2012/7/21 Erik Christiansen <dva...@internode.on.net>: > > Of the other machines that you've built, do any have a horizontal > ballscrew as long and slender as this one, spun at similar speeds?
That was the first time I used ballscrews, so I have no other experiece to compare with. For the next machines I am designing ballscrews only for Z axes, where the travel is relatively short. For X and Y, where travel is larger (for one of them it is up to 6 m) I will stick with rack and pinion. > Are you game to mention how badly eccentric the nut housing was > machined, in order to create the problem? Is there room to machine a > little off the outside of the bearing mount, and slip on an eccentric > outer, locktited in place with the equal eccentricities opposed, to > cancel them? (Or some other rectification.) I have no idea, how to measure it precisely. Anyway, I think that manufacturing new, more precise housings is the only way to go. > Admittedly, an 80% reduction > in maximum rapid speed doesn't mean an 80% reduction in production rate, > but it still seems a big loss. Yes of course, feedrates for milling certainly would not reach even close to max speeds. It is big loss in all the rapids. > If the eccentricity is very small, is there possibly a resonance in the > frame exacerbating the vibration? A significant mass tightly clamped in > several different places might help check for that? It is not eccentric. The thing is that center line of the ballscrew nut does not match the line it actually rotates around - there is some angle between them. So it pushes the ballscrew in one side of the nut in one direction and on the other side - in opposite direction. -- Viesturs If you can't fix it, you don't own it. http://www.ifixit.com/Manifesto ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
