Prusa Mini Silicone Bed Leveling Mod  

RE: Prusa Mini Silicone Bed Leveling Mod

I have been watching this forum for ages and ages and always wanting to do this mod but thinking it would be difficult and time consuming so I never did it - until today.

Once I followed the Github article and got those nuts on I found the levelling quite satisfying and not so overwhelming.

I thought Id share a few things I have found if anyone else is thinking this is too hard....

Heres my bed before the mod

I bought all the bits from Aliexpress - I know they dont stay forever as real links depending on  the seller but heres my shopping list:

M3 Nuts - https://www.aliexpress.com/item/32895830522.html?spm=a2g0o.order_list.0.0.79761802pp18o6
These are the correct height so you dont need to sand anything

16mm M3 Torx - https://www.aliexpress.com/item/1005002911566963.html?spm=a2g0o.order_list.0.0.79761802pp18o6

ID 3 Silicon Tubing - https://www.aliexpress.com/item/32879957386.html?spm=a2g0o.order_list.0.0.79761802pp18o6

I followed the guide step for step but when it came time to putting on the nuts, I used a quick grip - to make sure I didnt put pressure on the bed, I squeezed it with my hands to get the 16mm bolt through with enough to get a nut on, then locked it off with the quick grip - this freed up my other hand to do the fiddly bit - be careful you are clearing anything under the bed and dont squeeze too hard.

Also make sure you have all the bolts through before adding nuts on the corners - I fould my silicon tube slipped on a few and was fiddly to get the bolt through clear - I found pushing the bolt up from the bottom sometimes aligned the tube again and found the middle right the most difficult to do.

I used Octoprint bed visualiser add on to get the numbers - I found I could just copy and paste the results STRAIGHT into the output window without changing anything! was very quick to do repeated test - https://bbbenji.github.io/PMSBLM/

I found that going slow and steady, disabling the steppers each time and using the printed spanner and torx bit was the best bet and when the results came back to OCDish variances, the readings started to be a fraction different each time I ran a level so I stopped.  Pretty happy with the results

My bed now

Hope this helps someone, thanks to all those before me and this great mod and tools to get here.

RE:

After i changed the bearings on x and y, I got this weird dots on my bed. 

I guess something happened to the base plate. Seems hard to level this, even with the silicon levelers.

RE: Prusa Mini Silicone Bed Leveling Mod

Check for any debris between the heated bed and steel sheet.

RE: Prusa Mini Silicone Bed Leveling Mod

First thing i did, cleaned all with ipa.

RE: Prusa Mini Silicone Bed Leveling Mod

When I first did this, the heatbed was bumping into the top of one of the u-bolts holding it to the rails. I had to file the u-bolt down a little. This was on an original mini, not a plus.

RE: Prusa Mini Silicone Bed Leveling Mod

It seems like there is a pit and bulge on the bed which are quite consistent whatever i change. So that would be a logical case, checked, not the case here.
Currently printing the front and back as the molded back plate has cracked. Will check again when re-assemled with the new ones.

RE: Prusa Mini Silicone Bed Leveling Mod

Replaced the front and back plate.

This is the result i have now:

Still the bulge and bump. 
I guess i have to settle with this for now. 

RE: Prusa Mini Silicone Bed Leveling Mod

Figured out what was wrong, the x-axis was scewed a bit. Turning the x-axis-end made it better.

RE:

With this mod, is it necessary to adjust the bed every time I switch print sheets?  Since there may be manufacturing variances in the thickness of the sheets?

RE: Prusa Mini Silicone Bed Leveling Mod

In my case the sheets seem to be very similar, depending on how big the to-be-printed-part is - I might make some minor adjustments using Bed Visualizer.

If one of your sheets throws you off your calibration significantly - on the long run, you could consider to exchange the problematic sheet.

Of course you have to account for the general thickness difference by adjusting the z-offset, but I guess that is obvious.

RE: Prusa Mini Silicone Bed Leveling Mod

guys i just leveled my bed new but i still got some issues in the corner... shouldnt the sensor normally make that working?

RE: Prusa Mini Silicone Bed Leveling Mod

Was everyone aware you can do all the calcs direct from bed visualiser in Octoprint?

theres a corrections tab to tell you the degrees of turn - so easy

RE: Prusa Mini Silicone Bed Leveling Mod

@andrew-pawelski What version are you using?  My Bed Visualizer plugin doesn't have corrections for the Mini, it's only for a 4x4 bed not the Mini's 3x3 bed.

RE:

You might want to check if there is a skew on the x-axis. (   /  https://help.prusa3d.com/article/squaring-your-mini_158518)

As far as I know the Mini-sensor should compensate for your 0.2ish deviation, again making sure your Mini is squared is the foundation of that process.
After checking your axes try to get the average deviation further down, for me the magic starts below 0.1mm. 

RE:

I got a timeout for editing this post, so here is my last edit:

As far as I know the Mini-sensor should compensate for your 0.2ish deviation, making sure your Mini is squared is the foundation of that process.That might put your deviation down, if not you could try to get your average deviation lower, for me the magic starts below 0.1mm, if I am at around0.05-0.07mm most of my prints/first layers look really nice.

For calibration I open 3 instances of the bbbenji-tool ( https://bbbenji.github.io/PMSBLM/), make 3 tests and only adjust those values which replicate, as there are always tiny differences in the measurements (at least in my case). Also I try to make not too many adjustments in one run (1-2, max. 3 changes on the screws), for me that makes the calibration more reliable and quicker on the long run.

RE: Prusa Mini Silicone Bed Leveling Mod

Question.... when you make G29 bed leveling you use a texture plate, a satin plate or nothing? Becouse my valor change from a plate to another, ok thickness is different but changes are not regularry in all 9 points.

Thanks

RE: Prusa Mini Silicone Bed Leveling Mod

Posted by: @bmorgenthaler

@andrew-pawelski What version are you using?  My Bed Visualizer plugin doesn't have corrections for the Mini, it's only for a 4x4 bed not the Mini's 3x3 bed.

That's what I am wondering as well. @andrew-pawelski can help out here?

RE: Prusa Mini Silicone Bed Leveling Mod

RE:

Looks pretty good to me @3Ddesign-bySimon! If you get it down to 0.02mm of maximum deviance then you get an Easter egg:)

Btw, just yesterday I rewrote the entire logic for the converter. I believe it will give better results now. Not that they were bad previously. It also should support ABL output from not only the Mini, but also the MK2/3/S, Marlin and probably Kipper too: https://bbbenji.github.io/PMSBLM/beta/

Be aware that it hasn't been fully tested yet and maybe contain bugs or even inaccuracies.

RE: Prusa Mini Silicone Bed Leveling Mod

Anyone know of a good US-based supplier for the 16mm M3 Torx screws, or a hex screw that is compatible with this mod? The screws in the amazon link in the GitHub repo are not currently available.