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Mesh bed leveling and uneven first layer  

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and1hotsauce
(@and1hotsauce)
New Member
Mesh bed leveling and uneven first layer

Hi all,

I received my Prusa Mk3 last week and build it without any big problems (I already own an Anet A8 I built 2 years ago). I encounter some problems with the first layer beacause I can't find any Z-offset that fits good in all (or most) of the area of the bed. Even on a 75x75 square at the center, I can have a part with is perfectly printed but with another part where the nozzle is too high :

I looked on the forum and it seems that i'm not the only one with that problem but i did not find any magical solution (except the "Nylock mod" ?)

Here the thinks I've tried :

  • remove the bed and check that the "U" rings are not to tight. I think it's ok
  • Mesh bed leveling 3x3 and 7x7

I also installed the "prusa mesh map" plugin for octoprint (from PrusaOwners) to visualize the leveling of the bed. Here is the result with bed at 60°C and a 7x7 MBL: 

I understand that there is a 0.233 variance which is not the best. But Should not MBL correcting this variance ?

Some informations that could be useful (?) :

  • Using Prusa Slicer with 0.2mm speed (but with first layer width of 0.45 not 0.45)
  • Firmare 3.8.1-2869 (did not changed that, it is the pre-installed version)
  • Calibration - Y distance of min: 
    Left: 11.05mm
    Right : 10.99 mm
  • Deviation 0.06°
  • Textured sheet
  • Current Z-offset : -0.960

Thank you for you advices 😉

Vincent

Postato : 02/05/2020 10:55 pm
Jerry
(@jerry)
Estimable Member
RE: Mesh bed leveling and uneven first layer

Do you mean Z offset or live Z different animals

 

Postato : 03/05/2020 2:20 am
and1hotsauce
(@and1hotsauce)
New Member
Topic starter answered:
RE: Mesh bed leveling and uneven first layer

Hi,

Sorry for the misunderstanding, I meant live-Z.

IS there any difference ? Both are offsets to adjust z. But une can be changed during print. Right ?

 

Vincent

Postato : 03/05/2020 6:57 am
Jerry
(@jerry)
Estimable Member
RE: Mesh bed leveling and uneven first layer

I don't think of them  As the same. Z offset is in the slicer. And that value is used in where the layers are placed in the slicing. Live Z Is how far down or up from the distance the  Pinda  Probe has triggered and is the adjustment needed for the printer to establish 0.

Postato : 03/05/2020 5:46 pm
tacroy
(@tacroy)
New Member
RE: Mesh bed leveling and uneven first layer

@and1hotsauce did you get this resolved? I am having a similar output. 

Postato : 20/05/2020 1:56 pm
WegBier
(@wegbier)
New Member
RE: Mesh bed leveling and uneven first layer

Good point, I have the same issue as well, granted with a 0.5 variance according to the Mesh visualizer. It looks to me like the MBL is not doing what it is meant to do here... Interestingly enough I only get this with the smooth steel sheet (at least I can only observe it on there).

Currently trying to print ear tension releases for masks and with five on the bed, the top two most are coming out perfect, the middle one is a little bad on the right side. the last two are getting worse on the right side and also have some stickiness problem on the left... the center is actually good for all...(and according to mesh visualizer my center line of the bed is also not level)...

So is the only solution doing the nylock mod and getting a perfectly leveled bed?

When in trouble, when in doubt: run in circles, scream and shout

Postato : 20/05/2020 2:38 pm
WegBier
(@wegbier)
New Member
RE: Mesh bed leveling and uneven first layer

So I resolved this issue for me and it is a bit of an embarrassing realization of what has caused this...

My PEI sheet just was not clean all the way and hence it resulted in not sticking in all places.

I followed the advice from @joantabb from some of the other prints not sticking threads and gave my PEI sheet a good clean with dish soap and hot water and it now works perfectly. Should have tried this earlier and not believe to know better and just use isopropanol...

When in trouble, when in doubt: run in circles, scream and shout

Postato : 21/05/2020 6:52 am
JoanTabb
(@joantabb)
Veteran Member Moderator
RE: Mesh bed leveling and uneven first layer

🙂  
Happy Printing... 

save the IPA for disinfection  etc... 

Dish soap is way cheaper! Lol

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 : 21/05/2020 7:03 pm
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