Pulling Off a UV Add-On

Before worrying about funding a UV retrofit, make sure the system fits your objectives and your press.

By Susan Friedman

You're a prime candidate for a UV retrofit if, like most package printers making the $100,000 investment, you run narrow-web flexo or offset, or seek one press with water-based and UV ink capabilities, say experts.

It helps if the press to be enhanced is equally, if not more, retrofit-friendly than your budget. Other prerequisites include concrete system objectives and a more abstract ROI timeline.

"A year ROI seems early because of the learning curve," says Mark Hahn, director of sales and marketing, AAA Press International. "For most installations, you're looking at one to three years. And since most are not strictly used for UV, ROI depends on the percentage of UV business."

Initial Discussions

The circle of suppliers involved in a successful retrofit is wide. Tom Heffernan, marketing director, UV Process Supply, recommends involving press, curing system and UV ink suppliers. The press supplier can ensure new controls do not disrupt the existing package, and can aid in any necessary component changes, such as rollers, he explains. The press manufacturer may also have warranty and service issues with third party systems. The curing system supplier is the best source for adapting a specific system to the application, and helping printers navigate the learning curve, he adds.

An initial discussion with the UV system supplier will likely focus on the press itself. UV lamp configuration (the number of lamps and wattage) is determined by looking at ink laydowns, press speeds, frequently used colors and web widths, says Pete Kershner, new business development manager, EYE Ultraviolet. Later on, drawings from the press supplier can help design lamp housings and mounting brackets, while an on-site investigation of the press ensures areas designated for UV stations are free of other components.

Goals for the retrofit will govern the specifics of ink and equipment, so converters must be clear about their motivations. To run faster, printers may need a more reactive set of coatings and inks combined with more powerful lamps, suggests Jim Flynn, product manager, UV curing, Hanovia. To run colors of more vivid hues, check with the inkmaker on the power and speed specs for those chemistries, and whether additive "doped" lamps are needed, he adds.

Put Fit First

Retrofit budget constraints are secondary in the face of press space constraints. The biggest question is: "Will the system fit in here?" states Doug Colton, TITLE, Nordson Spectral Technology Group. "Unique pedestal designs are often needed for mounting. We're making the technology as small as possible, and consolidation is often what it comes down to. Filtered UV systems, which don't require exhaust ducts, can often fit into smaller areas."

Smaller irradiators can now fit inside press sidewalls, elaborates Hahn, and will not interfere with conventional drying capabilities if they are mounted above or below press heater hoods.

Web-fed retrofits are easier than sheet-fed retrofits because of comparatively more space, and no deck plate or gripper bar issues, remarks Kershner. In extreme squeezes, he says an alternate web path can be devised.

Curbing Costs

Printers can keep a tighter leash on UV retrofit costs by choosing an end-unit installation, easing into color curing, and avoiding equipment overkill.

"Adding a varnish station at the end of a press, followed by a UV curing unit, is pretty down and dirty," comments Hahn. "The main issue is appropriate space between stations for dwell time."

When curing color, an end-unit can cut the number of lamps needed by a third. For a ten-color job, dry trapping (drying after each color) requires 12 lamps, while wet trapping (applying multiple colors before drying) only requires four, contends Colton. Dry trapping does eliminate markings from rollers and reduces dot gain, he adds.

Retrofits for color curing aren't as cookie-cutter as varnish station add-ons, Hahn stresses, and may involve a steady line of suppliers. For UV flexo, metering roll compounds must accommodate UV inks/coatings chemistry. Anilox roll volume must suit higher yield, 100 percent solid UV inks. Additional purchases may include doctor blade systems, corona treaters and web cleaners.

If a budget is particularly limited, start with two UV stations and quick-change, mobile irradiators—a set-up that can be used for opaque white ink laydown or handling fine print, and which can gradually introduce the rheology of UV inks, Hahn asserts.

To skirt unnecessary equipment costs, make sure the system purchased is strictly customized to meet established objectives—and nothing more. "Be wary of preplanned UV curing packages that typically offer too much power," cautions Flynn. "Many applications do not need this expensive, unnecessary overkill."