Tips/Tricks - Flexographic Mastery.

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Tips/Tricks - Flexographic Mastery.

Postby Gorilla Printer » Mon May 13, 2019 10:54 pm

Hi All
I assume we all come here to learn of each other and get pointers etc.....A bit like "iron sharpens iron"
I thought I'd create this topic to sort of fast track the proccess of learning new ideas we might not have ever heard of or tried.
I'd also hope that if anyone tries something suggested,that they come back and give feedback .
As a budding apprentice years ago,this was my whole aim in coming to flexoExchange.

What tip/trick/skill have you learnt that you wish you knew earlier?What have you stumbled across or seen that has changed the way your shop works?

Please note: What you may think is a basic practice in your Print shop and shouldn't be mentioned ,might not be in others.Share it anyway.

I'll start the ball rolling.Years ago we use to use aluminium tape to hold plates down.But when we moved from analogue to digital plates for some reason the edges of the aluminium tape were getting printed.We complained to graphics who said the image/ floor depth was still the same.This went on for months and finally I had enough of the BS and started removing the tape.This in turn made our plate mounters clean the cylinders and the back of the plates properly before mounting.
It wasn't long before other presses followed suit.For years now we haven't used aluminium tape.And yes plates,even on 335mm repeat cylinders, don't lift.
Since changing to this process I have also learnt to wash my hands before moving any plate on the press -another tip.Your own body oils from your hands will compromise the plate's adhesiveness to the mounting tape.

This has been a win/win/win for the Press operators,Plate mounters and my Company.

Be interesting to read what you lot have to share :wink: :wink:

Cheers everyone
Last edited by Gorilla Printer on Tue May 14, 2019 9:26 am, edited 1 time in total.
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Re: Tips/Tricks - Flexographic Mastery.

Postby guy de cafmeyer » Tue May 14, 2019 5:18 am

Hi All , I've also learnt a few little things that make a difference ;
.The massive difference Hard/Medium/Soft tape can make on a halftone result .
.From "kiss" settings , always increase your impression slightly , and reduce your inker slightly . . . to keep print clean .
.Wipe a VERY fine layer of talcum powder onto the plate backing , and then using a solvent rag clean the outside 20mm ( inch ).
This allows for easy demounting of plates

Will think of a few more :)
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Re: Tips/Tricks - Flexographic Mastery.

Postby Frank Burgos » Tue May 14, 2019 8:59 am

Setting impression on a CI press starting from last color rather than first color.
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Re: Tips/Tricks - Flexographic Mastery.

Postby Gorilla Printer » Tue May 14, 2019 9:01 am

Thanks Guy de cafmeyer
Although I feel I run to kiss settings .I don't mind trying to put a couple more clicks on impression and maybe taking one click off for inkers.This will be interesting.
As for the Talcum powder I've never heard of it before.I'm interested in knowing if you tape down the front/back edge of your plates to the cylinder.Because if you don't then I'll consider passing this talcum powder trick onto our plate mounters.

Thanks for your Input
I'm keen to hear more

Cheers
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Re: Tips/Tricks - Flexographic Mastery.

Postby Gorilla Printer » Tue May 14, 2019 9:17 am

Frank Burgos wrote:Setting impression on a CI press starting from last color rather than first color.

Thats a great tip too Frank.I used to have to set my inkers impression from the last station forwards for years when I was an apprentice.It really helped me see what I was doing without getting cofused with other stations printing.
But now I think out of laziness I work from the front to the back as the last station is where I register all print before fine tuning down at the scanner.

Thanks for input frank
Cheers
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Re: Tips/Tricks - Flexographic Mastery.

Postby Frank Burgos » Wed May 15, 2019 9:35 am

[quote="guy de cafmeyer"] “always increase your impression slightly , and reduce your inker slightly . . . to keep print clean”
I agree. Moreover, if you set impression correctly, you are likely to have more impression plate-to-substrate than plate-to-anilox. The result is that ink getting on image shoulders from the anilox is taken off at impression because more of the shoulder touches the substrate than the anilox. Phew. That was a mouthful.

[quote="guy de cafmeyer"] "Wipe a VERY fine layer of talcum powder onto the plate backing , and then using a solvent rag clean the outside 20mm ( inch ).
This allows for easy demounting of plates"
Neat trick. Another one is blending 25% shellac in 75% normal-propyl alcohol and brushing it onto the back of the plate, also wiping about 20mm off at the leading and trailing edges.
That said, either method introduces a variable that you may want to avoid if you’re printing half-tones or 4-color process. I once took a black marker, made an “S” pattern on the back of a process plate and as able to see the resulting S-shaped pattern on the image due to the added dot gain the film of marker ink introduced.

[quote="Gorilla Printer"] “But when we moved from analogue to digital plates for some reason the edges of the aluminium tape were getting printed”
I don’t believe this is what you’re referring to, but it makes me recall discovering that tape does not adhere well to plates that are processed in thermal-wicking processors. I believe that this is due to the lower surface area of the floor of the plate, due to the texture the fabric impresses on it.
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Re: Tips/Tricks - Flexographic Mastery.

Postby Gorilla Printer » Thu May 16, 2019 3:24 am

Gorilla Printer wrote: “But when we moved from analogue to digital plates for some reason the edges of the aluminium tape were getting printed”
I don’t believe this is what you’re referring to, but it makes me recall discovering that tape does not adhere well to plates that are processed in thermal-wicking processors. I believe that this is due to the lower surface area of the floor of the plate, due to the texture the fabric impresses on it.


Yes Frank
You are correct,the tape was lifting.And lifted easily.We tried wiping the edges ,it did get better,but wasn't good enough.So thats when I started trialling not using Aluminium tape

Thanks for the reminder

Cheers
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Re: Tips/Tricks - Flexographic Mastery.

Postby wdustin1 » Thu May 16, 2019 7:59 am

We never had much luck with taping down the plate edges, we always wipe down the back of the plates real good with a solvent and mount the plates then peel back the edges and, VERY lightly wipe the tape with the solvent and then run a king size sharpie down both edges of the plate, wait for the marker to dry and then press it back down. Not sure on the science behind this one but it holds the plates down like super glue
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Re: Tips/Tricks - Flexographic Mastery.

Postby longtimefan » Thu May 16, 2019 10:27 am

We have had success heating up the edges with a heat gun and rolling edges down.. Seems like the adhesive re wets and then plate sticks better.

Hold heat gun away and watch for the property of the tape to start to bubble slightly and then lay down plate
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Re: Tips/Tricks - Flexographic Mastery.

Postby longtimefan » Thu May 16, 2019 10:31 am

wdustin1 wrote:We never had much luck with taping down the plate edges, we always wipe down the back of the plates real good with a solvent and mount the plates then peel back the edges and, VERY lightly wipe the tape with the solvent and then run a king size sharpie down both edges of the plate, wait for the marker to dry and then press it back down. Not sure on the science behind this one but it holds the plates down like super glue


Yes thick magic markers do work.


Speaking of those.. If there is a tiny tiny hole in a plate, the markers can fix that .

Need a new one, hold the tip down, shake it to try and draw the ink to the tip.. Take of cap and ink should drip out.. If done correctly, that ink fillils in the hole.. Should last a while.
Last edited by longtimefan on Thu May 16, 2019 10:37 am, edited 1 time in total.
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Re: Tips/Tricks - Flexographic Mastery.

Postby longtimefan » Thu May 16, 2019 10:33 am

Chips on anilox dead band areas... Harper and other places sell their fix for the chips... You can buy jb weld gray epoxy? And get same results.

I filled in the chips and then use water or solvent to sand it smooth.. I place tape on cell area to edge of dead band of the anilox so u don't ruin the anilox while sanding
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Re: Tips/Tricks - Flexographic Mastery.

Postby Gorilla Printer » Thu May 16, 2019 1:13 pm

That is a cool idea longtimefan!
Thank you very much.
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Re: Tips/Tricks - Flexographic Mastery.

Postby longtimefan » Thu May 16, 2019 2:02 pm

I assume everyone wraps their mounted sleeves? If so how.. What is the material.

We had small film slit to about 12 inches... Then maint made a hand held holder so it would unwrap as we spun the sleeve
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Re: Tips/Tricks - Flexographic Mastery.

Postby Buck from N.C. » Sun May 19, 2019 9:10 am

Spray silicon on screen plates. Keeps the screen clean.
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