Due to the differences in the length of the tube in different batches and versions of the whole printer configuration, under the premise of ensuring that the loading resistance meets the requirements, appropriately shortening the length of the tube can effectively reduce the printing time.
After testing and verification, the length of the tube from the AMS to the H2D is recommended to be no less than 600mm to ensure the best working condition of the equipment.
That kind of says to me to keep the teflon tube as short as possible (for obvious reson of reducing time and friction - if not bent too much of course) and at the same time it says the tube should be minimum 600 mm long (which would be a longer tube than what was actually delivered with my H2D/AMS combo).
Is that a typo in the wiki and in reality it should be “… is recommended to be less than 600mm …” (without the word “no”) or can someone explain this wiki entry to me in other words that I might understand better?
Good question! I wondered about that and asked Bambu Lab support. The answer received was “600mm is the most suitable after our internal testing. If it is too short, the tube may bend and be unfavorable for feeding”.
Apparently it is possible for the PTFE tubing between the AMS and the printer to be too short so not a typo.
Thanks for posting this!
Even though bending can be an issue it is not that Bambu team will know where exactly the AMS(s) are placed by their customers.
But I guess, given your conversation with the Bambu support, I guess it’s fair to conclude that it should be as short as possible without having any bending radius in the tube so small that the friction will be increased.
Also, one thing I have learned in the meantime is, the AMS will feed a significant amount of filament for the “remaining filament on the spool prediction”.
If the tube is getting too short this could interfere (“crash”) with filament already fed to the extruder via another AMS (in situations where you have multiple AMS connected to one extruder).
My AMS HT is around 350mm as it’s right next to the printer - has been fine so far… 2 of my AMS’s are also cut to less than 600mm - again, no issues…
Good point about the Bambu team not knowing where the AMS(s) are. I think the Bambu Lab frame of reference is having an AMS on top of the printer where the PTFE adopts a sort of “S” shape curving down and then left (as seen from the back) to enter the the printer. That is two turns so extra length makes sense. If one places the AMS(s) close and on the left of the printer (as seen from the front), it is a relatively gentle arc and a shorter than 600 mm may be possible.
Also, one thing I have learned in the meantime is, the AMS will feed a significant amount of filament for the “remaining filament on the spool prediction”. If the tube is getting too short this could interfere (“crash”) with filament already fed to the extruder via another AMS (in situations where you have multiple AMS connected to one extruder).
Do you have any info on that and have you experienced any “crashes” of the type you specified?
Based on this wiki entry, there is odometry going on so the system knows how much filament the AMS sent out and it “should” know how much to retract so there are no crashes. Still, it is something to watch for I guess!
No, I have not experienced and filament “crashes”.
But from my observation when putting in new filament in the AMS 2 Pro it will slightly turn the spool (I guess to read the RFID tag) and then it will feed filament through the tube coming pretty close to the buffer (I guess that’s for remaining material estimation) before pulling it back to the spool.
My tubes are the ones delivered and while I haven’t measured them they are roughly 600 mm I’d expect from holding a ruler next to it (haven’t disconnected them after creating that post) which means nearly 600 mm of filament is fed through the AMS tubes aber putting in a new spool.
So if the tubes are shorter and you have additional filament connected to the same extruder (like an external, non-AMS spool via the 4-in-1 PTFE adapter) I would expect that this filament (after inserting the spool) will reach (“crash”) any filament from other sources that’s already sitting in the tube to the extruder.
My writing kind of looks confusing, sorry for that, but I don’t know how I could phrase that in an easier to understand way.
(OT) Considering the equipment I guess you print a lot. Doesn’t that bother you having the two AMS on your printer?
I had also two AMS 2 Pro on top of my H2D but this got really annoying every time I wanted to open the top glass cover (which is for some tasks a lot more convenient than working from the front door) so I put them on a shelf 10 cm above the printer which makes maintenance easier.
