Teaching Tech Calibration Gcode

New SM2 owner here. Trying to go through the tuning tech calibration procedures. All his gcode generators ask what kind of ABL scheme is needed. I am assuming it is the “M420 S1” option?

If anyone else has tried his gcode I would like to know, I dont want to damage the machine we just got :slight_smile:

TIA

Good question. None is needed since it’s enabled automatically at startup, that is the setting “No ABL”.

You are also correct that M420 S1 is the command to enable the bed leveling mesh if somehow it was disabled.

Funny you should ask :grinning_face_with_smiling_eyes:

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Thank you Brent. Your post has been super helpful. I see you skipped the bed leveling print. What I am experiencing when runing TT’s bed leveling test is that the square at the center of the bed comes out nearly perfect, but the other 4 have major defects.

I am currently running the 5x5 auto bed leveling and heating the bed before leveling. Using the provided snapmaker calibration card.

Is this the ABL on the SM2 is no good or variance in the heated bed at the bed corners?

The bed is known to droop a bit in the corners. I can only guess how much problem you’re having without a picture to reference.

I think I have it sorted the best I am going to get it. I was experiencing ridging as if the nozzle was too close. The top left square is the worst.

I adjusted the Z offset to +.2mm and the center and bottom two squares are perfect and smooth. The top ones still have some ridges and globbing.

Not sure if the position of my sensor is off or what. I must have done the SM calibration procedure a dozen times up until now assuming it worked as advertised.

If you know what points need to be adjusted you can adjust the mesh with M421 Q and add or subtract some tenths.

Cannot say why it’s measuring incorrectly. I believe @scyto is experiencing possibly the same thing.

@scyto Any update on from support on your levelling issues? Do you think this is a similar issue?

@brent113 Not sure if it’s same thing. Easy to check though if @eacmen wants to.

  • do calibration
  • center bed with jogging and lower head to z0 using the jog on the touchscreen
  • put the white card under the nozzle and hold it there
  • move head to each of the calibration points and see if pressure on card varies from point to point but is consistent at each point.

If it is not consistent at any point it may be wobble in the y rails.
If it is not consistent between points it might be the strange issue I am having - support have replicated and are investigating.

It wouldn’t surprise me adjusting the offset for each point manually as you suggest works fine to mitigate. That’s my next step if I end up waiting too long for support.

@eacmen if you are interested take a look at this and see if you are having same after bed levelling head is not consistent height when jogged - YouTube

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Thanks a ton @scyto. I am definitely going to do this test next time I am in between prints.

You reference if its not consistent at any point then it might be “wobble” in the Y rails, if this is the case how can it be corrected?

I really wanted to love this machine, but at this point I am seriously considering returning it to microcenter for a refund.

if its wobble in the y rails it can be spotted like in this video wobble on brand new linear unit - YouTube
the fix is to a)get replacement rails [i advise people push for this] b)deconstruct the rails to adjust the bearings [this can be done if you are mechanically inclined, i am not, i destroyed one of my rails doing this, but snapmaker were awesome and replaced the rail] - but don’t adjust unless you can visibly see the wobble like that video.

and by not consistent at any point - what i mean is when you revist the identical XY coordinate the tension varies at that coordinate.