On 6/16/2013 6:57 AM, Ed Nisley wrote: > On 06/16/2013 04:24 AM, Erik Christiansen wrote: > >> current printer implementations just drag the spool >> > > with the filament feed capstan > > It's brutally simple: the filament drive hauls filament through a > flexible tube that arches between a holder at the spool and the > extruder, so the drive must overcome the tension required to unroll the > spool plus the friction required to drag the filament: > > http://softsolder.com/2013/04/24/makergear-m2-filament-guide-tube-friction/ > > Bowden drives put the feed at the spool end of the guide tube, which > makes retraction less effective. > > >> a couple of microswitches >> > The gotcha is that the filament loop thrashes around as the extruder > head zips back and forth. On the M2, that's only along the X axis, but > printers like the Ultimaker and Replicator move the extruder along both > X and Y. I'm not sure where the sensor would be happiest, because you > don't want to constrain the loop motion too much: pinning it to a board > at the top of the arch might be too confining. > >
This all sounds very much like the wire drive system used by a mig welder .. along with the associated problems, but probably at a smaller scale Feeding aluminum wire with a mig welder is tough because it does not like to be pushed, so they came up with spool guns and there was also at least one novel push/pull system developed that had a tugger system in the gun and a pusher system in the welding machine that worked together. It was very complicated and expensive. Dave Cole ------------------------------------------------------------------------------ This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
