Printer losing Z height calibration and mesh level failures
 
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dane.t
(@dane-t)
New Member
Printer losing Z height calibration and mesh level failures

I've been printing with my Mk2.5 for several years now and I'm running into a new set of issues.

First I was unable to complete mesh leveling because it would consistently fail on the second test point (3x3 array) and force Z calibration. Doing the calibration didn't solve it. I did a full XYZ calibration and had several problems getting the back right corner to calibrate properly but eventually got it working. That didn't fix the problem either though. I ensured the bed and nozzle were clean, nothing stuck under the bed. Upgraded to latest firmware, no change. Tried it with and without heat. Made sure the Pinda was working properly. After leaving the printer overnight and it seems to work occasionally now, but I've got a NEW problem.

As part of the full calibration I reset the Z level and did the first layer testing again. As it was before, I ended up with a value about -0.4 and it went as expected. However now when I print from a file the first "purge" line comes out fine but when it moves to print the object, it "forgets" the z level I had calibrated and prints into mid air. I do a quick live adjust Z and have to adjust down to -0.8 to get it right, but then when I start the next print the purge line doesn't even come out because the nozzle is dragging on the bed.

It seems like something is failing and both problems seem to be vaguely related, either to z control or the Pinda, but I can't figure out what to do from here. No similar problems with my Mk3 or two MK3S

Posted : 03/10/2020 8:22 pm
karl-herbert
(@karl-herbert)
Illustrious Member
RE: Printer losing Z height calibration and mesh level failures
Posted by: @dane-t

I've been printing with my Mk2.5 for several years now and I'm running into a new set of issues.

First I was unable to complete mesh leveling because it would consistently fail on the second test point (3x3 array) and force Z calibration. Doing the calibration didn't solve it. I did a full XYZ calibration and had several problems getting the back right corner to calibrate properly but eventually got it working. That didn't fix the problem either though. I ensured the bed and nozzle were clean, nothing stuck under the bed. Upgraded to latest firmware, no change. Tried it with and without heat. Made sure the Pinda was working properly. After leaving the printer overnight and it seems to work occasionally now, but I've got a NEW problem.

As part of the full calibration I reset the Z level and did the first layer testing again. As it was before, I ended up with a value about -0.4 and it went as expected. However now when I print from a file the first "purge" line comes out fine but when it moves to print the object, it "forgets" the z level I had calibrated and prints into mid air. I do a quick live adjust Z and have to adjust down to -0.8 to get it right, but then when I start the next print the purge line doesn't even come out because the nozzle is dragging on the bed.

It seems like something is failing and both problems seem to be vaguely related, either to z control or the Pinda, but I can't figure out what to do from here. No similar problems with my Mk3 or two MK3S

Hello and welcome to the Prusaforum!

Often a master reset (factory reset) and flashing the firmware again helps.
Have you ever checked the axis geometry (possible inclination) and the flatness of the printing bed?

Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen....
Posted : 03/10/2020 8:45 pm
dane.t
(@dane-t)
New Member
Topic starter answered:
RE: Printer losing Z height calibration and mesh level failures

@karl-herbert

Thanks, will try the reset and flash firmware again.

What do you mean about checking geometry? Is that in the menus somewhere you do you mean with a physical tool?

Posted : 03/10/2020 11:08 pm
karl-herbert
(@karl-herbert)
Illustrious Member
RE: Printer losing Z height calibration and mesh level failures

@dane-t

They are mechanical checks and corrections after first assembly:
By this I mean the parallelism of the axes and the height difference of the entire X-axis path to the printing bed. I have checked this with a dial gauge. For this purpose I printed a holder, attached the dial gauge to the extruder and traced some points on the printing bed. Due to an inclination of the X-axis I noticed and corrected deviations of up to one mm.

 
Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen....
Posted : 03/10/2020 11:19 pm
dane.t
(@dane-t)
New Member
Topic starter answered:
RE: Printer losing Z height calibration and mesh level failures

@karl-herbert

So I did a factory reset and flashed firmware, still had issues locating the third calibration point (back right corner). So I noticed when it did the spiral searching for the point, it was quite a bit further back from the center of the point. So I adjusted the frame by about 5mm forward and ran it again. It was able to find the third point after that, though it seemed to pick up a LOT of other noise around the center point. It finished calibration and was able to finish Z adjustment and get a print going well. No idea why the Y distance adjustment made the difference, or how it could have gotten out of alignment after over 600 days worth of print time. But so far so good! Thanks for your help.

Posted : 04/10/2020 1:19 am
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