At 12:08 PM 3/25/2010, you wrote: > >This is on a rack and pinion system, pulley mounted directly on > >stepper, pinion has pulley mounted directly to it, with cogged timing > >belt driving the pinion. All these numbers were with the gantry > >moving in one direction, jog and hold, jog and hold, while watching > >the dial indicator for movement between jogs, which there was > >none. Does backlash come into play when all moves are in the same > > direction? > > > >Mark > >Ahh so. I found when I was tuning up my new z axis drive which uses a gilmer >belt with a 17 to 42 ratio, that it had to be _very_ taut, any visible amount >of slack on the slack side of the movement and the detected backlash was very >inconsistent. That belt has got to be tightly stretched. Even a year+ later, >I'd imagine the tension is at least 25 pounds. That left me with about >.0036" to put into the backlash setting, the lowest amount on that cheap HF >mill. I could get better but the sled also tips on the post a few arcseconds >if the gibs are loose enough to move it. Tight gibs, by raising the drag, >actually make the tipping moment worse. Someday I have got to get a decent >mill...
Belts are pretty darn snug, as is the turnbuckle tensioneer that holds the stepper/pinion assembly up against the rack. No gibs on this machine, just linear rails... ;-) >-- >Cheers, Gene >"There are four boxes to be used in defense of liberty: > soap, ballot, jury, and ammo. Please use in that order." >-Ed Howdershelt (Author) > >VMS version 2.0 ==> Ah, VMS. DEC in all it's glory! Still my favorite OS! Mark ------------------------------------------------------------------------------ Download Intel® Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. See why Intel Parallel Studio got high marks during beta. http://p.sf.net/sfu/intel-sw-dev _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
