I’m running into an extruder/hotend issue on my Bambu Labs X1C and would appreciate some guidance. I’ve owned the printer for about 2 months, and until this week it has been working flawlessly.
Background / Setup
Printer: X1C
Filament (model + supports): Bambu ASA
Quality: 0.2 mm
Wall loops: 6
Sparse infill density: 60%
Bed & nozzle temps: Default profiles
Printer location: Indoors, ambient temps in the 60°F range
Issue
Last week, about 3 hours into a 4-hour ASA print, the printer suddenly began air-printing with no error message.
I disassembled the hotend and it appeared to be clogged (I’m fairly new to 3D printing, so I’m not 100% sure what “normal” looks like, but filament was clearly not flowing).
Since the printer came with a spare 0.4 mm hotend, I swapped it in. After that:
I successfully printed a simple PLA part using default settings.
I then attempted a different part using the same settings above
and model I’ve successfully printed 30+ times before.
About 20 minutes into that print, the printer again started air-printing with no error.
Questions
Does this sound like a hotend issue, extruder issue, or something else (heat creep, filament path, etc.)?
Is this something that could be covered under warranty, given the printer is only 2 months old?
Are there any recommended diagnostics I should run before opening a support ticket?
I’m using Bambu Studio - defaults other than Strength - Wall Loops & Sparse infill density listed above.
Process: 0.20mm Standard @BBL X1C
Heat: Initial/Other Layers 270 C
Speed: Initial Layer 50mm/s, Initial layer infill 105mm/s. (I can screenshot all speed settings if that will help?)
Diameter: 0.4
Flow: Standard (only option in the drop-down list)
ASA loves to absorb water and the filament page says to be sure it’s dry. I don’t have much experience with ASA (some) but how did you dry it and how do you store it?
Likely not hot end since you swapped with the same results. Feed when I’ve used ASA has seemed very similar to other filaments (unlike something like TPU) so since PLA is working I think the filament feed path is probably ok too. That doesn’t leave much left to be the issue but filament I think. Could be missing something though. Maybe something wrong with the extruder mechanism that pushes the filament into the hot end? But it was working with PLA so similar to the general filament path thing.
One more detail that may be relevant: I’m using an AWS, which I understood was intended to help mitigate filament moisture.
Given that, I’m trying to understand whether indoor humidity fluctuations could still realistically introduce enough moisture to cause a sudden clog mid-print, or whether this points more toward a temperature control issue or another hotend/extruder-related cause.
If anyone has seen similar behavior with ASA while using an AWS, I’d appreciate hearing what the root cause ended up being.
Your filament is wet.
Doesn’t just clog suddenly, the wet filament causes a jam that causes your issue. ASA can swell just a tad beyond 1.75. If you listen you can hear the water spit as the filament goes through the nozzle.
Even new spools can be wet. ASA likes water. Dry it thoroughly and then rerun the print. Clogged nozzles can be heated and a 1mm or thin wire can be used to open them up.
Most here, including those that have given you the advice that the ASA is wet, have been through this before. I suggest listening to the advice, cause this will happen to you again.
I’ve been printing with ASA (not bambu brand) for 3 years and never dried it once and never had any issues. I’m probably 30 rolls in without drying any of them. The way people point the finger at wet filament every chance they get is astounding. And it doesn’t help anyone solve the issue at hand.
Check your nozzle for a clog, they can be persistent and sometimes permanent. I run a small print farm and I have had several that I just had to throw away. If the same spool clogged 2 nozzles, you might have a contaminated roll of plastic full of debris or shrapnel. It happens. Get a new roll of filament and a new nozzle and see if it keeps happening.
I always keep several nozzles of each size at hand for cases like this. O’l faithful for clog testing is the 0.8mm fattie, I’ve never had one of those clog and its the ultimate debugger when you are beating your head on the wall on something goofy like this.
Yeah, sure, and for the last three years I’ve never once stopped at a stop sign either – blew past at least a hundred of them today alone and I’m still alive, so clearly traffic laws are just a myth and road safety is fearmongering.
That’s about the same logic as “I’ve run 30 spools of ASA without drying so moisture can’t ever be the problem,” while half the planet deals with humidity, popping, foaming, weak parts and the occasional steam‑powered nozzle clog.
In reality ASA, PLA, PETG and friends do absorb water, it can wreck prints, and yes, nozzles clog from crud, heat creep, ■■■■ filament and sometimes wet filament all at once – life is cruel like that.
Keeping spare nozzles and a 0.8 “debugger” is smart, but dismissing drying outright is like telling everyone with brake issues to just buy a new car because your 30 joyrides through red lights went fine.
A friendly middle ground would be: check the nozzle, check for debris, consider heat creep, and maybe accept that drying the filament occasionally isn’t witchcraft, it’s just one more tool in the box.
People need to understand that one person’s filament storage and ambient humidity is not the same as other people’s. Some are in air conditioned environments. Some are in unheated garages. Some have swamp cooler (evaporative) cooling that shoots humidity way up. And on and on.
Many don’t need to do anything with their filament so of course they are the ones telling others that their problems are bogus or not caused by humidity.
Others do have problems with humidity. People need to understand others can have humidity high enough to cause problems. I can speak from experience here. My prints were great when I first got my printer - in the winter when humidities HERE are low. As spring moved in my prints started going to hell. I have photos. It’s why I did a deep dive on drying filament and have photos there too.
It absolutely happens. People do have other experiences. And not everyone has the same low humidity as you apparently do.
The way people point the finger at wet filament is a result of EXPERIENCE that you luckily (for you) don’t have.
There’s always one isn’t there. At least name checks out.
What @L0rdS474n and @MZip said x 2.
What is your definition of a quality print? Finishes?
The way people dismiss wet filament every chance they get is astounding. And it doesn’t help anyone solve the issue at hand.
FIFY
Because there are folks who live in humid environments and your experience does not define what everyone should see. I’ve had clogs on TPU. Know why? Yep too wet. Even the manufacturer (Sirya Tech) suggested drying more.
I’ve had ABS clog. Know why? Yep too wet. Could hear the sizzle and popping. I was in a hurry. It was dried for 12-14 hrs and printed without issue afterwards.
Lastly, if you were to read the descriptions of BL, Polymaker, Sunlu, Elegoo, Anycubic and other brands ABS & blends, ASA and blends, PET, PC, and PC-ABS you will note they all recommend drying first.
So clearly, your experience is yours. Good for you.
I’ll add that probably many more see water issues than realize it. You can tune prints to help reduce the effects or compensate for them. One way is to just slow down the print which also speaks to why so many see water effects that used to not see them with other printers.
There’s a short time where filament is heated as it enters the extruder and that allows some water to escape. This is why slowing printing can sometimes reduce or eliminate the water effects. It gives a little more time before the water is physically trapped in the extruder to expand and force filament out uncontrolled. My previous printer was a much slower Makerbot and I never had water issues. I stored my filament open where all the spools were just sitting on shelves. Dust was more of an issue than water. Water didn’t matter with that printer. It matters with my X1C.
I’m able to use stock print settings across the board save things like line width or other cosmetic/model parameters not related to water effects. My filament is “known dry” (it still has moisture content - just uniformly low). I know how to keep tabs on water content and do, and my print issues are now all of my own doing.
And it’s not magic or hard to do. I had to buy a bunch of poly containers to store my filament, hygrometers to go in them, and silica gel packets to help keep them dry. But the hygrometers are how I keep track of my filament moisture level and at room temperature they all peg at 10% RH unless there’s a leak. But if filament isn’t pegging the meter it gets re-dried. It makes my AMS desiccant last about 6 months or so between changes and I change that whenever an AMS reaches 2 or 20%RH.
It’s all pretty simple. It takes some effort (small) but the reward is I get to concentrate on everything else but water. No mysteries. No sleuthing. I’ve been doing this routine now for almost a year and a half with zero water issues where before with open storage and no drying I simply couldn’t print many things without print failures.
Here’s a photo showing two parts that were printed with wet filament and then printed with the exact same spool and same printer settings after drying using my secret sauce - a dry air purge into my cheap Sunlu S2 dryer. That’s how I get my filament dry. I dry it in “dry” air. With nothing changing but moisture content it’s pretty obvious these were indeed water effects and water issues are absolutely real.
Thanks everyone for the suggestions — lots of good info here!
I’m going to work through the unclogging steps tonight (starting with the recommended pin push) and will load a different spool to see if I get a different result. I’ll report back with what I find.
I do run a lot of ASA, and I’m in the Dallas area where humidity can swing pretty significantly, so moisture is definitely something I’m taking seriously as part of the troubleshooting.
