Regarding Ball Screws...
If I do go with ball screws, what would be a good lead to choose? Nook has .200, .250 or .500 leads
I used .500 lead on the last router, and I was planning to use .500 lead acme screws on this. Judging from recent experience, maybe a finer resolution would be better though. I have more then enough RPM from the servos for the finer pitch screws, the limiting factor is whip from the x axis screw.
just thinking... If I went with .200 lead or 5 turns per inch I could possibly see 400IPM If I can get the longest (67") screw up to 2000 rpm?
According to Nooks critical speed calculator, I can get about 1900 RPM from a 1.15" screw, however, the ends need to be supported with angular contact bearings spread apart a minimum of 1.5x dia of the screw and at both ends. With regular ball bearings at both ends the RPM limit drops to 1266 or 253IPM.
So, are the calculations Nook uses conservative? Can I massage the numbers a little and still be OK?
My original goal was 600IPM, but 400IPM would be OK. Less then 400 may be a problem though.
What are your experiences?
Thanks
www.nookindustries.com/engineering/calculators/CriticalSpeed.cfm