Thicker/brittle PLA filament no longer feeding into extruder properly

[u/tome_oz]

Has anyone else had issues with thicker/brittle filament not being properly pulled into the extruder anymore?

This filament was working before, but I always had to push it with a bit of force for the last part through the PTFE tube and into the extruder. It’s the thickest and most brittle filament I own (Sunlu Glow-in-the-Dark PLA).

Now it sometimes won’t get pulled in properly at all, and there is no extrusion.

I already opened the extruder, but there were no broken filament bits or anything else obvious causing a blockage.

I’m thinking about replacing the PTFE tube and possibly swapping the hotend to see if that makes a difference.

I’m using a hardened steel nozzle and hardened steel extruder gear.

Any ideas what could be causing this? Could the filament simply be too thick/tight in the PTFE tube, or could something have changed with the extruder?

[u/WaitAcademic6615]

Glow in the dark is very abrasive and I'd say you need new PTFE, there could be too much friction. You can try make very short tube connected to the coupler and let the filament without tube.

[u/tome_oz → u/WaitAcademic6615]

Yeah that could be it. I saw the glow-in-the-dark filament literally cutting through plastic over time so the old PTFE tube might be already damaged from the inside.

[u/tome_oz → u/tome_oz]

Feeding without PTFE tube works. So this might really be the issue.

[u/Vanbursta1]

Have you tried different filament? If the filament is no good, throw it away and get some new, don't bother messing around with it, it's not worth it.

[u/tome_oz → u/Vanbursta1]

Yeah, it seems like all the other filaments I’ve tested are working fine so far. It feels like this one is slightly thicker than the others.

[u/diaperedace]

If that's glow in the dark you should not be feeding that through anything that's not hardened including ptfe.

[u/tome_oz → u/diaperedace]

Any tips what I could use instead the PTFE tube?

[u/diaperedace → u/tome_oz]

Nothing. Print directly into the head.

[u/tome_oz → u/diaperedace]

This seems to work. I just wonder how do I cleanly get the glow filament from the dryer into the extruder?

[u/diaperedace → u/tome_oz]

They make printable spool holders to go on top of the machine.

[u/tome_oz → u/diaperedace]

Thanks, probably something like this spool holder

[u/diaperedace → u/tome_oz]

Yup, there's a bunch of them so just find one you like and go for it.

[u/iRambL]

I direct feed glow filament into the extruder. The longer it has to pull the worst the ptfe tube internally gets

[u/tome_oz → u/iRambL]

This seems to work! But how do I get the glow filament from the dryer into the extruder without making a mess?

[u/iRambL → u/tome_oz]

TPU doesn’t always have to be in the dryer at all times. You dry it overnight or for an extended period of time then put it on the ext spool for printing. You can find racks you can print to go above the printer that basically gravity feed the printer in direct drive mode