The Truth Unfolds: Specialty Folding is More than Meets the Eye
by Kevin Rickard, president
Challenging fold angles, unusual paper stocks, large production runs: when it comes to specialty folding projects, skilled bindery professionals are able to accomplish extraordinary feats. Perhaps the most impressive feat is how professional binders are able to create complex folds that are visually stunning while appearing deceptively simple to produce.
Sometimes specialty folding is simply the ability to work with thick, thin or unusual paper stock. Some might ask, “Should a company’s ability to reduce or eliminate wrinkling qualify as specialty folding? What about holding brittle paper together as it travels though fold rollers and designing fold sequences that travel through machinery with the least amount of stress?” To this, specialty binders say, “Yes.” These capabilities solve customers’ difficult problems and are examples of specialty folding.
Specialty folding experts need to know what pieces of equipment are suitable for which jobs. For example, buckle folders don’t do well with stock 12pts or thicker, but plow and knife folders do. Knowing which resources to use prevents a lot of potential snags from becoming full-blown production problems. Some types of unusual miniature (at least one panel shorter than two inches) and oversized (large format) work qualifies as specialty folding, as does the inline application of EZ-release, permanent or removable glue.
Should a company’s ability to accept exceptionally large jobs qualify as specialty folding? As long as the work isn’t of commodity status, yes. Companies that claim to be specialty producers should be able to turnaround large jobs fast – and have redundant (multiple) machines allowing them to do this.
Let’s turn our attention to “tricky” folds. Unfortunately, there are few universal rules about what’s possible in the interesting world of tricky folds. Projects with lots of panels, folds at unusual angles, diagonal folds, unusual diecut shapes and no obvious side guides are sometimes possible and sometimes not. Some printing sales representatives run and hide when asked to bid on work involving tricky folds. Rather than passing on these types of projects, and opening doors for your competitors, you owe it to yourself to seek expert advice. Printing sales representatives that figure out how to produce unusual projects are more valuable than those that prematurely say, “No.” Here is a short list of some “how did they do that?” folds that are realistic and image enhancing:
- Iron cross folding
- Pop-up folding
- Multi-directional diecut folding
- Paper-doll style folding
- “Swinger” folding
- Narrow gap, no gap and wide gap gate folding
- No apparent side guide folding (ovals, circles, etc)
- Miniature folding with panels as short as 7/16"
- “Layflat” miniature folding (with or without using glue)
- Folding sheets as large as 80" long
Specialty folding companies should offer troubleshooting and design advice. To continue pulling rabbits out of their hats, some companies have staff machinists and engineers that design and customize bindery equipment. If your trade partner has a creative eye and a lot of real world experience, “how did they do that?” type folding projects are both possible and profitable.
Running gatefolds multiple-up is fraught with danger. To avoid gatefold “pullout” (an unintended fold located approximately 1/8" away from the intended fold), fold rollers should be loosely set. Although one-up work isn’t affected by running gatefold projects with loose fold rollers, multiple-up work certainly is. Since operators can’t get solid grips on gatefolds as they travel through the slitter shaft, slits are usually crooked, ragged or both. Since two-up formats don’t yield much more product than one-up production, designing multiple-up gatefolds projects rarely makes sense.
Gatefolds may have short gaps (less than ¼" total gap), no gaps and wide gaps (more than 2" gap). Since most commercial gate folding plates don’t handle these types of projects well, make sure your bindery has the necessary specialty machinery for your job.
Folding speed and paper stress
The immutable laws of physics apply to the field of specialty folding. Buckle folding machines apply different amounts of stress to the front and back ends of sheets as they travel through fold rollers and into fold plates. Every fold has two sides – one heading into the plate and the other being pushed from the back by fold rollers. The side of the fold that’s being pushed forms a “buckle” when the front end of the sheet hits the stop at the backend of the plate. As the sheet buckles, tremendous stress occurs in the paper on one side of the fold but not the other. The side being pushed by the fold rollers gets a severe bend. Fracturing of the paper surface or fibers is likely to occur if the stock is over 10 pts.
Folding speed stresses paper at a geometric rate of progression. For example, if the stress on a sheet is “5” when the speed is “5” (these numbers are only meant to be relative), doubling the speed to “10” means the stress jumps from “5” to “25” (instead of the linear “10”). In this case, doubling production speed translates to a five-fold increase in stress, perhaps enough to ruin a project. Many jobs that appear to be improperly setup are simply being run too fast. To think of it another way, assume you’re in a car crossing a railroad track with six-inch-high rails. If you cross the rails at three miles an hour, your tire raises up over the rail and down the other side with on a small bump. However, at five miles an hour the wheel feels like it’s coming through the fender as the shock absorbers top out from the explosive force of the tire springing off the rail.
If not planned well, paper stress created during right angle folding can be a huge problem. The structure of paper is such that it is stronger under tension than under compression. When poorly designed folding sequences cause two panels to “fight,” the top one under tension always wins and the bottom one under compression always wrinkles. If a panel is “trapped” during right angle folding, wrinkling will result.
Every week, I receive phone calls from all over the country wanting our company to rescue jobs from unsightly cracking programs. In general, cracking usually occurs on the first fold. Why? As the buckle starts in the right angle section, the first fold bends around a very tight corner, greatly stressing the first fold. Unless preventative measures are undertaken, the result is poor quality.
For example, a customer contacted Rickard about a wrinkling problem they were experiencing while folding a 16-panel poster. Unbeknownst to them, the folding sequences they attempted doomed them to failure. First, they tried four sequential right angle folds, but as they soon discovered, this produced wrinkled paper (i.e., tension vs. compression). Next, they tried a two-parallel, two-right angle folding sequence and again failed. Finally, they called Rickard, which suggested a folding sequence that allows the outside and the inside panels of the piece to flex during the folding process. This simple solution solved the customer’s wrinkling problem.
Speed vs. quality
The fastest way to do something rarely results in the best quality. If a client has endured the expense of putting a beautiful six-color job on a 100lb, #1 enamel sheet, it’s a good bet that ragged or crooked edges won’t be tolerated. On the other hand, if a job is printed on groundwood stock, time- and cost-saving suggestions are valued, if not expected.
Specialty folding also means knowing when to employ which manufacturing processes. If product quality is essential on a right angle folding project, the job plan should allow for one-up bindery production. While split-side guides certainly permit faster production speeds, they cause out-of-balance roller tension and result in poor quality.
Feeding, delivery and downstream considerations
One of the trickiest things about folding diecut products is getting them to feed cleanly. When a diecut sheet is fed out of a feeding unit, its edges and corners may catch on a sheet below it. Feeding considerations should be carefully thought out during the planning stage because these types of errors happen a lot.
Similarly, getting product successfully delivered out of a machine and properly packed is important, especially when automated operations are required downstream. For example, pharmaceutical manufacturers need miniature folded paper products to be automatically inserted into boxes, bottles and other containers. This usually requires folded work to lie flat and be neatly packed. Even if a bindery’s miniature folding is produced on budget and looks beautiful, it’s still a failure if it jams up downstream pharmaceutical inserting machinery. In short, specialty binderies should look beyond their own processes and consider how their work impacts other operations, either before or after them in the manufacturing chain.
Clearly, specialty folding is much more than tricky folds. It’s participating in the design stage, choosing the right processes and equipment for each job, having large-volume capacity and offering creative solutions to formidable challenges. The bottom line? Put your knowledge of specialty folding in your briefcase and use it to win more printing business.