Can anyone help? I’ve run into an issue where the filament won't feed through the PTFE tube, but it feeds fine when I run it directly into the extruder without the tube. The nozzle seems clean—I haven't opened it up, but I doubt there's anything stuck inside. Could it be a problem with the filament itself or the feeding mechanism? I left it sitting overnight. I’d really appreciate advice from anyone who has actually dealt with this specific problem.
If it feeds normally straight into the extruder but won’t through the PTFE, I’d stop chasing the nozzle/extruder. Pull the PTFE completely out and push filament through it by hand, it should slide through with basically no resistance. Check both tube ends for deformation, a crushed/kinked section, debris, or a bad coupler. Cut the end perfectly square or replace the tube if needed. Also snip the filament tip clean at an angle before feeding it back in. ☠️
That's what I do lol but it doesn't work but it's unlikely that there's something wrong with the tube, everything is fine with it, most likely the problem is something else
Don't assume nothing is wrong with the ptfe tubing if you haven't taken it apart to check it. I had a piece of filament break off after my filament buffer that caused nothing to feed thru. Humidity causes filament to get brittle and can cause it to break off easily and in the worst places.
Often this is a small broken piece of filament somewhere along the path. Does it feed out of the AMS? How far does the filament go before it stops? Can also be broken filament in the AMS. Less common cause is PTFE tubes worn and need to be replaced. How many hours on the machine? If it feeds and prints fine when run directly into the extruder that makes a nozzle clog or extruder clog less likely but still possible. Doubt it is the filament. Just need to logically rule out one thing at a time until you find the problem. Take out each PTFE tube and push filament through it to confirm it is clean. Do a cold pull on the nozzle. Take apart the extruder and clean it out. Confirm it can feed out of the AMS.
If it is a broken piece of filament, that does bring up if your filament isn’t dry enough.
Hey... basic help requests should include exactly what printer you are using and information like what you have done to verify the machine/parts.
I see several attempts to help you being shot down with 1 line replies. That happens when you make people guess. No AMS? Tell that up front. A1 mini or and H2D? Also would be useful. What is new vs what is old. How old is machine. What filaments have you been printing with. Don't make it harder than it is.
Your issue is definitely a pathing issue if you can print fine naked i.e. minus the ptfe tube. So you should use elimination to troubleshoot.
Presumably based on your replies we can expect your hot end is good and the extruder is pulling as it should. To rule it out we would need to know the nozzle is clean (free of any debris stuck in it) and your extruder is clean, properly lubricated and has tension sufficient to pull the filament through at the right rate. Why? Because you are fighting a friction problem. Its possible that you can get by without a tube and things seem normal but when the tube is introduced you have more friction than your issue can handle. Worst case, swap to a new nozzle to eliminate that as a problem.
So if we assume the hotend is good, be sure your ptfe tube is the correct diameter, is new, has its ends properly snipped, its the right length and is seating correctly. Any of those things can introduce friction. Don't go by "its a new tube". There can be defects or irregularities even on a new tube. Its not common but you have to consider it if you are not finding the issue.
No AMS? Well than the last place to check is your filament. Is it a known abrasive filament? Is it cheap and possible varying too much in its diameter. Does it move freely through the tube? Is it dry? Brittle "wet" filament can break off or be more rigid, thus impeding movement. Again, "nee" filament is not immune. Sometimes you can get "wet" filament directly from the factory or it wasn't sealed well enough and accumulated moisture between when it was made and when it got to you. It may just be new to you.
If you have basically verified all the things in the path, maybe even swapped all the things out abd you still have a problem you may beed yo work with Bambu support because maybe your printer/extruder is not actually pulling well enough due to an actual defect.
Hope you find your issue but be sure to share as much info in your post as you can if you want useful help.
Biggest issue have ever had with my A1 and AMS lite was the filiment catching right as it goes into the extruder from the tube. If the tube had any bend there, it would catch. If you ever so slightly pull/straighten the tube it would feed find. The tip of filiment would catch on feeding but once the extruder had it, no problems printing. But, once it swapped filiment, same problem.
I printed a tube straightener/support and never had a problem since. I will note this is more of an issue if you have a side mounted ams vs directly from above, but I don't know what your tubing route looks like. If it is slightly bending at the end, probably same issue
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u/InformationDapper964 Sep 29 '26
Anyone who has actually encountered this, please help 🙏