A Simple Signature Perforating Tip for Better Saddle Stitching

Here’s a print finishing technique that saddle stitcher operators will love but folding machine operators might hate. This particular folding machine accessory is called a crimp perforator or crimp lock device. The purpose of the tool is to crimp two or more sheets of paper together so that certain panels or pages are held in place for subsequent operations. I have two examples for you.

The first example is one that stitcher operators will love because it prevents feeding problems with signatures that have a short inside panel, as shown in the photo at right. It requires a little more work on the folding machine but the net result is that it can save a huge amount of time. Or it can make it possible to produce a job your bindery might otherwise have to send out.

The problem with this type of signature on the folder is that the short panel can open up as it’s dropping on the chain. This can cause jams if the signature doesn’t seat correctly. Or the panel can open up all the way. Of course the stitcher’s feeder pocket has timing adjustments and air blast to help control this but there are limits. Depending on the paper and grain direction, the short panel is hard to control.

There are two ways to add the crimp perf to the signature. In the first method you do the short fold in the main parallel section. (Photo at right.) The crimp is added on the slitter shafts. Close the fold plate deflectors in the first right angle and do the final fold in the second (16 page) right angle. The result is shown in the photo below at right. An added advantage of running through both right angles is that you’ll flatten out the perfs.

So now you see why it’s a bit more work for the folder operator. Those who are resistant to change or have a not-my-job mentality will squawk. Instead of running a simple two-fold parallel job, you now have all these extra elements to contend with. But when you take a good big-picture look and understand that it improves profits and productivity, it’s a good thing.

The second way to do it (not shown) is to do both folds and the crimping in the main parallel section without using the right angles. Just be aware that when you apply a crimp perf, it takes some effort to get them to open. In this method, all three panels are securely locked together.

Thus, if you use this technique, you want to make sure the signature will open easily on your pocket feeder. In the first technique, only the short panel is locked.

Another caution: if you’re accustomed to using 1/8” head and foot trim on your stitched books, be aware that you have to have about ¼” trim to use a crimp perforator. As with all bindery work, careful advance planning is necessary.

With the MBO crimp perforator shown you can use also use two perf channels to create an even stronger perf, should it be necessary. The photo below shows one perf line being applied to each side. You can see the two channels on the female side. Simply add another perforator blade to the male for the additional perf.

You also might find that a single perf at the head of a signature is sufficient to prevent problems. Again, a little testing and advance planning goes a long way to getting the most out of your folding machine accessories.

If you do a lot of saddle stitching work, this tool will come in handy for those signatures in which a panel tends to pop open.

Next week we’ll show you the second example in which you can automatically do a roll fold with a loose insert. In it, the crimp lock tool is used in conjunction with the Technifold Multi Tool to create a “how’d they do that” print finishing piece.