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Web Press Troubleshooting Guide - Folder - Crooked First Fold

Description:  The first fold describes the fold that takes place immediately upon leaving the cylinder with pins and cutting blocks and transferring by means of a tucker blade to the second cylinder.  The "jaw cylinder" as it is referred to as, then grips the signature between the moveable and stationary jaw and forms the first fold.  (technically the first fold happens over the former, but not all folds take place this way - eg: half webs)


Problem:  Cross-perf not timed with tucker blade.
Description:  This is basic rule for a web press folder.  If you are running the cross perf which is located below the former board, you must time it with the first fold.  
Solution:  Turn off the cross perf momentarily if possible.  Then you will see where your first fold is taking place without the help of the cross-perf.  Now turn it back on and time the cross perf to this spot.


Problem:  Cross-perf not aligned properly.
Description:  Sometimes the cross perf does not line up horizontally from side to side.  It may theoretically line up, but the reality due to tension differences on each side of the web is that it does not perforate straight. 
Solution:  Use shims to cock the cross-perf and line it up with the first fold.


Problem:  Tension difference at nips after former.
Description:  Before and after the cross-perf there are usually a set of nips.  These nips control tension on the web as it enters the folder.  It is important that both sides of these nips create equal tension.
Solution:  Adjust the nips on each side of the webs to ensure equal tension across the cross perf.


Problem:  Improper tucker blade height.
Description:  In what is referred to as the pin and tuck cylinder, there are a number of blades that tuck the copy into the next cylinder.  These blades must have exactly the same height as one another.  The number of these depends on the configuration of your folder.
Solution:  Measure the height of each tucker blade and adjust accordingly.  


Problem:  Broken moveable jaw.
Movable and stationary jaws
Solution:  Check carefully all the jaws and tucker blades and replace.


Problem:  Jaw pads worn out.
Description:  Each moveable jaw and stationary jaw have a very hard rubber coating.  This allows slight flexibility in the thickness of the product.  Expect these to wear over time.
Solution:  Inspect and replace as necessary.  If you have worn down to the metal or can no longer achieve enough grip on the copy, then it's time to replace.


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