I’ve been fighting a problem for the last couple of days and finally resolved it this morning.
I have a H2D and have been printing a very fine model using PETG-HF and PLA Basic for support interface with 0.2 nozzles. I printed a couple and then I started getting problems with the PLA in the right nozzle. I kept getting failed to extrude when switching to the right nozzle, left nozzle no problem at all. I went through all the normal causes, the obvious clogged nozzle and cleaning with a cleaning filament and it just kept coming. Even swapped out nozzles and switched to 0.4 in case that was contributing. It then got worse. The filament wouldn’t load from the AMS. Again I checked all the obvious problems but it looked like the filament was failing to grab in the extruder. I’ve printed quite a bit of TPE in the right nozzle so I wondered if it was residue in the drive wheel. I stripped the extruder and it was all spotless in there. I reassembled but still the same issue. All this time the left nozzle is working fine. I striped it all down a second time as it had to be something in the extruder. That’s when I found it. The extruder friction wheel was loose on the gear. Not floating around loose but I was able to rotate it with my fingers. Quite why this was not effecting the left nozzle feed I have no idea. I pulled the wheel right off and there is no key or any other mechanical aid to stop it rotating. There was a bit of white residue so I assume a spot of glue was used in assembly. I cleaned it off and reassembled using some Loctite 290. I reassembled and the filament loaded first time and is now feeding fine again. So if all else fails and you can’t get your extruder to feed, even if it is fine on one nozzle, check this failure.
Today I got a fan error for the extruder. I’m guessing that is the smoking gun for my problems. Having fixed the spinning filament feed wheel I now can’t print as the filament is softening in the extruder and causing extruder motor overload. This is likely what caused the wheel to come unstuck in the first place.. I’ve ordered a replacement fan assembly so I hope that will get me back to printing again. I do print a fair bit of high temp filaments so once I get the fan replaced I’ll see if I can find a better quality fan to refurb the one I take out. I strongly suspect this is going to be a recurring weakness.
If its the Hotend Cooling Fan, be careful when navigating the delicate contacs. Super easy to damage them, I have dismantled my printer so many times I can’t really remember but I’m still afraid of damaging those tiny delicate contacts.
I followed your advice but still ran in to a catastrophic failure. I was pulling the tape off of one of the lift to release connectors and the entire connector came off the board with the tape. Looking at it with a magnifier the front mounting points were not soldered to the pads…. This was on the TH PCB so I have realised a support ticket for this as I’m not inclined to fork out £50 for a bad part placement. I actually have SMD rework station in my workshop but the pins pulled out of the back of the connector moulding so there was no possibility to fix it myself.
Sorry to hear that. During my first disassembly, they had actually glued the Eddy sensor connectors to the sensors themselves, making it impossible to remove them without destroying the PCB. On the same TH board I also had a connector that simply fell off, exactly as you described.
This is what happens when you combine very tight space with sloppy factory assembly. I totally get that if you want a tiny footprint you have to sacrifice some serviceability, but when parts that are basically consumables force you to navigate that minefield every single time, it just becomes… YUK!
On top of the damage I already mentioned, I also have threads that were completely gone after a few (read: way too many) disassemblies. With this tool head – and probably all tool heads in the Bambu Lab lineup – you can’t replace individual parts without also replacing the entire X‑Y assembly.
For your warranty claim, just make sure you have clear photos of all the damage. In my case they replaced the parts without any real hassle, apart from the delayed work and far too many man‑hours on my side. They seem to be aware of these issues, so you’ll probably be fine as well.
Just imagine all those tiny, delicate connectors and how sensitive they are, then picture doing that assembly on a production line – the fact that things go wrong is almost guaranteed rather than optional.
The good news is the parts are on the way with absolutely no quibbles from Bambu.
I have to say I’m now concerned this is going to be a regular replacement process for the hotend fan. Fortunately I’m only a casual printer so this is an inconvenience rather than a commercial disaster.
Perhaps some enterprising company will put out some updated cooling parts it won’t help with the connectors but probably mean you don’t have to treat the fan as a consumable
Yeah—pretty much every Bambu Lab printer I’ve seen uses fans that feel a bit under-specced for the conditions we actually run: ~65 °C chamber, 120 °C bed, and 300–350 °C nozzle temps.
That’s what keeps taking my machine down. So far support has shipped enough spare parts to build roughly one and a half H2D Full Combo (40W Laser) units… and there are still more parts on the way.
Having done the fan swap I have to say I’m not impressed with the design. The whole hot end seems like a random collection of parts that have been squashed together rather than a coherent design. They have certainly not made any efforts to make it easy to repair. Anyway my printer is back up and running. Two false starts. First time I got it together the nozzle camera wasn’t working. I hadn’t clipped the retainer down properly, but I had to remove half the parts I put on to get to it again. Second time it printed fine but part way through I got a parts cooling fan warning. Yep on the second assembly I hadn’t seated the fan connector properly. Oh boy I hope this fan lasts longer than the last one. I don’t want to be doing this regularly.
Of course since it has been out of action for a couple weeks the roll of filament in the AMS-HT is now at 50% humidity. That’s on a drying cycle now
I have replaced that fan several times already, as well as a few of these: H2 Series Tool Head with X-Axis Assembly | Bambu Lab US Store
, along with many other components. Frankly, I am getting tired of spending more time repairing my printer than actually using it.
I experienced the same problem with the H2C; the right nozzle keeps clogging. The first thing I’ll do when I get home is check the part you mentioned. Thanks for sharing!
Got the printer on tuesday, having issues. They seem related. The printer is either not detecting the filament in print head, or it gears aren’t grabbing it. I lean towards it not sensing it, but not sure. Its an H2S with an AMS on it. I’ve torn the head down and reassembled it many times already. If I manually feed filament it seems happy, that is if I physically push the filament into the the grasp of the extruder gears. It will print for a bit, but looks to be under extruding. I’ve cleaned the toolhead, there is nothing it there. I’ve changed nozzles and even gone to PLA from my usual ABS. If I manually feed it with the AMS connected, it will go for a while like I said, then get to a point where there is not enough force, I guess, to extrude the filament. It goes to cut it, and I was running into an error there with the cutter. I skipped a tooth on the cutter lever thing. Thats been fixed, but still having extruder issues. Played with the tension, but nothing seems to make it happy. Any suggestions?
Watch the feed wheel when the filament gets to it. Check it is turning. They are glued on to the drive and in my case it was spinning. I had exactly the same symptoms you are seeing, with a bit of manual help the filament feeds fine but on its own it doesn’t. I pulled the wheel off and glued it back on with Loctite. It has been fine ever since. I did find that while the feed problem was resolved I very shortly after got a fan failure which I suspect was the root cause of the wheel glue failing in the first place. So if you are hearing a lot of noise from the extruder cooling fan then you may be headed towards that too.
