My Dear Fodler - II

28 Sep 2012

Why do we need to adjust the back plate/ lip of buckle plate?

The back plate has an adjustment to make sure the leading edge of the sheet enters the fold/buckle plate without "ducking" the mouth of the plate.

 

Normally, for thin papers, the back lip is brought inward toward the fold rollers. It assists easy entry of sheet in to the fold plate. This setting, however will not work with heavy weight paper. Here the sheet will enter the plate but the exiting is restricted - as the lip is too far down into the fold rollers. This will cause paper jam, bad slitting/cutting, crooked perforating with most of your accessories.

The hexagon adjustment (picture A) is for moving the back lip either in or out. Towards or away from the rollers (picture C). This adjustment deflects/catches the sheet to make sure it enters into the fold plate and doesn’t “duck” the plate. Normally this adjustment is used if the leading edge of the sheet has a bad up or down curl or the paper is extremely thin, 25lb - 40lb. This also depends on the plate being used, up #1 or down #2.

 

Picture Bshows the + and - on the side of the fold plate. The BLACK or RED mark is for reference on the back lip position. The O mark on the scale is the central position. Counter clockwise takes the lip in toward the + sign and clockwise takes it out toward the - sign.

 

When do I adjust the gap between the buckle plates?

We will need to make this adjustment to go well with the stability of the paper (This varies with different paper thickness).  Older type of folding machines never had this adjustment. What happens to the sheet when it enters the plate and hits the sheet stop? In a fraction of a second the sheet buckles (hence the name buckle folder), corrugates and many ripples are forced along the sheet from side to side.   Now if the gap between the buckle plates is more, then these ripples will lead to variations in fold. So what is the right gap? :  The gap should be not small so as to hinder the entry of the sheet into buckles; but just enough to keep the buckling problem to a minimum. You do not have to make this adjustment on every set up!  If you are getting variation then this will be another area to look at.

 

Why have I got plastic and steel marbles for my side guide?

This one is quite simple.  Either for HEAVY or LIGHT stock.   With the heavier paper you must have control of the sheet to make sure it enters into the side guide and stays there until it gets to the first roller. If the weight within the side guide marble rail is too light, then the paper will not register. Having said that, there are many other variables like grain direction, requirement of speed etc that will decide the flow of sheets through the alignment table into the buckles. Hence some trial and error is involved here. If the press room have some set up sheets of the job then test your set up with this.  This way you are not taking good sheets from the actual run.

 

When do I skew the side guide and why do I need to?

Many a times you may get sheets with the print-area not aligned to the paper. This is mostly due to cross cut papers - either bought cheap 'stock lot' or cut incorrectly.

 

If the sheet is folding "out of square" constantly then this is the first area for you to check.

 

Fold one sheet and check it straight from the first fold.  Lay it on a flat surface and palm the sheet until all the air is out and sheet is as flat as possible. Now check the leading edge side guide corner to see if the sheet is folded edge to edge!  The way to compensate this is: a slight adjustment on the side guide. You may have to combine this with your fold plate's skew adjustment.  Try your side guide first; if it's not giving the desired result, then combine it with your fold plate.  

 

The corner to corner registration is checked usually in such cases where you suspect the paper to be cross-cut. Otherwise registration to be checked with folding marks. Look forward to answering real time issues in folding, faced by WT readers. I will try my best to answer these.  Dave Trutzenbach is the CEO of www.partsforfolders.com, an online site which is a hub for ordering folding machine parts. He has 52 years experience in the industry and has worked as operator of folders, managed bookbinding units, besides imparting tips about bookbinding before his retirement from MBO.



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