Is the variability of the filament really an issue?
Are you having problems with the filament dimensions as you receive
the filament, or the consistency of the filament drive mechanism?
The diameter variability of 2.9 +- 0.1 is bad enough as it represents
a potential 13% variation from ideal (2.9).
But does a reel or spool of filament vary like that. I thought the
variation was primarily between reels, rather than within one reel.
I don't use 1.75, but if it is +- 0.1mm then it is a bigger
variation. My understanding was that the +-0.1mm was a manufacturing
measurement tolerance, in that it is not easy to measure below that
size in a repeatable, automated way.
If you wanted to measure the filament, you would need to measure its
cross-section to get its instantaneous area. The manufacturers don't
do that because it is too hard. I don't think there is an easy way to
In either case it would make extrusion more complex, as you would need
to adjust your extrusion distances, according to the current filament