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Adalinda leg breaking off  

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erwin.b
(@erwin-b)
Active Member
Adalinda leg breaking off

Hi everyone,

I finished building and calibrating my prusa i3 MK2 yesterday and managed to succesfully print the vase.
So I decided it was time to try a more difficult object, analinda!

It started printing nicely, but when I checked a few hours later I noticed the left leg broke away.
Any idea what I need to do to fix this? Getting the feeling that the leg let go of the heated bed halfway in or something.
I have searched this forum and saw others had this problem, but couldn't really find a solution or somewhere to look to start fixing the problem?

Postato : 31/08/2016 3:10 pm
David T.
(@david-t)
Noble Member
Re: Adalinda leg breaking off

I think it's the problem of adhesion (lack of). Looking at the skirt I guess the first layer is too high, but the image quality is rather poor. Please print the PRUSA logo and show us the photo of first layer (bottom).

Postato : 31/08/2016 3:36 pm
miferr
(@miferr)
Trusted Member
Re: Adalinda leg breaking off

Both legs on mine broke, too, but it definitely wasn't an adhesion issue. The hands were stuck on very well--in fact they were difficult to remove--but the legs broke all the same, so I think there might be a separate issue.

I started the print before going to bed, but before I left it, it had passed the break on the bottom of the leg on the right side of the picture (the dragon's left). It was not broken at that time, but I did notice a curl of plastic that came out around point where it eventually broke. You can still see the curl sticking out in the picture. In the morning, the leg was gone, as you see here. The leg was found pretty far from the printer, so it must have snapped with some force.

On the left side of the picture, the leg looked whole, but it broke when I removed the print. I thought I broke it while removing the print, but I noticed later that you can see the location of the crack in the picture. In fact, it seems to have happened in the exact same location as Erwin.

Here are my hypotheses on what may have happened. I do not plan on printing it again though; that's a lot of time and plastic!

  • My probe was really low at the time. It was above the nozzle, but very close to brushing the plastic. I thought maybe a piece that stuck out could have caught on the probe...but that doesn't explain the break on the left.

  • Could it be that the 9-point auto-leveling causes an issue with this print? If each leg starts in a different quadrant, perhaps the geometry does not quite line up when the pieces join back together? Maybe reslicing it so that the whole model is in one corner of the bed would help?

  • Perhaps there is a cooling or temperature issue that causes some layers to separate?
  • Postato : 31/08/2016 5:30 pm
    erwin.b
    (@erwin-b)
    Active Member
    Topic starter answered:
    Re: Adalinda leg breaking off

    I added a picture of the first layer of the prusa logo.
    Also with a better quality camera this time.

    If it's adhesion could it be wrong of me to clean the bed with glassex glas & multi cleaner?
    I have looked at some reddit posts where people had trouble getting things to stick properly if it wasnt cleaned with a certain brand of window cleaner?

    Postato : 31/08/2016 6:04 pm
    David T.
    (@david-t)
    Noble Member
    Re: Adalinda leg breaking off

    Go a bit lower using live Z adjust. I guess about 50um. There should be no gaps between perimeters and infill, also no gaps between infill lines themselves.
    Regarding window cleaners - my advice is: don't use them. Use rubbing alcohol or clean IPA (best choice). Window cleaners often contain additives affecting adhesion.

    Postato : 31/08/2016 7:24 pm
    erwin.b
    (@erwin-b)
    Active Member
    Topic starter answered:
    Re: Adalinda leg breaking off

    Hi david, thanks for your advice so far.
    I have tried moving the z live adjust further down, but it needed to go down more then 1 mm before the PLA sticked again.
    So i installed the pinda probe a tat higher and calibrated the printer again, but this time around nothing would stick.
    Lowered the pinda probe back, calibrated, played with the z live adjust until everything in the zig/zag line would stick properly again.
    Switched the window cleaner for rubbing alcohol (IPA is gonna come in somewhere today).
    Printed the Prusa logo without much trouble (still far fro where it should be, but good enough for a test run imo) so I decided to print the treefrog and the result well ermmm a picture says more I think

    I'm a bit scared of lowering the nozzle even further because I don't want the hot nozzle to hit the heatbed.
    I have no idea on what to change in/on the printer to get a better result so any insight or help is greatly appreciated.

    Postato : 02/09/2016 9:03 am
    David T.
    (@david-t)
    Noble Member
    Re: Adalinda leg breaking off

    Does your cooling fan work?

    Postato : 02/09/2016 9:31 am
    erwin.b
    (@erwin-b)
    Active Member
    Topic starter answered:
    Re: Adalinda leg breaking off

    The little one does, it starts spinning at 50 degrees.
    How do I check the large one? Doesn't seem to turn on when preheating?

    Postato : 02/09/2016 9:44 am
    David T.
    (@david-t)
    Noble Member
    Re: Adalinda leg breaking off

    It should start spinning at second layer of print when printing from PLA (never with ABS).
    You can check it's working while the printer is idle, use menu commands, set its value to 255, it should spin at maximum rpm. Then set to 216 (85%), that's some default value used by PLA Slic3r profile. It should spin a bit slower.

    If it doesn't spin at all, check its wiring, especially connector polarity.

    Postato : 02/09/2016 10:01 am
    Bill W
    (@bill-w)
    Trusted Member
    Re: Adalinda leg breaking off

    I had similar breakage with a different thing I was printing. It had a three tall narrow pieces and a few times one of the three would break printing near the top. I added Z-hop of 0.15 as in the Simplify3d profile that Prusa posted and that seems to have fixed the problem.

    What I think was happening was that the part became ever so slightly twisted and caused interference during movement with the extruder. Even when one didn't break I could sometimes hear a click as it moved from one part to the next but only high up during the print.

    Bill W
    "Even old dogs can learn new tricks!"

    Postato : 03/09/2016 4:34 am
    erwin.b
    (@erwin-b)
    Active Member
    Topic starter answered:
    Re: Adalinda leg breaking off

    Thanks again David.
    I tried everything you suggested, but the fan won't turn on whatever I try.
    So I contacted support and they're sending a replacement next Monday.

    Postato : 03/09/2016 4:30 pm
    erwin.b
    (@erwin-b)
    Active Member
    Topic starter answered:
    Re: Adalinda leg breaking off

    Ok so installed the new fan, re-adjusted the z-axis like David suggested and cleaned with IPA and guess what.
    It works wonders! Been printing non-stop since yesterday, thanks for all the help, greatly appreciated.

    Postato : 09/09/2016 3:41 pm
    carlos.p
    (@carlos-p)
    New Member
    Re: Adalinda leg breaking off

    Hi,

    I printed several times the tree frog and one of the front leg fell off and cleaning it with alcohol but didn't worked, so I tried an all purpose cleaner and now both front legs are not sticking. I just read in this forum that some cleaners can affect the adhesion. I cleaned it with pharmacy alcohol to remove the cleaner and the legs still not sticking. Somebody know what can I do to get adhesion again and save the PEI sheet? Thanks

    Postato : 13/09/2016 8:10 pm
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