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A different kind of PETG issue  

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crazymittens
(@crazymittens)
New Member
A different kind of PETG issue

Very strange PETG issue I've been experiencing lately (my sense is last 6mo or so, but is consistent now).

  • MK3S w. smooth sheet (using normal glue stick to help w. separation)
  • Enclosure w. circulation fan, external power supply mount, fan w. shroud for Einsy board air circulation, top-mounted exhaust fan w. charcoal and hepa filter.
  • Prusaslicer w. 0.15mm QUALITY preset
  • Prusament PETG w. Prusament PETG preset
  • the parts are not warping; they stay firmly adhered to the bed
  • no layer shifting or any other blemishes
  • detail seems to be fine aside from this strange malforming

Link to full picture here (details showing problem being cut off): https://imgur.com/gallery/petg-printing-issue-6sLz7yW

I can print PLA perfectly square, zero exhibition of this issue.

Open to suggestions!

Posted : 25/06/2024 12:44 am
crazymittens
(@crazymittens)
New Member
Topic starter answered:
RE: A different kind of PETG issue

I tried changing to a different roll of Prusament PETG, same result.  On a small object, much less impacted.  On something ~100mm long, it shows up again.

It's been suggested I try drying the filament, so will get a dryer ordered.

Posted : 25/06/2024 2:26 pm
Eef
 Eef
(@eef)
Reputable Member
RE: A different kind of PETG issue

I do not know what causes this exactly. I guess either the moisture (as already said) or maybe changing temperatures. 
There is a variation in flow, what causes the dimensions to change. 

Suggestion is to print it in an 45 degree angle, so with  supports (paint them on) just where the model touches the bed, and maybe at 1/3 and 2/3 of the height. 
Layers are then shorter. 

We will do what we have always done. We will find hope in the impossible.

Posted : 25/06/2024 8:08 pm
Eef
 Eef
(@eef)
Reputable Member
RE: A different kind of PETG issue

See this plugin: https://plugins.octoprint.org/plugins/bedlevelvisualizer/  

And for the 45 degree angle this is a nice video

We will do what we have always done. We will find hope in the impossible.

Posted : 26/06/2024 4:02 am
crazymittens
(@crazymittens)
New Member
Topic starter answered:
RE: A different kind of PETG issue

Thanks, Eef.  I will try the 45-degree test today.  Haha I've been watching Slant3D on youtube for a while now.

The only temperature variations would be 'slowly increasing' due to the enclosure.

If no joy from 45-deg, will be getting a dryer as next step.

Posted : 26/06/2024 11:33 am
crazymittens
(@crazymittens)
New Member
Topic starter answered:
RE: A different kind of PETG issue

Update.   Tried the 45-deg test, I did it wrong and it was terrible.  Shelving this for now.

I ran the belt test and both x and y belts were loose.  Tightened them up, and while I was in there discovered a few loose m3 bolts and tightened those.  Post-maintenance, PLA now prints with 0.00mm vertical runout, but PETG still exhibiting the same runout as before (0.30-0.40mm over 10mm), a mild improvement.  I ran the dryer on the PETG overnight (12hrs@65c) and no change to runout.  Am now trying the 0.05mm 'ultradetail' preset.

Only items left to check are replacing the nozzle and replacing the belts entirely (y-axis belt is green, but not 'middle of green').  At any rate, now that I have PLA printing perfectly, I might just switch to using that for dimensionally-critical parts and accept this foe is beyond me.

Posted : 30/06/2024 6:16 pm
EssaMattou
(@essamattou)
Member
RE: A different kind of PETG issue
Posted by: @crazymittens Head Soccer

Thanks, Eef.  I will try the 45-degree test today.  Haha I've been watching Slant3D on youtube for a while now.

The only temperature variations would be 'slowly increasing' due to the enclosure.

If no joy from 45-deg, will be getting a dryer as next step.

Your plan sounds good! The 45-degree test should reveal airflow or temperature issues. Watching Slant3D can teach you setup tricks.

The test may not show what you want, so a dryer can help adjust humidity and temperature. Just watch the environment to avoid overheating.

Posted : 29/07/2024 3:55 am
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