On Mon, 30 Apr 2012 16:52:21 -0500, you wrote: >from my experience - full step/ half step/ 1/4 step all seem to have >problems with resonance (although 1/4 step is much reduced). Once you >get into microstepping drives - that problems seems to go away. ie - we >have never had a resonance problem with drives we have used that are at >least 1000 steps per rev. > >at least from our experience...
My experience too, apart from my router Z axis. The X & Y axis have substantial square rails with linear ball type guides. However, the Z has 1" fully supported chromed and hardened round rails and with ball type guides it was terrible, would lock up regularly, always in the same feed range around 90 to 100 inches/min. I replaced the roller guides with low friction tercel type guides and it improved it greatly, but still locked very occasionally. Put the rattler type damper on and it's never locked up since. It will run in that range all day without problem. Rapids are 190 ipm - so mid-band seems a good description. All the steppers are large three stack size Nema 23's running at 70V 4A and 8x microstepping on 4mm pitch ball screws with 1:1 drive. I've a feeling I now know what added to the resonance and made it critical. The X & Y axis ballscrews are long and supported at both ends, but the Z ballscrew is only 15 inches long and only supported at the stepper end. I reckon it was whipping somewhat. My next call was to remove the ballscrew, turn the end down and fit a floating bearing in a support like the other axis - but never got around to it as the rattler worked. Steve Blackmore -- ------------------------------------------------------------------------------ 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 [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
