Hello everyone,
I’m having one heck of a time here. It doesn’t matter what I print the filament keeps breaking off in my hot end. I recently got a new hardened steel nozzle from bambu labs and it is still happening. I put a ticket in and they suggested it was heat creep so after installing the new nozzle, taking the glass top off and keeping the door open. I had the same problem… Very frustrating… Like I said I’ve replaced the hot end , The cutter , I tried using different brands of filament , Old filament , New filament and i cleaned out the extruder making sure there was no filament in there. Is there something that needs to be adjusted or properly properly tensioned? Could this be an AMS issue? Tonight I will try and run a print without the AMS and see what happens.
The printer was working perfectly for months and now all of a sudden I I haven’t had a successful print in weeks. Please help.
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I’ve had issues with filament getting brittle when it’s not “dry” so to speak. I’ve also noticed a strange phenomenon where it also gets brittle within a foot or two of the extruder; way beyond where any heat soak issues would be. I wish I could be more helpful.
Filament breaking in the hot end doesn’t sound like heat creep to me.
All the different filaments showing the issue is really odd. Without that bit I was interested in how your weather had changed recently and how you store your filament. Moisture can make filament brittle but there tends to be differences between types and even colors.
I don’t know any adjustments that lead to filament breaks in the extruder. Maybe someone else has seen this?
@t.mcgaughey and @Hondo Welcome to the forum!! I’ve noticed this phenomenon too. Even if the filament is dry and the humidity in the AMS is low, the very end will be brittle. I just assumed it absorbed moisture more rapidly at the freshly cut tip. That was just a guess. Now when ever I swap rolls I always flex the end and if it breaks off I flex the new end. Normally the second time it flexes.
PLA gets brittle when it absorbs moisture. So brittle, it can break in to many small segments just sitting on the spool. The bends in the filament path to the extruder are sharp enough to break PLA when it’s too “wet”. Doesn’t cause a problem when printing because the crack gets pushed until it’s “consumed” by the hot end. But on retraction, you end up with a few inches remaining in the PTFE tube after the AMS does a pull-back.
No such thing as “over dried” filament. You’re thinking of Spaghetti.
And plastic, being “plastic”, softens as it heats. The opposite of brittle.
I’m betting the OP is using PLA and doesn’t own a drier. Comprehensive list of things tried, none of which including anything specific to the filament itself. There’s no way I can envision for the filament to break anyplace along the filament path as a result of an issue with the printer. There’s nothing anywhere capable of doing damage to the filament except the cutter at the toolhead itself.
Thanks for the welcome! I actually came here in hopes of getting help with my particular problems, but this seems like a really weird forum to get going on; after having that post flagged “due to the content” as spam/bot initially, I logged out, never to return (until I saw your acknowledgement in the reply preview in the email notification).
Anyway - tagging on to other replies, yes this phenomenon is one I’ve only experienced with PLA, just about everything else I use just gets stringy and/or bubbly/crackly when the moisture content is too high.
It’s not the filament. It happens with brand new filament just out of the package and not just with pla. It’s happened with abs as well…
I’ve tried three different brands of Filament just so I could rule out that it’s not the filament.
I bought a new extruder gear. I’m going to try and install that tonight. I will let you guys know I appreciate all the responses.
When this occurs, do you have to take the extruder apart to remove the stuck filament, or can you get it by detaching the PTFE tube from the top of the extruder and pulling it out?
It breaks off right at the top of the hot end flush …
I may have figured it out .
I did 3 things
changed the setting in the printer to .4mm hardened steel hot end and calibrated
change the extruder gears to new hardened steel ones
I really tightened the tensioner on the extruder.
I think the culprit might have been that the tensioner screw wasn’t tight. I remember putting it back together the first time and wondering how tight that screw actually had to be.
I just just a successful test print … Now I’m printing something a little bigger. Tomorrow I’m going to try some thing with multiple colours, I’ll keep you posted.
I’ve had brand new filament still need drying. I use a vacuum chamber with color changing dessicant so I can visually tell if I’ve pulled moisture out, but I realize that’s a bit over the top for most people (also used for epoxy degassing and other non-printing stuff around the shop). This is one of the easier things to try so I’d start there before going in to deeper troubleshooting.
Rule #1 of Diagnostics; KCSSTF: Keep Calm, and Start with the Simple Things First.
