Prusa Mini Silicone Bed Leveling Mod  

RE: Prusa Mini Silicone Bed Leveling Mod

On my printer, to fix the Z-skew, the screws on the side really can not be tight.

RE: Prusa Mini Silicone Bed Leveling Mod

@orkelprint

Are you saying the two side screws that pull the electrical box into the side of the y extrusion? I could see how having them a little loose would allow the weight of the machine sitting on the electrical base foot might push the z axis in toward the bed helping with my issue. I’ll take a look at that. 

RE: Prusa Mini Silicone Bed Leveling Mod

Yes, exactly those. As soon as you feel them torquing, don't continue. It might feel better to give it one more turn, but it really starts skewing then (for my printer, there can be differences).

RE: Prusa Mini Silicone Bed Leveling Mod

@tankertech

The X-axis rods are not torsionally stiff. Possibly the extruder is not aligned parallel to the print bed (see pictures). The error increases the further the extruder moves to the x-end.

(everything in order)

(slight inclination - falsifies the Z-values in x direction)

RE: Prusa Mini Silicone Bed Leveling Mod

@karl-herbert

I would say the z error is true if the 30x30 rod extrusion is not vertical, an angled nozzle that perfectly arise vertically should only affect print quality as the filament doesn't flow as expected, or I'm wrong?

RE: Prusa Mini Silicone Bed Leveling Mod

@turro75

Move the X-axis (hotend) all the way to the left to the x-end and with the nozzle about 2mm above the print bed. Then try to rotate the x-end forward (as shown in the 2nd photo). You can observe how the nozzle moves closer to the print bed. Turn the x-end only so far that the nozzle does not touch the print bed. Then, in this position, slowly move the hotend all the way to the right with the x-axis and observe the distance of the nozzle to the print bed. You will notice that the Z-height changes considerably.

RE: Prusa Mini Silicone Bed Leveling Mod

Big thanks to @orkelprint and @karl-herbert as it was a combination of their suggestions that ultimately corrected my  xz skew.  You can see in my before/after images below that my bed now just shows normal undulations vs the drastic one way slant from before.  I did in fact have a little bit of twist in my x gantry as @karl-herbert suggested and I confirmed every tiny rotation of the two side screws in the electrical box will indeed pull the gantry unsupported end up away from the bed as mentioned by @orkelprint. Also while I was checking things I performed the xy skew check described HERE and was able to reduce my xy diagonal deviation from .35mm on a 100x100mm square to just .10mm using the provided shim files at the link. Thanks to the community for all the help!

RE: Prusa Mini Silicone Bed Leveling Mod

@tankertech

Congratulations on the successful adjustment! If the first layer should no longer fit, I would repeat the same steps and readjust if necessary.

happy printing!

RE: Prusa Mini Silicone Bed Leveling Mod

@raymate

Revising a thread I haven't looked at in a bit. My mini printed as far as I could tell printed perfectly out of the box, it's after seeing threads like this you go OCD about how much more perfect can you make it. Then you go down that rabbit hole. Welcome to 3d printing. Considering this mod is pretty cheap, the longest part of it was the screws I could only find from a seller in china that took about a month to arrive. The dis/re assembly and tweaking each of the screws, about an hour depending on how OCD you want to be with it.

RE: Prusa Mini Silicone Bed Leveling Mod

I've ordered all the parts for the mod now.. Hopefully I can sort out this mess:

RE: Prusa Mini Silicone Bed Leveling Mod

Today i got the nuts ... but no low profile. What’s the minimum high they can have? Actually I have 3,5mm high. Is it ok?

RE: Prusa Mini Silicone Bed Leveling Mod

@landvogt1893

No, 3.5mm is too high. It must be at most 3mm.
It's explained here in the notes section: https://github.com/bbbenji/PMSBLM#notes

RE: Prusa Mini Silicone Bed Leveling Mod

@landvogt1893

I used 3.5mm everywhere but a standard M3 nut in the rear center (the one ver Y motor) together with a cheap silicon 3x6.

mod installed in early January, not yet had any need to readjust it. 

RE: Prusa Mini Silicone Bed Leveling Mod

only for my understanding:

The plugins Prusa Leveling Guide and Prusa Mesh Map with G80/G81 are not necessary? 

I use only the page: Prusa Mini Silicone Bed Leveling Mod (bbbenji.github.io) ? 

RE: Prusa Mini Silicone Bed Leveling Mod

CAn someone explain what numbers from the OctoPrint visualaizer correspond to the GitHUB tool to calculate the adjustments ?

Here are my numbers for reference

RE: Prusa Mini Silicone Bed Leveling Mod

Go to Octoprint's terminal window and copy and paste them from there! You will have to trim a few characters from the start of each line (it would be great if the tool detected and stripped them for you, but it's not too hard to do it yourself) for it to work when you paste it in.

RE: Prusa Mini Silicone Bed Leveling Mod

@robee-shepherd

Can you give me an example of unstripped output? The following should all give the same output.

0 1 2 3
0 +0.048 -0.040 -0.066 -0.035
1 -0.040 -0.030 -0.044 +0.010
2 -0.065 -0.050 +0.061 -0.047
3 -0.347 +0.029 -0.045 -0.155
---
0 +0.048 -0.040 -0.066 -0.035
1 -0.040 -0.030 -0.044 +0.010
2 -0.065 -0.050 +0.061 -0.047
3 -0.347 +0.029 -0.045 -0.155
---
+0.048 -0.040 -0.066 -0.035
-0.040 -0.030 -0.044 +0.010
-0.065 -0.050 +0.061 -0.047
-0.347 +0.029 -0.045 -0.155
---
0 1 2 3
+0.048 -0.040 -0.066 -0.035
-0.040 -0.030 -0.044 +0.010
-0.065 -0.050 +0.061 -0.047
-0.347 +0.029 -0.045 -0.155

RE: Prusa Mini Silicone Bed Leveling Mod

@benji sure! Sorry this has to be an image, I am getting a horrible Wordpress plug error (oh gosh please tell me they are not using Wordpress) when I try to paste this as text...

RE: Prusa Mini Silicone Bed Leveling Mod

@robee-shepherd

you can add zipped files

regards Joan