Ripple marks on heavier cover stock when converting pocket folders

[davarino]

We have a Moll pocket-folder/gluer (Blue model) and get a ripple on one pocket when we fold stock heavier than 12 pt. (See my picture of a sheet of 14 pt.)

The ripples average about 7/16" apart with about 1/8" variance and happen only on the outer edge of the pocket on the operator's side. It happens occasionally: not all folders in a run get the flaw.

Our gluer operator says he has seen this as a problem in our shop and the one he started off in. So, even though he's got lots of years, he's mystified.

I would usually contend that it's too much pinch or maybe some drag, but his setup looked good. But what do I know: empirical data ALWAYS beats theory.

Any ideas?

 

[Guest]

I know nothing about moll converting machines but last year had a question about a finishing machine and emailed them. Kevin Moll immediately returned my email. You might try to contact them, they seemed very responsive at the time. I think it was mollbrothers.com .

Best of luck.

 

[Kees]

I have had this problem also years ago but the paper was more the problem, it just could not handle the forces that occur in the pocket-folder, you could try if the direction of the grain has an influence.

 

[D Ink Man]

I have had this problem also years ago but the paper was more the problem, it just could not handle the forces that occur in the pocket-folder, you could try if the direction of the grain has an influence.

That is a good point about the grain direction.

I would add that the moisture content of the stock is important; not to be too low is first thought. Also suggest to try another brand of substrate, 12 pt+, to see if you might get better results.

A good experienced paper rep tech may be in good order to contact.

D

 

[ondemandbindery]

That's alot of Face Cracking..... Are you using the Tipper Plate or Fold Plate? If the fold plate then your Sheet Stop may not be set right. We have one in our Plant and the are fairly user friendly.....

JW