It’s a Fine Line

Walking a tight rope is tricky business; one slip of the foot can cause a whole mess of problems. Plate mounting is much the same. It is an intricate part of the printing process, and requires much attention.

As market manager of paper, print, and film for tesa tape, Joe Prunier is familiar with converters’ plate-mounting nightmares. “I can give literally dozens of examples of when we have received calls from our customers (who say they are) having problems with edge-lift, bubbling, poor print, registration problems, adhesive delamination, and foam splitting,” he says. As a result of these drawbacks, materials are wasted and money is lost. It is critical to mount plates properly—the first time—to save valuable materials and dollars, and to prevent unwanted headaches.

“Improper mounting results in a slow makeready and
machine downtime as the plate is re-mounted,” says Mark Gibis, vice president of sales for Doyle Systems. “Also, re-mounting the plate increases the risk of accidental stretching.”

Doyle Systems offers a plate-mounting machine that holds the plate in place once it is in register to prevent stretching. “The operator can use the two adjusting wheels situated on the right and left hand side of the plate-bed to ‘swivel’ the plate bed for perfect registration,” Gibis explains. “Because the bar is still holding the plate precisely in position, the operator can then remove the backing on the tape and press the plate onto the cylinder. The holding bar prevents the plate from shifting while the operator tacks it down, achieving perfect registration every time.”

Many companies that supply plate-mounting tapes can also provide customers with a wealth of troubleshooting advice. “Make sure the plate surfaces are in 100 percent contact with the cylinder surfaces,” says Prunier. “Also, remember these are pressure-sensitive adhesives. That means putting pressure on the tape to ensure a correct bond is important. Using rubber rollers or soft squeegees to add more mounting pressure will help a lot.” In addition, using the correct adhesive combination for the plates and sleeves/cylinders goes a long way.

“Today, there are many different adhesive combinations customized for use with thick plates, thin plates, steel cylinders, and synthetic sleeves,” he explains. “It is extremely important to understand what type of equipment (plates) the tape was manufactured for and follow the procedures.” Working within the manufacturer’s recommended standard operating procedures for storage, handling, mounting, and demounting will also lessen the chance of error, says Prunier.

“In 99 percent of the cases, we have been able to resolve those problems just by re-educating the printers of the standard operating procedure of handling our tape,” he says. “We make the tape to do exactly what the printers want and need, and we know what they should do to maximize our plate-mounting tapes. All they have to do is follow our recommended best practices. pP

Tools of the Trade

The following products assist printers with the plate-mounting process.

Cushion-mount tapes

3M’s new Cushion-Mount Plus Tapes include the medium-soft combination 13 series and the medium combination 15 series. Both tape series are designed to bounce less on faster presses and print cleaner fine-type reverses and richer halftones. These 3M tapes, with Easy Mount Adhesive, feature microchannels that allow air to release to eliminate bubble problems from entrapped air, and remove cleanly from the print plate and the print cylinder.—3M, www.3m.com

Mounting and proofing machine

Anderson & Vreeland’s Mount-O-Matic 1000 DD is a mounting and proofing machine for medium- to wide-web flexo printing machines that offer a maximum width of 1,000 mm. The 1000 DD is suited with sleeves equipped with a pivot shaft and directly driven by a stepper motor.—Anderson & Vreeland, www.andersonvreeland.com

Firm adhesion with easy removal

The Eclipse Cushion Tape base features stable backing for tight register and ease in mounting and repositioning. This adhesive system (adopted from the aerospace industry) provides firm adhesion to various printing plate surfaces, cylinders, and sleeves. This formulation increases tack under pressure, but releases cleanly after use.—Edward Graphics, www.egs.com

Cushion mounting for flexo

R/bak Cushion Mounting Materials for film, label, and corrugated printing are open-cell urethanes that aim to improve registration, reduce dot gain, decrease plate deformation, improve ink transfer, and allow the use of finer screens for finer line work. R/bak materials reduce pressure and absorb shock for flexographic printing plates for longer plate and cushion life and higher print quality.—Rogers Corporation, www.rogerscorporation.com

Polyester platemount

Venture Tape offers a double-coated tape with a controlled gauge for mounting photopolymer letterpress and flexographic printing plates. The solvent-resistant adhesive system is designed to hold plates securely at high press speeds and elevated temperatures. It features a single liner and clean removability from print cylinders.—Venture Tape, www.venturetape.com