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First layer issues on MK3S+  

New Member
First layer issues on MK3S+



I received and built my printer around 9/1 and has been working pretty well for the most part, I have been having a weird issue with my first layer. the first layer is not consistant, some of it looks perfectly fine while some sections (primarily to the left side) start to get kind of rough and you can see like like its either dragging or something, I have contacted Prusa support multiple times, while they have been super friendly and willing to help we have not been able to fix the issue.

Here are some photos of the issue that I have been having.



With Prusa support we have tried many things to rectify the issue but still continue to have the same issue, here are some of the steps we have taken.

  • Making sure everything on the extruder is tight, we took it it apart to tighten the hot end to tighten it because it was not aligned correctly.
  • XYZ calibration multiple times, as well as multiple first layer calibrations, first layer height seems fine, prints adhere with no issue.
  • We loosened the screws on the heat bed, heated up for 15 minutes, and then tightened screws back down in a cross pattern.
  • We have changed the bed mesh level to do a 7x7 before each print to obtain a more accurate mesh.
  • Did a few cold pulls to make sure the nozzle was not clogged

I am sure there are some other things that I have done with them, but its been multiple multi hour chats and I just can't seem to resolve this issue, I have also tried multiple filaments changing the temp for them and still yielding the same issue.

The last two photos of the square test are more recent, and the two below are from two prints I started and cancelled today.

Any insight into what might be causing this inconsistent first layer would be greatly appreciated, hoping to not have to tear the printer apart and rebuild it, but will if it comes down to that.



Posted : 16/09/2021 6:47 pm
Dan Rogers
Noble Member
slow down cowboy

Your first job as the printer owner is to get live Z dialed in post calibration.  It looks like you stopped after calibration and didn't zero in a good live Z value.

Most of those photos look like Z is still too high.  The lines are almost separate and there are good valleys between the extrusion lines.  They should be fused smooth, with no wavy patterns (wavy means Z too low).  

The other thing you should enable is 7x7 bed mesh leveling.  That will handle the minute sectional differences across the bed.

So, nothing fancy like a cold pull or dissassemble this or that needed here -  you simply have not gotten your Z correct yet.  There is nothing Prusa can do for you to get you over that learning curve - the printer cannot be set to a single "good" z value at the factory - there are too many variables such as filament brand, filament color, live Z setting, which sheet is being used, initial pinda adjustment variances, etc.  

You need to get good at spotting a bed cleanliness problem (areas that don't stick and are roughly the size of fingerprints) and spotting a growing live Z issue.

Posted : 17/09/2021 8:51 pm
New Member
Topic starter answered:

Hello Dan, thanks for the response.

I have stated in the original post that I have switched to a 7x7 bed mesh, Some of the photos are from earlier on and don't show the exact problem I am having now, so for the most part the z seems good, and the layers for the most part are smooth and flat but from the two more recent photos below you still see some artifacts in the first layer randomly.

I have been cleaning the bed with warm water and soap like Prusa has suggested before every print, the corner in the picture with the leveling squares I do believe was caused by touching it there when placing the sheet down, so I am not worried about that.

even if I go lower I still seem to get these random deeper lines, and on some prints it favors the left side of the bed as you can see in the first picture I added, the smooth side is from the right side of the bed and it looks a lot better than the other half that starts to get the lines and spacing between the lines.

Posted : 18/09/2021 9:39 pm
Dan Rogers
Noble Member
Very close then

The transition from too far from the bed to too close to the bed looks like wavy lines .... you are there. Back it off a bit and you should be good to go.

Posted : 19/09/2021 10:20 am