Sounds like this might be heading in the direction where you could just have a cartridge unit for the spool.
On Sun, Jun 16, 2013 at 10:11 AM, Jon Elson <[email protected]> wrote: > Erik Christiansen wrote: > > On 15.06.13 15:00, Charles Steinkuehler wrote: > > > >> I've seen some setups where the filament loop closed a switch when it > >> began getting 'tight' and triggered the spool to unwind a bit. > >> > > > > But if that isn't what the "filament loop" always does, then do current > > printer implementations just drag the spool with the filament feed > > capstan, leading to loss of any filament loop soon after starting? > > > > > Yes, most I've seen work this way. A VERY unsophisticated scheme could be > a light-touch microswitch that activates a gear motor to turn the spool > (or feed > the filament off a spool) to keep a small loop. > > I don't recall whether the old Pertec tape drives used switches or a > > potentiometer (allowing PID control of the unspooling motor), but they > > maintained a tape loop at speed. > Yes, and that was a LOT more dynamic than a makerbot. There were drives > with vacuum sensors in the columns, photocells across the columns, > spring-arm > loops with switches or pots, and one I have here even has little rollers > with > AC tachometers to sense speed of the tape paying on/off the reels. The > speed of these tachs is supposed to match the capstan speed. When tuned > up right, the tape hardly ever touches the pressure sensing holes in the > vacuum columns. > > Jon > > > ------------------------------------------------------------------------------ > This SF.net email is sponsored by Windows: > > Build for Windows Store. > > http://p.sf.net/sfu/windows-dev2dev > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > ------------------------------------------------------------------------------ This SF.net email is sponsored by Windows: Build for Windows Store. http://p.sf.net/sfu/windows-dev2dev _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
