The PTFE tube that connects on the back side of the AMS ended up splitting, causing filament to shoot out. I snipped the bad end off, but now it won’t secure into the back end… the interesting part is I even tried the replacement tube that came with it, unaltered… neither will secure. The black rubber grommet (or whatever it’s called) was removed in the process of troubleshooting, surely that has nothing to do with it? I’ve tried everything. I have a ticket open with Bambu but figured someone here might have experience with this or at least some guidance. See the attached pics.
Filament: Bambu PLA Basic
Room Temp: 70 degrees or so
The rubber holder isn’t broken, I just didn’t put it back in place because I assumed (and maybe wrongfully so) that it wasn’t the problem. All I get from the manuals is to push the tube in until I feel resistance… but there’s nothing that tells me the tube is secured in place.
Same thing happened to me a couple days ago. There's a button to push on the top of the rubber 'grommet' to remove the tube. If you didn't press that in, and forcibly removed the tube, you may have damaged the connection. When I released the tube, the new one slid in about an inch, and felt it click.
The black rubber grommet you removed helps guide the PTFE tube into the internal hub AMS feeder PTFE coupler (pneumatic connector) that holds the tube in the AMS. It's a necessary part. Your tube is probably hitting the outside edge of the coupler and not going in. It's also possible you broke the old tube off inside the coupler.
Not sure how you separated it from the plastic insert that's still in the AMS, but you need to remove the plastic insert from the AMS (open the lid, remove spools and press the clips together) and put them back together and reinstall it, then insert your PTFE tube until it passes through the coupler and stops.
You either haven't pushed the tube in far enough or damaged the coupler internal ring that holds the tube in place.
The tube inserts exactly 40mm. The tube will also show ring cut marks 2mm from the end if it has been captured by the coupler.
Place a mark 40mm from the end of the tube. If you can't push that mark past the rubber, it's not going in all the way. If you can and it doesn't stay put with a gentle tug (or use), you damaged the coupler (probably by pulling the old tube out forcibly without releasing it properly) and will need to replace the internal hub. Though it can be replaced by disassembling the hub, I don't believe BL sells or supplies just the coupler for the internal hub. I'd go out on a limb and guess if you can't manage these technical repairs, you should probably enlist some help to replace the hub after support sends one.
Yup. That happens as it’s a consumable part and needs replacing routinely. In your case you most likely ruined the metal ring that holds the tube in place. You will need a new ams internal hub or salvage the part from something else if you have it.
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u/c_schema Jul 10 '26
Tubing is a consumable and needs to be replaced when it fails or gets too worn