I’ve suddenly started having problems with a blocked nozzle after around 2500 hours on my X1 Carbon, its causing my larger and taller prints to end up like the following images. Since i was at 2500 hours anyway, i decided to change the entire hot end, the entire extruder assembly, and the PTFE tube between the tool head and coupler, coupler and hub, and then both AMS devices. Everything I’ve replaced is proper Bambu Lab parts, including the PTFE tube.
I’ve made sure the lid is off, the door is open, and the chamber is only showing the temp to be 30c, but no matter what i do i’m still having prints like this and having to do a cold pull to clear the nozzle.
Looks like top was too thin and started to wobble around - but this less common on a core like an X1 and more likely to happen on a bedflinger. But I have had it happen on a core.
I suppose it could cause blockages if a blob hits the nozzle
Nothing was wobbling around, the part is the same thickness all the way up, it was still stuck to the bed really well, it’s done it with other parts too. It’s a strange one as I’ve never had to leave the door open before, in fact I’ve never even had to have the lid open with PLA, only PETG, so i’m not entirely convinced it’s heat creep. ALl i know is that replacing all those parts, as well as leaving the enclosure open, hasn’t fixed the issue.
I’ve also tried multiple filaments in both the AMS units, it doesn’t matter which i use.
Can that be printed in a different orientation? Tall and narrow things are hard to print in general.
If Eponymous is right about wobbling, maybe glue would help keep things stuck in addition to the brim you’re already using? Scratch wobbling - saw the new post.
The print looks generally really good in those photos but there’s fair stringing down low where the holes are. It’s a puzzle to me because the prints overall look good. Are there little zits on the prints we don’t see in the photos? The stringing points to maybe moisture in filament but that doesn’t seem that likely to me given those prints. How are you drying the filament or are you? Kind of a shot in the dark though.
In that case, check if the fans are coming on or off at certain heights, or which parts of the chamber the air is circulating around in. if it;s all going vortex at the base of the chambher, the top might too be too hot.
You can blow smoke into the printer to view the air circulation pattern.
It could but it would need a load of supports. Its definitely not wobbling though, and some of the other parts are taller and thinner, they printed OK and then it just started doing this.
Exaxctly, they’re pretty much perfect until the nozzle seems to clog slightly. The stringing down the bottom is just because of the holes, it just rubs off so i’m not concerned about that. There’s nothing that suggests the filament is wet, it’s something i listened for too, definitely no little zits that i’d expect if there was moisture in the filament. I use the AMS 2 pro to dry the filaments, but it’s never been a problem.
I’m really scratching my head with this one, my X1C has been absolutely perfect until these failed prints.
Tall thin parts can wobble without becoming unstuck, even with a substantial brim, but I don’t think that happened here. Wobble defects happen where the nozzle makes a turn, when the filament pulls the print out of position. Wobble defects start near corners and tend to settle down on the longer straight sections. In your prints, the nozzle is placing filament in the correct position, just not enough of it.
The defects are fairly consistent everywhere, though in the top picture, there is progressively less extrusion. I do think that is more typical of a heat creep clog, especially if you are getting better results after a cold pull.
I’m sorry that I cannot offer a solution. I’ve not had this problem, and door open/lid off/30° chamber all sounds good.
I think @blchandl2’s one at a time suggestion might help.
Is that PETG by chance? I either missed what filament or it wasn’t said. Reason I ask is looking more at it, the surfaces look a little “doughy” and the stringing while minimal is still fairly strong down around those holes. I’ve seen that in my own prints with not fully dried PETG.
The AMS2 Pro is I think less effective at drying PETG due to the higher temperature needed but I am not that familiar with them. If you are running with PETG it might still be moisture, maybe?
The only time I have seen something like this is when I accidentally had my addon chamber heater on while printing pla. I wounder with it being so long of a print if it could be getting to hot.
This was my main concern, but the chamber temp sits at about 30-31c so it shouldn’t be an issue.
This particular model was downloaded using the “online models” via bambu studio, i obviously synced my own filament settings, but i’m trying it once more with my own default settings to see how things go. I can’t see how this will have any effect though as i did try a different tall model with my own settings, it also failed in the same way, but then printed ok on the second attempt last night.
I’m still convinced its heat creep causing the blockage, i just don’t know why, or how i can stop it from happening when both the lid is off, and the door open. I’ve obviously checked all the fans are working as they should be too, AUX fan is off like it always has been.
If it is heat creep, I have a small fan that uses a clamp mount. It’s clamped to the printer table just in front of the printer so I can move it in front of the printer to blow room air in. It really helps especially in summer where temps in my office tend to be fairly warm.
Only thing is I’ve printed PLA with the chamber up to 36C without issues. That was accidentally above my intended limit of 35C (as recommended) but no issues.
I concur that this looks very much like heat creep or, less likely, an increase in filament tension in the routing.
What nozzle size and layer height are you using?
Indeed, the 31°C shouldn’t be an issue for PLA Basic. But I’d dry the roll regardless. Just to rule that out and to make sure it is covered.
I’d try again after doing a hot hex key cold pull on the nozzle, drying the roll and using a .4 nozzle and adaptive layer height to ensure that there’s enough flow to dispose of excess heat in the cold end of the hot end. And of course while keeping the chamber temp just above 30°C and occasionally checking the filament roll for binding, straight seating, …
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