Very odd drying pick off issue

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Very odd drying pick off issue

Postby longtimefan » Tue Mar 24, 2020 10:22 am

So this is odd..

A blue in deck 2 a square and small type..a orange in deck 3.. It is a rectangular shape.

What you see here is the blue picking off onto the orange plate sleeve.

We have tried different dryer settings, Temps and air flow.

We tried different speeds.

Different impression settings

Adjusting the deck dryer away from drum and close to drum

Different inks didn't make any difference..

No slow solvent was added that we know of.

We did try swapping out different colors and plates in deck 2.



I left, the next step was different sequence for a few decks..I have heard anything yet.

We ran in to this once b4 but the operator never wrote down what fixed it? Idiot.
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Pick off
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Re: Very odd drying pick off issue

Postby just Andy » Wed Mar 25, 2020 3:53 am

Hi longtimefan

Is the pick-off consistently in the same place, if no: What substrate was it on, was it ldpe by any chance? Perhaps it's not taut on the drum or the dryer (dryer box is filled with ink spills/sprays messing up the air flow) is flapping the film.

If it is in the same spot each time: then it's likely to do with the plate/sleeve. Some sort of imbalance is making the orange sleeve come into contact with the already printed blue right? So dryer settings and spacing out stations would only dry the ink but not resolve the orange sleeve still coming into contact with the already printed blue.

If it's the sleeve: perhaps there is a high spot on the sleeve, or a low spot where that "4 eye mark" is, so you need more impression to get it to print, squashing everything else. Perhaps check the TIR. If you don't have a dial indicator, try get one. I was gonna type put a solid plate down and set a kiss print but the sleeve manufacturer would not necessarily accept that.
If it's the plate: the thickness (specifically the relief) may be too short. I keep a micrometer gauge for so many uses, it's something to keep.
Or the station is faulty, but I would start looking at the sleeve.

Hope this helps
Andy
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Re: Very odd drying pick off issue

Postby Frank Burgos » Wed Mar 25, 2020 8:33 am

Is the prime nip on the drum completely taking the air out from under the film?
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Re: Very odd drying pick off issue

Postby longtimefan » Wed Mar 25, 2020 9:46 pm

Tension was adjusted on unwind as well..It was poly..2 mil. Drum nip was good..

I was told all they did was re mount the plate in deck 3 with new sticky back. Not sure if used diff sleeve.
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Re: Very odd drying pick off issue

Postby just Andy » Thu Mar 26, 2020 5:13 am

I was gonna say that it looked like the stickyback was all the same thickness. And that unlikely you would have such a big air bubble as you are using the E-range air release. I've also never encountered such drastic thickness variation on the tape especially with 3M. I still think it could be the sleeve. If someone used solvents like ethyl acetate, toluene, MEK, they could have made it bubble. (I've never seen it, though, only heard about it. So if anyone can confirm this).

Cheers
Andy
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Re: Very odd drying pick off issue

Postby longtimefan » Thu Mar 26, 2020 10:39 am

just Andy wrote:I was gonna say that it looked like the stickyback was all the same thickness. And that unlikely you would have such a big air bubble as you are using the E-range air release. I've also never encountered such drastic thickness variation on the tape especially with 3M. I still think it could be the sleeve. If someone used solvents like ethyl acetate, toluene, MEK, they could have made it bubble. (I've never seen it, though, only heard about it. So if anyone can confirm this).

Cheers
Andy


We don't use any of that on plate or sleeve.

Very odd issues...if we wipe back of certain plate material with acetate, the plates will be super glued to sticky back.

So we don't use anything but alcohol on plates or sleeves
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Re: Very odd drying pick off issue

Postby Frank Burgos » Thu Mar 26, 2020 11:38 am

By "new sticky back", do you mean fresh and the same firmness or different firmness?
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Re: Very odd drying pick off issue

Postby longtimefan » Thu Mar 26, 2020 12:06 pm

Frank Burgos wrote:By "new sticky back", do you mean fresh and the same firmness or different firmness?


Same 3m yellow. Is that 1920? These guys really trying my patience..no notes, no samples, nothing of the issues and how to fix it.
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Re: Very odd drying pick off issue

Postby Frank Burgos » Thu Mar 26, 2020 12:11 pm

I think 1920 is pink. 1320 is yellow.

You're on the soft side. This is a stretch, but I wonder whether soft tape + excess impression = plate floor getting too close to image printed on film.
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Re: Very odd drying pick off issue

Postby donaldwal » Sat Mar 28, 2020 3:56 pm

I would try different material and see if you get the same result....Then different ink.... Sounds like a bad dyne to me....
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Re: Very odd drying pick off issue

Postby longtimefan » Sat Mar 28, 2020 6:06 pm

donaldwal wrote:I would try different material and see if you get the same result....Then different ink.... Sounds like a bad dyne to me....

Yeah we tried diff film.
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Re: Very odd drying pick off issue

Postby Gorilla Printer » Sat Mar 28, 2020 9:08 pm

Frank Burgos wrote:I think 1920 is pink. 1320 is yellow.

You're on the soft side. This is a stretch, but I wonder whether soft tape + excess impression = plate floor getting too close to image printed on film.


I have been coming back to this post daily. Frank could be on the right lines. Especially so when proofers don't strip cylinders and use the same plate/mounting tape on multiple runs. The plate image does eventually sink down into the mounting tape, thus needing more squash which makes it easier for the preceding station's image to transfer. I also notice there is white on the plate. But to tell you the truth if you are going to replace with new mounting tape, why not change the plate as well. Or at least check the plate image relief for the right depth? The coworkers said they changed tape, so might as well try that

I don't think it will be that hard to find out what is really going on.

Which leads to my favourite part of printing -finding the root cause, through the process of elimination.I'd be looking for clues all over the place, while making sure all components concerning all aspects the print are in spec.

I don't think it is dyne as all colours would be picking off. Although, I can understand, as the blue seems to be transferring pretty cleanly.

Sometimes problems can be the total of a number of factors.

From experience using stations 1,2 and 3, at the same time should be avoided if possible, especially if the white is a heavy laydown. If your white is a 150 anilox that would definitely be a factor. Even at a slow speed, it would still be too heavy a laydown.I'm assuming what I'm seeing in the pic is white remnants on the plate (station 3)but also within the plate image.That shouldn't be happening.I can understand if it was #2. Mind you the white around the orange image is minimal.

If the job was a critical and had to go out I'd do "Gorilla styles" and cut out the floor of the orange plate where all blue is transferring lol.

What bothers me is blue is transferring too easy. I would look for white build up on blue image to see if it is drying properly. Make sure all 3 ink viscosities, plate depths and inkers/impression set are within good printing specs. I'd quickly smoke test the three heater boxes just in case. It would take 5 minutes max.

The more I think about it, the more I'm thinking about white being on the plate on the third station?
Imagine whats happening to #2 the blue plate. And whenever you see other colours on plates 99% of the time the preceding colour isn't drying properly.Not having enough plate image relief on orange would exacerbate the problem

Moving heaters in or out wouldn't be the problem if this issue isn't on all jobs. But heater airflow balance could be. It's just that it's showing up on this job.

If all these things are checked and ok , the next move would be the check plate cylinder and shaft for TIR issues.

Last but not least change stations if you can. Or wipe plates and print without white on for a while on make ready material to see if it's is a factor

Please update us on your fix

Good Luck

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Re: Very odd drying pick off issue

Postby longtimefan » Sun Mar 29, 2020 5:27 am

Gorilla Printer wrote:
Frank Burgos wrote:I think 1920 is pink. 1320 is yellow.

You're on the soft side. This is a stretch, but I wonder whether soft tape + excess impression = plate floor getting too close to image printed on film.


I have been coming back to this post daily. Frank could be on the right lines. Especially so when proofers don't strip cylinders and use the same plate/mounting tape on multiple runs. The plate image does eventually sink down into the mounting tape, thus needing more squash which makes it easier for the preceding station's image to transfer. I also notice there is white on the plate. But to tell you the truth if you are going to replace with new mounting tape, why not change the plate as well. Or at least check the plate image relief for the right depth? The coworkers said they changed tape, so might as well try that

I don't think it will be that hard to find out what is really going on.

Which leads to my favourite part of printing -finding the root cause, through the process of elimination.I'd be looking for clues all over the place, while making sure all components concerning all aspects the print are in spec.

I don't think it is dyne as all colours would be picking off. Although, I can understand, as the blue seems to be transferring pretty cleanly.

Sometimes problems can be the total of a number of factors.

From experience using stations 1,2 and 3, at the same time should be avoided if possible, especially if the white is a heavy laydown. If your white is a 150 anilox that would definitely be a factor. Even at a slow speed, it would still be too heavy a laydown.I'm assuming what I'm seeing in the pic is white remnants on the plate (station 3)but also within the plate image.That shouldn't be happening.I can understand if it was #2. Mind you the white around the orange image is minimal.

If the job was a critical and had to go out I'd do "Gorilla styles" and cut out the floor of the orange plate where all blue is transferring lol.

What bothers me is blue is transferring too easy. I would look for white build up on blue image to see if it is drying properly. Make sure all 3 ink viscosities, plate depths and inkers/impression set are within good printing specs. I'd quickly smoke test the three heater boxes just in case. It would take 5 minutes max.

The more I think about it, the more I'm thinking about white being on the plate on the third station?
Imagine whats happening to #2 the blue plate. And whenever you see other colours on plates 99% of the time the preceding colour isn't drying properly.Not having enough plate image relief on orange would exacerbate the problem

Moving heaters in or out wouldn't be the problem if this issue isn't on all jobs. But heater airflow balance could be. It's just that it's showing up on this job.

If all these things are checked and ok , the next move would be the check plate cylinder and shaft for TIR issues.

Last but not least change stations if you can. Or wipe plates and print without white on for a while on make ready material to see if it's is a factor

Please update us on your fix

Good Luck

Gorilla


There is no white. It's pro black, that blue, then orange then green.

What you see was a rag that may have had some white on it and someone prob cleaned the plate not all the way. I did think of cutting out the floor area, so not to dar fetched! And we don't re use the tape.
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Re: Very odd drying pick off issue

Postby longtimefan » Sun Mar 29, 2020 5:36 am

The fix was just changing the tape .

We did try decks individual to see what was causing what..and it was deck 3 only picking off 2.

This press had the same diameter sleeves used in prev job. The operator used same setting but did reset all impression.. When a deck was engaged it was already printing and hard.

So possible it destroyed the tape.

And the po was consistently same spot every repeat
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Re: Very odd drying pick off issue

Postby Gorilla Printer » Sun Mar 29, 2020 5:52 am

longtimefan wrote:The fix was just changing the tape .

We did try decks individual to see what was causing what..and it was deck 3 only picking off 2.

This press had the same diameter sleeves used in prev job. The operator used same setting but did reset all impression.. When a deck was engaged it was already printing and hard.

So possible it destroyed the tape.

And the po was consistently same spot every repeat


Thanks for the feedback longtimefan
I missed by a Country mile :smile:

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