> > I believe Stuart is referring to the vastly different speed/torque > requirements needed for a spindle and a positioning axis. > > Spindles spin fast, but with relatively little torque. Rotary > positioning axes are much slower, but need to be extremely "stiff" > compared to a spindle drive. A spindle that slows down by a few RPM > under a few N*m of torque load is not a problem. But a rotary axis that > shifts even a single degree under a few HUNDRED N*m load is a big problem. > > Usually rotary positioning axes use worm gears to lower the speed and > increase the torque. A direct drive motor is very unlikely to have > enough torque. > > EMC + HAL can control such an arrangement, but the real challenges are > mechanical, not control. > > Regards, > > John Kasunich
Hi, our CHNC has this, not a C axis, but just a rotary indexable spindle, C axis would be full positioning and contouring so you could power tool while moving the spindle, as others have said you need a very good spindle drive and 1KW i think would not be enough to hold position tightly. with the indexable spindles, they normally have a locking pin that can engage and lock the spindle at its position, resolution is always dependent on encoder on the spindle end. to find position when moving from spindle to index they rotate the spindle to find the encoder index pulse, mark that as spindle zero then move the spindle to the requested position via a M19 S(degreese), using a M code to switch from spindle mode to index mode throughout a program. robert > > ------------------------------------------------------------------------- > This SF.Net email is sponsored by the Moblin Your Move Developer's challenge > Build the coolest Linux based applications with Moblin SDK & win great prizes > Grand prize is a trip for two to an Open Source event anywhere in the world > http://moblin-contest.org/redirect.php?banner_id=100&url=/ > ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
