Well, it happened to me, HUGE Globbing of hotend

Bambu Lab H2 Series
1

Last night started a job on my H2D, and walked away. I should have waited until it actually started printing, but coulda shoulda woulda. It ran the entire job, but it never left a drop of goo on the bed, instead it globbed around the hotend and AI totally blew it. !!!

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OK, figured out pictures, so how the heck to I clean this mess and find out why it failed? Ticket opened last night but not expecting anything until next week and I really would like this printer running this weekend. I got things to get done and a deadline to meet.

2

heat up the nozzle and it should come off. Then you’ll see what needs to be repaired if anything.

3 Likes
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It was still hot when I found it as it had just finished. The app said it couldn’t cut the filament, I thought it was the completed task that popped up so ignored it for about 20 minutes, then went downstairs and found it was covered with hard, hot plastic. The plastic fully surrounds the hotend up and over and around the heatsink. The boot is actually embedded in the stuff. It ran the entire job spewing plastic, and not a drop of it went on the bed, so what the hell happened to cause it to flow UP and around the hotend and why didn’t the AI stop it when it started? It is active and set to medium, the default settings. I have a reflow gun that barely softened the bottom at 350C.

Edit, as I typed this, Bambu responded to my ticket with the link to the blob cleanup wiki, now I have to go out and buy a paint remover gun, no way a hair dryer will soften PETG when a reflow gun barely softens a tiny part of it. I responded in I want to know WHY the AI failed more than anything else. Had it functioned as advertised It would not have made such a huge mess.

4

Just heat up the nozzle for now to the temp of whatever it is.

We all have been there. Believe it or not this happens to all printers and people printing sooner or later. It’ll come off.

As for what happened? Was it recording at all? I don’t have and HD but the P1 series and X1 record, you can look at that to get an idea.

Edit: it’s can’t cut because it would look like the cutter is frozen in there. Again, heat the nozzle up, that’s the first step. Remove what you can once it’s heated. Be patient and remember it’s hot.

Remove what you can with gloves or cloth. Once you get to the point you can remove the hotend then you’ll be nearly done. make sure to remove as much as you can around the hotend before taking it out. Theh sock is gone, lol, but the nozzle maybe fine if it’s not bent.

4 Likes
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What detection profile was active when this happened? I use High across the board and get occasional false positives, but I haven’t had a miss.

6

I’m definitely switching it to high from medium after this. I have yet to receive a false let alone an actual problem with spaghetti or clumping. What I can’t figure out is how the filament got behind the sock and went up the sides like it did and not a spot anywhere on the bed yet ran through the entire print. It took a bit to cut the filament and got lucky the lever didn’t break. My only concerned is I will melt the plastic around the hotend that I don’t want to melt since its so high up almost to the extractor.

The one I took that shows it from the back is too blurry to see.

7

Could you share your bed, chamber, and nozzle temperatures? An overly high bed temperature can reduce first-layer adhesion, and certain combinations of those three settings can produce similar issues.

8

Bed adhesion wasn’t the issue, it never left the first strip of goo at the front of the plate, it failed from the very start of the job and had I stayed around to check that it was printing would have caught it in time. I have never had an issue with adhesion, getting it OFF the bed, yes, but never with it not sticking, not with the H2D, X1C yes, but got that under control too. I don’t have a timelapse for yesterday either, never really put much effort in them. Now I wish I did so I could watch the print head swell like , well, PG-13, eh?

9

Adhesion issues appear at the most inconvenient moments. Even if you never had them before.

This really looks like the first layer didn’t hold. You are quite lucky in my opinion because this could have resulted in the “blob of death”. And that can be quite a struggle or sometimes impossible to remove without damage to other parts.

1 Like
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It is REALLY close to that. I was able to remove the majority in one pull by heating to 235C and hitting the outside with the paint stripper to soften it up to get pliers on it. The rest though is like TAR! It oozed up above the back of the hot end and got into the screws, into the clamp, and up and behind and not sure if there are any wires back there so need to actually remove the entire head from the machine so I can see back inside there without breaking anything, namely my neck trying to see. The blob weighs 56 grams, the actual part weighs 66 grams. The other 10 grams is still in the head.

11

Heres the damage after taking it apart far enough to get the heaters out. Right side heater wires are melted, and some melting happened to the lift motor base. That was some HOT plastic.

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That is supposed to be MATTE filament, yet look at that SHINE!

12

That’s some impressive mining to get that thing out of the glob.

Hopefully parts ships fast.

13

Yeah I got the right heater cleaned up but the wires damaged all the way to the end and risks damaging the control board if I use it so its out of service until I get a replacement. I went to Amazon to see if something was available, there is but its 2 weeks shipping.

Does anyone know what is different between the heater for the A1 and the H2D? They damn near are identical to each other.

14

I’ll tell you I’ve seen them interchangeable on Aliexpress, the ones that you can unscrew the nozzle from the end. Take that as you will.

15

Well, the replacement parts shipped on the 30th. The tracker showed it not picked up all week. Today it updated with the USPS information. Now heres a puzzling thing.
2025-10-05 16:44

ROCKFORD, IL, US 61125, Arrived at USPS Destination Facility → Your item arrived at our ROCKFORD, IL 61125 destination facility on October 5, 2025 at 4:44 pm. The item is currently in transit to the destination.

2025-10-04 22:45

PALATINE IL DISTRIBUTION CENTER, US, Arrived at USPS Regional Facility

2025-10-04 21:31

ROCKFORD, IL, US 61125, Departed USPS Facility

2025-10-04 20:49

ROCKFORD, IL, US 61125, Arrived at USPS Facility

2025-10-04 19:39

PALATINE IL DISTRIBUTION CENTER, US, Departed USPS Regional Facility

2025-10-04 16:48

PALATINE IL DISTRIBUTION CENTER, US, Arrived at USPS Regional Destination Facility

2025-09-30 15:53

LOS ANGELES, CA, US 90052, Shipment Received, Package Acceptance Pending

2025-09-29 21:36

LOS ANGELES, CA, US 90022, Shipping Label Created, USPS Awaiting Item

Status did not get updated until yesterday when it arrived in Palatine. Then it went to Rockford, then it went back to Palatine, then it went back to Rockford. I wonder if it will bounce back and forth a few more times before it finally arrives in my mailbox.

Welcome to the wonderful world of USPS Ping Pong!

16

Had the same issue last week. The nozzle got pushed out, and it scratched my build plate raw where the prime tower should have been. Thought it was the hotend, since I had just switched to the Biqu Panda Juicer high flow hotend, but now I’m wondering if it was a bug in the printer

Like you, mine definitely wasn’t a bed adhesion issue. If it was, it wouldn’t have scratched the plate. So i’m leaning towards a glitch. Wouldn’t be the first weird issue i’ve had with the H2D. There’s this one file I just can’t print on the H2D because the printer always makes a wrong move at the same point in each copy resulting in colour bleed.