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Smarter folding

Feb 1, 2003 12:00 AM


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Short runs, faster-turnaround demands and a shrinking supply of skilled bindery professionals have focused printers' folder requirements squarely on quick setup, changeover and makeready. And manufacturers have been quick to respond with systems that provide automated fold setup; storage of previous jobs; adjustment of plates, roller gaps, alignment rails and other components — all controlled from a central machine interface. Despite these efficiencies, however, operating a floor-model folder still requires old-fashioned brain power.

AUTOMATION ON PARADE

Recent trade-show visitors have been introduced to automated folders from almost all of the major vendors. The ultimate goal — the seamless transition of jobs from prepress to the bindery — is becoming a reality as manufacturers equip their high-volume folder lines with CIP3/4 capabilities. Here's a look at some of the more common features. (For a more in-depth overview of floor-model automation, see “A new breed of floor-model folders,” January 2002, p. 30.)

Computer interfaces present a simplified, highly accessible means of setting up even the most complicated folding job. GBR Systems Corp. (Chester, CT), distributor of the Mathias Bäuerle folder line, offers an icon-based operator interface on its Multimaster CAS 52-B SetMATIC computer-controlled folder. Standard Finishing Systems (Andover, MA) provides a touchscreen for its new Horizon AFC-544AKT, which debuted at Graphics of the Americas this past January. Heidelberg (Kennesaw, GA) features the DCT 2000 controller on its Stahl TD series bucklefolders and KD series combination folders. And MBO America's (Westampton, NJ) Perfection line has the Navigator operating system, with optional touchscreen monitor.

Automated setup of standard folds is another popular feature on all of these machines. Heidelberg's DCT 2000, for example, has CompuFold software with a fold catalog of 81 pre-programmed patterns. Setting up a fold is just a matter of entering a sheet's width and length and choosing a pattern. Many of the systems will also store custom folds and previous jobs — Standard's AFC-544AKT, for example, holds specifications for up to 100 jobs. Users simply choose a standard fold pattern and input variations via the touchscreen. GBR's SetMatic has seven pre-programmed folds and room for 60 custom jobs, while MBO's Rapidset has 65 standard folds and can hold 250 additional impositions.

Although CIP3/4 bindery success stories rarely go beyond cutter setups, many new folders are being equipped with the capability. “It's something new and is being talked about and implemented in some environments, but is it widespread today? No,” says Bob Flinn, director of business development at Standard Finishing. “Do we anticipate it to be more widespread in the future? Absolutely.”

The exec predicts that within the next five years there will be significant integration of workflow between prepress, press and postpress. Current vendor solutions include MBO's Navigator with Data Manager digital integration software, which can interface to other vendors' systems for job management. At Graph Expo, MBO also announced that ScenicSoft's UpFront 2.0 will let users of MBO folders equipped with Navigator Rapidset directly export finishing information. Heidelberg's Compufold, part of the company's Prinect suite of modular products that focuses on standard workflow connectivity, accepts folder and slittershaft settings from prepress.

FINE TUNING REQUIRED

Automation isn't, however, the equivalent of cruise control in the bindery. There are some functions that require a skilled operator's touch; likewise, a pre-programmed imposition does not take all of the guesswork out of creating an accurate gatefold.

“If you're going to use an automated system, regardless of whose it is, fine adjustments are going to be required because paper is paper, and it's a different piece every time you handle it,” says Flinn. The exec explains that Standard does not offer automatic gap setting, for example, because paper varies so greatly by type and even lot. (He advises that operators set the gap based on a sample of the stock they'll be folding for a truer, more accurate fold.)

Flinn cites bulk, thickness, caliper, finish, grain direction, printing or imaging process, additives and varnishing techniques as a few of the variables that can make folding interesting. Folding against the paper's grain requires scoring to prevent cracking. The weight of stock can determine the speed of the folder: Both lightweight and extremely heavyweight stock require slower folding. (See “A new breed of floor-model folders” for scoring and creasing solutions from Rollem and Tech-ni-fold.)

Flinn notes that operators also need to consider stock weight and texture when setting up the feed table; because pile height has defied automation efforts, operators must determine, depending on stock thickness, how fast the table raises to keep it at optimal feeding height.

TRICKY FOLDS, STICKY STOCK

Complicated folds also require operator intervention. One of the most challenging applications is the gatefold. “The settings for gatefolds defy usual folder-setting convention, since they are quite different from the usual settings,” says Joe Niehueser, product manager for Heidelberg's Stahlfolder and mailing systems. Standard's Flinn adds that operators must fine-tune settings to ensure the panels fall correctly and to prevent overlapping or buckling on the outside fold panel.

Closed-gate — or double-gate — folds require a special foldplate to close the last flap so that it is tucked in properly. Mark Pellman, marketing manager at Baumfolder Corp. (Sidney, OH), explains that without the attachment, the crease for the panel will be created but the folder won't be able to tuck the final fold inside. In addition, the double gatefold must be set up one foldplate at a time.

Digital printing has introduced its own set of variables into the folding process. Shops that traditionally provided offset work but are moving into on-demand will have to adopt a new mindset about layout prior to folding. The 12-page signature common in digital print requires different pagination, and as a result, tweaked folding impositions. Exposure to high levels of heat during the toner-fusing process dries out stock and can make it brittle. Scoring is a good preventive measure; letting stock acclimate after imaging to the room's humidity level can also help, although this proves impractical in an on-demand environment.

Because toner sits on the surface of stock — rather than being absorbed like ink — ruboff can occur during the friction of folding. Flinn notes that this is more of a problem with continuous-feed folders, as page separation can be set adequately on a folder equipped with a high-pile feeder. Also, toner formulations are improving to make this problem a rare occurrence.

Perhaps the most challenging aspect of folding digitally printed stock is static. “You're generally going to have a much higher static charge coming off a digital print engine than from an offset press,” Flinn says. This is especially troublesome if you're utilizing a high-pile feeder. To counter this, many folder operators use an ionizing air-blast system to separate and neutralize the static-charged paper. The exec points out that most of these feeding issues are avoided when a folder is integrated inline with the digital print engine, primarily because sheets are fed into the folder one at a time.

TRAINING OPPORTUNITIES

How long does it take an operator to go from novice to expert?

“It will take about two years of constant exposure to folding to mold a folder operator,” opines Niehueser. “But a computer-guided program will put anybody on the same level of education and provides a common starting point, regardless of skill level and equipment used. Even an unskilled operator will be able to set the parameters and learn from there.”

David Trutzenbach, a folding guru who got his start as a bookbinding apprentice in London at the age of 15, teaches MBO's Folding School. He says folder operators are born and then molded — he estimates that it takes three to five years for their skills to reach the “experienced” stage.

MBO offers both basic and advanced courses at its Westampton headquarters and its Schiller Park, IL, location. Trutzenbach leads the three-day courses, which are free to MBO folder operators. “Folding 101” is for beginners, and teaches the fundamentals of folding paper and safely operating machinery and accessories. It includes setting up difficult paper types and solving problems hands-on. The advanced “Folding 102” targets more complex problems and emphasizes folder mechanics and electronics (see mboamerica.com for seminar dates).

Heidelberg's Print Media Academy hosts courses on its Stahlfolder line at the company's regional technology centers: the New York City, Atlanta, Los Angeles and Chicago areas, as well as Cranbury, NJ (see heidelbergusa.com for course dates and registration information).

Self-education on the job is important too. In fact, according to Trutzenbach, the worst mistake a folder operator can make is ignoring the learning opportunities afforded by a failed folding job. “A lot of operators try to pitch a jammed sheet — after removing it from the folder — into the waste bin. They do not look at it and try to see why the sheet was improperly registered or where the fault occurred,” he laments. “They adjust every nut, bolt and roller on the machine to try and fix a simple problem. This leads to bigger problems than they already have!”

FIND THE FOLDING CULPRIT

When a folded product disappoints a client, various departments may launch a round of the blame game. It's easy to point a finger at the last one to touch it — usually the bindery — but it's important to know that your first instinct isn't always the right one. Below are some common scenarios most often blamed on the bindery. You may be surprised at who the real culprit is.

Problem: Fold-in panel overcompensation

  • Usual suspect: bad trim or careless bindery

  • Real culprit: designer error or poor communication

Standard single-panel compensation is generally between 1/16 inch and ⅛ inch, although multiple layers of paper or heavy paper weight can raise the measurement. So, if the printed brochure delivers with a panel compensation greater than necessary, an overzealous trim job can certainly be the culprit, but oftentimes it's the designer asking the printer to compensate for folding rather than setting the compensations correctly in the file. This problem happens a lot with simple folds that no one likes to compensate for, like letter folds. It's easier to ask the printer to trim the third panel short than it is to set up the file with the third panel 3/32-inch short. It's smarter, however, to take control of the results by setting up the file correctly or specifying that the compensation should be no greater than ⅛ inch.

Problem: Brochure does not fold at crucial color breaks

  • Usual suspect: sloppy bindery work

  • Real culprit: designer error or prepress oversight

Paper is dimensional, and this fact must be taken into consideration when designing a folded piece. If one panel is to fold into another, then the fold-in panel must be slightly smaller. If panels aren't compensated correctly, the fold-in panel(s) will push against each other and the brochure will not lay flat — also known as “telescoping.” Graphic designers should be aware of this principle, and if they are unsure about proper compensation, they should ask the printer for a diagram. If the flawed file makes it to the printer, the problem should be caught in prepress. But, if all else fails, the bindery will be forced to compensate the panels during the folding process — which will be very noticeable if folds are supposed to be on crucial color breaks.

Problem: Cracking at folds

  • Usual suspect: bindery was careless with the brochure

  • Real culprit: bad advice or dry paper

Cracking is the separation of paper fibers when they've been stretched too far. It's ugly — especially through areas of heavy ink coverage. There are several possible reasons for cracking, such as low moisture in the paper and improper folder-nip settings, but the most common reason for cracking at the fold is the absence of scoring. Clients expect good production value, even on low-budget projects, and should be advised by the printer in situations where it would be appropriate to incur the extra expense of scoring for the benefit of production and aesthetics. This is especially true when folding across the grain of the paper, if areas of heavy ink coverage cross through the folds or if paper weight is greater than 80-lb. text.

Problem: Wrinkles in the corner joints of folds

  • Usual suspect: sloppy bindery work

  • Real culprit: stress or paper problem

Multiple right-angle folds can cause panels to get trapped under compression and wrinkle. And since no one is going to stop using multiple, sequential right-angle folds, it may take some creativity in the bindery to get around the problem. Something as simple as a poorly designed folding sequence can cause unnecessary stress to the paper during the folding process, and may force the bindery professional to re-think his or her machinery configuration. Slowing down the machinery can be a simple solution, as speed tremendously increases stress on the paper during the folding process. A change in paper can be helpful as well — recycled papers have shorter fibers, less strength and a greater probability of wrinkling. Paper weight can also be a contributing factor. If all else fails, a call to a specialty bindery may inspire an innovative solution.

Problem: Text or image trimmed off or too close to trimmed edge

  • Usual suspect: trimming error

  • Real culprit: designer or prepress department

Trimming errors do occasionally happen, but if the brochure measures the correct finished size, the folds are flat and square, and the compensations are correct, then the text or image was probably too close to the trim edge in the first place. To be safe, text and image should be at least ⅜-inch from the trim edge. This problem should have been identified in an earlier stage of the project, such as during laser proofs or on the blueline.

Problem: Final product too bulky or too flimsy

  • Usual suspect: paper problem

  • Real culprit: poor planning

It's common to make a quick paper choice based on a glance at a swatchbook or a verbal recommendation. The problem is that paper seems standard because of the weight system it is classified by, but surprisingly, different sheets at the same basis weight can actually caliper very differently. There are also distinct differences between U.S. and European sheets. So, an experience with one brand of paper at 80-lb. text may have been fine, but a blind spec of a different sheet at that same weight can be disappointing. To prevent surprises, request a paper dummy in the early stages of the job.

Trish Witkowski is creative director for a Baltimore-based marketing and communications firm. She is also president of Finishing Experts Group, Inc. (Reisterstown, MD) and author of “FOLD: The Professional's Guide to Folding,” available at expertsinfinishing.com.

COMMON FOLDING PROBLEMS

Despite advances in automation, folding can still be problematic for even the most experienced operators. Mark Pellman, marketing manager at folder manufacturer Baumfolder Corp. (Sidney, OH), provides the following common folding snafus and their remedies:

Scoring

Right-angle folding requires scoring, which creates a weakened line where the fold is to be performed in the folder. Failure to score will result in irregular folds. Some operators think that they have a problem with the right-angle folder when in fact the problem is created by not scoring the paper before it enters the right angle. A curved score can result if the pullout tires are not placed close to the scoring blade and at each edge of the sheet.

Perforating

The selection of the proper blade is important. Large-tooth blades allow air to escape when folding signatures for books. Finer-tooth blades are normally for tear-off items. A perforator blade must be placed against a lower anvil to make a clean cut. Failure to use a stripper mounted above will result in the paper wrapping around the slittershaft. A curved perforation can result if the pullout tires are not placed closed to the perforator blade and at each edge of the sheet.

Slitting

Removing an edge or center trim of paper requires that a stripper be mounted to direct the waste to the floor. If the slitting blade and stripper are not mounted correctly, the waste will travel with the finished product onto the delivery stacker. Crooked slitting will occur if the pullout tires are not placed correctly to hold the sheet straight.

Trapping air

Some folds require a double-parallel or letter fold in the first folder, and then right angle to a double-parallel or letter fold in the right-angle folder. This type of fold can trap air — to relieve this, make the fold in the first folder an accordion or “Z” fold.

Proper gap between sheets

Many paper jams are caused by not leaving the proper space or gap between sheets on the register table or crosscarrier. When folding less than half of the sheet length into the folder, a shorter gap can be used. A gap of one inch to two inches will accommodate most common letter and half folds that are folded short length into the fold plates. When folding longer than half of the sheet length, a longer gap is needed to allow the sheet in front to get out of the path of the sheet coming in from behind. When folding a letter fold going deep into the first plate, at least one panel length of the letter fold should be used for the gap.

Roller gap settings

The easiest concept to remember is that the tailing-edge thickness that passes through the fold roller is the paper thickness that is to be inserted in the gapset lever above (see baumfolder.com for more details and animated paper-path information). Too many thicknesses in a gap set will allow the paper to slip and lose drive in the folder. Too few can mark the paper from too much roller pressure.

Improper roller tension

For gap sets to work properly, the initial roller tension from fold roller to roller must be set and maintained as a common maintenance item. This is similar to periodic maintenance that you would perform on your car. Folding rollers will wear and the pressure will change. Inattention to this will result in poor folding quality. When roller tensions cannot be set, it is a sign that replacement fold rollers are needed. It is always best to go direct to the folder manufacturer for high-quality replacement parts and factory support.