Flexo Capping Resin Improvement v. Cost

tsfx

Active member
Good Day,
In my facility, we produce 0.112 plates and do 90% linework and 10% screened work @ 55LPI on 300 annilox (depending on graphics, then it can go to 85LPI on 600 annilox). We consistently hold a 4% dot. We can push for 3% if need be. and 99% of our art doesn't call for 2% dot.

Capping plates can be beneficial. I agree with this. But for our print, we are hitting dots and longevity in plates without. Meaning, even if capping adds benefits, we would be waisting since the process in place is already producing expected results.

HERE IS THE ISSUE:
For approximately six months we will run fine. Then, there will be times when screens become an issue and of course the go-to answer is bad plates and to put the blame on them not being capped. I then showcase that we do not have proper dotgain/TVI feedback from the press. We need PMs in the plateroom and to change our exposure lamps. We need to ensure our calibrations on our film output is accurate and up-to-date. We need to ensure we measure: density of films, dots on films, dots on the plate using our Plate-II-Print tools, etc. After doing all this, we were back to hitting our expected dots without issue.
Problem is, this problem is solved until the next time we have screen issues and we go through this cycle once again.

QUESTION:
So my question(s) is/are. Should I just get my platemaker to cap all plates with screens? Saving myself the heartache.
If we aren't implementing the proper processes mentioned above would capping even help?
I feel, that instead of performing the proper processes, everyone wants to paint with a broad brush and just say cap, as if the problem will go away.
I feel that we could cap, and still have the same problems. Or we would cap and some problems would go away, making everyone adequate with the outcome, but never resolving the underlying issues.

If I am trying to hit a 40% dot I have to setup my prepress to compensate for dotgain.
So when I measure my finished plate, it should read 30% (this is what we found out after testing).
If I have my platemaker cap screens, will he be able to measure the dots at 40% and the press will hit that 40 or will there still be dotgain of 10% or some other unknown we have yet to test for?

Sorry for the long post and multiple questions.
Thanks for any feedback you are able to provide.
 

gordo

Well-known member
In my facility, we produce 0.112 plates and do 90% linework and 10% screened work @ 55LPI on 300 annilox (depending on graphics, then it can go to 85LPI on 600 annilox). We consistently hold a 4% dot. We can push for 3% if need be. and 99% of our art doesn't call for 2% dot.

Capping plates can be beneficial. I agree with this. But for our print, we are hitting dots and longevity in plates without. Meaning, even if capping adds benefits, we would be waisting since the process in place is already producing expected results.

Capping is intended to increase solid ink density not hitting dots or plate longevity.

:
For approximately six months we will run fine. Then, there will be times when screens become an issue and of course the go-to answer is bad plates and to put the blame on them not being capped.

It depends on what you mean by screens become an issue.

I then showcase that we do not have proper dotgain/TVI feedback from the press. We need PMs in the plateroom and to change our exposure lamps. We need to ensure our calibrations on our film output is accurate and up-to-date. We need to ensure we measure: density of films, dots on films, dots on the plate using our Plate-II-Print tools, etc. After doing all this, we were back to hitting our expected dots without issue.

Bingo.

So my question(s) is/are. Should I just get my platemaker to cap all plates with screens?

It probably won't have any effect on your issue.

If we aren't implementing the proper processes mentioned above would capping even help?

Probably not.

If I am trying to hit a 40% dot I have to setup my prepress to compensate for dotgain.
So when I measure my finished plate, it should read 30% (this is what we found out after testing).
If I have my platemaker cap screens, will he be able to measure the dots at 40% and the press will hit that 40 or will there still be dotgain of 10% or some other unknown we have yet to test for?

Dot gain occurs at the dot perimeter. Capping (punching holes in solids) does not affect the perimeter of the dot.
 

tsfx

Active member
Thank you for your responses Gordo.
This really puts my mind at ease.

Capping is intended to increase solid ink density not hitting dots or plate longevity.
This may be. Though I may have some misinformation or may need to read up more. I was told capping plates would widen exposure latitude and give less distortion on the printing surface. Allowing for deeper reliefs and less dot gain from plate to print impression​


It depends on what you mean by screens become an issue.
Usually, the issue is screens are either lighter or dark than expected. This is why I wanted to resolve our dotgain problem before committing to Capping Resin, which would add another variable.​

Dot gain occurs at the dot perimeter. Capping (punching holes in solids) does not affect the perimeter of the dot.
The only part in this response that confuses me a bit is where you mention "punching holes". Just to ensure we are on the same page with your previous responses, the capped plate is capping resin that sits atop the photopolymer resin creating a flat top, so-to-speak. This is what you are referring to, correct.​


Once again, thanks so much for your responses.
 

gordo

Well-known member
Hah! Resin capping not halftone capping :)
My bad.
I have minimal resin capping experience since AFAIK it's primarily used in corrugated. :-(
If I were you I would start by getting your process under control since without that foundation you will likely continue having problems whatever you do.
Next, you could ask your RIP vendor if they have a screening solution similar to creo/kodak hyperflex. This might give you a more robust dot than what you currently have and may solve or reduce the issues. Since it's screening it's easy to incorporate into your workflow and easy to test - e.g. your vendor could give you a time limited test period to see if it reduces the issue.
Last would be resin capping since it is likely the most expensive solution.
Remember that consistency is more important than accuracy. Consistency provides the foundation.
 

tsfx

Active member
Hah! Resin capping not halftone capping :)
My bad.
I have minimal resin capping experience since AFAIK it's primarily used in corrugated. :-(
If I were you I would start by getting your process under control since without that foundation you will likely continue having problems whatever you do.
Next, you could ask your RIP vendor if they have a screening solution similar to creo/kodak hyperflex. This might give you a more robust dot than what you currently have and may solve or reduce the issues. Since it's screening it's easy to incorporate into your workflow and easy to test - e.g. your vendor could give you a time limited test period to see if it reduces the issue.
Last would be resin capping since it is likely the most expensive solution.
Remember that consistency is more important than accuracy. Consistency provides the foundation.

Right on!
Thanks again.
My apologies for not clarifying the first go-round.
But we still got to the goal of putting my mind at ease.

Agreed, getting the process down is better than getting the fancy-schmancy broad brush to make things "better".
Once we know our process is correct, then we can add in the capping resin, adjust the process accordingly for the added variable, and produce with confidence.

Thanks again.

If anyone else has added input, please feel free. But I feel this issue may be resolved.
 

Alois Senefelder

Well-known member
Hello tsfx,

Flexo, not an area of my expertise, A PDF that might be of interest and value.

Regards, Alois
 

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