I just ran into a partially clogged 0.4 mm HF nozzle that refuses to clear — not with a cold pull, a needle, or even my old reliable cleaning-filament trick.
The strange thing is that I didn’t notice the clog during printing. It only became apparent when I ran a cleaning cycle and saw that the filament strings coming out were very inconsistent. I know… I’ve printed just about every type of filament through this nozzle — even CF and POM — but what could cause such a stubborn clog?
I usually treat my nozzles as consumables, so it’s not a big deal. Still, I’ve tried everything just out of curiosity to see what’s blocking it. The last material I printed successfully with this nozzle was PC FR, so that’s probably what caused the clog. However, since I printed it at 290 °C, I’d expect a cleaning run at 330 °C to clear it out.
Anyway, when I tested it afterward, I got an “Extruder Overload” warning. So for anyone new to 3D printing — keep in mind that a partially clogged nozzle can trigger that error too. Even if the clog doesn’t visibly affect your print, back pressure builds up over time, and with slightly aggressive settings, the overload will hit you sooner or later.
If you ran the 0.4mm needle through it, and did a cold pull, and the extrusion is still “weedy”, try a different filament before concluding it’s the nozzle.
I always clear a nozzle clog with a clog poker, like the ones below. You heat them up with a blowtorch and push them in, never failed to clear a clog for me. I have the creality and I shortened it by cutting it down to a manageable size.
Sometimes the nozzle tip/hole can be damaged and cause similar symptoms. You can take a photo with a phone and zoom in to check.
Regarding the extruder overload error, it could also be caused by a loose piece of filament in the extruder gear or filament guide.
Extruder overload in this case was caused by excessive extrusion beyond what the nozzle could handle. It was resolved by fine-tuning the line settings and a few other parameters.
I haven’t discarded the nozzles — they’re kept for later inspection. I might just order a better cleaning tool than the one I already have
Were any of the spools you used made out of cardboard? Nowadays it’s not uncommon. I’ve noticed that some of them shed particles onto the filament. I think I have maybe sometimes experienced those particles creating an unclearable clog. Those particles aren’t going to melt, any more than wood or paper would, and in that sense it’s consistent with your experience of hotter temperatures still not allowing the nozzle to be cleared out.
Likewise, I’ve also noticed large dusty detritus on some brand new filament spools, even if the spools themselves are plastic. This is more the exception than the rule, but it looks like maybe the filament was pulled in a fairly dusty/dirty/contaminated environment when it was manufactured. Same result.
In recognition of this, mostly in the dark ages before Bambulab took over, some people would run their filament through a “filament cleaner” as it came off the spool and before it went into the extruder. This “filament cleaner” was most often just some spongy foam in a small confinement vessel that was clamped around the filament. I’m not advocating for that solution, but just pointing out that its mere existence was a recognition of the problem.
Maybe this could be a factor in your case? You’re in a better position to judge the likelihood for your case than any of us.
Most of my nozzles are HF, and as long as there is still some filament in the hot end it works just fine. Or you can cut a tiny piece and drop it in before doing the procedure, but I have not needed to do that.
Ive found that i can never unclog a h2d hf nozzle because of the internal design being a wall that the needle hits. Maybe if the clog was after that point(close to the actual nozzle hole).
As i said a while back, bambu hf is not the same internal design as a cht nozzle. A cht nozzle can be unclogged, if you can get the needle to take the correct path. If the path is also larger than the needle. .4’s are a bitch
The only luck ive had with unclogging a bambu hf nozzle was cranking the temp way up and tying to extrude. Or by heating the nozzle tip with a torch and shoving an allen wrench down it, fast and hard.
Are you using just the regular Bambu hotend-nozzle’s then? Or are you doing some third party thing?
Given the relatively high price for the HF nozzles, it’s disheartening to hear they may be resistant to clog clearing.
But ultimately, what would be causing them to clog in the first place, if not contaminants? Only other thing I can think of is that the filament diameter suddenly goes too wide, and maybe that’s what causes the jam. You could maybe test for that using a micrometer on the filament near the jam point and comparing against the 1.75mm spec. Either that, or else an earlier higher temp filament left residual behind, creating a narrow channel for a lower temp filament, resulting in a jam that way. For that reason, I dedicate nozzles to higher temp filaments like PPS-CF, that I don’t later mix with trying to extrude PLA or PETG. I thought maybe that was overkill, but maybe not. If fixing is not an option, then that leaves prevention as the only rational pathway.
For some anecdotal evidence, I have been using the 0.4HF nozzles from day one, Im 2500 hours into ownership with zero nozzle clogs. And I print a lot of ABS-GF, PAHT-CF and TPU 95A and 90A, mostly bambu filaments.
I did have one extruder/filament guide clog but that was my fault due to not waiting for the machine to cool down after high temp filament going to PLA.
I also ran 0.4 CHT nozzles (ali V1/V2/V3/V4 and E3D Obxidian) on my P1 and X1s with no problems, 10k hours total. Clogs were easy to clear with the tools I linked before, they did not happen on the E3D, ali were a different story thats why I stopped using them.
Normal hotends. They seem to last forever and flow enough for the speeds I actually print at. I also print mostly cf and gf these days.
All nozzles clog sometimes, but not all nozzles are user friendly when it comes to unclogging, was what I meant.
I think the biggest reason for the original clogs is running high temp filament followed by low temp or just mixing filaments back and forth that dont stick to each other. Can sometimes be fixed by purging at really high temps
Playing around in orca with the toolchanger. I see that you can set specific toolheads for specific tasks. Like outer wall, inner wall, infill…I also know you can set the toolchanger up to use different size nozzles and even completely different types of toolheads, hitends and extruders on each tool. I havnt tried yet, but I bet I can run a .4mm nozzle for outer wall, .6 for inner wall and .8 for infill. all at .2mm layer height. And just change the line width of infill to .84, inner wall to .64 and outer wall to .44
Just did my first 5 color test print. Just a 5 slice pie
Not really solve, partially solves probably.
But it will be an expensive story on the Vortex since every nozzle there is pretty high price if my information is correct.
One trick i learned before throwing out nozzles that were clogged like this in my x1c is this, i grab radiator with pliers and heat heatzone with torch so radiator is also would heat a little bit, then i insert nozzle cleaning needle and then use any plastic i have to push filament, this helped me with such severe clogs. As i understand the issue is when clog happens not in cool zone, but in heat break and radiator area, which you can’t unclog unless heat them up a little bit.
I also tried to burning plastic inside with a torch, but it didn’t help, above method saved me several nozzles.
CHT nozzles are a real pain to clear, as @StreetSports mentioned earlier.
The clog is deep in the melt zone, and none of the usual methods seem to reach it. I never throw away clogged nozzles — I keep them for later inspection. I just swapped the clogged one and kept the print going.
On my X1C, I use SliceEngineer’s MAKO hotend, which is both easy and inexpensive to service, even for CHT variants. Replacement parts cost around €10, making it a simple swap.
I considered this, but I was worried that really blasting it with heat would turn whatever was in it into sticky carbonized crud, like what boils off and builds up over time on the outside of the nozzle during regular printing…
Maybe soaking it in acetone over a lengthy period of time would eventually just dissolve away the clog?
With the regular nozzles, it’s more practical to just toss it away and slot in a new one that go through an extensive rescue, but the bar gets raised a bit with the HF.
