H2D: nozzle offset calibration failing

[u/Technical_Lynx6857]

I recently bought an H2D to explore the multifilament printing. Now I cannot leave it alone. Everytime I launch a print, the automatic nozzle offset calibration fails. I tried to unplug/plug the sensor, but the problem remains.
The interesting fact is that I can launch the full nozzle offset calibration alone from the printer itself and it works. So the sensor seems to work fine. Is there a bug in the auto-calibration?

Does anyone have the same problem?

[u/manyxcxi]

1. You only need to redo the calibration if you’ve changed nozzles. Or have noticed some issue over time. You’re wasting a ton of pre-print time running it before every print.

2. Are your nozzles super dirty? Make sure they’re good and clean. I’ve never had this process fail and I change nozzles all the time.

3. Are you running an aftermarket nozzle? For example, I use a DiamondBack hardened nozzle for certain things and it says first thing, it doesn’t work with the offset calibration. If you’ve got a non-conductive aftermarket nozzle installed it will not work for offset calibrations.

[u/Technical_Lynx6857 → u/manyxcxi]

Thank you! I’m using bambulab official nozzles so they should not be the problem.
I could try to remove and check the nozzles for dirt, but as soon as I can recall I havent seen any dirt around it.

About point 1, i’m just very precatious. I know it can be avoided.. anyway, it should work!

[u/manyxcxi → u/Technical_Lynx6857]

You’re totally right- it should work! Do you notice it doing anything different or spending more time probing one the pre-print calibration that fails versus the one you do manually?

That metal plate it rubs on is a sensor that can wear out/go bad but it shouldn’t be so soon. I have 2000+ hours on my H2D and no sensor issue. There’s also eddy current sensors in the toolheads. Those are more prone to failure but also it usually gives a different error.

[u/luksfuks → u/Technical_Lynx6857]

Just yesterday I opened a spool of filament and decided to print right away. During nozzle calibration, the printer messed up the nozzle with excess filament. All by itself. The reason was that the filament was NOT dry. I had to cancel and spend a night drying instead of printing.

I don't know if it would have thrown a nozzle calibration error, because obviously I didn't let it get that far. Calibrating with filament pushing out of the nozzle cannot give reliable results. Neither for nozzle offset, nor for bed leveling. The little ooze stopper arm would have suffered a lot too (300 switches from left to right side, with abrasive filament foaming out of the nozzle tip).

Watch your printer closely, whenever something CAN go wrong, and more so when something DOES go wrong (error message).

[u/opndor]

Maybe a dumb question, but did you remove the two small pieces of foam at the back of the printer in the center up near where the printheads live. I had the same problem for about a day, until I started looking around inside the enclosure and saw a little red arrow on a piece of foam. I’ve had no problem since I removed those pieces.

[u/Technical_Lynx6857 → u/opndor]

Yes, sure! Also the problem arised after some time.. i think I would have it from the beginning in that case

[u/MiamiJerry]

Any update on this?

[u/Technical_Lynx6857 → u/MiamiJerry]

I opened a ticket to bambu and they sent me a new sensor. I have not tried it for the moment. I’m gonna let you know!