I just want to preface I’ve been lucky to not have any feed issues / stopped prints. I have had several instances of AMS warnings for too high of resistence, but nothing that physically stopped it.
I just wanted people to be aware that it appears the default PTFE tubing going from the buffer to the internal feeder on the left nozzle (black translucent PTFE tube) is waaay too sharp of a double turn. It’s essentially asking the ams to push it through the buffer, do a 180 in the tube with the height of the 180 change only being a few inches. That’s a SHARP ANGLE!
Also, inside the printer, the left nozzle (black translucent PTFE tube) is too long going into the extruder. If you look at the toolhead, left hand nozzle PTFE tube (black), when it’s parked near the back of the plate by the nozzle scrubber, it’s forced to do almost a 270 degree 3d turn right at the extruder because the tube is coming from behind, looping over the top with the extra length pushing the tube so far that it actually hangs over the front of the toolhead. then has to loop back then down again to get to the extruder.
So the buffer to the feeder tube I made a new piece (remember it’s 4mm OD x 2.5mm ID PTFE) that was longer with a more gradual curve. And the inside left nozzle PTFE tubing.., I placed the tool head at the front of the plate at the extreme left and right, and shortened the tube by about 1cm to stop that loop from happening in the parked position and allowing it to have plenty of slack at the extreme ends of the plate in the other direction.
Seems by “listening and watching” the AMS is feeding much better. And I’ve already gotten the AMS in a terrible position as it’s placed in front of the printer and elevated above the machine.
Just something to look out for. Some of these angles are very sharp.., too sharp for the AMS IMO.
On my unit it’s so bad that even when loading by hand (only possible when printhead in the front) the PSMS extruder gives up during print. Before finding this thread I helped myself with a rubber band (see photo) to avoid the grey tube taking the worst position. With this “fix” in place I can print softer materials like PLA+ or PETG, but plain PLA or matte PLA won’t work at all.
I’m reluctant to shorten the tube before hearing back from Bambu Lab Support. Is the tubing from buffer to left extruder continuous? If yes, can I somehow just pull 10mm to the outside? So I don’t have to cut, but the tube gets shorter inside? I didn’t find any information in the Wiki about maintaining/exchanging the tubes.
It seems I’m unable to add photos. What I did is that I connected the white and the grey tubes together with a rubber band in the middle between the two clips that fix the tubes to the chain
Well, the interesting thing is, that the filament from the AMS runs thru all the tubing and the 4-1 connector and the buffer up to the nozzles pretty good but NOT thru the Filament Track Switch. This is the point where it get stuck during loading very frequently, although I have it installed exactly as described in the Wiki.
Sharp bends are an issue, no doubt, and using the AMS exit PTFE tube guides to maintain defined bends wherever it is needed is very helpful indeed.
My X1C + 2 x AMS I could not stand the struggling AMS motors even with mild bends. Fixed it. Looking to the same to the X2D after warranty. I wish the X2D filament switch was like this one with 4 in 2 out. It would have to be bigger but it would be easier to manage than the octopus you need now for adding 2 total AMS. 4 seems like it would be a nightmare
1st off, there’s nothing special about the PTFE tubing in that printer other than the size. It’s 4mm OD by 2.5mm ID. They use a couple different colors to distinguish between 2 heads etc. I literally have a 100M roll of the stuff (granted I have quite a few bambu printers).
To answer your question. No.. the buffer to the feeder is a single piece of tubing. As there’s another quick fitting on the feeder that follows another quick fitting on the inside. So 2 seperate PTFE pieces (buffer to feeder then feeder to toolhead). You can see it plain as day with the tool head parked that the PTFE for the left nozzle is so long it actually hangs over the front of the toolhead even though the tube is coming from behind.
It’s literally a 1cm removal or less. Super easily done at the toolhead.
Yeah.. the buffer going from one side to the other than making a 180 to enter the machine is a strange choice. I’m sure it’s done for engineering / space concerns for components.
But the buffer, if on the outside, should be flipped 180 degrees and a straight path to the feeder coming in instead of having to go past the feeder and make 2 separate PTFE tubes do a 180 degree turn to enter the machine.
I was unable to get the tube out of the fitting, unfortunately. I printed a tool to apply even pressure all around and pulled as hard as I dared to. No chance. I also tried to push, then pull. Also to wiggle around. No luck.
I have a feeling you tried to remove it wrong or something.
Those tubes come out super easy. You should be able to press one side of it down with a finger nail while also being able to remove the tube at the same time.
For instance, I have many instances of filmament breaking during long prints on H2Cs and H2Ds because the 2ndary nozzle / colors will sit in the tool head for 10+ hours without retracting until the end of the print. I can hold the glass up with one hand, and with the other hand use a finger to push down on the collar of the PTFE release, pull the tube out, and grab the loose, broken filament (all the while my one hand is still holding glass top at an angle.)
There must be something you are doing wrong there. They should be super super easy to remove, especially on a new’ish’ machine.
Yeah, I don’t completely trust my own practical skills either. That said, I also don’t see much opportunity to do much wrong. You press the collet fully and pull while still pressing.
Dr. Internet says there are failure modes like the teeth getting stuck in the tube…
My rubberband “fix” at least allows me to print materials other than plain PLA in the meantime.
I forgot to mention that this my 6th printer over more than a decade, just my first Bambu.
If terms like “Wade Extruder” / “hobbed bolt” ring a bell…. that was my starting point, but I digress.
I removed 8.0mm of the grey tube. (I eyeballed 10mm and ended up with 8). It helps a lot. Since my PTFE tube is stuck at the extruder end, I removed from the other end of the tube. Might shorten it by another 4mm tomorrow. @Tool_Maker Thanks a lot for your help!
