On Wed, Jan 26, 2011 at 03:43:33PM -0600, Igor Chudov wrote: > > I finally got the table work with EMC2 (thanks to Jon), and have a problem > with is a high following error. The error is 0.04 degrees. Since there is a > considerable reduction ratio in the work drive, the following error amounts > to something like 5 degrees of a turn of the motor (I may be off with my > math VERY easily, but clearly it is huge with that much reduction). > > Right or wrong, I attribute this to the friction in the worm drive system -- > the servo motor develops following error when working against friction.
But an X or Y axis also works against friction, when lugging lots of kilos of cast iron (plus the workpiece) back and forth on slideways. Is there perhaps backlash, in addition to friction? My rotary table has about 15° of handle backlash, and it's brand new. (I haven't pulled it apart yet, to see if I can increase the swing of the variable (worm <-> wheel) engagement, to try to decrease the backlash, before trying to make a cnc axis of it.) Erik -- Vegetarian: It's an old Indian word meaning "lousy hunter". - Red Green Tofu: Old Eskimo word. Means "whale snot". - GB in ASR ------------------------------------------------------------------------------ Special Offer-- Download ArcSight Logger for FREE (a $49 USD value)! Finally, a world-class log management solution at an even better price-free! Download using promo code Free_Logger_4_Dev2Dev. Offer expires February 28th, so secure your free ArcSight Logger TODAY! http://p.sf.net/sfu/arcsight-sfd2d _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
