I’ve been having an issue with filament repeatedly breaking in the left-hand filament path on my H2C, and I’m wondering whether anyone else has experienced the same thing.
I use the left nozzle primarily for black filament, as I use black in a lot of prints. I therefore have the left PTFE path connected to an external spool and tend to leave black permanently loaded.
The problem seems to occur when the printer is doing a lot of printing with the right nozzle while the left nozzle remains loaded but unused.
My suspicion is that, although the black filament isn’t actually being fed through the left nozzle during this time, the movement of the toolhead is continually flexing/moving the PTFE tube and the stationary filament inside it. Over a long print, I’m wondering whether this is repeatedly bending the same section of filament and eventually causing it to fatigue and snap.
When it does break, it seems to be around the filament buffer/PTFE area, rather than at the spool itself.
I’ve now had this happen several times and it’s becoming quite frustrating because once the filament breaks I have to stop what I’m doing, dismantle the filament buffer/path to retrieve the broken piece, reload it and potentially deal with a failed print.
Has anyone else with an H2C experienced this, particularly when leaving filament permanently loaded in the left nozzle while predominantly printing from the right?
This is known to Bambu, for any of the dual extruder models the filament not being actively extruded can fatigue and break - so for that reason filament on the unused side is retracted back to the buffer specifically to avoid this fatigue breakage.
In your case, because you are loading an external spool, there is no way for the printer to retract the filament, it just sits there and gets flexed back and forth until it breaks.
The easiest solution for you is to unload your filament when not in use. Alternatively, get an AMS HT for the left nozzle.
I have had issues with filament breaking and what I found was the issue is that I live in the humid environment and the filament (PLA) absorbs moisture and becomes brittle. This was a brand-new role of filament. Upon feeling the filament I can feel a slight roughness on the inside of the curve of the filament. The filament should be smooth. So I have to unravel the filament to see how far back this roughness goes. This rock filament is no longer useful for printing and is waste.
There is another reason why it could also be breaking is that the filament does have a life span. Even if you open a brand-new box of filament it may already be passed use by date.
Thanks for that. My only thing with the ams HT is that I don’t think it will pull back the filament from the left side. I may need to add an ams to the right side using the vortek.
If the filament is loaded using an AMS (including HT), the printer will unload filament to the AMS after printing. If the print does not include the nozzle the AMS is conencted to, it will not be loaded in the first place unless you do it manually.