Nozzle Offset Calibration Failed (H2C)

Bambu Lab H2 Series
1

So the recent firmware update has greatly improved the amount of success I have had in starting my prints (used to always fault on calibration offset of left nozzle), but it is still failing because the material oozes out when the nozzle is heated up. Yes, I read the other posts, yes the material has been fully dried. It seems like it only takes the tiniest amount of material to mess up the calibration.

Can we get a feature where you change the order of operations of the calibration so that the nozzle is simply not loaded with material during nozzle offset calibration? This is driving me crazy.

2

The printer goes through nozzle wipes a couple of times during the calibration process. It lowers the extruder temp below the temperature the plastic will flow while slowly moving the nozzle back and forth over the wipe area at the back of the build plate. It doesn’t do the offset calibration until after that wipe is complete.

I don’t think it can have plastic still coming out unless there’s something else wrong. The extruder should be down around 140 after the wipe. If your machine consistently does this but no one else seems to be having the problem (I’ve never seen it on my H2C, and don’t remember anyone else having the problem), it’s something specific to your setup, not a general problem that effects everyone.

You don’t say what plastic. You don’t say if you’re printing with the left or right nozzle, you don’t say what temperatures the filament profile is using, and while you say “fully dried” you don’t say what that means (time and temperature). Figuring out what’s going on needs these kinds of details.

3

Don’t dismiss their claim so quickly. I’m experiencing the same issue and all of my nozzles for the right are Bambu HF 0.4 and my left nozzle is HF 0.4. I didn’t start getting this issue until I swapped all of the nozzles out to HF nozzles. I checked here now to see if anyone was having an issue because I just had the issue pop up again. The problem is intermittent, however. When I send the same print back to the printer after the Nozzle Calibration error, the print works just fine. I’m using the Bambu HF 0.4 Nozzle Preset for each of the filament profiles. I never had an issue until I switched to HF nozzles.

I’m switching back to the Standard nozzles to see if I continue to experience the same calibration error.

4

Monitor the nozzle temperature when the machine is doing the nozzle cleaning step, make sure it’s dropping below the melt temp of the plastic you’re using. I could imagine a HF nozzle oozing a bit more than a standard, but not if the nozzle temp is 140ºC, which is what it’s supposed to be after the wipe is done…

5

Thanks for the info. I’m going to try that after my current print. I’ve been trying to dial in this HF nozzle for over a week now. I keep getting failed prints that have decent height to them. Anything with with a low extrusion height prints just fine. Not really the reason I bought the nozzle, however LOL. Thanks again.

6

Stackoverflow, I missed you.

Material types in which this error applies: Bambu PLA Basic, Bambu PLA Silk+, Bambu PLA Matte, Generic PLA (Overture), Bambu PETG-HF, Bambu PETG Basic. If you need specifics, here are the SKUs (13405, 11700, 30107, 30105, 10101, 10402, 33400, 33102). Filament profiles = default, system preset 0.2mm Standard @BBL H2C for BambuStudio 2.5.0.66. Fully dried meaning completed default drying cycle for each filament type with environmental RH < 9% but if you need exact time and temperature, it is 16H at bambu system defaults for each material type designated for the AMS2 Pro (see below for firmware information if you have further questions).

As indicated above, error only occurs on left nozzle. Nozzle is not HF, it is a “Bambu Hotend - H2/P2S Standard Flow / H2C (Left) / 0.4mm Hardened Steel” (no SKU available). Multiple of this nozzle have been tested with the same result.

I can check the temperature, but it is unlikely to be anything other than the expected value set by firmware revision OTA 01.01.05.00, unless you know a setting to change it during the wiping process?

Anyway for those catching up, the only way we have found to get around this problem is to manually wipe down the calibration offset sensor before calibrating, then wait until the left nozzle begins it’s calibration, then rapidly grab the plastic that is being oozed onto the sensor plate with a pair of tweezers.

I’d love to believe this could be remedied with a fresh wiper pad, but this issue is exclusive to the left nozzle. Even after changing it to another 0.4 nozzle replacement.

So the remaining inquiry is, hey Bambu, can we get a feature to retract or unload the filament for nozzle offset calibration to prevent this issue from occurring?

7

I’ve been having this issue since the weekend. I just wiped the calibration offset sensor with a microfiber towel and the issue went away. Time will tell if it returns.

8

I’m still having this issue, just replaced left head with brand new one. It dribbled all over the sensor. It also made a blob on the wiping blade.

9

Same issue with a brand‑new H2C — very annoying. During the preparation sequence, right after the nozzle is cleaned, it dribbles a tiny bit. I’m using original Bambu Lab filaments plus a few Elegoo spools, and it doesn’t matter which filament I use. Sometimes it takes 2–5 attempts to get past the calibration.

10

Welcome to the forum!

Oozing is usually caused by moisture in the filament. Have you properly dried your filament?

11

Having the exact same issue with my H2C #2. Its the newest one. My original H2C doesn’t do this EVER but this one seems to keep failing Nozzle offset. I am beginning to think it is a bed level issue though because the nozzle is destroying the sensor, gouging it until it has to be replaced. I really hate dealing with support and solve 99% of their problems without them but might have to give up because this newest H2C is a steaming pile of garbage…

12

@printer_dad I had this exact issue on my first H2C, it actually ripped the side off the offset sensor and gouged the build plate quite badly.

Support really didn’t seem to have a clear path to resolving the issue, after being asked to repeat some of the initial troubleshooting steps the third time I asked them to show me their troubleshooting tree for this specific error; they wouldn’t do it so that was enough for me to conclude there was no end in sight and I requested a warranty replacement.

The replacement unit has been flawless, zero issues.

13

You replaced the sensor or the printer?

14

Both - I told support that something obviously caused the printer to not know it’s height and that’s how it destroyed the sensor, they sent me a new sensor, it still couldn’t complete a nozzle offers calibration so that’s when I started asking for their troubleshooting tree and then went to asking for a new unit.

I’d suggest you should start leaning on them to replace the unit.

Where did you get this H2C from? Bambu or a retailer?

15

I am in the US. I have already purchased are replaced the sensor twice. Each time it destroys it again after a few prints. Anytime I am trying to to do a bigger print at the back of the plate, the print fails. Anything at the front seems to work fine… Hate to admit it but it might be a dud…

Purchased from bambu Direct

16

I could only get dual nozzle printing to work if it was a relatively small print in the middle of the bed. Dual nozzle and larger prints would fail during bed probing/nozzle offset.

I could print in left nozzle only mode on the whole bed with no problems.

I concur that it’s a dud, get a return process going.

When I sent mine back, I didn’t want to wait for the whole inspection and blah blah blah process and paid for a second unit to be sent out immediately, with the understanding they would credit me back - I believe it was called an “advanced replacement” - only thing there is they will be slow to actually inspect and credit back the first unit, I had to threaten them with a chargeback and magically the refund was processed that day!

17

Sounds like yours was worse than mine. My failures only are happening on the rear of the plate and I can use both sides.

18

My original sensor lasted about 2500 hours, now I keep a replacement ready just in case. The part is cheap, good idea to have it on hand to reduce downtime.

I also got in the habit of cleaning the filament leftover pieces from the sensor after each print.

19

My printer is nearing 2500. What happened? Did it just stop working? Or did it get damaged? I never tgought about buying one to have in hand in case of failure.

20

It started throwing an error when I sent a print job, and when i inspected it I saw the top layer from the sensor was peeled away. The error would cancel the print it was not possible to ignore it but I could still use the printer by turning off “nozzle offset calibration” when sending print job.