Edit Apr 2026: Since last firmware update, this problem is much worse because the buffer is slammed to max on every feed. I found none of the solutions here to work anymore. If anyone has a solution, or has an H2S without this problem, please share with us what works.
I got the new H2S and it has been perfect so far, but there is one thing I am not sure about. The buffer clicks in when full and only when the printer is printing towards the front of the plate. I found this post that shows exactly what is happening on mine too:
From looking at it while the click happens, it seems that the ptfe tube pulls the buffer’s internal connector toward the front, and that causes it to catch into the front of the hole and cause that click.
So from that it seems the easy solution is to put a longer ptfe tube, I tried that and now it only clikcs in the very front of the plate, but also the tube now rubs against the top glass.
Has anyone seen this or have a solution for it?
One thing to add, the print quality doesn’t seem to be affected and the prints come out perfect, but I think the catching of the buffer might be causing accelerated wear so would be worth fixing.
For anyone coming across this, I made some changes and haven’t seen the buffer clicking since then:
Changed the PTFE tube from buffer to toolhead to be a bit longer, but making sure it is not too long to hit the top glass or the sides. It has to be a goldilock size, unfortunately, I can’t give you a centimetre because I cut too long and then shortened it bit by bit.
Shortened the PTFE from the AMS units to the buffer and straightened the bends, reducing the buffer “overflow”
I think some sort of bracket can also be printed to prevent the core of the buffer or the PTFE tube from moving too much forward, but since I haven’t seen it happening again with the above changes, I have not tried that yet.
That sounds frustrating! I can see how if that buffer core gets stuck while the AMS is trying to push filament through, the motor would overload. I think for your case it is severe enough to create a support ticket.If you did, please let us know here how it went too, for anyone else coming across this.
I think the core reason of the issue is that the buffer core (orange) gets pulled toward the front of the printer (toward the door) with the PTFE tube, and then it can’t freely come out the buffer hole when AMS tries to push a length of filament to max the buffer.
Exactly what I suggested for many others. Both H2S and H2D since they’re using the same buffer.
The original tubes were definitely not cut correctly for some units, and I don’t know why lol.
I generally suggest everyone with a banging buffer give the tube one 1cm more length.
Yesterday I was printing something and I noticed that the buffer clicked, only once though during the purge line that it does in the very front of the plate.
Any additional length of PTFE would cause it to hit the leds during printing. Given that this is once, and only happens during initial purge I am not alarmed but still wondering if it is common.
What is strange though, is that I have two AMS units and from the other one I do not remember it clicking with the same filament when doing the purge line.
Edit: Just today multiple prints and it did not click at all.
I own a H2S since a view days, from beginning with my AMS i have had the clicking noise, with an external spool, there was no problem. i have changed the ptf tube with a longer one (aprox 3cm) the klick sound is now gone
Hello I am running into the potentially same problem. I started to have extruder overload issues. At one point it was as if the nozzle was not warm enough and filament was bent in the head and was not able to feed or extract. It started running PLA and I did a quick look and hit problem resolved and the print finished. I switched to PC/ABS and had is overload again to the point where I removed the extractor and pulled the filament out manually. I had to cut the filament and PTFE tube to even remove the filament. I added a new ptfe tube and noticed the clicking. Then based on the forum I cut a different tube a bit longer than the factory tube and I am still running into issues. Not sure if anyone has any ideas as to the cause. It still clicks now and it still does get the overload.
Here is a more refined and slightly more factual version:
Hello,
Since yesterday, I’ve been hearing the same clicking noise coming from the filament buffer. The H2C printer is now a little over a month old.
Unfortunately, opening a support ticket with Bambu Lab didn’t help, as they reportedly classified the video I submitted as normal operational noise. To be honest, I find it strange that such an expensive device is causing these kinds of problems after such a short time. The issue with the filament buffer also seems to be a known problem.
If you’d like, I can also provide a clearer, more diplomatic, or more technically precise version of this.