Rotary Screen Resources

Ask or answer questions related to the flexo pressroom environment

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Andy.Walker
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Joined: Fri Dec 02, 2011 1:02 pm
Location: Carolinas

Rotary Screen Resources

Post by Andy.Walker »

I realize this is a flexo forum, but I figure a few of you have been involved in combination printing over the years.

I am using a wet color match system to what Frank descripes here:
http://www.flexoexchange.com/articles/reprod-color.html

we are using a zero mayer rod and a proofing device from RK Print.

I want to learn more about rotary screen printing, especially with how settings relate to color reproduction. I have a wet match ink that measures very close to the standard, and the previous 7 drawdown samples, but on press I still need to go more towards the blue shade.

Could this color shift be attributed to a squeege setting changing the ink film thickness and thus changing the color?

Any links to good resources and rotory screen would be greatly appreciated.
Frank Burgos
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Re: Rotary Screen Resources

Post by Frank Burgos »

Hi Adam,

You question is appropriate for and welcome in this forum. Thanks for posting it.

The color shift could possible be attributed to the change in ink film thickness. A lot of guys out there will tell you that. However, to me it just means that, at that thickness, the wet sample is off but you just notice it more at the thickness you’re printing at. If my read is correct, you need to tweak the formula.

I don’t know any rotary resources, off hand. However, I went to Stork’s facility in Charlotte, NC years back and they had an excellent presentation and demonstration facility where I learned a bunch about how the screens are designed and made and how they affect ink film thickness, etc. You may want to ask those folks there if they have any materials for you and if they know of any resources you can tap into.

I hope this helps a little.

Have a great weekend!

Frank
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Andy.Walker
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Location: Carolinas

Re: Rotary Screen Resources

Post by Andy.Walker »

Thanks for the reply frank, if you could PM me your email address I have some more pointed question for you as far as wet sample matching and some of the specific struggles our ink room seems to be having.

We are located geographically close to the Stork facility and Charlotte. We are moving exclusively to their screen material. They have provided some good resources, but I figured some people here have some insite that is not tied to a salesman or a "this is how we've always done it at this company" attitute that comes from some of our press operators and screen makers.
Frank Burgos
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Re: Rotary Screen Resources

Post by Frank Burgos »

Andy,

I just PM'd my email address, which happens to be frankb@flexoexchange.com.

Thank you all for your excellent participation on this forum, and have a great weekend. I really appreciate all of you. My life is richer, thanks to you.

Frank
flexo.uk
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Re: Rotary Screen Resources

Post by flexo.uk »

Hi Andy

I have been using the stork rotary screen unit for a few years now. You can find that different film weights will change the colour. It can depend on the pigment weight and size. Sometimes if the film weight is to high the pigment or particle can "sink" due to its weight leaving more of the polymers on the surface. This tends to be more with varnishs and special effect inks. To me it sounds like you need tweak the ink. Doing a draw down for screen is more difficult then if it was going to be printed using an anilox. The screen settings open so many variables its a tough one.
One thing that always bugged me was how to work out ink consumption. I have talked to the screen suppliers and ink companies and have now finally worked out a pretty good method. I can send you a copy of this if it would be of any use.
bubbles
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Joined: Sat Apr 07, 2012 9:13 am

Re: Rotary Screen Resources

Post by bubbles »

hi and
ive been doing rotary screen going on 18 years
now ur mech on the screen could affect your colour
we use screeny lets say km is 8 micron ks is 10 micron
it will affect ur colour i dont have the tech imfo for stork
also your squgee dlade can affect it yellow lets out more
than red less in my experience settings dont make much ofa diffrence.
i find stork screens dont last as long as gallus screeny material
depends what your screeny unit is like internal bearing systems
will fracture the stork material little cracks external bearing
system seems to be alittle more forgiving.
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