Can't unload on filament runout  

RE: Can't unload on filament runout

Posted by: @shideral

Hi!

I have a scoured the forums and support pages but not found a solution for my problem. If there is a topic or support page that discuss my problem please give me a link to that. 

My problem:

When my filament run out the printer have problem unloading the filament. I have tried to find the error to no avail. I usually try to change filament before run out and that works without problem. If i fail to do it before runout, I ususally heat the nozzel to high temperature and push the filament threw the nozzle and then insert new filament. 

I have tried cleaning the gear that load or unload the filament. I have tried to change the tension of the screw that set force between the gears and the filament. 

Do any of you have any tips or pointers for me?

Regards from a very happy prusa mk3s owner

Christer

 

Can you loosen the tension completely till the door comes open and remove it manually?  It will need to be manually heated first but try.  

RE: Can't unload on filament runout

@cwbullet

That works to. I tried that and can remove the filament using that technique. I've tried most suggested removal techniques and they work but I would prefer to fix the problem of it not unloading the "right" way. 

Perhaps there is some known problem with unloading when you run out of filament. 

RE: Can't unload on filament runout

@shideral

Can you post a photo of the inside of that door with the filament loaded?

RE: Can't unload on filament runout

Does the end of the filament make it past the gears or does it stop earlier? I’ve had this happen to me with one specific brand and I blamed it on the end of the filament being crooked so it wouldn’t unload and had to be removed manually. No problems with other brands though. 

RE: Can't unload on filament runout

Thanks for the tips and comments! 

@cwbullet: I'll in the middle of a spool but I'll start some agressive printing and take a photo through the door when it has run out. I'm a little bit embarrassed, I really should have posted a photo in my first post. 

@fuchsr: I think it stops in height of the gears. Lets see when I get a photo.

I'll print and have my camera ready!

RE: Can't unload on filament runout

Here's a picture with the door open. 

I did some more searching and testing and here's what I found:

Even when releasing stutters I can not move the filament upwards towards the exit using a pliers. But I can use the pliers to move it down, and surprisingly then up again, but only back to the original position. Heating the nozzle to 285 degrees celsius I can press down using the pliers and get filament to extrude through the nozzle. But when I try to move it upwards, once again only to the original position.

This makes me wonder if there is something that catches the upper end of the filament, a ledge or something similar, that prevents it from exit upwards when it is short. 

Grateful for ideas.

RE: Can't unload on filament runout

I occasional have this issue.  I use pliers and a pair of cutters and cut mid way on the window and remove both parts with pliers.  You must cut mid way on the filament to allow enough gripping space on both ends.  

RE: Can't unload on filament runout

@shideral

That’s what happens to me with every spool of Sunlu PETG filament when it runs out. When I remove the filament (the way @cwbullet described), I see that the upper part is bent slightly, probably from where it was attached to the spool. I suspect that is the culprit but I can’t be sure. 

RE: Can't unload on filament runout

I found it thanks to you guys!!!!!!

Here's a picture of the end of my filament:

It turns out the end is bent. Exactly as you suspected. 

I made some test runs and when I have a non-bent end there is no problem at all to unload. 

For information I use e-sun pla+ for filament. 

Thanks for all your our comments and help!!!!!!!!!!!!!