Recent

Author Topic: Cutting press blankets for coating tower  (Read 582 times)

0 Members and 1 Guest are viewing this topic.

Offline TBKeffer

  • Color Management and Workflow Specialist, G7
  • New Member
  • *
  • Posts: 10
  • Gender: Male
Cutting press blankets for coating tower
« on: January 16, 2020, 12:27:02 PM »
I want to set up pdf/vector files to cut blankets on my ZUND cutter. From what I can see, there is distortion caused by the cylinder. Assuming that some of you are machine cutting your blankets, how on earth do you do this?
G7 Process Control Master Printer - Prinergy - Insite - Metrix

Offline david

  • WTF?
  • Global Moderator
  • Supreme Ninja
  • *****
  • Posts: 15210
  • Gender: Male
  • arrrrrrrggg....
Re: Cutting press blankets for coating tower
« Reply #1 on: January 16, 2020, 01:11:55 PM »
We cut blankets on our zund.
We send an Illustrator (.ai file) to the zund. We distort (scale) the vector art in Illustrator before sending.

Really easy.
Prepress guy - doin' jobs one at a time

Offline DigiCorn

  • Terrorizing humans since 1971
  • Supreme Ninja
  • ***
  • Posts: 15198
  • Gender: Male
  • There is no Dana, only Zul!
    • Clerks.
Re: Cutting press blankets for coating tower
« Reply #2 on: January 16, 2020, 01:50:37 PM »
We only have a couple Ryobi 2-color presses at the new shop. One of them has a shared blanket. We just cut them by hand with an Exact-O™.

It's funny that this topic popped up; we've had to cut two different blankets in two days. One for a 5x7.5 in Envelope with a metal clasp attached and today for some Tyvek baggage tags with a metal grommet.
"Selling my soul would be a lot easier if I could just find it."
– Nikki Sixx

“Always do sober what you said you'd do drunk. That will teach you to keep your mouth shut.”
― Ernest Hemingway

Offline TBKeffer

  • Color Management and Workflow Specialist, G7
  • New Member
  • *
  • Posts: 10
  • Gender: Male
Re: Cutting press blankets for coating tower
« Reply #3 on: January 16, 2020, 01:52:43 PM »
We cut blankets on our zund.
We send an Illustrator (.ai file) to the zund. We distort (scale) the vector art in Illustrator before sending.

Really easy.

But how can I figure out the distortion and scaling??
G7 Process Control Master Printer - Prinergy - Insite - Metrix

Offline david

  • WTF?
  • Global Moderator
  • Supreme Ninja
  • *****
  • Posts: 15210
  • Gender: Male
  • arrrrrrrggg....
Re: Cutting press blankets for coating tower
« Reply #4 on: January 16, 2020, 02:11:21 PM »
Print a press sheet out that is the correct size, then measure the distance from an object at the Gripper to an object at the tail of the sheet. (A large grid with lines spaced at .125 in. works great for this.)
Compare that to the actual size of the file, then calculate the percent.
Our scale factor is 99.26% vertical and 100% horizontal.
Yours will be different due to it being a different press with a different cylinder circumference.

HTH
Prepress guy - doin' jobs one at a time

Offline Foozball

  • Hero Member
  • *****
  • Posts: 942
  • Gender: Male
Re: Cutting press blankets for coating tower
« Reply #5 on: January 16, 2020, 07:26:12 PM »
My pressman did this on press a few years back regularly ... Ink up the press and get his first approval (coating unit OFF), then exacto out the area he wanted on one of the approved sheets. Manually feed that sheet into the press, so the position (pull) is perfect. Cycle the press, I think we settled on 28 sheets as the magic number where he'd stop it and creep it forward so he could see his "exacto'd sheet" on the blanket and cut the blanket right on press. 
It's nuts to try and get prepress to do the calculations for this ... among the millions of things that can be wrong/off with the press, this should be the pressman's job. This was on a full size Kimori, so moving the cylinder backward was easier than the Heidelberg. 
He'd then get a 2nd approval with the coating unit ON.
 
On a bad day we'd screw up some blankets, but he'd always say if they don't like it, they need to get the right equipment.

Offline born2print

  • Post count: purtygood
  • Supreme Ninja
  • ***
  • Posts: 12050
  • Gender: Male
Re: Cutting press blankets for coating tower
« Reply #6 on: January 17, 2020, 11:43:46 AM »
That's a good way to hand-cut the blanket accurately.
Another way is to output an extra "FPO" plate and ink it, image on blanket, cut blanket.
Quote from: Tracy link=msg=301939 date=1534265274
I get back to my dept and I'm all bleep you and bleep this bleep :laugh:

Offline AaronH

  • Hero Member
  • *****
  • Posts: 505
  • Gender: Male
Re: Cutting press blankets for coating tower
« Reply #7 on: January 17, 2020, 01:19:00 PM »
This is kinda how we cut the blankets here. We make a plate of what they want varnished or coated or whatever (or they just use whatever plate has the most ink coverage) and they cut to that plate image that gets transferred to the blanket. We have two Komori presses and they both do it the same way.

We don't have to do this often though, usually its a flood or spot using one of the ink towers.
Mac & Windows | XMF | Fiery | Oris