RE: [CAD_CAM_EDM_DRO] Affordable ball screws

>Time to show some stupidity, but why do we want to create the

hydrodynamic

>screw again?

To avoid having to buy ball screws to get zero backlash. And to do
something
interresting.

Also, hydrostatic bearings give you zero wear, and very low static
friction.

Even just combining hydrostatic bearings on the ways with ballscrew
actuation
should allow the machine to run much faster and more accurately.

>Seems like one of those money saving plans that actually ends up
>with you having bought a brand new hydraulic pump

Money versus time tradeoff. The first guy to get it going will certianly

spend more money and time than just getting ballscrews. But once it's
done
and documented it may very well become cheaper.

>but why can't the holes be drilled into
>the nut? The way I remember it being arranged was the screw was sitting

That's the idea. But you feed the oil into all the holes, and it squirts
out
of the ends of the nut.

Lift will be a function of clearance between nut and screws, oil
thickness, oil
pressure, and flow volume.

Given that the geometry of the nut+screw will be far from optimal, a
practical
setup would have to compensate by pumping through lots of heavy oil.


Has anyone managed to measure the fead (pitch?) error on a screw
accurately? If
you can measure the actual error of the screw you can compensate for the
error
in software.

Regards,
Nic.