Here is a great little innovation on one of our web presses that really helps eliminate folder problems. First let's orientate ourselves with the above picture. If you are at the folder of an offset web printing press, you would be looking at the bottom of the former board. What I want you to look at is the device that is riding against the folded edge just as it goes down and leaves the former. Take another look at the picture below.
This is a great little innovation by Manroland. I would be curious to know if other press manufacturers like Goss or Muller Martini have something similar, but for now I have only seen this on Manroland web presses. Notice the bolt on the left of it. You can manually adjust the pressure of this ski against the web as needed. A simple feature, easy to imitate.
What It Does
The idler rollers at the base of the former board are used to even the tension and guide the web coming down the former board. However quite often what results are "cracks" in the folded edge as it comes down the former board. The stress of the air blowing on the web underneath the former board as well as the folding action as it leaves creates a lot of stress on that folded edge. This small "ski" absorbs most of that stress and helps is stabilize before going down to the nips below. This problem is controlled on most presses by adjusting the idler rollers just below the former, but this little device gives opens the operating window significantly. A handy little tool for troubleshooting web press folder problems.
Here is a closer look at what that "ski" looks like.
It's simply plastic and is the same as the ones used for Manroland's magnetic brakes used on the quarter folder.
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