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Issue: My Ender 3 is creating distorted prints with layer separation and deformations.

Example Here

Can anyone point me in the right direction?

Setup:

  • Ender 3
  • TH3D EZABL Auto Bed Leveling
  • 1.75 mm ABS filament (245 °C)
  • Heated Bed (100 °C)
  • Sliced in Ultimaker Cura (with 1.75 mm filament diameter and 0.2 mm layer height)

What I have tried:

  1. Tightening Z axis screw
  2. Tightening Y axis belt
  3. Tightening X axis belt
  4. Switching to a different spool of ABS
  5. Printing a temperature tower (same problem across different temperatures)
  6. Turning off the auto bed leveling.

Update:

  1. I've measured the temperature of the hot end, it is reading around 205°C +- 20°C
  2. As per suggestion from the TH3D support team, I tuned the PID of my hot end. Unfortunately the results did not turn out much better (1,2) and the support technician is suggesting(a long with many people from the comments) that I should try to replace the thermistor. As per suggestion from @Trish, I measured the impedence of the thermistor and it does seem to be somewhat off from stock (118kΩ vs 100kΩ). Will update again once the replacement arrives.
  3. As requested, here are some more photos front, back, left side, right side. The cube isn't hollowed out just to save material while I calibrate the dimensions.
  4. I printed the same cube out, rotated 90 degrees. I got similar results though: front, back, left side, right side.
  5. Swapping the nozzle out solved the issue! Thanks for the help everyone!
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    $\begingroup$ Welcome to 3dPrinting.SE! $\endgroup$
    – Pᴀᴜʟsᴛᴇʀ2
    Feb 26, 2019 at 18:49
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    $\begingroup$ What is the diameter of the filament in Ultimaker Cura, default this is 2.85 mm. This looks like an underextruded printed part. $\endgroup$
    – 0scar ♦
    Feb 26, 2019 at 19:05
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    $\begingroup$ 245° ABS? The average ABS is listed somewhat lower, about 230 °C. $\endgroup$
    – Trish
    Feb 26, 2019 at 19:21
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    $\begingroup$ Have you done successful prints with another filament type (e.g. PLA)? $\endgroup$
    – Mick
    Feb 26, 2019 at 19:53
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    $\begingroup$ carefully inspecting the photo, it seems that yoru filament is either too hot or you have underextrusion for other reasons. $\endgroup$
    – Trish
    Feb 26, 2019 at 22:55

1 Answer 1

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Resolution: After many trials and errors, I finally replaced the nozzle with one that that was not partially blocked by filament at its entrance.

Likely cause: A careful examination of the old part hints, that the repeated blockage in the nozzle seems to have been caused by a gap between the PTFE tube and the nozzle, which has considerably moved backwards under the stress of printing as one can see here in a photo of the PTFE tube.

It took me about a month and I went down a few rabbit holes until @user77232 made a great suggestion to check the nozzle and see if it needs to be cleaned. Thanks for helping me out everyone!

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    $\begingroup$ Would you have any idea as to why their would be buildup around between the thread of the nozzle? - Dust can get onto the filament (like cement dust) or burnt filament which can clog a nozzle. Metal flakes from the tip of brass nozzle as it wears can also get sucked in when the retraction occurs. $\endgroup$
    – user77232
    Mar 22, 2019 at 21:28
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    $\begingroup$ @user77232 I can think if more causes: the tube might not be fastened correctly and slip ever so slightly, or it was cut slanted. Or, as you also said, the nozzle was bent/worn, creating the blockage $\endgroup$
    – Trish
    Mar 22, 2019 at 22:09
  • $\begingroup$ @user77232, here is a photo of the nozzle. It's a bit hard to see but there is a ring of plastic at the end of the nozzle. I am guessing that I didn't properly insert the tube back or it shifted out of place somehow (I also swapped the fitting just in case). $\endgroup$
    – Dr. Mantis Tobbogan
    Mar 22, 2019 at 23:20
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    $\begingroup$ the photo of the frizzled PTFE shows, that part of the reason might be the clamp holding the PTFE in the hotend - the tube might have slipped, bit by bit. $\endgroup$
    – Trish
    Mar 23, 2019 at 21:00
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    $\begingroup$ This has been a common-enough issue that there's a well-designed fix for it: thingiverse.com/thing:3203831 Essentially it involves using two sections of PTFE tube, one inside the hot-end throat and tightened down using a washer and the bowden tube fitting itself. Then the second tube is used as a bowden tube to feed filament into the hot-end. The bowden fitting's ring is no longer responsible for keeping the tube in the throat flush. $\endgroup$
    – GDorn
    Jun 30, 2019 at 23:57

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