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Improving the cutting process

Feb 1, 2002 12:00 AM


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Cutting is the heart and soul of most printers' production process — paper often must be cut before, as well as after, it goes through the press. And printers are constantly cutting stocks to different sizes.

But it's labor-intensive — depending on the application, the paper may need to be lifted, jogged, aerated, turned and repeatedly moved. Material-handling and cutter upgrades reportedly can yield significant labor savings while increasing throughput by as much as 200 percent. (See “Cutters revisited,” January 2001, p. 44.)

Cutter workflow automation prevents bindery bottlenecks while reducing the potential for operator strain and repetitive-motion injuries. Automation also ensures consistency in the cutting process — an important benefit, considering paper typically represents 35 percent of a job's total printing cost.

“By the time paper moves to the cutter, money and time have already been invested in the job,” observes Rob Kuehl, marketing director of Polar cutting systems at Heidelberg USA (Kennesaw, GA). “A mistake at the cutter can be very expensive.”

More printers are recognizing the benefits of a workflow system. Brett Stow, managing director of Perfecta USA (Indianapolis), says many of its Print 01 customers evaluated handling systems. “They didn't just want to buy a cutter,” he observes. “They wanted the cutter, lifter, joggers, loaders and unloaders. The trend seems to be more handling and automation.”

Automation options range from simple pallet jacks to sophisticated high-speed systems. Candidates for high-end equipment include label and other specialty printers, printers that use cutters for more than one shift a day and operations that use a 45-inch or larger machine.

PALLET JACKS, SKIDLIFTS AND JOGGERS

“As the day progresses, operator inefficiency, caused by constant bending and lifting, increases,” notes Jeff Marr, vice president of sales at Colter & Peterson (Paterson, NJ).

Fortunately, there are low-cost solutions for moving paper to the cutter and keeping lifts at a constant level. An operator can use a standard pallet jack, adjusting the height of the lift while he or she works. Unfortunately, pallet jacks are like pens — someone's always walking off with them.

“Jacks have a way of disappearing to some other area of the plant,” says Marr. “They're constantly being ‘borrowed.’”

An automatic mobile skidlift that can be moved and locked into place alongside the cutter is another option, and one that won't walk away. The lift size matches press size (28 × 40 inches or 48 × 48 inches). High-end skidlifts offer automatic leveling — a built-in photo eye adjusts the lift so that it remains at a constant level as the paper lifts are unloaded and worked. The operator now can work at a comfortable and constant height. Automatic mobile skidlifts range in price from $500 to $15,000.

Jogging, often done by an operator manually pushing the paper against the backgauge, can also be automated. Popular features include pedal adjustments to adjust the jog angle, as well as provisions for jogging to the left or right. More expensive automatic joggers have an air table for moving the jogged lift onto the cutter table.

Automatän (Plover, WI) offers jogger/aerators that automatically invert pallet loads of sheets, aerate and align the loads, clean sheets and let the user combine multitier loads onto one pallet or break apart single loads onto multiple skids.

You can also get a paper jogger with back clamps and squeeze rollers. As each lift finishes the jogging process, clamps hold the back of the lift and a pneumatically driven squeeze-roller assembly removes the air from the paper. This process enables the operator to build a dense, perfectly jogged paper lift. Perfecta offers a jogger with an adjustable air-expulsion roller, so it always positions in the center, regardless of sheet size. The SA110A can handle a 30 × 40-inch sheet.

PILE TURNERS

Adding a mobile skidlift, and a jogger with squeeze rollers, improves productivity by as much as 50 percent, according to John Neilsen, Western regional manager for LDR International, the Portland, OR-based importer of Itoh cutting systems and Kudo automatic mobile skidlifts, joggers, pile turners and removal systems. (This division was not part of the Pitman Co. [Totowa, NJ] acquisition.) Neilsen explains that the jogger and clamps eliminate the need to manually fan stock, while the squeeze rollers accommodate larger and denser lifts. Since the air has been removed, the lifts are more compact — they easily fit into the cutter-blade opening.

Some people confuse joggers with pile turners. If you don't have a perfecting press, paper lifts and piles may need to be turned prior to cutting. Turning a small lift is easy, but turning a skid full of paper is another story.

Baumann Maschinenbau (Solms, Germany), a long-term partner of MAN Roland (Westmont, IL), recently released the BSW 3 Mobile, a mobile pile turner with a 2,200-lb. carrying capacity and a maximum fork opening of 52.4 inches. The company also offers stainless-steel and Formica airflow tables for any machine, in virtually any size.

To clean the sheets, some pile-turner systems offer paper-sheet aeration. Some may also feature paper clamps or grippers, joggers and squeeze rollers. Static removal using a de-ionization “air blow” is another option.

MOVING FINISHED WORK TO A SKID

Moving finished work from a cutter to a skid can be a two-person operation — unless you opt for automation. On a high-end system, such as Heidelberg's Transomat and MAN Roland's Cut-tec 137, an operator simply pushes a button after cutting a lift. The lift is then clamped and moved automatically along an air table on the skid. While this is happening, the operator works the next lift through the cutter — there's no need to stop and move finished work.

With the Transomat, the operator pushes cut lifts onto an air table linked to a Transomat table, where the lifts automatically accumulate until they are transferred to a pallet as a finished pallet layer. Automatic banders are optional.

At Print 01, MAN Roland displayed a Cut-tec 137 with ASE automatic waste disposal, jogger, gripper transport system and an unloader.

A combined jogging and material-movement system can push the price of a large-format cutter into the $200,000 to $1 million range. Heidelberg's Kuehl, however, maintains that even the high-cost options can have an ROI of as little as six months because of the ability to accommodate a dramatic increase of work.

The CIP3/4 job definition language standard is paving the way toward total postpress automation. CIP-compliant cutters enable imposition and trim specifications to be sent directly to the cutter control system, provided the user has a robust CIP implementation from prepress onward. Since paper is subject to many variables, such as humidity, inks and sheet-weight variance, the cutting process can't be completely automated — some minor adjustments may be necessary. Heidelberg's CompuCut software for its Polar cutter offers automatic compensation of the gripper and guide cuts.

Even if a printer's cutting requirements don't stray beyond cutting 11 × 17-inch sheets into 8.5 × 11-inch sheets, minor changes can yield significant labor and process improvements. Smaller to medium-sized printers should evaluate stacklifts and integrated jogging systems. High-volume plants may benefit from a wide range of partially or fully automated paper-handling systems directly integrated into the cutter.

Cutters: Take a look at automation

A paper cutter has four basic components: guillotine, table, clamps and backgauge. The automated backgauge is probably the most significant improvement in recent years.

The operator sets up a cutter equipped with an automated backgauge from a control panel. After the guillotine completes a cut, the backgauge repositions itself for the next programmed cut.

Since the backgauge must move quickly and accurately, frequency-controlled drives and servo motors are often used for high-speed cutters. Automatic tilting and swiveling of the backgauge are also available.

Most new cutters are equipped with automated backgauges; older models can be retrofitted. Graphic Machinery & Systems (GMS) (San Rafael, CA) offers the microcut+, which includes networking capability, and the microcut jr., for cutters 37 inches and smaller. Global Systems (Dallas) also retrofits cutters.

Some cutters offer PC-based programs that help the user identify the most efficient way to cut a job — these parameters can then be stored for repeat work. The software also helps standardize and optimize the workflow across work shifts and among different operators.

Automatic trim removal is another cutter option. The cutter table opens to let the trim-out fall into a waste receptacle emptied by a vacuum. For label printers, where the lift may be “stepped” 70 times or more, automatic removal is a lifesaver.

Scales for weighing paper lifts are now built-in. Accurate lift weighing allows the operator to produce lifts with identical sheet counts as another quality-control measure.

Automatic rear-loading is another improvement. Working at the rear of a cutter, a bindery helper jogs lifts and then loads them into a rear-mounted air table. When the helper pushes a button, a gripper mechanism takes the lift and pulls it into the guillotine. This system allows a continuous and logical workflow, from rear-to-front. And, the cutter operator never has to stop to load the machine.

More cutter information

Colter & Peterson (Paterson, NJ) recently introduced the Maxima PLUS cutter for cutting 6.5-inch stacks of large-format materials. The cutter is offered in four sizes: 78 inches, 102 inches, 126 inches and 149 inches. It includes a GMS microcut+ computer-controlled backgauge, variable clamp-pressure regulation to accommodate different stocks, and more. Colter & Peterson also distributes Knorr paper handling equipment, including air tables, stacklifts, joggers, automatic loaders and unloaders, as well as Rachner pile-turners.

For more information on cutters and related products, visit our article archive at www.americanprinter.com. “Applying ergonomics in postpress operations,” October 2001, p. 28, offers tips for keeping employees safe and productive. “Cutters revisited,” January 2001, p. 44, features the latest from Adast, Challenge Machinery, Colter & Peterson, Dexter-Lawson, GMS, Heidelberg, MAN Roland, Polly, Standard Duplicating Machines and Vijuk.