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Unanswered Part cooling fan configuration.

Discussion in 'Troubleshooting' started by Oisin, Oct 25, 2016.

  1. Geof

    Geof Volunteer Moderator
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    If your using ones like mine you should have no issues with new fans
     
  2. Oisin

    Oisin Member

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    The shrouds won't fit 40 X 20mm fans though. I'll modify them when I get the chance.
     
  3. Oisin

    Oisin Member

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    Okay I got the 40 x 20mm fans. They managed to fit in to your shrouds, Geof. I did a few test prints and still can't print overhangs well despite much better airflow. I put it down to the enclosure capturing and holding heat from the bed. That hot air was then being blown over the print instead of cold air. I removed the enclosure and had slightly better results. Nothing to shout about.

    So what I've got so far:
    Printing at 180C and 40C on the bed.
    No enclosure, so cool air.
    Dual 40 x 20mm fans. Lots of airflow.
    Printing at 20mm/s. (Also tried at 40mm/s).
    Printing at 0.1mm. (Also tried 0.2mm).

    Can anyone think of why quality overhangs are not doable with the above setup? I see curl immediately after the first layer of the overhang goes down.
     
  4. Rigmarol

    Rigmarol Well-Known Member

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    I get curls on overhangs too but they seem to even out as the next layers get layed down.
    That's just me and I'm pretty easy to please.
     
  5. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Maybe a picture?
     
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  6. Rigmarol

    Rigmarol Well-Known Member

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    I have none, but if do one soon i'll try. I might try a calibration print later, I've never done one with overhangs. Suggestions?

    Sent from my SM-N910P using Tapatalk
     
  7. Oisin

    Oisin Member

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    This is an image I posted earlier in the thread but it's the same thing that's happening now. Any overhang at all immediately curls. The best success I had was at 190C with no enclosure at 0.2mm. It wasn't amazing but it was the best I've had so far. However I never print with 0.2 so that's not much good to me. It was an accidental slice at that layer height.

    Trying a different model now.
     

    Attached Files:

  8. Rigmarol

    Rigmarol Well-Known Member

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    Lol, sorry I thought he was asking me for a picture.. I can be so self centered...

    Sent from my SM-N910P using Tapatalk
     
  9. Oisin

    Oisin Member

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    It's okay Rigmarol :) It'd still like to see pictures of your overhangs to compare mine.
     
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  10. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    That is not an overhang, at least not in common use 3D printing terminology :)
    It is flat on the bed. Overhangs are literally that ... bits of layers that hang out over the air (unsupported by anything).

    What you are seeing there may be an issue with the nozzle coming back over a part too soon. If so that is a slicer configuration.
    Usually it happens when a layer gets small and a new layer goes down on one still plastic/hot, but you can get the same effect if your lines of filament are close and put down next to each other too quickly.

    Start by trying another slicer. Perhaps slowdown the layer speed, but really another slicer.

    edit: the slicer should avoid toolpaths that do that sort of thing, but you can help it with more parts cooling fan.
     
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  11. Oisin

    Oisin Member

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    I can assure you that it happens from that point all the way up. On the few occasions I got the overhang to print for a few layers, this happened further upwards. What you see in that image is the beginning of a 70 degree overhang.

    The time between when the nozzle passes over that part of the print on one layer to when it passed over it again was 4 minutes. 4 minutes per layer with 2 40X20mm fans on 100% with no enclosure. Not sure what more I can add. I can't seem so solve this issue. The speed was already 20mm/s and the slicer is Simplify3D.
     
  12. Geof

    Geof Volunteer Moderator
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    @Oisin are you always trying the same file ? Maybe attach it and I'll try to printing of you?
     
  13. Oisin

    Oisin Member

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    Yes, Geof. I appreciate that offer. I can't attach my gcode file since it's too big, but I've attached the STL. It'll be interesting to see how your machine deals with it.
     

    Attached Files:

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  14. Rigmarol

    Rigmarol Well-Known Member

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    I will try printing it too with pictures.
     
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  15. Oisin

    Oisin Member

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    Thanks very much Rigmarol.
     
  16. Geof

    Geof Volunteer Moderator
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    @Oisin your stl is currently printing. Ill post some pics when its done. Shows roughly 2 hrs on the estimate.
     
  17. Rigmarol

    Rigmarol Well-Known Member

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    Mine will take 3 hours 15 minutes and I just started it at 6:20pm pst.

    Sent from my SM-N910P using Tapatalk
     
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  18. Rigmarol

    Rigmarol Well-Known Member

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    With a raft lol.

    Sent from my SM-N910P using Tapatalk
     
  19. Oisin

    Oisin Member

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    Thank you both very much. If the overhangs print fine at 0.2mm, can they be expected to print fine at 0.1mm or lower?
     
  20. Geof

    Geof Volunteer Moderator
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    Yes more or less.
     

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