PTFE tube issue
Hi all, I recently got a new PTFE tube from the Prusa site, but when I went to replace my old PTFE while doing a nozzle replacement two things happened.
First, the new tube was way too long. Am I supposed to cut it to length? How long should it be? Will cutting it deform it and make it difficult to feed filament?
Second, I put it back together with the original PTFE, since I didn't know how to handle the longer new ones. Once I did, I found loading filament is now much harder. I have to remove the hob gear's pressure wheel so I can align the filament with the hole. Once in the hole there is no problem. But, loading is now harder that it was.
I suppose that the PTFE's alignement with the opening may now be off a little. Do I need to take it apart again to fix it?
Re: PTFE tube issue
have you tried the tubing the other way round?
have you checked the tubing with filament once it is outside of the printer?
do you need to trim the ends off the original to get them round again?
or insert a piece of filament before inserting the ptfe tubing to get the alignment correct
this may help, i have not tried it.
the ptfe tube can be cut weasily using a sharp knife
place a piece of filament inside it to reduce the deformation and roll it on a flat surface with the knife on top.
good luck
phil
best3dprinter.stan-tech.com
helping others with 3d printer problems
building 3d printers
showing you can repair almost anything with a 3d printer and innovation - well, design!!
www.best3dprinter.stan-tech.com
Re: PTFE tube issue
I didn't try it the other way. I was under the impression that the convex side is supposed to be down towards the nozzle, as that is how I believe my printer came assembled. Is that wrong?
So, I should cut the PTFE, that is expected. I was shocked that the new one were so much longer.
Thanks,
Johin
Re: PTFE tube issue
Hi John,
i was under the impression you were replacing the ptfe from a bowden extruder, but now think it is from a direct extruder.
the bowden extruder has a long feed tube from a motor drive located on the chassis, the direct drive has the motor located next to the hotend
you are correct the ptfe needs to go into the tube the right way round. there need to be no air gaps along the length of the hotend
the shape on the end will be difficult to recreate from a standard piece of tubing
removing and replacing the ptfe, as you suspected, may not have gone back in straight, or it may have been damaged when replacing. as the ptfe is a very soft material any pressure on the top pushing it in may have deformed the bore, causing the filament to snag or experience a lot more friction.
what you need to do is to replace the threaded hotend tube as an assembly, with the ptfe tubing fitted internally,i found mine on ebay cheaply
i hope you get it sorted
phil
helping others with 3d printer problems
building 3d printers
showing you can repair almost anything with a 3d printer and innovation - well, design!!
www.best3dprinter.stan-tech.com
Re: PTFE tube issue
So I'm having a similar problem I can't load the filament into the printer at the moment, it seems to hit the top of the hole and then stop. If I unscrew the spring screws I can bend it into the hole then it feed through no problem, or if I go around the top hole, it works too, but it won't go in assembled, it's sort of madenning because it's hard to load the printer.
Re: PTFE tube issue
When I replaced mine I cut the replacement slightly longer than the original, then used a 45deg reemer to chamfer the lead in. Filament loading is a breeze now.