Chill Roll Pinning Takes Scrap to the Mat

November 1999

multipage

by Susan Friedman

Can the experience of a 30-year-old, 185-employee, short-run heat-set litho publication printer hold static control lessons for package printers? Quite likely.

For United Litho, the stage for a static solution was set when a move from Falls Church, VA, to a new 70,000 sq. ft. building in Ashburn, VA, in March 1997 coincided with the purchase of two new Heidelberg/Harris M130 offset presses.

"The M130 was a brand new design in 1997," recalls Press and Finishing Manager Tom Naquin. He estimates United Litho bought the seventh or eighth press off the production line, and start-up proved to be a bit bumpy. "The press operators and the presses weren't yet in sync," Naquin remembers.

A particularly persistent problem was mastering control of the 35" web once it passed the chill rolls and was slit into two 17 1/2" ribbons. The ribbons, which were then married in the folder, tended to float and cause misfolded signatures. "We were at the mercy of a press operator paying attention and reacting quickly," Naquin relates.

While seeking out solutions with visits to other printers who had recently installed M130s, Naquin hit pay dirt when he saw static charge chill roll pinning in action at NY-based Wilcox Printing.

Universal advantages of such electrostatic bonding systems include positive control of the web at the chill roll, reduced smearing in offset printing, and reduced waste.

Two and a half years later, United Litho's $10,000 investment in three electrostatic bonding systems from SIMCO (one on a 5-unit M130, and two on a double-web 8-unit M130) has reduced its paper consumption—typically 1 million to 1.2 million lbs. per month—by 1 percent to 1.5 percent, Naquin estimates. Each SIMCO system consists of a charge bar mounted right across the chill roll and a variable voltage power supply. After a bit of experimentation, press operators have established optimum voltages to hold the ribbons in place during folding (50 percent to 75 percent of charge) and sheeting (25 percent to 50 percent of charge) operations, and simply dial the voltage up or down accordingly. Operators' focus can now shift back to the quality of the printed product, Naquin sums up.

United Litho's only problem now may be too much of a good static thing. "The system controls the ribbons so well, it controls the sheets right through the bindery," Naquin explains. With the advent of cooler weather, static charges stay more stubbornly on the sheets, making it difficult to open signatures for binding.

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