SPARE CHANGEOVER (Will personnel concerns limit quick-changeo

(Will personnel concerns limit quick-changeo

by Jessica Millward, Associate Editor

IF TIME TRULY is money, interruptions in production translate into significant economic sag for package printers. The industry has never been more aware of this fact, with the rise of short runs and their requisite changeovers. Advanced sleeve systems whittle away at downtime between jobs, but limited training/personnel resources anchor printers to the changeover times of yesterday's equipment.

The demand for profitable shorter runs cultivated many of the wide-web flexo press design trends so popular today: servo drives, sleeve systems, and automated set-up among them. Fischer & Krecke (F&K) VP/Sales Manager Kurt Flathmann points out the complementary nature of these technology advances, stating they can be used in combination to reduce changeover times "by more than the sums of the individual timesavings."

Sleeve evolution has especially influenced changeover capacity of wide-web flexo presses, though the quest for easier-to-handle sleeves is sometimes at odds with improved press performance. Suppliers have created bridge sleeves to lighten the load of the system, but their usage introduces new tolerance issues. "A mandrel, bridge mandrel, and sleeve combination can have no better than 0.0025˝ to 0.004˝ tolerance when new," attests Joe Tremper, sales manager, Windmoeller & Hoelscher (W&H) Corp.

Questions about the efficacy of sleeve systems also surface in regards to extremely wide-web presses. Tremper explains, "If sleeves become so cumbersome that a sleeve-handling robot is required … then the true advantage of the sleeve press … has been lost."

On the standard wide-web unit the sleeve system's mettle has been proven repeatedly, so manufacturers have focused much of their development efforts on that press aspect. F&K premiered an improved sleeve system on its Flexpress 16 S, while the new sleeve presentation system on PCMC's Infiniti press was also designed to cut changeover time and reduce sleeve damage and operator injury. W&H has introduced an automatic sleeve extracting system, through which pneumatic collars break bonds formed between mandrels and sleeves.

Other areas of enhanced changeover performance include more efficient wash-up systems and expanded computerized set-up capacity. BHS Printing Machinery Corp.'s Promet Print Management System, for instance, keeps several thousand orders in memory and automatically resets the press for relevant data.

On the clock

Though the prep time of any job is dependent on a multitude of specifics, including number of colors, number of aniloxes, type of consumables, and if the job has been run before, suppliers are well-armed with average changeover numbers for their equipment. For BHS machines, President Dieter Langendorf predicts maximum changeover times of eight to ten minutes per color, less with a self-cleaning chambered doctor blades.

F&K's Flathmann estimates typical eight-color job changes from production to production last between 35 minutes and one hour, depending on variables.

Comexi America Sales Manager Rick Ruenzel concurs an eight-color, 50˝, gearless CI press with a dedicated sleeve system is capable of a complete changeover in less than ten minutes per deck. He is quick to add that figure can be influenced by issues other than the press itself. Color matching, he says, "remains one of the key factors in press downtime."

PCMC has paid particular attention to changeover technology in the last decade, according to Global Business Development Manager Tom Jacques. The company's eXsys three-robot system, available on eXell presses, enables changeover of 11 color decks within 15 minutes through its machine-based functionality, eliminating dependence on the operator. The Infiniti and Avanti gearless presses clock in at 30-35 minute changeovers.

Using the updated TURBOCLEAN® wash-up system, Tremper says operators can changeover the 10-color W&H NOVOFLEX® in 27 minutes, while the eight-color model requires just 25 minutes.

Labor lag

"The ultimate idea," Jacques maintains, "is to have zero downtime by coupling two CI printing sections together, such that one eight-color press section can be running while the other eight-color section is being set-up." Capital cost for the press would be covered by money saved in production, Jacques continues.

Suppliers agree there exists a sizable gap in changeover potential and performance. Flathmann is convinced companies are generally not as concerned with changeover time capability as they could be. These companies reach an improved level of time savings, he says, but don't pursue the improvement level possible. Flathmann wonders: "If half-hour changeover times are possible and easily demonstrable, why are half-hour-per-color changeovers the standard of the industry?"

The answer, Tremper agrees, lies in the state of operator and maintenance training. He believes to capitalize fully on changeover capability, press operation must become even simpler to address "the labor turnover typical of our industry." Tremper adds presses also would benefit from becoming less dependent on proper upkeep, as minimum maintenance is a reality of today's business.