Layer Shifting - thought this didn't happen on MK3 - EDIT: Slic3r PE Error
 
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Layer Shifting - thought this didn't happen on MK3 - EDIT: Slic3r PE Error  

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Ira S
(@ira-s)
Trusted Member
Layer Shifting - thought this didn't happen on MK3 - EDIT: Slic3r PE Error

EDIT 3-9-2018: This turned out to be an error in the GCODE generated by Slic3r PE and not an MK3 problem - see answers below.

I just printed a part on my MK3. Other than telling it to print a 3mm brim (which apparently I didn't need, adhesion was great) I used default Prusa settings for PLA. Also used Prusa PLA filament (silver that came with the MK3).

I have two problems:

1-At about 7mm high, both x and y axis shifted. From there things got ugly. I thought the MK3 was supposed to recognize that and correct for it.

2-The mounting standoffs (4 round things that will accept screws) don't appear solid - they are 4 distinct circles that don't appear connected. My guess on this is a Slic3r PE issue, but I've never seen this before with my old printer using plain old Slic3r.

Ignore the perimeter of the first (smallest) layer of the pyramid - I started to peel the brim off - that's all that is.

Does anyone know what's going on here and how to fix it?

Pictures:

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Postato : 08/03/2018 10:40 pm
Ira S
(@ira-s)
Trusted Member
Topic starter answered:
Re: Layer Shifting - thought this didn't happen on MK3

Just printed again and it did EXACTLY the same thing at exactly the same place. And I don't think the nozzle actually hit anything.

I tried to attach GCODE to this post but I get "invalid file extension". Problem occurs at approx 7mm height (maybe plus a layer or two). I looked at the layer-by-layer view in Slic3r PE and this offset doesn't appear in the layer previews.

Ideas?

Postato : 08/03/2018 11:45 pm
JoanTabb
(@joantabb)
Veteran Member Moderator
Re: Layer Shifting - thought this didn't happen on MK3

Hi Ira,

zip the gcode and stl, and attach the zip file!

regards Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK

Postato : 08/03/2018 11:52 pm
Olef
 Olef
(@olef)
Prominent Member
Re: Layer Shifting - thought this didn't happen on MK3

You may be suffering the layer shift bug caused by firmware. There was a multi page thread here not long ago.

The printer is detecting a crash and rehoming but resuming the print in the wrong place.

Update your firmware to the latest 3.1.2 which has a fix for the issue, alternatively disable the crash detection.

Edit: Found the thread - https://shop.prusa3d.com/forum/original-prusa-i3-mk3-f30/layer-shift-detection-not-working-t6981.html#p67921

Postato : 08/03/2018 11:55 pm
Ira S
(@ira-s)
Trusted Member
Topic starter answered:
Re: Layer Shifting - thought this didn't happen on MK3

I'm not sure it is a crash - when I go to FAIL STATS on the printer, everything is 0. Or is that part of the bug/fix?

Attached is the GCODE and STL file for the print.

Since it happened exactly the same way twice, could this be a Slic3r PE issues? If I slice with the MK2 Slic3r PE version, can I print that GCODE to the MK3?

Postato : 09/03/2018 12:07 am
JoanTabb
(@joantabb)
Veteran Member Moderator
Re: Layer Shifting - thought this didn't happen on MK3

Hi Ira,

The G code is certainly at fault.

if you import the Gcode into Prusa Control, you will see the square layer on the build plate...

if you move the slider up in the bottom right hand box, you will see successive layers, and as you found, it suddenly jumps to the side...

try reslicing it!
and leave off the brim... I don't think you need it!

regards Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK

Postato : 09/03/2018 1:02 am
Olef
 Olef
(@olef)
Prominent Member
Re: Layer Shifting - thought this didn't happen on MK3

I've never really bothered with Prusa Control, just stayed with the Slic3r PE so I did not know that it could import a gcode and step through it.

Thank you for that Joan, and good call on the OP's issue - the sudden jump is plain to see.

Long may you continue in this forum, your willingness to help everyone is inspiring! 🙂

Postato : 09/03/2018 8:07 am
JoanTabb
(@joantabb)
Veteran Member Moderator
Re: Layer Shifting - thought this didn't happen on MK3

I re sliced the file and did a test print
[attachment=0]20180309_074839[1].jpg[/attachment]

there was no layer slip
make sure that you have full cooling set... the over hangs are quite severe

consider printing at low layer height.
this was 0.15 mm

regards Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK

Postato : 09/03/2018 8:52 am
Ira S
(@ira-s)
Trusted Member
Topic starter answered:
Re: Layer Shifting - thought this didn't happen on MK3 - EDIT: Slic3r PE Error

Joan,

Your comments were very helpful - I learned a few things:

1-I've never used Prusa Control. Prior to getting a genuine Prusa printer (now 2) I used Repetier Host & regular Slic3r for several years and never had a problem with badly generated GCODE. Now I see the usefulness of Prusa Control.

2-Slic3r PE can screw up. Never thought that was a possibility.

I've edited the original post and title in case someone else has a similar problem in the future.

Prior to seeing your first reply identifying the bad GCODE, I tried using Slic3r PE MK2 and the generated GCODE from that printed just fine. After seeing your post I re-sliced with the MK3 version and the layer shift went away. Very confusing as to why this might happen. I guess I'll need to do a quick verification of generated GCODE before printing from now on.

You have been very helpful - Thank you! And printing a sample is "above and beyond" . Thanks again.

Postato : 09/03/2018 1:28 pm
JoanTabb
(@joantabb)
Veteran Member Moderator
Re: Layer Shifting - thought this didn't happen on MK3 - EDIT: Slic3r PE Error

glad to help Ira.

regards Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK

Postato : 09/03/2018 2:52 pm
john.n13
(@john-n13)
Estimable Member
Re: Layer Shifting - thought this didn't happen on MK3


Hi Ira,

The G code is certainly at fault.

if you import the Gcode into Prusa Control, you will see the square layer on the build plate...

if you move the slider up in the bottom right hand box, you will see successive layers, and as you found, it suddenly jumps to the side...

try reslicing it!
and leave off the brim... I don't think you need it!

regards Joan

Thanks for a very useful tutorial.

Postato : 09/03/2018 10:34 pm
JoanTabb
(@joantabb)
Veteran Member Moderator
Re: Layer Shifting - thought this didn't happen on MK3 - EDIT: Slic3r PE Error

Thanks.

Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK

Postato : 09/03/2018 11:39 pm
xhillb61
(@xhillb61)
Trusted Member
Re: Layer Shifting - thought this didn't happen on MK3 - EDIT: Slic3r PE Error

Joan,

simply the best!!!

Thanks

Postato : 10/03/2018 12:51 pm
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