Difficulty unloading filament / blobs / breaking below gears...
Although printing fine otherwise, I have been having great difficulty unloading filament. After auto-unload stops spinning I usually have to pull on it pretty forcefully to get it out and when it it removed the end has these blobs with strings on the end (first pic below). Most recently the filament broke below the gears and now it's stuck in the PTFE tube (second pic). I have no idea how I'm going to get that out... I tried heating and pushing some new filament in but it didn't move... guess I have to start disassembling.
So, I assume this means that the filament is getting soft too high in the extruder? (I also had "clicking filament" problems but only with the Prusa filament). I have adjusted the tension on the gear screws and I don't believe it is too tight or loose. I saw the Joel Telling youtube video recently where he seemed to have a similar problem but never saw a resolution.
Any suggestions on the root of the problem or how to free the current jam are appreciated.
Re: Difficulty unloading filament / blobs / breaking below gears...
Pat, those ends are worse than what I was getting. Review this thread below for others that have been experiencing this type of problem. I'm not sure if you have the same other issues that I had, but they are going to replace my entire hotend due to other compounded issues.
1 The bulb you have is similar to mine except you have a double bulb. Do you know how that formed? It is thought that the bulb forms in the space where the PTFE vacates from the hot end. As the PTFE is pulled upwards and deforms it creates a pocket below it I'm told.
Once the deformed tube reaches the bottom of the gears or whatever else it hits it starts expanding it seems.
2. The picture of the deformed PTFE tube is what I had. Mine was pulled up and deformed also. Could this be the indication of it starting? As filament is unloaded the hot part sticks to the PTFE tube and pulls it upwards. The more it happens the higher it goes.
Re: Difficulty unloading filament / blobs / breaking below gears...
1 The bulb you have is similar to mine except you have a double bulb. Do you know how that formed?
Thanks. No, I'm afraid I don't know how the bulbs are forming other than the obvious that it seems the filament is getting soft too high in the stack. I bought my MK3 pre-assembled so I don't have a good mental model of what the filament path looks like below the gears.
Previously when I had the “clicking” skipping during extrusion Prusa asked me to check the fans, heat break, extruder gears and gear spring tension… I have also tried unplugging the filament sensor (based on reports of it overheating), but I don’t think any of those were the cause. In that case I just switched from Prusa filament and the skipping stopped. But I'm guessing this is another symptom of some underlying issue.
I have emailed Prusa support and I'll report back their suggestions.
Side note: I was really looking forward to the upcoming MMU, but given how much trouble I have unloading filament I am having a hard time imagining how that can possibly work reliably.
Re: Difficulty unloading filament / blobs / breaking below gears...
Hi, if you want to unload filament with no probleme. Juste heat your hotend,extrude 10-20mm of filament and unload imediately. its work great for me. 😀
Re: Difficulty unloading filament / blobs / breaking below gears...
Hi, if you want to unload filament with no probleme. Juste heat your hotend,extrude 10-20mm of filament and unload imediately. its work great for me. 😀
I will try extruding some prior to unloading in the future, thanks.
Re: Difficulty unloading filament / blobs / breaking below gears...
Thanks. No, I'm afraid I don't know how the bulbs are forming other than the obvious that it seems the filament is getting soft too high in the stack. I bought my MK3 pre-assembled so I don't have a good mental model of what the filament path looks like below the gears.
If you haven't already I would review the different sections of the build manuals under support. I bought a kit and being a tinkering kind of person I've enjoyed digging into the parts.
Previously when I had the “clicking” skipping during extrusion Prusa asked me to check the fans, heat break, extruder gears and gear spring tension… I have also tried unplugging the filament sensor (based on reports of it overheating), but I don’t think any of those were the cause. In that case I just switched from Prusa filament and the skipping stopped. But I'm guessing this is another symptom of some underlying issue.
I had the same thing and over time it got worse and worse.
### For those that haven't yet or just now experiencing the bulb at the end of filament when you change them "MONITOR the PTFE TUBE" for creeping upwards.
1. Take a picture of the current top of the PTFE so you have a reference to go by. Open the idler door to view the top of the tube.
2. As you experience more and more problems review the position of the PTFE tube and watch for the opening to expand like the one in this thread and mine.
I have emailed Prusa support and I'll report back their suggestions.
Like I said, I had multiple issues besides the bulb issue and jams, but I'll wait until you get a fix before I share notes other than what I've already side. I'm no expert and I'm learning as I go.
Side note: I was really looking forward to the upcoming MMU, but given how much trouble I have unloading filament I am having a hard time imagining how that can possibly work reliably.
*** Play toys for adults can be expensive, you just have to decide how deep you can afford to go and how fast. I'm still new enough to just keep on printing and I need to slow down and learn how to print well.
I'm seeing more and more comments on print speed, layer height, retraction, fan speed and more entries. We need to learn to adjust the prints for maximum accuracy rather than "Warp Speed Scotty"!
This is an area I need to slow down and learn. Until then I'm going to continue to have issues, so I guess I need to do some training before taking off again...
Good Luck
Re: Difficulty unloading filament / blobs / breaking below gears...
Hi, if you want to unload filament with no probleme. Juste heat your hotend,extrude 10-20mm of filament and unload imediately. its work great for me. 😀
This works really well (extruding to get fresh filament into the chamber before reversing). It should probably be part of the automated unload procedure!
Re: Difficulty unloading filament / blobs / breaking below gears...
Hi Pat.
There is nothing to stop you writing a short gcode file to do exactly what you want. And keeping it handy for unloading at leisure...
Probably worth including a command to ensure the extruder is hot, say 190C for PLA first.
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: Difficulty unloading filament / blobs / breaking below gears...
There is nothing to stop you writing a short gcode file to do exactly what you want. And keeping it handy for unloading at leisure...
Probably worth including a command to ensure the extruder is hot, say 190C for PLA first.
Great idea! So I take it there is nothing special about the Prusa auto unload procedure and it's just reversing the filament and then issuing the beep? It seems like it runs at two speeds, wonder what that is about. I guess I can go look at the source for the firmware on github and see what gcode it is issuing.
Re: Difficulty unloading filament / blobs / breaking below gears...
Indeed Pat
You are encouraged to experiment.
That way your understanding improves
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