Notifications
Clear all

Strange First Layer Issue  

  RSS
Simon Tratter
(@simon-tratter)
Eminent Member
Strange First Layer Issue

I experience a bed level issue on my original prusa mini+. The nozzle is too far away on the left side of the print sheet where there is no z axis support, while it is perfect on the right and middle of the print sheet. This Problem startet in the beginning of this year and was really bad. Now with the new alpha firmware for the mini it got better, but it is still not good which means I can not print big parts because they will not stick on the left side very well to the print sheet. I added a picture of a bed level test I recently made.

Unfortunately squaring the mini did not help. All axis are 90 degrees to each other and the Nozzle is nearly the same height on each point of the print bed. 
I testet different heights of the nozzle to the bed while squaring:
1. The nozzle is higher on the left side but lower on the right
2. The nozzle distance is the same everywhere
3. The nozzle is closer on the left and higher on the right.
The results are always identical: While printing the first layer, the nozzle is always higher on the left like in the picture I attached below. So the software is compensating the height always wrong.
Because the first layer depends only on the PINDA sensor I guess the sensor has a problem or is some magnetic field disturbing the Sensor?

I am aware that squaring the mini should eliminate this Problem, but not in my case. This is really strange. (I then chatted with Prusa support and they just said I should sqare the Mini)

Simon 🙂

Posted : 06/11/2023 6:14 pm
PrusaTester2020
(@prusatester2020)
Estimable Member
RE: Strange First Layer Issue

Would you please share the result of Auto Bed Leveling “G29” command? In my Mini it looks like this:

0 -0.018 -0.032 -0.014 -0.036
1 +0.041 +0.079 +0.070 +0.019
2 +0.030 +0.015 +0.022 +0.014
3 -0.011 +0.051 +0.054 +0.041

and you could visualize it at Prusa Mini Silicone Bed Leveling Mod (bbbenji.github.io)

Posted : 08/11/2023 7:36 am
Simon Tratter
(@simon-tratter)
Eminent Member
Topic starter answered:
RE: Strange First Layer Issue

This is the output of the G29 command:

I also tested different firmware types but the same bad result. Even if the nozzle is the same height everywhere (squaring the mini before)

Simon

Posted : 14/11/2023 4:40 pm
PrusaTester2020
(@prusatester2020)
Estimable Member
RE: Strange First Layer Issue

These are strange results. For my Mini they are aways + and - values as if they are relative. In your case you have +1.1 on ALL your measurements as if your Mini works with absolute coordinates, not relative. There should be a command to fix this may be G90?

What is the exact G29 sequence you use? In my case it's the following:

M104 S170 ; set extruder temp for bed leveling
M140 S60 ; set bed temp
M109 R170 ; wait for bed leveling temp
M190 S60 ; wait for bed temp
G28 ; home all without mesh bed
G29 ; mesh bed leveling

 

 

 

Posted : 14/11/2023 8:29 pm
Simon Tratter
(@simon-tratter)
Eminent Member
Topic starter answered:
RE: Strange First Layer Issue

I simply set the bed temperature via the menu and then I sent G28 and G29 via pronterface. 

I will try G90 in the next days...

Posted : 14/11/2023 8:37 pm
PrusaTester2020
(@prusatester2020)
Estimable Member
RE:

According to your results your surface is nearly perfectly flat. May be you could lower the X-axis a little bit from the left side using "Fine-tuning the XZ-axis" ( https://help.prusa3d.com/article/squaring-your-mini_158518 ).

B.t.w. how do you conclude that the left side is aways higher when printing? Could it be that the print surface is with decreased adhesion on the left side?

Do you have a new spring-steel sheet in order to test this possibility?

This post was modified 4 months ago by PrusaTester2020
Posted : 14/11/2023 9:47 pm
Simon Tratter
(@simon-tratter)
Eminent Member
Topic starter answered:
RE: Strange First Layer Issue

After changing the Hotend from the revo to the original one and adjusting more screws it works now quite well.

Posted : 26/11/2023 8:44 pm
Share: