2009/6/9 Frank Tkalcevic <[email protected]>: > > How much "backlash" would the rubber teeth on the belt contribute?
"Some" I guess. Though it might matter less than you think. In fact, that thought has been occurring to me throughout this thread. There has been a lot of concern over absolute accuracy, when repeatability is probably more important in the real world. I can't think of many things where dimensions over a couple of feet have been important to a few thousandths, and in cases where they are, if the two parts are made on the same machine then they will fit anyway. (And it has been a source of some frustration to me watching machinists fretting over the last n-th of accuracy on a part I wanted yesterday, and where I have specified +/- 5mm "I don't care" accuracy. ) Similarly with a resilient belt or "springy" ballnut, it will always sit in the same place for the same cutting force, so if you have a light finishing cut you will probably get better accuracy than the ballscrew spec suggests. (or even if you have a consistent roughing cut) You will, however, probably get more chatter and vibration, but then a visco-elastic element might damp vibration that would be there in a fully rigid system. (Note, I am not a machinist, I am not even really an engineer, but I play one on the internet) -- atp ------------------------------------------------------------------------------ Crystal Reports - New Free Runtime and 30 Day Trial Check out the new simplified licensing option that enables unlimited royalty-free distribution of the report engine for externally facing server and web deployment. http://p.sf.net/sfu/businessobjects _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
