Gto printmaster impression problem

Discussion in 'Heidelberg Printing Presses' started by asem alsafady, Jan 19, 2018.

  1. asem alsafady

    asem alsafady Senior Member

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    Dear all,
    I have a strange problem in a 4colors Gto printmaster. Model 2001 50'000'000 impressions.
    When I print solid, the blanket won't take ink equally. (Photo is attached).
    I used a new blanket (1.95 mm), and calibrated packaging sheets (1.10mm).
    We know the different between blanket cylinder and bearer is (-3.00mm).
    Then I have(3.05-300=0.05 mm above bearer.
    The plate is (0.12mm above the bearer).
    Then I must achieve a pressure of (0.17 mm) between plate and blanket.
    The strange thing is that I measured the different between blanket and bearer using the dial gauge, it was (-0.12 mm???).
    Note: bearer on bearer adjustment between plate and blanket, blanket and impression cylinder was done.
     

    Attached Files:

  2. mantman

    mantman Senior Member

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    Are you absolutely certain that packing sheet thickness is 1.10mm? Measure with micrometer packing AND blanket thickness
    What do you mean bearer adjustment of plate to blanket was done??
    Gauge pin might be unscrewed ergo your -0.12mm
    You could try switching blanket from a known good tower to problematic so you can eliminate blanket+packing

    PS You print solid with no dampening i presume
     
  3. asem alsafady

    asem alsafady Senior Member

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    Dear mantman,
    Thanks for reply.
    I mean that I have checked the adjustment between plate bearer and blanket bearer using the feeler gauge 0.10 mm, and between blanket bearer and impression bearer 0.35 mm.
    And I measured the blanket and the calibrated sheets by micrometer.
    The gauge is ready and I used it regularly.
    It is strange because I used the same blankets and packaging for all units??
    And I am printing without dampening.
     
  4. CHOCK

    CHOCK Senior Member

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    Hi sir
    Good day
    Have questions:
    1) did you adjustment the rollers very well¿¿
    2) why are using without dampening¿¿
    3) the machine has suffered some Impact in the cylinders?
    4) would you check the cylinders are parallel¿¿
    5) is the packging from Plate -blanket-impression Good¿
    6) is the bearer very clean ¿¿
    7) are the rollers clean¿
    8) rollers bearig is working good¿
     
  5. asem alsafady

    asem alsafady Senior Member

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    Thanks Chock,
    Actually, I am repairing the machine for another customer, it is not my machine.
    They call me for a problem in printing, when I checked, I found that the printer used to use more packing sheets in order to see his image.
    I went back with the packing sheets to the standard, and tried to print, but the image was not appear clearly on the sheet.
    I am sorry to tell you that it is not a rollers problem.
    I cleaned the bearers, and adjust the bearer pressure, and made the impression on manually, and the result was the attached photo???
    The cylinders looked in good condition.
     
  6. mantman

    mantman Senior Member

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    Blanket to impression is 0.35 when dial at 0 is correct, as for plate to blanket bearer should touch without any gap, as far as i know there is an adjustment inside the frame -personally i wouldnt touch that, i would leave it to heidelberg techs- for bearers to come less/more in contact and check with compressible steel strips. You could do the fingerprint test of bearers to see how they transfer from plate to blanket
     
  7. junker1984

    junker1984 Senior Member

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    As was mentioned, hope tyou didn't try to make any adjustments on plate/blanket pressure without proper knowledge. You don't show in your picture the condition of image at lead/tail. Does image taper off from either? Have you dial indicated the run out of the cylinder with blanket removed. This does appear to be a caved cylinder...I do hope not.
     
  8. asem alsafady

    asem alsafady Senior Member

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    Thank you Junker,
    I have checked and adjusted the plate,blanket pressure several times and on several (old) machines.
    But at this machine strange things are happening, because I measured the difference between blanket cylinder and bearer at different areas from lead edge and tail edge. It was all (-0.12 mm).
    Thanks for your interest.
     
  9. junker1984

    junker1984 Senior Member

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    I understand that, but did you mount an indicator o the side frame and check cylinder run-out?
     
  10. asem alsafady

    asem alsafady Senior Member

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    No, just I used the gauge for measuring the bearers height, and on different areas of the blanket cylinder.
     
  11. junker1984

    junker1984 Senior Member

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    Won't tell you what you need to know.
     
  12. contractor

    contractor Member

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    Hi asem - junker is correct you must check the cylinder for damage with a dial indicator not a feeler gauge. By the sound of your post i would say you incorrectly adjusted the plate blanket and now you have problems. The blanket impression is correct at 0.35 with impression on and paper thickness on 0 at the dial on GTO printmaster. Plate to blanket has no gap it has pressure on the bearer via 2 eccentric bolts on either side. You really need to be trained on this before adjusting but rarely do you touch this. Generally its the blanket impression as that's the one that gets constantly changed because of paper thickness. The other stays constant.
    Good luck!
     
  13. mantman

    mantman Senior Member

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    IMHO he should check the transfer of bearers around from plate to blanket with fingerprint, if bearers tranfer properly it could be a cave in or journals bent.

    PS When operator used higher thicnkess did he have issues with registration?
     
  14. CHOCK

    CHOCK Senior Member

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    You must be trained and need
    tech documentation for
    properly use.
     
  15. junker1984

    junker1984 Senior Member

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    Psssst... wanna buy a watch?
     
  16. CHOCK

    CHOCK Senior Member

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    ¿¿¿¿
     
  17. contractor

    contractor Member

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    Showing your age junker no one buys watches anymore they buy i phones and they don't make pssst noises they tweet it.
     
  18. junker1984

    junker1984 Senior Member

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    Got me on that one, mate!
     
  19. alibryan

    alibryan Senior Member

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    Out of curiosity; what is a caved cylinder, and what can cause it?
     

  20. HPC

    HPC Senior Member

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    Dial indicator will tell you whats going on. We had a press do this, ran compressible blankets but registration was a problem, one day it became a big problem. We put a dial indicator on the impression cyl to find out the final grind had never been done on the impression cyl.
     
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