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LoaderB0T
(@loaderb0t)
New Member
Weird consistent layer shifting

Hi all!

I have a really annoying problem with a model I created.

Screenshots of the model can be found here and here. You can download the current STL of it here.

All of the prints (I did like 8 of them) have the same layer shift at the same location but my model and gcode looks correct to me.

The shirt happens where the outside cylinder joins the circle. You can see it here, here and here.

Those pictures are from prints with PLA. And here is a picture of a currently running ABS print with the exact same issue.

 

I do not have had those issues with other models and I cant see how this would be a hardware problem with my printer as its always the exact same layer that shifts.

 

So my question would be if anyone of you had problems with a similar model or any idea to prevent this to happen?

 

If you need additional info feel free to ask as I'm happy to provide you with it 🙂

 

Thanks,

Janik

Back in the day I've been undetermined. Today I'm not sure anymore.

Posted : 15/06/2019 12:03 pm
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(@)
Illustrious Member
RE: Weird consistent layer shifting

Why post images to some odd third party site when they can be uploaded here?  Just use the Link To Media File option so we can zoom in easily.

Shifts where a part has filled surfaces is a known issue.  Slowing down print speeds seems to help.  There was a recent long discussion of the issue somewhere on this forum.

 

This post was modified 5 years ago by --
Posted : 15/06/2019 6:02 pm
Dave Avery
(@dave-avery)
Honorable Member
RE: Weird consistent layer shifting

read this thread https://forum.prusa3d.com/forum/original-prusa-i3-mk3s-mk3-how-do-i-print-this-printing-help/buldge-when-print-reaches-solid-layers/#_ga=2.43354789.1842322604.1560571303-1895960709.1560063108

it happens when you have a change from a filled area to an unfilled one

Posted : 15/06/2019 6:31 pm
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(@)
Illustrious Member
RE: Weird consistent layer shifting

Thanks David - I had lost my link to it - lol.   

Bob did a lot of work trying to understand the issue, and I did my fair share of tests.  A couple of factors stood out, but root cause was never fully established.  Printing perimeters a lot slower seems to help, I found below 20 mm/s and ensuring all print speeds were uniform worked best, as does controlling wall size in the design. Some wall thicknesses make the issue worse than other wall thicknesses - again, no clear reason.  There also seems to be some directionality at play... and that Slic3r has speed variation for layer cooling that seem to exacerbate the issue, but not all cases.

There is anecdotal evidence some slicers seem to do better, yet it isn't clear what they do differently, except speed management. 

Anyway - read Bob's posts in the above thread, he discusses in detail things that work for him.  A couple of my random observations may also be helpful.

 

Posted : 15/06/2019 6:52 pm
LoaderB0T liked
LoaderB0T
(@loaderb0t)
New Member
Topic starter answered:
RE: Weird consistent layer shifting

Thank you for your answers! I'm sure they will be helpful and I'm currently printing at a lower speed & lower temps.

Tomorrow I will be able to see how it went and I will post an update here.

Posted by: Tim

Why post images to some odd third party site when they can be uploaded here?  Just use the Link To Media File option so we can zoom in easily.

Sorry, I usually use this this tool for making cropped screenshots, I will do better next time!

Back in the day I've been undetermined. Today I'm not sure anymore.

Posted : 15/06/2019 8:03 pm
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(@)
Illustrious Member
RE: Weird consistent layer shifting

Sorry, I usually use this this tool for making cropped screenshots, I will do better next time!

The concern is more about retention and longevity. Offsite images tend to break and go away making the thread useless to future readers.  And the Link To: Media File a pet peeve; it should be default, but so far the devs have ignored requests to make it so.

Posted : 15/06/2019 8:08 pm
LoaderB0T
(@loaderb0t)
New Member
Topic starter answered:
RE: Weird consistent layer shifting
Posted by: Tim

The concern is more about retention and longevity. Offsite images tend to break and go away making the thread useless to future readers.  And the Link To: Media File a pet peeve; it should be default, but so far the devs have ignored requests to make it so.

Yes, I would also just edit my original post but I can only do so a few seconds after creating it, right?

Back in the day I've been undetermined. Today I'm not sure anymore.

Posted : 15/06/2019 8:30 pm
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(@)
Illustrious Member
RE: Weird consistent layer shifting

Here's a setting that is often missed:  change it from 20 to 1 to see if it's the layer cooling enforcement...

Posted : 16/06/2019 5:07 am
david.j49
(@david-j49)
Eminent Member
RE: Weird consistent layer shifting
Posted by: Tim

Offsite images tend to break and go away…

Unlike images uploaded to this forum before the “upgrade?” 

Posted : 17/06/2019 5:57 pm
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(@)
Illustrious Member
RE: Weird consistent layer shifting
Posted by: david.j49
Posted by: Tim

Offsite images tend to break and go away…

Unlike images uploaded to this forum before the “upgrade?” 

Oh - those images still exist, just a lot of them got caught up in a naming issue during the transfer.  Prusa has told me eventually they'll get the issue resolved..

Posted : 17/06/2019 6:58 pm
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