Head driven into build plate during leveling from `Calibration` menu

Head driven into build plate during leveling from `Calibration` menu  

New Member

I updated to 4.1.0 this morning and figured I should re-run the calibration wizard. I tried that, but during the hotend/bed test (I believe) the selftest failed. Strange. I then selected `Mesh Leveling` from the `Calibration` tab. The mesh level ran as normal, except on the last (16th) point it drove the head down into the PEI sheet, burning a divot into it. Sadness.

I homed it and redid the first-layer calibration, which seems much lower than it used to be (-0.955 vs -0.6something), but printing seems to be working fine.

It's unclear to me why the selftest failed and why the mesh leveling would crash. I've never had any issue with mesh leveling before, and I do think that it succeeded before it drove into the plate...

Posted : 29/07/2020 6:25 pm
New Member

I had the same thing happen, except mesh bed leveling now constantly fails and rams the print head into the build plate, RIP plate 😥 

Posted : 01/08/2020 4:29 pm
New Member

As a followup, the extruder ended up chewing up filament after a few more hours and I had a lot of trouble getting it to print reliably. I disassembled the hotend and reassembled everything with the inner PTFE maybe 2mm higher than previously and have now printed four hours with no grinding or extrusion issues. I think what happened is that on the nosedive that the PTFE got squished a little bit due to the heatbreak sliding upwards in the grub screws. I suspect the squished PTFE mushroomed enough under load that it was gripping the filament causing the extrusion issues.


@james-b93, that's brutal! Is the level sensor triggering as it moves down (the red light at the top end will turn off when it triggers)?

Posted : 01/08/2020 4:58 pm
Veteran Member Moderator


I have no idea in which order the 16 points are tested on the mini,

on the Mk3, if the X axis is a bit gritty, you can have a situation where the X axis fails to home fully to the left, and then when the extruder gets to test point 7, the Pinda is actually overhanging the edge of the build plate, and has nothing to sense, 

can you see if lining the nozzle up with the divvot, actually places the Minda off the edge of the build plate? 

regards Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK...
Posted : 01/08/2020 11:56 pm
New Member

This happened to me as well. The calibration started mid-sheet and the minda probe was out of boundary smashing the left edge of the PEI sheet with the hotend. The L square between Y and X axis was deformed by at least 5 degrees before I rotated the leadscrew manually back right after hitting the reset button. The sheet looks okay and I'm yet to find any permantent damage.

Posted : 03/08/2020 11:24 am
Honorable Member


MINI homes to lower right corner and starts probing from there. But that's actually a good point, if you go to the very left end of X axis, MINDA is already out outside of build plate as it is mounted left from nozzle. I can see this happen, especially when stallguard is overzealous, detects any slight resistance in motion as end of axis and starts from there. Happened to me too, on Y axis though so no damage to build plate.

Posted : 03/08/2020 4:02 pm

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