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Z no longer goes low enough  

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TheBobGeezer
(@thebobgeezer)
Active Member
Z no longer goes low enough

I have a pre-assembled i3 MKs3+ printer.  I got "some problem encountered. Z-levelling enforced" - topics here said all sorts of things, but mainly calibrate.  So I did full calibration.  This did not help.

During second calibration I found a bit of PLA under the sheet.  This was the cause of "some problem encountered. Z-levelling enforced."  All good I thought.

Not so.  After recalibration, Z will never go low enough.  It is about 200 microns too high and nothing sticks to the bed, not Z calibration, not prints, nothing.  I have recalibrated so many times now I have spent many hours in 20 minute chunks.  It does not help.  I even tried really thin bible paper.

Live Z and calibration can only make the extruder higher, not lower.  Negative values make it higher and +ve values are not allowed.

How can I get the Z to go lower?

Thanks in advance

Best Answer by Neophyl:

 

Posted by: @thebobgeezer

I have a pre-assembled i3 MKs3+ printer.  I got "some problem encountered. Z-levelling enforced" - topics here said all sorts of things, but mainly calibrate.  So I did full calibration.  This did not help.

During second calibration I found a bit of PLA under the sheet.  This was the cause of "some problem encountered. Z-levelling enforced."  All good I thought.

 Negative values make it higher and +ve values are not allowed.

How can I get the Z to go lower?

Thanks in advance

This statement is incorrect.  Negative values make the nozzle go lower/closer to the bed.  If you are operating off this faulty assumption then, yes you wont be able to go closer to the bed, ever.  

Questa discussione è stata modificata 3 years fa 2 tempo da TheBobGeezer
Postato : 06/03/2022 10:35 pm
TheBobGeezer
(@thebobgeezer)
Active Member
Topic starter answered:
RE: Z no longer goes low enough

Oh, I do not want to mess with the PINDA sensor.  It was set up by the factory.  It cannot have moved as it is tightly fixed and was fine before this Z problem.

Postato : 06/03/2022 10:58 pm
FoxRun3D
(@foxrun3d)
Famed Member
RE: Z no longer goes low enough

If you're close to or more negative than -2.000 and still can't get a good live z, your only option really is to move the PINDA sensor higher. It's trivial. Loosen the screw that holds it in place, wiggle the sensor to move it up a bit, the retighten the screw. As far as mechanical exercises are concerned, it doesn't get much easier than that.  

Formerly known on this forum as @fuchsr -- until all hell broke loose with the forum software...

Postato : 07/03/2022 1:34 pm
TheBobGeezer
(@thebobgeezer)
Active Member
Topic starter answered:
RE: Z no longer goes low enough

Thanks fuchsr.  Apart from my reservations about this, how accurate must the change be?  If I mark it with a pen and aim for 0.5 mm, will that be good enough?  Do I have to get the exact 200 microns to avoid the extruder crashing into the bed or sheet?

Thanks for replying.

 

Postato : 08/03/2022 12:09 am
Neophyl
(@neophyl)
Illustrious Member
RE: Z no longer goes low enough

 

Posted by: @thebobgeezer

I have a pre-assembled i3 MKs3+ printer.  I got "some problem encountered. Z-levelling enforced" - topics here said all sorts of things, but mainly calibrate.  So I did full calibration.  This did not help.

During second calibration I found a bit of PLA under the sheet.  This was the cause of "some problem encountered. Z-levelling enforced."  All good I thought.

 Negative values make it higher and +ve values are not allowed.

How can I get the Z to go lower?

Thanks in advance

This statement is incorrect.  Negative values make the nozzle go lower/closer to the bed.  If you are operating off this faulty assumption then, yes you wont be able to go closer to the bed, ever.  

Postato : 08/03/2022 1:01 pm
TheBobGeezer
(@thebobgeezer)
Active Member
Topic starter answered:
RE: Z no longer goes low enough

Oh, you star!

I was adjusting in the 0.1 to 0.2 mm range and it seemed to make the filament skid more, not less.

After your encouragment, I eventually I got to 1.6 mm!!  I just had to be bold.  This paints a becautiful flat cake on the zig-zag section at the end.

Thank you.

 

Postato : 08/03/2022 2:30 pm
FoxRun3D
(@foxrun3d)
Famed Member
RE: Z no longer goes low enough

@thebobgeezer

The Super PINDA should have about 1.5 mm distance between nozzle and sensor, so that you’re around -1 when your Live Z is correct. That gives you enough wiggle room up and down.

Instructions for adjusting the PINDA are in:

Mini: https://help.prusa3d.com/en/guide/how-to-replace-superpinda-mini-mini_179912

Mk3S: https://help.prusa3d.com/en/guide/how-to-replace-superpinda-mk3s-mk3s_179920

I put this little helper on Prusaprinters.org to help position the PINDA: https://www.prusaprinters.org/prints/57192.

Works better than zip ties or credit cards, which have less well-defined heights.

Formerly known on this forum as @fuchsr -- until all hell broke loose with the forum software...

Postato : 08/03/2022 3:46 pm
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