Horrible quality on a round object with overhang on all sides
 
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Slople
(@slople)
Eminent Member
Horrible quality on a round object with overhang on all sides

Hello everyone

first post here, huge fan of Prusa and my MK3s.

I print really complicated geometries in PETG without any problems, but on this seemingly easy object, I'm having massive troubles with really ugly (unusable) overhangs.

Tried it with 0.2mm, 0.15mm default profiles, results are similar.

Any idea what I could try?

Using supports and printing it the other way around is not possible due to various reasons.

view in slicer

orthogonal, analysis view in Fusion 360 of both parts stacked

resulting print

It always seems to fail at the same height. It prints fine in PLA.

Out of ideas, looking for any input 🙂

Thanks,
Raphi

Posted : 02/03/2022 1:07 pm
Slople
(@slople)
Eminent Member
Topic starter answered:
RE: Horrible quality on a round object with overhang on all sides

lol, first post and wrong subforum, sorry. This is an MK3s...

If you're asking "why no supports":

  1. all angles are less than 45 degrees, so should be unnecessary
  2. the lower part has a 0.2mm layer at the very bottom, which closes the "tube", this would never work with supports. It's only 0.2mm thin, and I set the slicer to print it as 2 x 0.1mm layers which works perfect.
  3. this is a small serial production product, so removing supports from 200 pieces is... cumbersome
Posted : 02/03/2022 1:19 pm
Bob
 Bob
(@bob-2)
Reputable Member
RE: Horrible quality on a round object with overhang on all sides

You might want to repost your photo, that's an admirable photo of your thumb, or finger or big toe, if there's a flaw there you're doing a remarkable job of covering it up.  I do see some funkiness there, but it's not the focal point of the photo.  Perhaps a photo with the flaw as the star of the photo would help.  If you want to hilight it put a red circle around it.

Cheers

-Bob

Prusa I3 Mk2 kit upgraded to Mk2.5s, Ender3 with many mods, Prusa Mini kit with Bondtech heat break, Prusa I3 Mk3s+ kit

Posted : 02/03/2022 4:08 pm
Slople
(@slople)
Eminent Member
Topic starter answered:
RE:

Thanks Bob 😀

i will, later. Laying in bed shivering of C19.

you should see it if you enlarge it. 

This post was modified 2 years ago by Slople
Posted : 02/03/2022 5:42 pm
Slople
(@slople)
Eminent Member
Topic starter answered:
RE: Horrible quality on a round object with overhang on all sides

Hope you see it better now 🙂

Any idea?

Posted : 03/03/2022 3:27 pm
Slople
(@slople)
Eminent Member
Topic starter answered:
RE: Horrible quality on a round object with overhang on all sides

Anyone any idea?

Posted : 04/03/2022 12:40 pm
Bob
 Bob
(@bob-2)
Reputable Member
RE: Horrible quality on a round object with overhang on all sides

The only thing I can think of is wet filament, but I'd expect it to be represented by the entire print not half of it.  What is the filament?  Have you tried printing this with a different filament?

Looking at the photo again, on the upper right it seems there's a patch without funkiness.  Is this only on one side?  If so maybe a grub screw came loose and loosed a belt and either your X or Y axis has some slop in it.

Cheers

-Bob

Prusa I3 Mk2 kit upgraded to Mk2.5s, Ender3 with many mods, Prusa Mini kit with Bondtech heat break, Prusa I3 Mk3s+ kit

Posted : 04/03/2022 4:19 pm
Slople
(@slople)
Eminent Member
Topic starter answered:
RE: Horrible quality on a round object with overhang on all sides

It‘s Prusament PETG. 
I can try this exact same geometry again with PLA. Earlier versions printed in PLA without any problems… 

the problems are all around the object, starting on the same height (more or less). 
Otherwise I would have thought of cooling issues, but as I said, it‘s rotationnally symmetrical. 

Posted : 04/03/2022 5:33 pm
Bob
 Bob
(@bob-2)
Reputable Member
RE: Horrible quality on a round object with overhang on all sides

How long has that filament been open?  PETG is less forgiving with wet filament than PLA.

Regards

-Bob

Prusa I3 Mk2 kit upgraded to Mk2.5s, Ender3 with many mods, Prusa Mini kit with Bondtech heat break, Prusa I3 Mk3s+ kit

Posted : 04/03/2022 6:38 pm
Slople
(@slople)
Eminent Member
Topic starter answered:
RE: Horrible quality on a round object with overhang on all sides

4-6 weeks in a dry room. Other objects print fine with it… and the probleme always start on the same height!

Posted : 04/03/2022 6:49 pm
Bob
 Bob
(@bob-2)
Reputable Member
RE: Horrible quality on a round object with overhang on all sides

If it's always at the same height then it's got to be mechanical.  Not sure how to help you with that.  Print something small but tall and watch it when it goes awry and see if you can isolate it.

Cheers

-Bob

Prusa I3 Mk2 kit upgraded to Mk2.5s, Ender3 with many mods, Prusa Mini kit with Bondtech heat break, Prusa I3 Mk3s+ kit

Posted : 04/03/2022 11:03 pm
towlerg
(@towlerg)
Noble Member
RE: Horrible quality on a round object with overhang on all sides

Is the funkiness happening at the height where the horizontal faces of the pink and yellow touch?

Posted : 05/03/2022 1:11 pm
Slople
(@slople)
Eminent Member
Topic starter answered:
RE: Horrible quality on a round object with overhang on all sides

I would say so, yes!?

Posted : 05/03/2022 1:31 pm
Diem
 Diem
(@diem)
Illustrious Member

What density percentage is your infill?

Cheerio,

Posted : 05/03/2022 5:30 pm
Slople
(@slople)
Eminent Member
Topic starter answered:
RE:

15%, and 4 walls vertical. 
should I upload the sliced file?

This post was modified 2 years ago by Slople
Posted : 05/03/2022 6:36 pm
Slople
(@slople)
Eminent Member
Topic starter answered:
RE: Horrible quality on a round object with overhang on all sides

Archiv 4

attached you will find the stl and gcode file.
I really appreciate any help in this!

I just reprinted it in vase mode, just to test the outer geometry and look for mechanical problems. It printed PERFECT. I don't understand this!?

Now splitted it into two halves at the height where the funkyness starts and print it separately, not that this would be a solution, but to understand the problem better, hopefully.

Posted : 07/03/2022 12:00 pm
towlerg
(@towlerg)
Noble Member
RE: Horrible quality on a round object with overhang on all sides

What is the designed thickness in the funky area?

Posted : 07/03/2022 1:25 pm
Slople
(@slople)
Eminent Member
Topic starter answered:
RE: Horrible quality on a round object with overhang on all sides

Around 1mm...

Did you see the attached "Archiv 4" file containing the stl and gcode?
Maybe it has to do with the change from a octagon to a circle, leading to many changes in wall thickness around the perimeter and per layer...

If someone of you would be fancy to print it, I would be very happy to see the results.

I'm not a pro in the slicer-game, maybe that's the culprit?

Posted : 07/03/2022 2:27 pm
Neophyl
(@neophyl)
Illustrious Member
RE: Horrible quality on a round object with overhang on all sides

Unfortunately my printer is busy at the moment with other projects.  Might be able to free up some time later in the week though to try a few prints.

First thing that springs to mind though after slicing the part for a default mk3 and with a 0.2 quality profile is that where you have the problem areas is exactly where PS is using solid infill.  Solid infill like that can cause excessive heat in those areas and can (and often does) cause issues like you are seeing.
My initial suggestion is to increase your perimeter count by 1 and try a print.  That replaces the solid infill with perimeters.  It might not help in this case but its my first instinct.

Posted : 07/03/2022 2:44 pm
Slople
(@slople)
Eminent Member
Topic starter answered:
RE: Horrible quality on a round object with overhang on all sides

Thank you so much.

So, you mean using 3 perimeters (from default 2) or from my 4 to 5? I already printed it with 4 perimeters...

Posted : 07/03/2022 4:20 pm
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