Prusa Mini Silicone Bed Leveling Mod  

RE: Prusa Mini Silicone Bed Leveling Mod

Thought I had last night was about how temp affects the leveling, aside from the MINDA issues. Things tend to expand by varying degrees when heated. I have to wonder how much that fiberglass PCB used for the heatbed expands when heated. When it's fixed to 9 points like that and expands, it's only options is to bow up or down slightly between where it is fixed.

RE: Prusa Mini Silicone Bed Leveling Mod

Sigh,  I pulled a funny bonehead thing today with my silicon mod.

I am so used to my MK3s nyloc mod that  I forgot on my mini I have to hold the bolt on the bottom when adjusting! haha.

I installed the new Super Pinda probe, went to level it and kept following the fractions of a turn, but of course the bolt on the bottom was just spinning so I kept getting "CCW 100 degrees"  and thinking "I just turned it 100 degrees"  

After a few times trying to level it I spotted the small wrench I printed out and then had the "AHA" moment. 

So remember kids! always hold your lock nut when adjusting and don't waste your time like I did!

RE: Prusa Mini Silicone Bed Leveling Mod

@whosinaname

The devil is often in the details - but you continuously learn 😊 👍 

RE: Prusa Mini Silicone Bed Leveling Mod

@benji / @all

This needs to be said with big bold flashing lights, preferably edited into the original post:

MAKE SURE YOUR XZ-AXIS IS PROPERLY CALIBRATED AND LEVEL FIRST!

https://help.prusa3d.com/en/article/xz-axis-skew-correction-mini_158518

Prusa recently added a KB article on how to do this properly, and I'd recommend picking up an inclinometer to get it perfect.

All of the mostly planar but wildly tilted bed's we've seen posted in this thread over and over can be corrected with this simple calibration by eyeball.

My particular unit was only 0.2 degrees out of alignment but that made a +/- 0.25mm deviation across the bed (total of 0.5mm).

I also noticed that I was able to dial in the silicone mod much easier after fixing this: the turns actually seem to match up with the effect now.

I hope this helps somebody!

Between the new SPINDA and properly calibrating XZ and XY, the silicone mod will probably not even be necessary for most.

But it is fun having a perfectly level bed 🙂

Happy Printing

RE: Prusa Mini Silicone Bed Leveling Mod

Straylit I agree with you, its most important to level your whole assembly first and then perform the mod if you want to achieve that extra something. Although I understand why many (including myself) want to level their bed like this. I recently moved to a new country and I shipped my printer too. Well after assembling it again I found out that all the calibrations had to be done again haha 😥 After assembly it was looking like this:

After some minutes of adjusting the screws on Z and also the XY axis as shown in prusa knowledge page I ended up with this.

Still not perfect but nothing like it was. When I find more time I can fine tune it and then move on with the rest of the mods.

RE: Prusa Mini Silicone Bed Leveling Mod

@straylit

It's literally the first step of the directions on Github.
https://github.com/bbbenji/PMSBLM#user-content-installationsetup-procedure:~:text=Make%20sure%20your%20X%2DZ%20assembly%20is,please%20follow%20the%20official%20KB%20article.
Unfortunately, I can no longer edit the first post of this thread due to the edit timeout. Which sucks because there are errors there and just plain outdated.

RE: Prusa Mini Silicone Bed Leveling Mod

After transporting or repositioning the printer, calibration is usually recommended.
After assembling the Mini I installed a dial gauge (in the area of the hotend), moved the X/Y axes and turned the screws until the result was in the range of about 0.3-0.4mm. Afterwards I made a fine calibration with the mentioned mod (silicone, springs, whatever). This allowed me to work my way into the range of 0.1mm without much effort, which is usually completely sufficient.

RE: Prusa Mini Silicone Bed Leveling Mod

@straylit

latest commit on the GitHub page is was made 26 days ago.... by SM26.... ain't those nice numbers? haha

I've added exactly what you are talking about.

now on the GitHub the first step has the same picture and link to the KB

RE: Prusa Mini Silicone Bed Leveling Mod

@karl-herbert how did you get so many reference points? Or did you sneak in a picture from your MK3S? 😀

RE: Prusa Mini Silicone Bed Leveling Mod

@benji ♥♥♥ I was not aware there was an edit timeout! Thanks!

RE: Prusa Mini Silicone Bed Leveling Mod

@gaetanle

Yes, for example the MK3, but with the Mini I could achieve similar results. I do not have a picture ready now.

RE: Prusa Mini Silicone Bed Leveling Mod

I installed 4.3RC1 and my mini started failing the XYZ test on the Z axis. I assumed the mod might of raised the bed a bit so I lowered the superpinda a bit closer to the bed. It then passed the XYZ test, but now when I do a First Layer Calibration I cannot bring the head down enough because the adjustment stops at 2. I guess failing the XYZ doesn't really matter.

RE: Prusa Mini Silicone Bed Leveling Mod

@gardiner

I'm also failing the Z test, even though everything is working fine.
I was wondering if I'm the only one....

And another thing I "found" that I haven't seen talked about here;

https://www.prusaprinters.org/prints/43629 - bed tightening jig
https://www.prusaprinters.org/prints/43563 - locknut sanding jig
https://www.prusaprinters.org/prints/45308 - (another) M3 (5.5mm) wrench

those tools look very nice and could come in handy.....

RE: Prusa Mini Silicone Bed Leveling Mod

Thanks for this guide and all the other links for tools and supplies. I just got finished putting this mod together and took my bed from this

to this

I'm in the Chicago area so I had trouble finding the exact screws recommended but did find both M3 screws and nuts at Ace Hardware that worked fine. The screws were M3 x 16mm hex heads and the nuts were the nylon locking kind. The nuts measured in at 3.86mm and didn't need any sanding to clear the Y motor. I did sand that one nut down a bit though just to give some extra clearance since it was close.

Here is how the screws sat in the headed bed. I checked each hole before starting and they all had clearance.

I couldn't find the tubing at an auto parts store but did get these vacuum caps instead and cut them down to 10mm. Worked like a charm.

After tightening all 8 screws down carefully to 6mm I checked the center post and this is how it looked.

The conversion tool was semi-helpful and I used it at first but eventually used the bed visualizer in octopi instead. Octopi keeps flipping my Y axis and I can't get it to stop. Then conversion tool also didn't have any marking to help me match up my inverted results to the ones provided to ensure I was reading the adjustments for the correct point.

RE: Prusa Mini Silicone Bed Leveling Mod

This is rather interesting, im new to Prusa and still waiting for my first Mini+ to arrive, so basically I should check the bed is level before I get going with it?

RE: Prusa Mini Silicone Bed Leveling Mod

Posted by: @raymate

This is rather interesting, im new to Prusa and still waiting for my first Mini+ to arrive, so basically I should check the bed is level before I get going with it?

Yes and No. My printer worked just fine before this mod and I have yet to print anything after I finished it. Who knows, I may have screwed all sorts of things up.

If your printer comes and the axis are nice and square and the bed looks level enough give it a few prints. If there are no issues and you are happy, then you don't need to mess with it. If you are a bit crazy like me and just like to tinker with things to get them closer to perfect, then maybe give this a try.

RE: Prusa Mini Silicone Bed Leveling Mod

Posted by: @obv

Posted by: @raymate

This is rather interesting, im new to Prusa and still waiting for my first Mini+ to arrive, so basically I should check the bed is level before I get going with it?

Yes and No. My printer worked just fine before this mod and I have yet to print anything after I finished it. Who knows, I may have screwed all sorts of things up.

 

If your printer comes and the axis are nice and square and the bed looks level enough give it a few prints. If there are no issues and you are happy, then you don't need to mess with it. If you are a bit crazy like me and just like to tinker with things to get them closer to perfect, then maybe give this a try.

You might be right, I should see how it prints first 🙂

RE: Prusa Mini Silicone Bed Leveling Mod

First print after the mod and the initial layer is looking pretty good (maybe a bit under extruded). Overall happy with the change!

RE: Prusa Mini Silicone Bed Leveling Mod

Just for everyone's info, I can confirm these din7991 hex head screws work just fine:

https://www.amazon.com/gp/product/B07D686M7N/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1

They sit marginally taller than the torx screws, but still fit flush or slightly under the heatbed holes.

RE: Prusa Mini Silicone Bed Leveling Mod

Definitely planning to do the silicone mod - but have been playing with the bed visualiser plugin in Octoprint and using masking tape to make adjustments. - not too shabby 🙂