At 12:38 PM 3/25/2010, you wrote: >On Thursday 25 March 2010, Mark Wendt (Contractor) wrote: > >At 11:56 AM 3/25/2010, you wrote: > >>At 165 pounds, it may be that the gantry is actually taking up some > >> backlash as its stopping from the longer moves which would be faster. > >> Can you, as its hooked up & the motors enabled, induce a motion visible > >> on the indicator by manually pushing or pulling it? And, equally > >> important, does this 'slack' remain constant as you move it with the > >> motors? If constant, then perhaps adding some backlash comp might help > >> (but that's only effective for motion reversals of course), or if its > >> position related, it might be possible to map the screws error. Wear > >> patterns can be elusive, and mapping a cyclic error can be 'fun' for some > >> definitions of fun. If you have many hours on the machine doing the same > >> cuts over and over it might even be advisable to replace the screws. Or > >> if the cutting dust can get to them, a really good cleaning might help. > > > >I'll give it a try manually moving the machine while the motion > >control system is up and running. Haven't tried that as of > >yet. It's a brand, spankin' new machine that has not cut anything > >yet, so if there's wear patterns anywhere, it'll be on my forehead > >where I've been rubbing in consternation... ;-) > > >ROTFLMAO!
Heh, I've been designing and building this monstrosity for a little over 5 years now. Been much hair pulling and forehead rubbing during that time, and now that it's almost all together, I just want the damn thing to work right... ;-) > >> > I disconnected the pinion gears from the racks, moved the gantry > >> >back and forth the length of the X axis a few times by hand, and > >> >didn't really notice any binding. It seemed pretty smooth, and > >> >relatively easy to move a 165 lb gantry on the rails. > >> > >>Pinion gears, same thoughts about cleaning apply. I assume they are > >>preloaded? > > > >Pinions are preloaded. Here's the R&P > >setup: > ><http://www.cncrouterparts.com/product_info.php?cPath=21&products_id=50> > > >Cool. I'd have reservations about sub thou accuracy with it. Straight cut >rack & pinions will have some cyclic errors, repeatable on a tooth per basis, >but that has already been said. Yeh, sub-thou ain't necessary, but a wee bit less than .005" - .010" is definitely what I'm shooting for. >-- >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) > >Once harm has been done, even a fool understands it. > -- Homer 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 [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
