Spray problems sm52

Discussion in '4-Color Offset Presses +' started by PRINTENG, Nov 29, 2010.

  1. PRINTENG

    PRINTENG Member

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    ENGLAND
    I am using a Heidelberg SM52, I am having issues with over spraying, even though my air mixture dial is turned down to between 1 and 2 it is still over spraying, if I turn this down to 1 the job will set off. I have cleaned all filters - nozzles - tubes etc. Any suggestions would be greatly appreciated.

    cheers
     
  2. turbotom1052

    turbotom1052 Senior Member

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    what kind of powder unit?
     
  3. PRINTENG

    PRINTENG Member

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    Hi Sorry I should have said its a MEDIPRINT T-TECH
     
  4. turbotom1052

    turbotom1052 Senior Member

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    im not familiar with that unit but have you tried running a smaller powder. Id suggest a powder under 30 microns for most commercial applications. On a small press like that you might even be able to get down under 25 microns and still be safe. Do you make it a point to fluff your powder on a daily basis? Powder left in the powder hopper can get compacted (particularly with high pressroom humidity) and require a higher air flow just to get it moving through the lines. If you fluff your powder hopper on a daily basis before your first job in the morning you will have a better chance of getting the powder in suspension with a lower air flow through the unit.
     
  5. jmt

    jmt Senior Member

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    we have the same spray unit on are 52 .i have never liked the media print powder unit i can never find a happy meduim place to run the powder its either offsetting or way to much powder. we only run short runs on are sm longer runs go on are 74's so its not to bad .if your running longer runs on your sm i would look into getting the powder star unit.i ran a sm with one for years and its tens better than the media print unit much more control.i geuss that all depends if your company is willing to invest in one.i have mangaged to get the unit to run a little better by setting the individual nossel sprayers at about 75% and doing all your adjustments with the air mixture dial .right now i can run a heavy coverage job at about 1 1/2 air mixture and having better results.but it has taken a few months of trail and error(and a few reprints) to find the correct setting. good luck.
     
  6. tim enigma

    tim enigma Senior Member

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    on the pm52 i run, i set the individual nozzle sprayers at just under 50% and set the overall just under 1 and it seems to work good. it does still underspray or over spray at times, but this has been the best setting i have found. i believe we use varn 20 micron powder. also before i start running in the morning i stir up the powder good and also blow compressed air through the lines. dont know why this helps, but ever since i started to blow air through i had had way less problems.
     
  7. jmt

    jmt Senior Member

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    we are still having probs with are unit .even with weekly and daily maintance.just wondering what powder are you all using on that unit.we are using varn c270.
     

  8. Pressman Jay

    Pressman Jay Member

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    Dec 2011
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    It's funny, on our 52, we run the same varn powder, I think the same spray box, set at 1-2 and every Friday it looks like Christmas in the delivery! So we clean it out,

    later, rinse and repeat....

    If we turn it down lower it too will set off.
    I feel your pain...
     
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