> On Sep 10, 2015, at 1:58 PM, John Kasunich <[email protected]> wrote: > …<a very long well thought out list of questions and suggestions that ultimately pointed to the issue>...
It was a good suggestion to forget about G33 and run the spindle my itself. Even at max rpm (3000) we still have the same noisy spindle-speed-in signal. So to make a long story short, the source of the variation in the spindle-speed-in is the VFD (which Peter Wallace essentially pointed out as well). But this variation is there at all speeds from 50rpm to 3000rpm. If I spin the spindle by hand and watch that signal it looks smooth as it should - the encoder is fine and there is no mechanical problem. The second I spin with the VFD I get the ripple in the signal. Also if I allow it to coast to a stop as John suggested the ripple stops as it coasts. A question: We would like to perhaps smooth the velocity input that the trajectory planner uses for G33 commands. What signal does it use for the velocity in spindle coordinated motion? It isn’t motion.spindle-speed-in - we set that to zero and G33 happily did it’s thing. Is it a smoothed version of the ddt of motion.spindle-revs? We can’t filter motion.spindle-revs because that gets reset to zero but… Perhaps what we have now is just as good as it gets. Ultimately I think the fix is a vector drive VFD or even more radical would be to replace the spindle motor with a servo (might do the former, won’t be doing the latter). Also, fwiw, here is a picture of the spindle motor to spindle head mechanism (when I had the cover off the machine). There is a very slight reduction(~0.85) between motor and spindle pulleys. https://www.flickr.com/photos/37438950@N00/16941293785/in/album-72157651167328249/ -Tom ------------------------------------------------------------------------------ Monitor Your Dynamic Infrastructure at Any Scale With Datadog! Get real-time metrics from all of your servers, apps and tools in one place. SourceForge users - Click here to start your Free Trial of Datadog now! http://pubads.g.doubleclick.net/gampad/clk?id=241902991&iu=/4140 _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
