KOMPAC Water Problem

Discussion in '1-Color and 2-Color Offset Presses' started by Buloke Times, Jun 20, 2011.

  1. Buloke Times

    Buloke Times Member

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    Just wondering if anyone else has encountered our problem or if any suggestions.
    We have a GTO 46 with a Varn KOMPAC. When we print smaller jobs — in particular glossy (non-absorbent) stocks, beads of water build up after a few hundred sheets at the trail end of the blanket, which drip down beside and onto the printed stock on the delivery tray.
    We have adjusted every setting under the sun eg rollers, fountain solution packing.
    We use mainly polyester plates — metal plates do seem to give a bit better result.
    We have a MO right beside with a KOMPAC and it works fine but we always run a full size sheet with bond.
    We might try some etch but not sure what else to try.
    The KOMPAC on GTO 46 is two years old but very little impressions.
     
  2. HPC

    HPC Senior Member

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    Not familiar with Kompac, we run Quadflow, Triflow, Dalgren and conventional. On all of them the web is run to one side, on the other side we have it set to squeeze the water away from going into the offset tower. On the conventional system we use rubber "limiters" to prevent the pan roller from putting too much water on the ductor. By small jobs I think you are referring to sheet size???
     
  3. Buloke Times

    Buloke Times Member

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    Thanks for responding.

    We also used rubber "squeegees" on our MO when we previously used conventional but KOMPAC is a different system.

    By smaller jobs — yes i meant sheet size.

    I forgot to mention that i use rain water with fountain solution. I have tried a variety of brands and strengths to no avail.
     
  4. plotter

    plotter Senior Member

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    it can only be the nip, or even a worn roller i think
     
  5. FFR428

    FFR428 Senior Member

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    Agreed ^^^^. Or the teflon side seals are worn and leaking as it runs and dripping down the sides. Or water level in the nip is too high. Normally the Kompac runs on the dry side. You should really see no extra water buildup on the sides. Did anyone catch a rag or something in it? That can bend and tweak the unit. If there was roller damage you'd see the rollers lowspot flash when running.

    Per a 28 oz mix I use 4 oz mega (pink) fountain solution 2 oz of mega plate etch and 22 oz distilled water for poly plates with oil base inks. No issues ever. Kompacs are really a no brainer system and normally run well. I know there have been problems in the past with the wider units. I'd think they'd be more sensitive on a the GTO with a 14 x 20 sheet. That's a WIDE unit to carry a small nip of water.
     
  6. Inky

    Inky Senior Member

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    Kompac

    I'd say seals, have they been run in dry?
     
  7. Buloke Times

    Buloke Times Member

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    response

    Yes, the seals have been run in dry. The beads of water often run right across the trail of the blanket. It's more like a gradual build up than a sudden leak.
     
  8. Inky

    Inky Senior Member

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    Have you tried running it with between 5-10% alcohol?
    Varn suggested this to me years ago, I'm sure a lot of people will disagree, it may if nothing else prove or disprove something. I had a Kompac that like yours just started running wet over night.
    A long time later I heard there had been a bad batch of rollers.
    Good luck.
     
  9. Buloke Times

    Buloke Times Member

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    Thanks i'll try some of these ideas with alcohol and etch and see how i get on.
     
  10. Variprint

    Variprint New Member

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    I have a Multi 1250LW with a Kompac dampener. When running smaller width sheets, in this case #10 envelopes, I had the same problem, water all over the place, even to the extent of drops betwen the form and oscillator ink rollers migrating over to the envelope side and washing out the image. A smaller sheet size subtracts less water from the blanket, a small amount each impression, so it has nowhere to go but to the end of the blanket, and then to the impression cylinder also.

    In my case, I was able to remedy this by merely turning the Kompac form roller shaft knob on, and then some extra beyond the all the way on notch, to give more Kompac form roller pressure to the plate. Now when I do this particular job of 3,000 envelopes in reflex blue they all print dry and dense.

    You are running a different press and different plates, but the same principle may apply. I would try adjusting the Kompac form roller down on the plate a little harder, even if this is beyond what the specs call for.
     
  11. Buloke Times

    Buloke Times Member

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    Thanks to Variprint. This does sound like the same problem. The G.T.O. doesn't have a roller shaft knob but I might be able to put extra pressure from the forme roller to plate by adjusting the eccentric screws at both ends and the two knurled knobs which give the "bounce" on the plate.
     
  12. William Taylor

    William Taylor Senior Member

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    I wouldn't over adjust your roller to plate pressure, it will only make things worse plus it may stretch or wear your poly plate out.
    You need to adjust your "nip" as its the stock that is causing your problem. Some coated stocks won't absorb your excess water as easily as an uncoated one.
    The Kompac sytem meters only the amount of fount it needs providing it is set properly. Start your setting at 2 then decrease (higher number) until it starts to scum. Then increase the nip until you have a crisp, mottle free print with no flood!
     
  13. Buloke Times

    Buloke Times Member

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    Thanks William. That's one of the frustrating things. Even when I squeeze the forme and metering rollers tight together beyond the No. 4 setting on the nip it makes no difference. The plate doesn't scum and beads of water are still there. If I turn the knurled knobs and lift forme roller away from plate it does scum - but the beads of water continue!
     
  14. William Taylor

    William Taylor Senior Member

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    When the Kompac system is clean and dry, open the nip as far open as you can. Place a strip of 20# (80 gms) of bond in between the meter/form rollers. Close the nip until you can't pull the paper strip out. I just want to make sure that the pressure is there between the rollers.
    The only other thing I can think off is that the form roller is worn and therefore no longer adjustable to the meter roller.
    Maybe give Varn a shout. http://www.kompactech.com/
     
  15. FSA

    FSA Senior Member

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    Buloke Times
    Your form roller has too much nip to the plate, back it up.
     

  16. plotter

    plotter Senior Member

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    i took one of mine out a while ago when i had probs with it, sorry only just remembered.. One of the bearings was grinding and was very wobbly, even though it sat in a kind of seating. i replaced it reset the roller and then it was fine.
     
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