Calibration problems after a print failure
Hi everyone, I have a Prusa i3 Mk3S that I've had for probably 5 years or so, and I've never had a significant problem since the printer was new. I print a lot, so this machine (and it's sibling) has seen a lot of use.
I had a long-running job fail yesterday, printing parts for a Milo v1.5 CNC mill, so it was a 20+ hour job printing in ABS, so relatively high temps. I wasn't there when the job failed, but there was some sort of crash that caused the build sheet to shift and the rest of the job turned into spaghetti. I cleaned everything up, and I was re-running the full calibration wizard to make sure nothing got knocked out of true.
The first few tests went fine, but the XYZ axis check failed when the nozzle rammed into the bed. The PINDA sensor looked way too high, so I lowered it to about 1mm higher than the nozzle. I also put a piece of steel under it to verify that the light went out - the sensor seems to be working okay. I re-ran the XYZ check and this time, the nozzle moved down in the Z axis and stopped about 1mm up from the bed, but the wizard stopped with the error:
Calibration failed! Check the axes and run again.
That wasn't much to go on - no indication of what exactly failed. The support page ( https://help.prusa3d.com/article/calibration-failed_2033) doesn't really say how to get more information, but I followed the steps to check for physical issues. I also upgraded the firmware and did a full reset and ran the wizard again - no improvement.
I've tried moving the PINDA probe up and down by about .5mm, same result.
So, I can't rule out a physical issue of some kind because the printer did crash catastrophically, but all of the articles I've found in the forum are build issues for new printers - this printer has been an absolute champ for years so, for example, I know my bed isn't installed backwards.
Can anyone advise on how to determine exactly what the cause of the XYZ calibration failure is?
RE: Calibration problems after a print failure
Hi Jeff.
General advice is to make sure X and Y axis Move Smoothly across the full length of the smooth rods
Often older printers need a bit of Lubrication on the smooth rods these knowledge base pages may help.
https://help.prusa3d.com/guide/maintenance-tips_23200
https://help.prusa3d.com/article/i3-printer-regular-maintenance_2072
I have used various lubricants with success... either a light grease such as white lithium, or LM2 Lithium
Or a light oil such as 3 in1 or Slug Slime will do
Hope
If the X axis fails to home correctly the mesh bed levelling will fail because the pinda goes over the edge of the heatbed and has nothing to sense on the right hand side.
Probably a good idea to reset live z to 0.00 and re set the pinda properly then re run a live Z calibration
Hope fully this will sort your XYZ calibration situation...
If the X axis fails to home correctly the mesh bed levelling will fail because the pinda goes over the edge of the heatbed and has nothing to sense on the right hand side. this might be what happened for you...
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
RE: Calibration problems after a print failure
I think I found the issue. The hot end somehow slipped down below the intended position - so when I first thought the PINDA sensor was too low, it probably hadn't moved - it was the hot end that moved, and I was incorrectly diagnosing it as a PINDA problem, its position being relative to the now displaced nozzle. It's hard to see, but here's the hot end, the top chunky rib should not be visible:
Diassembly confirms it, here is my part next to the one from the assembly guide, you can see that the big ridge that supports the upper part of the hot end is just gone.
Looks like I'm printing a new one...
RE: Calibration problems after a print failure
Never seen that before.
Good spot...
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
RE: Calibration problems after a print failure
Quick follow up, I printed a new extruder body to replace the one that failed spectacularly. I can't really complain after ~5 years of heavy use, I think. In any case, I tore it down, sorted out some problems with a hot end clog, and rebuilt the extruder with the new part. The color doesn't match, but the calibration just passed with no issues - so I'm back up and running.
Thanks for the support,
Jeff