Piece of filament stuck in the PTFE tube
A piece of filament that broke off and got stuck in the PTFE tube. This happened when unloading filament — I chose "Unload filament", waited for the message "remove filament immediately" and removed filament immediately. But loading the next one failed, with nothing coming out of the nozzle and extruder starting to make clicking noises.
Eventually I had to disassemble things to remove the blockage — it was a small (~1.5mm in length) piece of filament stuck inside the PTFE tube. It was almost in the middle, but I do not know if it's because it broke off there, or because I pushed it in from the other side, because I also tried using the acupuncture needle from the nozzle side. I might have pushed it deeper in.
This is the second time that this happened to me (with two different filaments, both Prusament PLA), so I thought I'd ask for advice — surely that's not something that is expected and normal?
The only "irregular" thing I can think of is that these filament changes were done about 10 minutes after the printer was turned on. In other words, the changes were not done just after a print, but after a night's pause and a heat-up.
RE: Piece of filament stuck in the PTFE tube
I just realized that I did not add an important detail: when the "remove filament immediately" message comes up, I am unable to remove the filament. What I did both times was loosen the extruder spring screw and then use pliers to pull out the filament.
RE: Piece of filament stuck in the PTFE tube
Since I asked, I encountered similar problems two more times. Each time I was unable to pull out the filament when the "remove filament immediately" message came up. But I was able to force the filament down into the extruder, which made the removal work on the next try.
All failures were with PLA.
I'm puzzled, there is clearly something wrong, but I don't know what.
RE: Piece of filament stuck in the PTFE tube
Ok — nobody else encountering this? I'm getting this problem regularly now. If I'm the only one, I guess it's time to contact support.
RE: Piece of filament stuck in the PTFE tube
I have had this happen twice.
The first time, I was able to remove the PFTE tube, but with the filament stuck in it. I was able to remove it with pliers outside the printer, and reinsert the PFTE tube later.
The second time happened a few days ago for me, only this time, the filament was stuck to the hotend too. I think I did something dangerous by partially disassembling my extruder while still on the printer, moving the extruder out while it was still connected, and then preheating my extruder. I was able to pull out the filament while wearing gloves, and some pliers.
RE: Piece of filament stuck in the PTFE tube
When I got filament stuck in the PTFE tube I turned up the nozzle temp really high then pointed a heat gun at the top of PTFE tube for a few seconds. Then I stuck a thin tool through the hole to the tube to push out the clog. Worked like magic!
RE: Piece of filament stuck in the PTFE tube
This has happened to me three times now. The first two times, after heating the hot end, I was able to get a hold of the filament just below the bondtech gears with small pliers and remove it.
This time was different. The drive was clicking and no filament would extrude and I couldn't get it out. I wasn't able to remove the filament by heating up the hot end and grasping the filament with pliers as before; the filament would only move slightly and then break off.
Using the procedure here, I removed the hot end. I wasn't able to remove the PTFE tube without first heating up the hot end. Upon inspection it appears that the filament had balled up on the end and lodged in the PTFE tube.
RE: Piece of filament stuck in the PTFE tube
Detailed follow up post:
I was printing with Printed Solid PLA quarter white. Normally with PLA I print at 210-215° however with this filament/part combination I had to lower my print temp to 180° after the first 10 layers or so to get a good results. It may be important to note that I printed a temp tower 220-180° with no problems.
After replacing the PTFE tube I confirmed that I didn't have a clogged nozzle. Seeing that my print failed from zero extrusion, my hypothesis is that the filament probably got lodged in the PTFE tube during a retract.
I was able to extract the jammed filament from the PTFE tube and have a good look at it under the microscope.
Wondering how the end formed, I continued to investigate. With precision pin gages (±.005 mm), I measured the inside diameter of a new nozzle at 1.994 mm and the inside diameter of the used PTFE tube. The PTFE tube measured at 2.096 mm from the end to the point of the clog with the remaining length at 1.955 mm inside diameter. Using a micrometer, I measured the end of the filament at 2.184 mm.
Working Theory
Perhaps I was printing close to the transition point of the filament such that during retraction the filament cooled and expanded. After repeated cycles the PTFE tube inner diameter increased and the filament expanded further until the filament became lodged in the PTFE tube.
RE: Piece of filament stuck in the PTFE tube
you might find that reducing your retraction distance from 0.8mm to 0.4mm reduces this effect.
regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
RE: Piece of filament stuck in the PTFE tube
Responding to myself (I am the OP): what solved the problem in my case was pulling on the filament while unloading. I started to gently pull the filament while it was being unloaded, BEFORE the printer told me to "quickly remove filament". Tens of unloads later, not a single jam.
RE: Piece of filament stuck in the PTFE tube
just throwing 0.02$ into the discussion:
How dry was the filament that broke off during unloading? Some if not all PLA's get very brittle when wet and that promotes breaking in the wrong place at the wrong time.
Printing at lower than usual temps shouldn't lead to the problems if the unloading is done at the usual 210 degrees.
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I started to gently pull the filament while it was being unloaded, BEFORE the printer told me to "quickly remove filament".
Funny; I would never have imagined that someone would *not* just do that.... I always pull the filament already when I hit the unload button.... (and I do make sure the hotend is properly heated for unloading). So far to expectation horizon when trying to help solving issues.
(FWIW: What I certainly would NEVER do is pointing a heat gun to any part of the printer....)
I try to give answers to the best of my ability, but I am not a 3D printing pro by any means, and anything you do you do at your own risk. BTW: I have no food for…
RE:
Well, I just followed the instructions, which tell you to start pulling "IMMEDIATELY" *after* the message pops up.
And no, my filaments were definitely not wet.
In any case, I consider the problem solved now: pulling gently all the time while the filament is being retracted is the way to go for me.