I have a relatively simple extruder design and a pinch wheel filament drive mechanism. Yet it can extruder very fast and still have a sharp stop and start.
It also uses a bowden cable, a flexible tube through which the filament is pushed.
I ordered two variants, I think they are the same:
From www.Adtech.co.uk
PTFE Tube 1/8" ID x 1/4" OD
Adtech Part Number: PT1/8X1/4
Price: £3.98 per metre (when I ordered)
and
PTFE Tube 1/8" ID x 3/16" OD
Adtech Part Number: PT1/8X3/16
Price: £1.80 per metre (when I ordered)
The thinner tube seems to have a slightly wider ID, it is compatible with all of the filaments that I have and guides it with the least friction. I believe your green filament, of which you gave me a sample, feeds through either. The thicker tube is a bit more rigid and will not stretch as much due to tension exerted by the filament push. This is not necessarily a good thing, since the compression will allow short term blockages of the nozzle orifice to be overcome while the drive mechanism doesn't skip or strip the filament.
You can use my coupling to attach the PTFE to the extruder input and drive mechanism's output. See related video: [ Ссылка ]
The part can be downloaded here:
[ Ссылка ]
The printable, modular drag chain element could also work as a filament guide. If you're going to try anything with cable guides, that might be a nicer option. It could be made from HDPE to have even lower friction.
Bowden tubes are used in the Ultimaker, a state of the art design 3D printer: [ Ссылка ]
