Post your MINI Z-offsets  

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k00p
 k00p
(@k00p)
New Member

I've had my MINI running for just a few weeks and have been prodding and poking various settings to dial in performance. One thing that has left me feeling deeply uneasy is how high the Z offset is ending up. I am printing primarily in PETG, and despite reports of needing to back off on the Z offset to avoid too much adhesion, I am getting that nozzle wayyyy down there in order to get enough adhesion to get a decent first layer.

It seems that the biggest problem prints are anything that has a curved base - rather than drop onto the sheet and adhere like PETG seems to do for everyone else, the filament gets dragged by the nozzle and the perimeter of the first layer becomes a big problem. Lots of failed prints. I have to print the first layer with a hotter nozzle and sheet than the default Prusament PETG profile to get good outcomes.

So, with that, I have to wonder if anyone else is having a similar experience. With my Z offset being so crazy (~ -1.65 for smooth or rough PEI), I have to wonder if there is something specific to my MINI hardware that I may need to adjust. I checked my PINDA Z height with the zip-tie method, and it seemed OK, but maybe I have some weird thing going on with chemtrails or magnetic lay lines or aliens.  

 

Here's my setup:  

 

Z offsets:  

 

  • Smooth PEI: -1.672
  • Rough PEI: -1.633

 

If you're reading this post, would you mind sharing your Z offset? I've seen some info on Z offsets in the wild for other Prusa printers, but really want to know what "normal" looks like. 

 

Posted : 10/05/2021 10:56 pm
fuchsr
(@fuchsr)
Prominent Member

Okay, I'm usually trying to be more polite but this is just a bad idea. There's no "normal" value. The "best" Live Z depends on your very specific setup, your hotend assembly, what sheet you're using, how tight the nozzle is screwed in, etc. So sharing a bunch of meaningless values is not the most productive exercise.

Having said that, a few more specific points:

  • I would consider anything between -0.5 and -1.5 as "appropriate" because it provides enough wiggle to adjust up and down as needed. But if you never switch nozzles or sheets, hey, even something like -1.9 is fine if it works for you.
  • If you get close to -2.0 I would reposition the Super PINDA higher, again to gain some wiggle room.  Instructions are in Step 16 of https://help.prusa3d.com/en/guide/how-to-replace-superpinda-mini-mini_179912 (Mini) or https://help.prusa3d.com/en/guide/how-to-replace-superpinda-mk3s-mk3s_179920 (Mk3S). For an illustration of relationship of distance of PINDA to nozzle and sheet, see
  • The Super PINDA should have about 1.5 mm distance between nozzle and SPINDA, so that you’re around -1 when your Live Z is correct. (For the old PINDA, it was 0.8mm).
  • I put this little helper on Prusaprinters.org to help position the SPINDA: https://www.prusaprinters.org/prints/57192-spinda-height-adjustment-tool-mounts-into-3030-ext. Works better than zip ties or credit cards, which have less well-defined heights.
  • Textured and satin sheets are thinner than smooth sheets and require lower (more negative) Live Z. Even within one type (e.g. smooth) two sheets may differ in enough in thickness due to manufacturing tolerances to warrant different Live Z.
  • Any change to the hotend may require readjusting Live Z (including something as simple as a nozzle change).
This post was modified 1 month ago by fuchsr
Posted : 11/05/2021 11:57 am
k00p
 k00p
(@k00p)
New Member
Wow, what an exceptionally detailed answer! Thank you for your time.
 
Posted by: @fuchsr

Okay, I'm usually trying to be more polite but this is just a bad idea.

Trying to be more polite is a good idea, don't be so hard on yourself!

There's no "normal" value. The "best" Live Z depends on your very specific setup, your hotend assembly, what sheet you're using, how tight the nozzle is screwed in, etc. So sharing a bunch of meaningless values is not the most productive exercise.

Having said that, a few more specific points:

  • I would consider anything between -0.5 and -1.5 as "appropriate" because it provides enough wiggle to adjust up and down as needed. But if you never switch nozzles or sheets, hey, even something like -1.9 is fine if it works for you.

This is helpful.

These suggestions are all very nice, thank you! I'm an empirical sort of person though, so with all of that, I have to ask...

 

What's your Z-offset? Post below! 

Posted : 11/05/2021 1:58 pm
cwbullet
(@cwbullet)
Illustrious Member

Superpinda -2.1

--------------------
Chuck H
3D Printer Review Blog...
Posted : 11/05/2021 9:25 pm
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