I had an issue with a filament breaking during while being loaded and had to remove the broken piece.
After that I still couldn’t print, I got a message saying extruder might be clogged.
I opened up the extruder and verified there are no pieces of filament stuck, also manually fed filament into hot end and it melted just fine.
Tried printing and AMS kept on trying to feed filament, but as soon as it reached the print head it would retract, after several tries it would give me a message error about extruder being clogged.
I know extruder is not clogged, I am able to remove the AMS and manually load a filament from the exterior spool and it prints properly, I also know the AMS is not clogged, as it pushed filament perfectly fine all the way to the print head, but once it reaches printhead it retracts.
So why can I manually feed but the AMS can’t if there is no blockage?
Thanks
If you are confident that the extruder isn’t clogged, check the PTFE tube path, as you may have changed when removing the broken piece.
Non-optimal length and entrance angles at the connectors may result in excessive resistance, especially with the velocity that AMS feed it; thus, when you do it manually, it works as you control the feeding speed.
You can do a swift test by holding the PTFE tube to make a smooth angle at the printer and extruder inlet during the AMS feeding process… if it works, you know the cause and can solve it.
I think you are on the right track about the filament encountering excessive resistance, but since the filament stops right at the entrance of the extruder head I think this is where I should see an issue but I don’t see anything wrong there.
Unless there is some extra resistance inside the AMS and even though it’s able to push filament through it once it reaches the extruder and it encounters more resistance then the total combined resistance through the full path is too much for it to handle?
Or something else I was thinking is, I saw there is a tensioning screw on the extruder (I had to remove the extruder to inspect it and followed Bambu’s instructions) I noticed when I was playing with the extruder in my hand I was not able to push filament through it by hand, if I loosen the tensioning screw then I was able to push it, maybe the tension is too much? I don’t think I the screw should be left loose when re-assembling the extruder though.
Once the filament reaches the extruder, gently pull the PTFE tube between the AMS buffer and extruder to compress the spring that is inside the buffer.
Recently I was able to print from filament attached to the back of the printer but not through the AMS.
@SPStudio on MakerWorld created a number of designs to fix AMS-related issues. I printed and installed 4 models from his collection and they resolved the issue. Maybe yours too: V2 AMS Popular Fixes | Collection - MakerWorld
Just in case anyone has this issue, if you disassembled the buffer there is a chance you could have reversed the magnet orientation, that is what happened to me and reversing it back fixed my issue.
There is a microswitch between the PTFE tubing end at the toolhead and the extruder. It works to trigger the clog fault I believe and if it is sticking that will cause issues.
I have a short video that BL tech support had me film that shows. I can’t find it right now but if you are still having issues I can find it with some digging in laptop.
If you decide to remove the part in picture you need to be ultra careful you do not damage the micro-sized ribbon cable that plugs in at top.
These are the 5 models from @SPStudio’s AMS Fixes V2 collection that fixed my AMS issue. Most likely only one was necessary, but I installed all 5 at the same time to obliterate the error.
I posted above but basically I had reversed the orientation in the buffer when I had taken it apart to clean it, so I reversed it again and it was fine after that.
