NO FLASH IN THE PAN (Laser digital converting presents compe

Laser digital converting's efficiency and flexibility present compelling competition for conventional diecutting.

by Sue Friedman, Editor

WITH ALL ITS flashy trappings, laser digital converting technology could have been hyped to the max. The process, which actually vaporizes material in order to accomplish various finishing operations, is instead quietly edging toward mainstream applications. How deep a niche will it ultimately etch?

A typical laser digital converting system can include a CO2 laser, power unit, chiller, controller, software, smoke containment system, and web handling system (if not integrated into an existing press or finishing line). Camera-based vision systems may be needed for critical registration requirements. All in all, converters considering this technology should expect an investment to the tune of $180,000-$300,000—similar to the costs involved in a major prepress upgrade, notes John Dillon, VP/sales and marketing for LasX.

Older systems used a fixed laser with a moving x-y table underneath; some potential customers shied away from this technology because of speed limitations, relates Chris Chow, VP/converting at Laser Machining. Newer "galvo" systems (which employ scanning galvanometers) use steered beams and rotating mirrors to help the laser move faster. Typical processing speeds reported range from 80 ips to 600 ips.

A roll-to-roll laser system can be step and repeat, running with an intermittent or indexing motion, or cut on the fly, continuously moving as the laser follows the programmed pattern. Material is through-cut by adjusting the cutting speed to allow the beam to fully penetrate the material. By applying different laser parameters, material can be kiss-cut to a liner, scored to a depth, or perforated.

Tracing parameters and benefits

Laser digital converting harbors a notable array of benefits. From a flexibility standpoint, any programmed shape can be processed; lasers can cut in any direction. Die shapes can be changed on the fly, without tooling, offering potential for complete personalization of a run of packages or labels. Accuracy, too, is a digital system strong point. Laser converting is said to routinely achieve 3 mil tolerances, and can even compensate for inaccuracies inherent in the printing and finishing process. "Materials may stretch," notes Chow, "and lasers can adjust to this. A die cannot."

The systems also score favorably in efficiency and productivity, allowing last-minute changes to be made without interrupting production. Simple and complex shapes can be produced at the same cost, in the same amount of time. "From a payback standpoint, end users have control over short- and medium-run product introductions without the need to build an extensive die infrastructure," Dillon points out. "They can more immediately respond to customers because there is no diemaking time required."

"Laser cutting eliminates all tools," confirms Dr. Jules Farkas, managing director of Wave Front Technologies, "not just rotary dies but also tools for perfing, hole punching, and cutting forms out of the web."

Aesthetic results, too, figure on the positive side. The laser's forceless cutting process does not typically damage materials, and pressure-sensitive label tests have shown better peel on laser kiss-cut labels than rotary diecut labels.

Scanning the field

The market for laser digital converting in packaging could be described as either wide open, or hidden behind closed doors. LasX's LaserSharp® module, which can be used for a range of converting applications, falls on the wide open side. To date, Dillon reports no systems have been sold into packaging applications. "The market is still on the threshold," he states.

Dillon has seen a lot of interest recently from digital press manufacturers who see digital laser converting as a possible solution to digital printing's diecutting challenges. Laser line speeds are comparable to digital press line speeds, and users could theoretically run ten different printing and finishing jobs without ever stopping the press, he notes.

Wave Front Technologies' Softdie™ digital laser conversion system, which is targeted specifically to the label converting market, claims compatibility with almost every existing label press; it can also be used for offline processing. Features include multiple laser operation and speeds to 600 ips.

"Digital laser converting is already installed in all packaging market segments," Wave Front's Farkas reveals. "Most of these installations are rather well-kept secrets, with the manufacturers of the systems often bound by non-disclosure agreements. However, although the technology is now available, the market itself is still in its infancy."

Introduced in January 2000, Laser Machining's AcuTear™ and AcuBreathe™ laser systems and equipment provide laser scoring and laser micro-perforating for flexible packaging. "Lasers can cut precisely without damaging multiple barrier layers," Chow explains. "The package retains hermetic properties because holes aren't being created."

Chow emphasizes laser technology accomplishes other very specific processes for flexible packages which diecutting cannot. "Very small holes to ensure respiration are not possible with rotary dies," he points out. "Rotary might not cut such a small hole cleanly, and may end up actually closing up the hole with residual material."

Further evolution

Suppliers continue to work to remove potential obstacles to a laser installation. Material compatibility issues are steadily tackled with substrate manufacturers, particularly in terms of the laser's ability to negotiate sharp corners, and to cut facestocks without damaging liners.

More specialized controllers, such as Laser Machining's Acu-Power® galvo controller, have been developed to automatically adjust to laser power levels typically required when tracing a complex pattern or a sharp corner. Suppliers also continue to pursue processing speeds that mirror conventional press speeds. Wave Front Technologies reports its SoftDie system has demonstrated speeds in the 100 fpm to 300 fpm range, depending on material and job complexity.

Will the laser eventually become the standard for diecutting? Farkas says yes. "In ten years time, traditional dies will have almost disappeared from the major converting companies. Everyone will be using laser systems," he estimates.

Chow maintains, for now, that lasers claim a very specific portion of finishing applications. "Laser digital converting is very precise, high-level technology, and there is a cost to that," he comments. "If you can achieve desired speed and accuracy with rotary, go rotary." Both technologies have their place, he adds, and both could work well together on the same manufacturing line.