As the title says, I had to replace a PTFE tube in my P1S after it got a hole worn in it where it rubs against the glass. The hole did cause an error but thankfully it was at the end of a print, so i didnt have any issues there.
I ended up swapping the ruined tube with the replacement that came with my P1S new, but since doing so, nothing will load into the print head from the AMS. Ive tried swapping the PTFE tube around, printing one of those attachments to make the bend into the head nicer, diassembled my hot end and extruder gear to check for clogs, to no avail. The AMS will push the filament all the way to the print head, but it gets stuck at the bend right at the clamp on the top of the print head, then does a billion back and forth pulls that does nothing but ■■■■ me off.
THE ONLY LUCK, that ive had so far, is loading manually from the external holder, and even then, it only went if i grabbed the ptfe tube where it meets the print head and wiggled it around until the filament pushed in enough to be grabbed.
Ive tried several different filaments, PLA, ASA, doesnt matter, the issue doesnt change.
First, I’ll say that the PTFE needs to be Bambu-sized, as it has a wider inner diameter than generic PTFE has.
Second, make sure the end of your PTFE is cut very squarely and is fully inserted. If not, the filament won’t insert properly.
Also make sure the PTFE length is correct - if the bend at the toolhead is too sharp it will case similar issues.
Carefully trim the ends to make sure they are straight. You dont have to take off much.
Then make sure it is inserted all the way into the inlet on the toolhead.
They said it was the spare that the printer came with. That shouldnt be the issue.
Yeah, i used the spare from when the printer was new and checked the length and it appeared to be the same length. I cut one end and noticed it made the tube very square from the cutters, so i put that end away from the toolhead to see if that would make a difference, to no avail.
It appears the tube is as far into the toolhead as it will go, ive tried pushing it farther with nothing seeming to happen.
There will be a mark on the tubes where the “latches” grabbed it. You can use the position of that to see if the insertion depth is the same.
edit Also silly question, i assume you have manually put filament into the tube all the way to check it is not blocked?
Yes sir, I had to fiddle with the ptfe tube where it goes into the toolhead to get the external spool holder to feed, gotta figure out if I can get it to feed from the AMS now without forcing me to fiddle with it.
Ill pull the PTFE when I get home and see where the marks are compared to the old one.
Pneumatic fittings have little teethies that engage and lock the tube in place on the Pull-stroke.
Push in a very flatly cut end into the fitting allllll the way to the bottom, before you attempt to pull back. If you pull back early, it sets the teeth into the tube a little early and you’re left with a lip that pushes itself open and closed.
X-ray:::
One last detail, when we say “flatly-cut end” that doesn’t mean just cut at 90 degrees. The end face of the tube itself has to be FLAT and ROUND, no little burrs or sharp corners sticking into the bore. If you cut the tube with regular nippers or scissors the end will be distorted somewhat, crimped a bit and forced out-of-round. A razor blade or X-acto knife blade held at a 90 degree angle works if you are careful, and there are little cutters meant specifically for cutting PTFE tubing that give the proper cut.
I appreciate all of your assistance with this!
I do believe i just didnt have the PTFE trimmed quite well enough, as i did a bit more trimming and it feeds in with minimal resistance. I believe i need to trim it just a tiny bit more, as i do have a slight resistance when feeding before feeling it slip into the toolhead.
Thank you again so much for all your knowledge and suggestions!
Here’s a thing to try. Pull off the top glass and set the AMS off to the side IF you can (assuming it’s sitting on top) and see if it auto feeds. If it does that means the unit is NOT happy with the bend for the tool head tube. I would then recommend removing said PTFE tube and physically measuring it to ensure it’s at the appropriate 550mm they recommend. Could be you got a pipe that is too short or wrong.
Those helper motors are not very strong and WILL not like tight bends etc.
