Cutter, what is the usual tolerance?

[Colorblind]

Prepared a double-page spread ad for a magazine, followed their specs. Safety zone was at 3/8" from the trim so every element was within that zone. Received the magazine and noticed that the elements were now at 1/8" from the trim. Called the magazine. Answer: it's within our tolerance range. So my question is: can cutters be that unprecise (it's a 1/4 " difference). And since the measured size of the magazine is the same as the specs, my opinion is that it could also be an imposition issue, the ad was probably placed too close from the trim in the imposition. Anyways, just trying to understand what may have happened. So, are cutters precise? What is the usual tolerance? Thanks!

 

[Michael Fry]

Re: Cutter, what is the usual tolerance?

The problem may not be the cutter...
is the magazine "Saddle Stitch" or "Perfect Bound"
If it is Saddle stitched, and the center spread has less margins than page 1.
(on the left and right margins)
It is because of push out, or Creep.
Which can normally be taken into account.
(except when the center spread has a cross over)

 

[rich apollo]

Re: Cutter, what is the usual tolerance?

Cutters are very, very precise - but I don't think that's what you're up against.

Sounds like the publication is being produced on a web press. That creates some other challenges

1) The webs walk. The webs are running at very high speeds and the paper can travel side to side - up to an 1/8 inch
2) Paper stretches. The webs are under tension and as the paper travels through the printing units it takes on water which changes the structural stability. This can effect your registration and your cut-off.
3) The signatures come off the press finished. The paper travels from the printing units directly into the folder. The sigs are ribboned, folded, and slit and come off at "press-finished" size.
4) Then the folded sigs go into the bindery, where they are stitched (or scathed and glued) and 3-knife trimmed.

That's why they specified the 3/8 inch margins. Web printing requires much looser tolerances - the payoff for you, the customer, is cost and speed of production.

And, as with any printing process, all these things vary. Do you have more than one copy of the publication? The issue may be non-existent at other points in the production run.

rich

 

[Colorblind]

Re: Cutter, what is the usual tolerance?

Yes, I have 6 copies of the magazine, and the distance from the trim is from 1/8" to 1/4" on some copies.
Anyways, thanks for your precious input guys, it is much appreciated.