Re: [CAD_CAM_EDM_DRO] Re: Max feedrate of ball screws?

In a message dated 12/5/2002 5:20:14 AM Central Standard Time, scsm@...
writes:

> Other than a rotating nut, (which I may end up going with) what other
> method is there to acheive high travel speeds (300+ IPM) I really like the
> idea of a rotating nut, but unless someone has already built one and is
> willing to release the design...
> It looks like it will be a complex engineering progect, and rather
> expensive to machine...
>

Seth and others:

Decades back, in a galaxay far, far away, I had to do some engineering on a
large X-Y table with LONG lead-screws. For the 10'+ "X axis", I used a pair
of 1.5" dia. ball-screws with a 0.5" lead. (Yes, cost some $$$!!!). The BSA
catalog has some reasonably-clear engineering-suggestions how to overcome the
"whipping" a long lead-screw does when rotating, and that, already, is
"involved". The idea of a rotating nut is NOT a bad idea, as that way, the
screw can be rigidly fastened at both ends, and the screw's RPM will not be a
hassle.

Complex engineering project? Expensive to machine? What do you expect, a
"free lunch" (paid for by HEW) ? ? ?

If precision is not a factor, you might consider sprocket-chain or even
"timing belt" and toothed sheaves, etc. UGH! Makes me thing of earth-moving
machinery, not "precision gear"!

But yes, I agree! BSA should be reading this thread and publish drawings in
their catalog which SHOW how one might rotate the dual, preloaded nut, rather
than the screw. Hmmm . . .

On the other hand, if you are building only a small X-Y PCB-drill,
ACME-screws with Turcite/sprung preloaded nuts should do (mine works fine!),
with the 1/2" dia. x 0.125" pitch/4-start/0.5"-lead, screws turning.


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