785.271.5816 | info@fsea.com

Question and Answer

Working with Pocket Folder Challenges on a Folder/Gluer

by Staff

August-September, 2004
From a trade finishing standpoint, there is not a more popular product that is constantly on a folder/gluer machine than a pocket folder. Of course, pocket or presentation folder is a very general term for what can be a variety of sizes and types. Folders can have one or two pockets, glued or unglued pockets, reinforced edges, special die cut covers, etc. The list goes on and on. InsideFinishing called upon a few experts in the field of folding/gluing pocket folders to discuss some of the more common challenges operators face in today’s world.

1. What challenges does the operator face when working with reinforced edges on a pocket folder?
The first item to consider when working with reinforced edges is that they are properly scored before entering the folding/gluing machine. If there is a weak score on the edges, the operator will fight the job all the way through. When working with reinforced edges, it is like working with a narrow tab that is long in length. With this narrow long tab, the operator must contend with the “memory” of the score. Even with a proper score, this can still be a challenge. The best solution is to make sure and use a hot melt glue verses a cold glue on folders with reinforced edges. The hot glue will provide an immediate bond, diminishing the possibility of the edges opening up. This is especially important if there is a final fold on the folders as opposed to the folder being delivered flat.

2. What challenges are most common with different types of paper stocks?
Grain direction is the number one consideration when working with a particular stock. Stocks with very distinct grains can be difficult to fold and glue. This is especially the case if the pocket folder is being folded and glued against the grain. Although recycled stocks tend to have less grain (inconsistent in different directions), all paper has grain direction. For this reason, it is important to be aware of grain direction and the end product when die cutting, foil stamping and/or printing. It is much easier to fold with the grain. Of course, there are folders where a horizontal and a vertical pocket are incorporated into one folder. This does create a situation where one fold is going to be more difficult than the other. In this case, it is recommended to fold and glue the pocket that is against the grain last.

3. What options are available when working with difficult coatings?
The other challenge relating to paper stock is when a pocket folder comes in with a difficult coating to fold and glue. This is when communication between the finisher and printer is key. The best answer is to keep the glue flap areas free of printing or coating. This will help eliminate any potential problems. However, this is not what always happens in the real world. One suggestion is to make sure and have the capabilities to utilize hot melt glue. Hot melt glues, of which there are many different types, can many times work quite well on certain aqueous coatings and varnishes. An experienced glue supplier is aware of the problems finishers face with coatings and should be able to match the appropriate glue with the corresponding coating. There are also glue systems that include a solvent that can cut through certain coatings. This can be a potential option if a folder comes in with a coating that just will not accept glue.

Another trick to potentially deal with difficult-to-glue coatings, is the utilize glue assists on the area of the folder that glues during the die cutting process. Glue assists are a special set of knives or steel rule that are included with the cutting die that will penetrate (not perforate) the coating. When the surface of the coating has been broken with the glue assists, glue will be able to pass through the coating into the fibers of the paper stock. Lastly, there are folder/gluers on the market that include a grinding wheel that can be mounted on the machine to grind the coating surface away where the glue is applied. This can be an excellent option, but not all machines have this capability.

4. How can wrinkling or “crows feet” be prevented and what stocks are prone to it?
Crows feet is the wrinkling or cracking of the paper at the folded edge. Heavier cover stocks have a tendency to crows feet over lighter stocks. Many of the recycled stocks today are subject to cracking and crows feet as well. Making sure the folder is running through the folder/gluer with the grain is great place to start to help decrease wrinkles.

Many folder/gluers on the market today have features to prevent this problem by having the folder go straight through the machine verses going around rollers. This can be accomplished by using a vertical fold plate attachment. If the stock does have to pass over a buckle fold section, traveling around the circumference of the fold rollers, wrinkling can occur. However, adjustments in the design and making sure that the folder is properly scored can minimize the potential of the wrinkles and crows feet.

5. What challenges/solutions are involved with CD-sized pockets on a pocket folder?
As business today is moving away from VCR formats to CD media, the integration of CD wallets on pockets folders is increasing on a daily basis. When working with a folder that includes a CD wallet, there must be special consideration to the different requirements for selective tab turning and two-directional folds that may require right-angle capabilities. This is especially important for the completion of this style of layout in one pass on the machine. Adding a CD wallet is not especially difficult, but pre-planning will help make the job much easier. n

InsideFinishing would like to thank Ron Brajkovich of Brandtjen & Kluge, Inc. (800-826-7320) and Bill LeFevre “The Folder Gluer Man” (800-353-1264) for their assistance with this article.