeds and better quality by removing idler rolls.

"A second trend is combination dryers. Combining different drying technologies, such as convection (flotation) combined with radio frequency, allows customers to create a unique system to optimize their process."

"The old standbys—convection air and infrared—are by far the most popular forms of drying," says MEGTEC's Scullion. "It's not unusual to see hybrid dryers using a combination of convection and IR. It is becoming more common to see hybrid designs combining convection and UV."

Packing more drying energy into a given amount of dryer space is the key, according to Jim Alimena, marketing manager for Glenro Inc., Paterson, N.J.. "This can be done by combining infrared energy with the hot air in a typical web dryer. Infrared heating modules can be placed between the nozzles of a hot-air dryer. Another effective combination is to add an infrared predryer prior to the hot-air dryer. A few feet of infrared can quickly raise the temperature of the coating so that when the product enters the dryer, the water is ready to vaporize."

What happens when inks and coatings cure, instead of drying? According to suppliers of UV and electron beam (EB) drying and curing systems, the whole process goes faster and converters save money.

"Because UV inks cure immediately when exposed to a Prime UV curing system, offsetting [when running roll-to-roll] is no longer an issue," says Juliet Midlik of Prime UV, Carol Stream, Ill. "Another major issue for the printer is putting down a dense solid. With UV ink a dense solid is able to cure instantaneously."

"UV inks and coatings with reduced photoinitiator contents are less expensive, can be cured at higher speeds and result in odor-free product," says William Asmann, vice president of operations, IST America Corp., Bolingbrook, Ill. "This is a particularly important aspect in cosmetic, pharmaceutical, and food-packaging applications. It can be accomplished when the cure takes place in an oxygen-reduced atmosphere."

Electron-beam curing of both printed and laminated jobs also speeds up processing, according to Ed Maguire, vice president of marketing and sales for Energy Sciences, Inc., Wilmington, Mass. "The standard in the industry today is to use solventless adhesives, which can take from one to five days to completely cure. This means the converter has a great deal of work-in-process inventory tying up cash.

"It also means they need to wait days before completing quality control," he continues. "EB removes all of these barriers and allows converters to print and laminate in-line. Since EB cures instantly, QC can be completed in real time. All of this results in reducing the converter's costs while [helping them] respond to their customers' needs much faster."

Yet problems remain. According to Steve Utschig, flexo instructor at Fox Valley Technical College, and contributing technical editor for Converting, "Technology must be further developed to address the VOC issues that still plague our industry. In the case of curing, more efficiency needs to be introduced to guarantee full cure, and testing methods developed to further prove full cure."

One other trend for the future is similar to that taking place in other types of industrial machinery—the increasing popularization of PC and PLC control.

"We see increased use of PLC control of dryers and better electronic feedback for temperature sensing and control," says Matthew Litzler. "Customers can create historical databases and 'recipes' for every product to optimize energy efficiency and improve product quality."

"Longer ovens require better material handling features," adds Bob Narang of Radiant Energy Systems, Inc., Wayne, N.J. "Use of PLCs and software packages provide the means of achieving [performance] goals in today's ovens."

Drying and curing systems, far from being an afterthought to a converting system, have become a value-added part of the overall process, and a way for some converters to differentiate themselves from the competition.

With choices exploding, and environmental considerations also part of the decision-making process, converters need to examine their options carefully before submitting that final spec sheet.