Mystery Filament

#1

Hi. I am currently printing with some cheap no-name flexible filament that is labelled as TPE. Strangely it doesn’t behave like any flexible filament I have used before.
Firstly, straight off the roll it is extremely flexible, bending with a radius of only a few cm umder its own weight.
Secondly, I had a heck of a time trying to get it to stick to anything.
I am using a PEI sheet on my heated bed and everything I have read says that TPE sticks to PEI too well.
I have had to heat my bed up to 90c and use a brim just to get the stuff to stick at all.
Also I have found that I need to spool off the estimated length of filament needed before starting a print.
Just letting the extruder pull the filament off of the roll causes a lot of under extrusion issues.
Finally, I printed a few 20mm test cubes. The best finish I got was bed @ 90c; Hotend @ 225C; 5 top and bottom layers; 3 shell and at least 25% infill.
The end result is a cube that is only slightly flexible (about the same texture as one of those cheap tubelike doorstops that you screw onto the bottom of your doors.
It’s quite stiff but returns to original shape.
This stuff is weird!
If you have any idea of what it actually is I’d be interested to find out.

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#2

Regarding spooling, depending on how your spool is set up you could make a custom insert for it that runs on bearings, standard skate bearings are fine and cheap. That sort of setup is bad for rigid filaments because the spool moves with almost no friction, so it unspools too much as it gets pulled, but I think it would work nicely for flexible since it takes so little effort to pull, and the slight overshooting of the unspooling would mean you always have some slack.

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