picking question?

Discussion in '4-Color Offset Presses +' started by eagleI, Feb 27, 2010.

  1. eagleI

    eagleI Member

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    sorry piling.main causes?
     
    Last edited: Feb 27, 2010
  2. steveo

    steveo Senior Member

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    do you mean piling?
     
  3. rolandman

    rolandman Senior Member

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    Picking? on the plate and blanket?
     
  4. steveo

    steveo Senior Member

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    he must mean piling ??
     
  5. eagleI

    eagleI Member

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    so much for my screen name!
     
  6. steveo

    steveo Senior Member

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    if it is piling the ink probably doesn't have a good flow and / or is setting to fast , could also be a paper prob or chemistry , I would gel the ink first and see if that helps , also if your running with temp controled rollers check that the rollers aren't too cold....
    Steve
     
  7. RichardK

    RichardK Senior Member

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    Paper piling...characterised by trailing edges of solids building up a deposit of paper coating, can be minimsed by gel reducer, as mentioned, and/or increasing damp and ink levels in unison.

    Long runs without blanket washing and removal of the buildup can indent blankets permanently.

    Depending on the severity the above can reduce or eliminate the issue but we used to have this problem with one of our monthly jobs and nothing would help until we changed the paper (for a cheaper grade!) and suddenly no piling.
     
  8. turbotom1052

    turbotom1052 Senior Member

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    i try to stay away from gel reducer whenever possible because it tends to be a little too greasy for my liking. if you must use gel then use it sparingly. theres a product out in the market called sterling perfect print thats a much better reducer than the gel. you can use lots of it without filling in of the halftones. its an old letterpress product but works good in offset applications too. it doesnt mix in the ink as easily as gel but in my opinion works alot better
     
  9. timc

    timc Senior Member

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    stelings used to do a reducer called thixoprint gel Which was excellent very hard to over dose with the product We used it on packaging boards Also spraying the blanket before running with a anti ink skin spray helped
     
  10. steveo

    steveo Senior Member

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    No doubt sterling is amazing stuff!! have used it since I started printing , I dont have a problem with gel at all or if you have an ink lab they should also have oil (linseed) in a pinch it works , Ive also bleached the blankets if you have bad picking , take the oil out of the rubber.....but whatever you find works for you , Sterling would be my 1st choice! Prisco sells it except they call it "Gold" good luck
    Steve
     
  11. Loupeyeyed

    Loupeyeyed Senior Member

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    Paper coating!
     
  12. RichardK

    RichardK Senior Member

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    I still think it's more of a paper issue but just a further thought...are your blankets quick release in the sense of low inherent surface tack?
     
  13. steveo

    steveo Senior Member

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    Lou and Richard are right on the money with the paper.....if Im working in a shop and I dont normally have an issue with piling Ill try a different stock during the m/r just to see if it goes away , if you absolutley have to run the paper then I see theres been several good replies with solutions to get the job done.....paper today is the worst Ive ever seen but this is what we are given to work with......

    Steve
     
  14. Loupeyeyed

    Loupeyeyed Senior Member

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    Cleaning the blankets and then applying a light coat of anti-skin spray to the picking area is a great fix for sheetfed presses. I was very suprised to read this about this trick in a thread because I was the only one that I know that had come up with this idea. Piling is usually the worst, first thing in the morning, especially on a Monday. And in my experience, only seems to happen on coverage like solid bars spaced out by 6-10" of non image area. I've actually yanked a job because of piling on a Monday morning and put it back on the press towards the end of my shift and had no problems. It's deffinatley enhanced by cold starts and a certain type of coverage. I used to spray my blankets with anti-skin after cleaning the areas that were piling and finished the job succesfully. And another good trick to work around the problem is to put a few hundred sheets of another "non piling" stock on top of your pile after you have achieved color and keep the press running. This allows the tack to release from your cold inks. On the other hand, I've worked around web presses that could not run certain rolls without piling period! Almost always a top grade dull text. I hate to reduce inks because I like to print a good dot. I think the problem is most certainly a paper coating issue but there are ways around it. After the press room heats up, your rollers heat up and your tack releases try putting the job back on the press. Also, watch your bearer pressure, this can be crucial with dull stocks. It's funny to me actually, the company orders a number 1 grade sheet and has more problems with it than a descent dull or enamel. I've never owned a Print Shop so I was never involved with the paper ordering but if I had been, I'd print a lot of jobs on a number 2 or 3 grade sheet with more absorption then aqueous coat it. I've heard so many excuses to the problem throughout the years but after acquiring a web in the shop, I was totally schooled again on the problem. Some papers just would not stop piling on them and as soon as they changed the roll, the problem went away. Now that's printing at 40,000 an hour. I implemented the ant-skin trick or a start up with another similar coated stock and was able to control the piling. I know one thing for sure, some stocks do it and some stocks don't. And, press temperature aggravates the problem. Being cold that is. Hope this helps and I have to say this is a great website and I'm sorry if I got started on the wrong foot with a few of you guys!
     
  15. print101

    print101 Senior Member

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    Good Post Loup - I agree 110%
     
  16. eagleI

    eagleI Member

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    Wow Thanks alot!
     
  17. KGM

    KGM Senior Member

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    I had terrible problems with piling using 2sheet pulpboard (150g) on very long runs. switched sheet and the problems went away. there was a huge difference, the first lot i could be cleaning the impression cylinder every 3-4000 runs. now i dont even need to even on runs up to 60000
     
  18. RichardK

    RichardK Senior Member

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    I rest my case...have a good weekend all
     
  19. KGM

    KGM Senior Member

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    sometimes doing it on the cheap just isnt worth it.
     

  20. turbotom1052

    turbotom1052 Senior Member

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    we still have a few cans of a product called rycoline blanket hardener. its a banana oil extract that will remove the tack from the blanket. ive used it with success when faced with picking problems. theres also a product that goes with it to restore your blanket to pre hardened condition. its called blanket hardener remover. imagine that!!!! i dont know if the stuff is still available as im thinkin it has very high voc
     
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