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Outer walls "shrink" during printing  

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LitoWelt
(@litowelt)
Active Member
Outer walls "shrink" during printing

Hello all,

I currently have the problem that when I print something, the outer walls in the middle "shrink". First layer and top layer fit, but in between it looks like it is shrinking.

Printer is a Prusa i3 Mk3S with Prusament PETG. Print settings are close to standard, the only thing I had to do since the hotend change is to set the print temperatures extremely low. Otherwise there was stringing without end. Currently I am printing the PETG at 225°C, but I strongly suspect that the read temperature is not correct. At 225°C it behaves now as before the Hotend exchange ( It is a original V6 with Prusa components). Problems were also before, so is not only with the exchange arose.

I have attached a picture. Left is first layer and right the top layer 😉

Otherwise, I have already checked and calibrated everything possible, travels should also fit (of all axes).

Does anyone have an idea where something like this can come from? Firmware and Prusa Slicer are up to date.

 

Greetings

Sascha

Posted : 06/11/2022 10:02 pm
Tim Weston
(@tim-weston)
Estimable Member
RE: Outer walls "shrink" during printing

Please post a zipped version of the .3mf project file. With that we can get a much better idea of what the model is, and the settings that you are using to slice and print it.

Cheers,

Tim

Posted : 06/11/2022 10:17 pm
LitoWelt liked
LitoWelt
(@litowelt)
Active Member
Topic starter answered:
RE: Outer walls "shrink" during printing

The original .3mf file is a little bit difficult because of licence problems 😉

But i also printed some benchys with 100% original prusa settings. And there you can see the same issues.

Settings:
- 0.2 quality preset
- Prusament PETG preset
- Prusa i3 MK3s preset

Posted : 06/11/2022 10:30 pm
jsw
 jsw
(@jsw)
Famed Member
RE: Outer walls "shrink" during printing

The bulge on one side of your original print looks like it may be over-compensated 'elephant foot' compensation and the other side looks like the common bulge that some prints get on many printers when transitioning from a hollow section to a solid (top) section.

Posted : 06/11/2022 10:55 pm
LitoWelt liked
Tim Weston
(@tim-weston)
Estimable Member
RE: Outer walls "shrink" during printing

As jsw said, it certainly looks like the 'bulge' problem. There is lots on here about that - have a search for 'bulge' and 'buldge'.

That said it does look more accentuated than I am accustomed to seeing on a 'benchy', so maybe there is something else at work.

If you can post the zipped .3mf file for that benchy, I'll try printing one on my machine for a comparison.

Cheers,

Tim

Posted : 07/11/2022 3:59 pm
LitoWelt
(@litowelt)
Active Member
Topic starter answered:
RE: Outer walls "shrink" during printing

Thank you both for you excellent help! The "elephant foot" compensation was on stock settings, by increasing it from 0.2 to 0.3mm i get much better results. Only the other "bulge" is still there. And i know that the printer could do a much better job, because in the beginning it was not so much visible. But thank you for the tip, i will search in the forum for a solution for this problem

@Tim: Attached is the 3mf for the benchy and also for the model from the picture i posted in the start post. It is not the whole model, i had to cut it in the middle. But the round section (this is the part you see on the photo) and a little bit more from the rest of the model is still there.

Posted : 07/11/2022 5:29 pm
Tim Weston
(@tim-weston)
Estimable Member
RE: Outer walls "shrink" during printing

Coming back to this...

I printed your 'benchy' file and also got a noticeable (finger-feelable) bulge on the transition line. All the other printed 'benchies' I have show some artefact in the same place but it is barely visible. I sliced the file with the 'Arachne' perimeter generator. For comparison I will print one with the 'Classic' generator to see if there is a difference.

I'll post back in due course,

Cheers,

Tim

Posted : 11/11/2022 3:38 pm
LitoWelt
(@litowelt)
Active Member
Topic starter answered:
RE: Outer walls "shrink" during printing

Hi Tim,

sounds good (not good for me, but good that you can see the same issue with my file 😉 ). Thank you very much for your help!!! Could you upload your 3mf file so that i can test it on my printer?

Cheers,

Sascha

Posted : 14/11/2022 9:50 pm
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