The filament level indication on my A1 with an AMS2 Pro seems incorrect. I have it loaded with 4 spools of Bambu Lab PLA Basic. Spools 1 and 3 are black, spool 2 is red, spool 4 is white.
Spool 1 is full. I just loaded a new spool to be a backup for spool 3. However if you look at the indication Spool 1 is only showing about half full. This is both on the A1 screen and in Bambu Studio.
Hi Mark,
My experience with the AMS2 and HT is that the levels are “guesstimates” at best. The printer definitely needs to start using it (pulling filament off the spool) before it can get even close to actual. From what I understand it measures how many times the spool rotates for a given length of filament pulled off.
Once it gets that initial estimate, it seems reasonably OK… until close to the end of the spool when the filament is loose enough so it doesn’t rotate the spool on every pull… then the AMS thinks the spool is full again! 
Doesn’t seem to affect filament runout detection or anything vital though. Just watch out for that tape at the end of the spools if doing “auto refill!”
-Max
Thanks for the reply. You’re right, the AMS determines filament remaining by how fast the spool rotates, but I figured that it does that measurement when you first load the spool because it spools a fair amount out and back, but maybe it takes more filament movement such as when it’s actually printing.
Could you clarify your warning about watching out for tape if doing auto-refill? One of the reasons, I got the AMS was for autorefill. I did see a print on MakerWorld to fix the “tape of death.” Is that really a problem I should be worried about?
Ah, the infamous tape. The Bambu filaments are taped down at that end to the core of the spool. Depending on phase of the moon or whatever, the tape may release properly, may stick and not let go at all, causing an error, may let go the spool but stick to the filament, jamming up the AMS, or may release prematurely making the AMS not be able to retract it if it needs to. There may be some other things it could do, really… quite unpredictable, that wily tape.
Other threads (there are more):
H2D AMS 2 Pro gets wedged if end of filament fails to detach from spool,
Tape at the end of spool,
P2S + AMS Pro 2 Filament feed when end of spool
So yea my “auto” refills haven’t been very auto because I babysit the spool and snip the filament just before the tape as it is about to run out. Then the auto-switchover works great! Personally I’m not really “sold” on the anti-tape devices I’ve seen out there… a complication that most of the time just increases drag, seems like, and adds point of failure. But yea would be nice to put a reliable “auto” into that “auto refill” feature.
-Max
Thanks for the reply. That is concerning. My general workflow is to start the print and let the AMS worry about auto-refill. With the open frame of the A1, I prefer to stay out of the room as much as possible when it is printing. I also do a lot of printing when I’m away or asleep.
Prior to the AMS 2 Pro, I did a lot of printing with an AMS Lite relying on auto-refill. I never had an issue with the AMS Lite, in its stock configuration. FWIW, I’ve only had one instance with the AMS 2 Pro so far where auto-refill was used and it did not have an issue.
Right out of the box with the AMS2 Pro, I had to print a piece to manage the PTFE tube between the buffer and the hot end as without it, on almost every print attempt filament would get caught in the buffer and prints would fail with an filament feeding error. I also had a defective internal hub in the AMS 2 that, while BL did supply a replacement after the problem was identified, I had to take the AMS apart. So my out of the box experience with the AMS 2 Pro was less than what I have come to expect from BL. If you purchase the AMS Lite as a combo with the A1, it’s only $100 extra. With the required buffer and external power supply, the AMS 2 Pro is over $350. I’m not sure I get 3.5 times the benefit versus the AMS Lite and now you point out a potential issue with tape.
Mark
