Unloading Breaks Tip of Filament
This started the other night:
When I unload the current filament (head nozzle to 250, click UNLOAD, and pull the filament straight up and out) I am finding the very tip is breaking off causing a jam.
To clear the jam, I need to remove the nozzle and stick a narrow allen wrench up there. A chunk of the previous filament SOMETIMES comes out top. However, to really finish the job, I have an unfolded paper clip that runs all the way up and I can it stick so far up it comes out the top (once the jam is clear).
Inevitably the same looking end chunk (maybe 2mm long) of the previous filament pops out the top out and is rock hard (maybe I need to yank faster since this possibly cooling?)
This has happened the last 4 out of 5 filament changes I've done over the last 2 days. This can't continue as the norm.
I've read the PTFE tube can go bad - is this an indicator of that problem? If not, what would continuously cause just the very end to snap off and get stuck deep down inside?
I am ALMOST to the point where I might cut the old filament off and start feeding in the new color as the raft prints!
Please help! I am getting a little concerned...
Thanks-
Dave
Re: Unloading Breaks Tip of Filament
Do you have a collet lock keeping the slightly coned bottom of the ptfe in full contact with the top of the heartbreak? If the ptfe rides up even a little this provides a space where a slightly larger plug of plastic can form.
If this is the case Joan has recently provided the steps to correct the problem and install a collet lock. If you don’t have one though they are easy to print and a zip tie can also be used though the space available at the top of the heatsink is limited for this rather bulky expedient
Re: Unloading Breaks Tip of Filament
So does the filament pretty much unload by itself when you heat the nozzle and click UNLOAD?
I am in the middle of a large print so I can't test now, but I am curious how I am supposed to be removing the filament?
Does this video capture it correctly?
-Dave
Re: Unloading Breaks Tip of Filament
Unless the extruder has been actively extruding in the past few minutes, I find filament removal is most trouble free if I
1. Preheat the extruder to extrusion temperature. Nothing unusual here
2. Advance the extruder slightly to freshly melt the tip of the filament.
3. Remove the filament
This renders the tip nice and soft so it comes out effortlessly. No more getting stuck.
BTW +1 on adding a collet locking ring to keep the PTFE tube fully seated.
Re: Unloading Breaks Tip of Filament
Yes this is when you change the filament manually.
If the printer is configured "Filament Sensor = On" then the filament is fed in automatically and you do not need to confirm the charge with any button press.
Bear MK3 with Bondtech extruder
Re: Unloading Breaks Tip of Filament
Unless the extruder has been actively extruding in the past few minutes, I find filament removal is most trouble free if I
1. Preheat the extruder to extrusion temperature. Nothing unusual here
2. Advance the extruder slightly to freshly melt the tip of the filament.
3. Remove the filament
This renders the tip nice and soft so it comes out effortlessly. No more getting stuck.
BTW +1 on adding a collet locking ring to keep the PTFE tube fully seated.
How do you remove the filament? Are you pulling it out at any point or does the unload do it all for you?
Re: Unloading Breaks Tip of Filament
There is also one corner case I used to hit when I had my retraction set too high and was printing with more heat. The filiment would create a blob right above that PFTE tube and while the filament was a little warm it could handle it. After the filament cooled some the blob would be rigid enough that I could neither advance ... nor retract the filament fully... it would get caught as you describe.
This was solved with shorter retraction distances and lower temperature.
You could possibly be creating a small blob someplace due to retraction ... maybe if there is a gap below the PFTE tube like the one poster suggested, or, if something has warped or otherwise made a pocket.
Re: Unloading Breaks Tip of Filament
How do you remove the filament? Are you pulling it out at any point or does the unload do it all for you?
The unload filament command
Re: Unloading Breaks Tip of Filament
1. First, check the "Settings" menu that "Filament sensor" is On.
2. Then choose "Unload Filament" and hit the button. The filament is now fed out about 7 cm.
3. When you hear a "Beep", pull immediately out the filament.
4. Then insert the new filament into the extruder and the filament is loaded automatically.
Bear MK3 with Bondtech extruder
Re: Unloading Breaks Tip of Filament
Unless the extruder has been actively extruding in the past few minutes, I find filament removal is most trouble free if I
1. Preheat the extruder to extrusion temperature. Nothing unusual here
2. Advance the extruder slightly to freshly melt the tip of the filament.
3. Remove the filament
This renders the tip nice and soft so it comes out effortlessly. No more getting stuck.
BTW +1 on adding a collet locking ring to keep the PTFE tube fully seated.
this is important that the plastic is warm enough to be soft... if you go to change filament for your first print of the day you want the plastic at the tip warm to start the process.