In the Groove
Advances in electronic and laser technology and expanded cylinder choices push the dynamic progression of gravure engraving.
By Susan Friedman
Gravure engraving technology and service suppliers are carving out distinct grooves that can help package printers make more educated decisions about handling engraving themselves or engaging a trade shop.
Bob Balzan, VP sales/marketing at Max Daetwyler Corp., says printers who also engrave typically have two to 10 presses, 25-120 employees, and spend $300,000 to $500,000 for an engraving machine.
Engraving service providers contend that taking on the complexities of engraving in-house often results in costly mistakes, and can distract from the core business of package printing or converting. Marty Marino, GM at Southern Graphic Systems' Exton, PA, facility, relates that Southern has taken over several internal engraving operations recently due to cost, environment and personnel challenges. At Southern Exton, a production department completes file stripping and trapping, and then step-and-repeats and marks-placement duties are delegated to an operator who specializes in the mechanics of getting the image onto the cylinder. Engraving is done on Hell Klischograph engravers driven by an OKI front-end.
At CNW, Inc., Cincinnati, where six Ohio engravers are on-line, Production Manager Kerry Smith says the design department often ends up rebuilding "ready-to-engrave" files provided by end-users. "CNW is working with designers in an effort to obtain files that satisfy press and end-user needs," he relates. "Continuous education will be the key to keeping rework costs down."
There is little dissension among suppliers that filmless engraving has taken the upper hand. "Film is actually becoming more expensive than digital," comments Dick Chesnut, president of W. R. Chesnut Engineering. Digital's biggest financial burden remains transition costs—primarily for scanning of older jobs on film, he notes.
New equipment continues to push electronic engraving's consistency and quality forward. Ohio Electronic Engravers Director of Product Management, Dick Dunnington, reports several recent hardware introductions, including the High Output 130 engraving head that achieves cell depths of 130 microns; a head with 275-micron engraving capability coming in early 1999; and Ohio's trans-Cell engraving system, which improves linework through real-time processing of image data. Newer engraving function developments include Midtone Correction, which fine-tunes cells for changes in stylus wear; and Ink Volume Calculator for accurate ink usage predictions.
Suppliers offer much discussion, with varying degrees of enthusiasm, on laser engraving technology. Balzan says laser technology can achieve speeds of 35 kHz—17 times faster than electro-mechanical engraving—or 70 kHz in dual laser applications. The laser can be positioned to accomplish screens of 300 lines per centimeter and finer, while diamond cutting tool wear limits electro-mechanically engraved screens to 175 lines per inch.
Daetwyler's LASERSTAR, introduced three years ago, works without a gliding shoe, shooting high-powered laserbeams into a zinc cylinder layer and evaporating the material to create a cell. Balzan reports one Daetwyler laser installation in the United States, and expects five worldwide by year's end. A basic installation, including peripheral plating and finishing equipment, costs $2.5 million to $3 million.
"The laser is being touted as the next savior for gravure because of its engraving speed," reflects Dunnington. "In truth, on an eight-color job one laser would be up against two or three electromechanical engravers. The difference in turnaround time for the total job is two to three hours, which may be lost during the longer zinc plating process. The capital and operating costs simply do not justify the small benefit a laser offers today."
Smith believes laser engraving needs "to prove itself" by addressing environmental issues related to the zinc ablation process.
In response, Balzan contends Daetwyler's present zinc plating process takes a few minutes less than standard plating, and says zinc harbors the same environmental issues as copper.
Turning up cylinder options
Advances in cylinder design and production have streamlined steel base cylinder manufacturing, and created several user-friendly material alternatives.
On the steel cylinder front, Marino says finishing machines can now cut and polish cylinders in one pass, while ultrasonic copper plating can plate the cylinder to size, eliminating the grinding step.
Alternative cylinder considerations include uncoated plastic cylinders that can be directly engraved, which Marino says work best in narrow-web, because deflection hurts wide-web jobs. Steel cylinders with expanding air shafts are another possibility. These can be copper-plated, are lighter and slightly less expensive than steel base cylinders. They won't deflect like plastic, and don't cause injuries linked with nickel sleeves, he adds.
Further developments and analyses led by W. R. Chesnut, Daetwyler and Stork cluster around sleeve technology. "The use of sleeves in the rotogravure industry is limited in the United States, and still more experimental than a fully accepted commercial product," comments David Share, Stork Rotaform. He believes nickel's dimensional precision and surface finish makes it the gravure sleeve material of choice. It can be copper-plated and conventionally engraved if supported on a stable, accurate mandrel.
Marino points out nickel sleeves' shipping expediency: they travel easily via FedEx. The one sleeve caveat he highlights is finding the correct mandrel fit within gravure's "infinite" size range.
W. R. Chesnut will soon release a nickel sleeve with a thin plastic coating for electronic engraving without chemicals or plating. Sleeves require minor adjustments on-press, such as new doctor blade materials, and need a base specially prepared for sleeves, both of which represent one-time costs, says President Dick Chesnut. Sleeves' biggest advantage is the elimination of repeated base purchases, he emphasizes.
Chesnut believes polymeric sleeves will make it feasible for the small printer to engrave in-house—a trend he feels is opposite to what's happening in flexo, where high capital costs of quality digital platemaking are driving more work toward tradeshops.
Closing gravure gaps
Alongside gravure's heady digital leadership are areas where a little more homework is required. "Gravure has lent itself to becoming digital," states Marino. "Gravure presses need to catch up with the revolution happening in flexo with robotics, chambered doctor blades and laser-engraved anilox rolls."
Dunnington cites need for improvement in the job planning process, where production parameters are sometimes entered manually many times over, and the approval process, which is burdened partly by the industry's reluctance to accept digital proofs.
"Color accuracy and fidelity of reproduction still guarantees that for long runs, gravure cannot be matched," sums up Share. "But as shorter runs become more in demand, quality alone will not take care of lost business. Speed and cost efficiencies are the only way gravure will recapture and increase its market share."
