Problems with filament with rough surface?

Hi

I just got filement from a local supplier that has - contrary to the faberdashery filament - a very rough surface. Therefore the friction within the PTFE tube is quite high.
This friction causes the PTFE tubing to be nearly (it is not, but the end of the PTFE tubing is deformed) pulled into the hole of the extruder.
Additionally, I seem to have getting some problems lately with this material. The first few meters ran through without any problems, but yesterday I had massive trouble with no filament coming out of the hotend.....

Has someone made similar experiences? Is such rough filament a problem for the Mendel90?

thanks!

Crap filament is a problem for all FFF machines! I have never experienced any with a rough exterior. If it is caused by some form of contamination or course filler material then it might not fit through the nozzle aperture.

I don't think it will be friction forcing the PTFE into the extruder. PTFE should slip over anything being the most slippery substance known to man. More likely the force to unwind the filament is what pushes it in. The force to pull the filament off the reel is borne by the tube and is also additional force the extruder needs to supply.

The end of the tube does get a bit distorted over time. I am thinking of adding a printed ferrule. Simply a close fitting tube with a smaller hole at the bottom just big enough to pass the filament but not the PTFE tube.

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[www.hydraraptor.blogspot.com]

Didn't the earlier machines have exactly such a thing?

Yes they had a cap at the end of the tube but it was held on with tape and the bottom end was open.

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[www.hydraraptor.blogspot.com]