Plates are randomly to short or too long...

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Plates are randomly to short or too long...

Postby MrPlateMaker » Mon Jun 07, 2021 10:37 am

So Recently some of our plates have been coming back out of register (to short or too long) we use crosshairs as our reference points, most of the time our mounters are catching this issue but sometimes it makes it out to press before we notice it..
Plates are Asahi .067 DSH 50x80 burned on a Esko CDI Advance 5080, nothing has changed on any of the machines everything else about the plates are perfect except the random (too long to short) im thinking its a dryer issue and its randomly getting hot and over drying certain parts of the sheet...
i checked with a temperature gun and everything seems okay while i am standing there reading with the probe the wire isn't long enough to get all the way to the back of the dryer though....

its just really bothering us because sometimes it will just be 1 of the plates off of the full sheet thats not right and the next time it will be 2-3 of the plates that aren't right, i cannot replicate the issue if i tried.

we know this is not a pressside issue because out mounters catch the issue most of the time..

has anybody ever seen random shrinking issues, is it typically the dryers?? any help will be appreciated.

Thanks a bunch..
MrPlateMaker
 
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Re: Plates are randomly to short or too long...

Postby Frank Burgos » Mon Jun 07, 2021 10:46 am

You don't say whether you measure the plates to confirm they don't measure the same, but on the off-chance that it's not the plates, here are a couple of mechanical conditions, at mounting, that have result in something like what you describe:

Differences in bare-cylinder/sleeve diameters
Differences in mounting tape
A combination of these

If you haven't confirmed by measuring, I would. If they measure correctly, I'd measure the cylinder/sleeve diameters, precisely, and test with only one type of tape off the same roll.
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Re: Plates are randomly to short or too long...

Postby MrPlateMaker » Mon Jun 07, 2021 11:23 am

sorry i wasn't clear enough,
our mounters have the ability to check the length of our crosshairs without fully mounting the plate on a cylinder, so they can essentially measure them and see that they are short/long...(some mounters have been taking this extra step since we have been having this issue, to save us time and money before the plates get mounted and on the press)

My Manager and Myself have essentially narrowed it down to the CDI or the Dryers, I am under the impression if it was the CDI we would be seeing it a lot more often so i think its a dryer issue..
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Re: Plates are randomly to short or too long...

Postby Frank Burgos » Mon Jun 07, 2021 11:40 am

Thanks for the clarification. Looking forward to other responses
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Re: Plates are randomly to short or too long...

Postby dandelehanty » Thu Jul 01, 2021 9:54 am

*Disclaimer*...I'm not at all familiar with this platemaking system nor am I in any way, shape or form a pre press guy, but I know we have occasionally had issues when the incorrect distortion factor was mistakenly used for an image. This obviously could not be the case if images are ganged together and distorted at the same time, but if they are created individually and then grouped together it could happen? I'm sure I'm way off base, but just a thought.
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Re: Plates are randomly to short or too long...

Postby MrPlateMaker » Mon Jul 12, 2021 9:35 am

Well after multiple temperature tests with our dryers and changes made to our esko/CDI, the issue still remains....extremely random and we cannot pin point the culprit...

i was hoping somebody here could tell me the temperatures within their Finisher we run 3 minutes UVA and 10 Minutes UVC...if somebody could grab the middle temperatures(back,Middle,Front) when the uva gets down to 1 minute that would awesome so i can compare it to our temperatures here...

also on everybody elses dryers does your fans turn on when the dryer door closes or opens, just trying to get a feel for what other peoples equipment does...(older dryers and our maintenance crew are not much help right now)

thanks!!
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