Tips/Tricks - Flexographic Mastery.

Ask or answer questions related to the flexo pressroom environment

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Frank Burgos
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Re: Tips/Tricks - Flexographic Mastery.

Post by Frank Burgos »

Great stuff, Gorilla! Thanks!
barb
Posts: 83
Joined: Sun Sep 18, 2016 10:49 pm

Re: Tips/Tricks - Flexographic Mastery.

Post by barb »

Great tips guys!!

My share for now:

- don't trust your automatic viscosity meters if you have them - you can use it as a 'side help' or as a monitoring service, but still insist on measuring it manually as often as you can, especially on the long runs with the same ink. previously of course make sure your viscosimeters are calibrated properly

- you can reduce bounce problem by adding straight lines on each side of the design or if possible, when you have such design and you have two images on the plate - align them unevenly so that the second image is lower than the first

- don't rely much on the 'compare' function on your x-rite but rather on the 'search tool' so you can be more sure the color is by the book. that way you can be sure if the PMS 485 was correct for the job #1 it will be also correct for the job #345. of course, in case they're ran under the same conditions

- be careful when using different types of mounting tape - I had multiple cases when I used eg. medium hard tape for MK and medium for CY I couldn't set the register properly due to tape thickness deviation, even though they were fresh new and not reused

- if you're in a position of a pressroom manager learn as much as you can from the operators and then use that knowledge to reduce the possibility of operator 'self willing' changing of the press parameters. I believe Frank once mentioned how badly you can end up when you have a press operator who has the freedom of changing the aniloxes as he wishes (eg. 'hm my ink is weak, screw it (then proceeds to avoid measuring the viscosity and the pressure and everything possible) - I'll just change it to stronger anilox)

- do fingerprint tests on a monthly basis, on all substrates you print on (transparent, white, glossy or matte, etc) - it will reduce the amount of time you waste on explaining your customer why are colors not exactly the same on glossy proof paper and on the matte film

- you can use base ink and a proofing rod to determine which side is chemical or corona treated on polyester

Also, I had a problem with a triple film lamination job that required inside printing in combination with outside printing with heavy coating to achieve glossy/matte effect but it's too specific to go public so in case you guys will have such jobs in the future - feel free to PM me so I can fill you in with tips.
sharbel abdo
Posts: 31
Joined: Thu Sep 20, 2012 1:44 am

Re: Tips/Tricks - Flexographic Mastery.

Post by sharbel abdo »

Many thanks Barb for these great tips.
i wanted to ask you if you can elaborate more on the automatic viscosity control issue.
we are currently running a wide web CI; does your theory also apply to it?
Would you please detail it more?

thank you
Gorilla Printer
Posts: 317
Joined: Wed Oct 06, 2010 1:13 pm

Re: Tips/Tricks - Flexographic Mastery.

Post by Gorilla Printer »

sharbel abdo wrote:Many thanks Barb for these great tips.
i wanted to ask you if you can elaborate more on the automatic viscosity control issue.
we are currently running a wide web CI; does your theory also apply to it?
Would you please detail it more?

thank you
Hi Sharbel
I think Barb is saying don't depend on an automatic viscousity units maintaining viscousities of ink.Actually check them with a zahn cup every now and then
If I checked and entered 8 vicousities into our automatic control,I could guarantee a few would be out by 5 secs after running the same job for 12 hours.


Cheers
barb
Posts: 83
Joined: Sun Sep 18, 2016 10:49 pm

Re: Tips/Tricks - Flexographic Mastery.

Post by barb »

Gorilla is correct!

Just today I had a good example, I went to randomly check the viscosity for the spot ink that operator swore was 23 and it was set on auto 23. I measured 18.

So it's not just the time factor for the long runs but also much needed checkup on how your operators control the ink. If he had manually check the ink after ~10 minutes of setup he would've noticed the error (which possibly happened due to wrong viscosity correction in the press software when he prepared the job) and fixed it immediately rather than loose 15 minutes of work time and extra ink to high up the viscosity again.
sharbel abdo
Posts: 31
Joined: Thu Sep 20, 2012 1:44 am

Re: Tips/Tricks - Flexographic Mastery.

Post by sharbel abdo »

Barb, Gorilla
many thanks for the time and the replies

cheers
:wink:
Gorilla Printer
Posts: 317
Joined: Wed Oct 06, 2010 1:13 pm

Re: Tips/Tricks - Flexographic Mastery.

Post by Gorilla Printer »

sharbel abdo wrote:Barb, Gorilla
many thanks for the time and the replies

cheers
:wink:
Thanks, and oh , one more thing.On our viscousity units there is a "quick" way of setting it which is enter the viscousity and turn it on auto.This is wrong and is less lilely to stay correct.The proper way is do what the instructions say which is enter viscousity,keep the unit in manual,and wait for it to give a reading itself.When its reading is within about .2 of a second thats when I switch it onto automatic.If it isn't I keep on correcting it till it is right.Sometimes it can take five minutes of me going back and forth.But this way you sort of "teach" the unit the station's viscousity.

Cheers
longtimefan
Posts: 425
Joined: Sat Jun 13, 2015 1:10 pm

Re: Tips/Tricks - Flexographic Mastery.

Post by longtimefan »

barb wrote:Great tips guys!!

My share for now:

- don't trust your automatic viscosity meters if you have them - you can use it as a 'side help' or as a monitoring service, but still insist on measuring it manually as often as you can, especially on the long runs with the same ink. previously of course make sure your viscosimeters are calibrated properly

- you can reduce bounce problem by adding straight lines on each side of the design or if possible, when you have such design and you have two images on the plate - align them unevenly so that the second image is lower than the first

- don't rely much on the 'compare' function on your x-rite but rather on the 'search tool' so you can be more sure the color is by the book. that way you can be sure if the PMS 485 was correct for the job #1 it will be also correct for the job #345. of course, in case they're ran under the same conditions

- be careful when using different types of mounting tape - I had multiple cases when I used eg. medium hard tape for MK and medium for CY I couldn't set the register properly due to tape thickness deviation, even though they were fresh new and not reused

- if you're in a position of a pressroom manager learn as much as you can from the operators and then use that knowledge to reduce the possibility of operator 'self willing' changing of the press parameters. I believe Frank once mentioned how badly you can end up when you have a press operator who has the freedom of changing the aniloxes as he wishes (eg. 'hm my ink is weak, screw it (then proceeds to avoid measuring the viscosity and the pressure and everything possible) - I'll just change it to stronger anilox)

- do fingerprint tests on a monthly basis, on all substrates you print on (transparent, white, glossy or matte, etc) - it will reduce the amount of time you waste on explaining your customer why are colors not exactly the same on glossy proof paper and on the matte film

- you can use base ink and a proofing rod to determine which side is chemical or corona treated on polyester

Also, I had a problem with a triple film lamination job that required inside printing in combination with outside printing with heavy coating to achieve glossy/matte effect but it's too specific to go public so in case you guys will have such jobs in the future - feel free to PM me so I can fill you in with tips.

Can you try dry easier board marker on pet? Mark both sides than use scotch tape to pull off..one that pulls is treated
Gorilla Printer
Posts: 317
Joined: Wed Oct 06, 2010 1:13 pm

Re: Tips/Tricks - Flexographic Mastery.

Post by Gorilla Printer »

guy de cafmeyer wrote:.
.Wipe a VERY fine layer of talcum powder onto the plate backing , and then using a solvent rag clean the outside 20mm ( inch ).
)
Hi guy de cafmeyer
I tried this and it works.
We don't have talcum powder so I used Anti offset powder (we have boxes of it).
It does add a little time but works a treat

Thanks
Gorilla
longtimefan
Posts: 425
Joined: Sat Jun 13, 2015 1:10 pm

Re: Tips/Tricks - Flexographic Mastery.

Post by longtimefan »

Gorilla Printer wrote:
guy de cafmeyer wrote:.
.Wipe a VERY fine layer of talcum powder onto the plate backing , and then using a solvent rag clean the outside 20mm ( inch ).
)
Hi guy de cafmeyer
I tried this and it works.
We don't have talcum powder so I used Anti offset powder (we have boxes of it).
It does add a little time but works a treat

Thanks
Gorilla
Big plates?
Gorilla Printer
Posts: 317
Joined: Wed Oct 06, 2010 1:13 pm

Re: Tips/Tricks - Flexographic Mastery.

Post by Gorilla Printer »

[/quote]
Big plates?[/quote]

No, longtime fan.
But I see there being no problem for big plates.

Cheers
longtimefan
Posts: 425
Joined: Sat Jun 13, 2015 1:10 pm

Re: Tips/Tricks - Flexographic Mastery.

Post by longtimefan »

Could you put 2 inch piece of tape along edges than coat with the powder? Then pull tape off.. Not sure which way is easiest
Gorilla Printer
Posts: 317
Joined: Wed Oct 06, 2010 1:13 pm

Re: Tips/Tricks - Flexographic Mastery.

Post by Gorilla Printer »

longtimefan wrote:Could you put 2 inch piece of tape along edges than coat with the powder? Then pull tape off.. Not sure which way is easiest
I think I'd rather wipe the edge with solvent thanks :smile:
Gorilla Printer
Posts: 317
Joined: Wed Oct 06, 2010 1:13 pm

Re: Tips/Tricks - Flexographic Mastery.

Post by Gorilla Printer »

Something else I wasn't taught but learnt from experience and wished I knew earlier is have all ink flows to stations set as minimal as possible.Which is practically so your anilox doesn't dry out.
Increased ink flow,viscousity and press speed equates to more pressure in the chamber.
Resulting in more leaks and sometimes blow outs.
Keeping flows to a reasonable minimum has saved me a lot of unneccesary extra work

Cheers

Gorilla
Gorilla Printer
Posts: 317
Joined: Wed Oct 06, 2010 1:13 pm

Re: Tips/Tricks - Flexographic Mastery.

Post by Gorilla Printer »

For those that use anilox sleeves that tend to get stuck if enough ink covers the edges:
Put a light smear of vaseline or similar on the inside and adjacent outside edges of the clean anilox before installing.
The anilox should float off or be much easier when taking it out.

Cheers
Gorilla
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