Failed prints - middle layers warping (?)
 
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bartlomiej.s
(@bartlomiej-s)
Active Member
Failed prints - middle layers warping (?)

Dear more experienced users,

My print failed in a weird (at least for me) way, don't even know how to describe it, picture speaks a thousand words:

https://photos.app.goo.gl/irHinnzMRL44XH9z2
https://photos.app.goo.gl/n6N8fTWUWIIOtkC73

In this print, first 3 flat layers printed nicely, outline and infill also did not showcase any problems. Then, on top of infill there was another three flat layers, third of which you can see in the pictures bending and coming off from the center.

Printed using:

  • PLA, default Prusa's Slic3r settings (215/205 hotend, 60 bed)

  • Layer height: FAST 35mm

  • Printer is in open enclosure (5 out of 6 Plexiglas walls, more ore less uniform temperature of around 30 - 35 Celsius degrees inside)
  • Additional information:

  • This happened multiple times, also with different PLA spool and an ABS filament

  • This happened with another object, partially similar (rectangular, relatively large)

  • In between prints, I've even replaced a nozzle with a brand new one, re calibrated the printer and adjusted Z correction. Did not help, although the overall first layer quality, and many other thinks visibly improved after replacing the nozzle.
  • It only happens with large, flat (also rectangular) surfaces, and it happens pretty consistently. Other prints turn out pretty good. First layers, infill, outlines, bed stickiness etc. all seems intact.

    Any suggestions are greatly appreciated, thanks in advance!

    Cheers,
    Bartlomiej

    Napsal : 04/03/2018 10:56 pm
    alexander.s27
    (@alexander-s27)
    Estimable Member
    Re: Failed prints - middle layers warping (?)

    Obviously there is no layer bonding between the topmost faulty layer and the one below.
    Reason could be the temperature too low and /or to much cooling.
    As far as I could determine on the pictures other settings as multiplier are quite ok.

    Edit: Could be something mechanical as bent rods e.g., too.

    Napsal : 05/03/2018 7:26 am
    bartlomiej.s
    (@bartlomiej-s)
    Active Member
    Topic starter answered:
    Re: Failed prints - middle layers warping (?)

    Thanks for the suggestion!

    I've increased the extruder temperature to 215/210 and decreased cooling to 75% - 100%, same thing happened, although I think one layer later.

    Right now I reduced cooling down to 50% - 75%, will see the result within half an hour. Funny thing is, for a long time I was able to print similar objects with much lower temperatures, I have no idea what changed in the meantime.

    Napsal : 05/03/2018 9:01 pm
    Nikolai
    (@nikolai)
    Noble Member
    Re: Failed prints - middle layers warping (?)

    I would guess the layer height of 0.35 with a 0.4 nozzle is a little bit too high. You shouldn't go more the 1/2 the nozzle diameter.
    Check this site for reference.

    Often linked posts:
    Going small with MMU2
    Real Multi Material
    My prints on Instagram

    Napsal : 06/03/2018 1:14 am
    bartlomiej.s
    (@bartlomiej-s)
    Active Member
    Topic starter answered:
    Re: Failed prints - middle layers warping (?)

    Yes, I figured that out yesterday. I changed the filament for a one with bright colour to see any imperfections, changed the layer height to 0.3mm and live tuned everything until I got perfectly covered flat layers. I'm still not there yet, as I've ran into some other troubles, but I should have it working today, I'll post the final settings that work.

    As a side note, this is a little confusing as Prusa's Slicer comes with predefined settings for 0.35mm layer height (I think the previous version even had a 0.4mm fast setting). Also no more than a month ago I've printed a large, rough part (even few copies!) with a 0.40mm without any troubles, at first try with no adjustments on my part. That's why it came as a surprise.

    Thanks for clearing the layer height issue for me!

    Napsal : 06/03/2018 9:03 am
    bartlomiej.s
    (@bartlomiej-s)
    Active Member
    Topic starter answered:
    Re: Failed prints - middle layers warping (?)

    As it happens, nikolai.r was completely right about the layer height. The above print turned out nicely with layer height of 0.2 mm but I also gave a shot at 0.3 mm and it went fine (considerably lower quality, but no "structural" issues like on the pictures).

    Thanks for help!

    Napsal : 07/03/2018 1:47 pm
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