Re: [CAD_CAM_EDM_DRO] Re: greetings

dave engvall wrote:

> If my memory serves me correctly; hydraulics were used in the early
> cnc. Hydraulic servo valves are expensive and I suspect the
> control was not quite as good (or easy).

There are 2 ways to do hydraulics. One is to use a hydraulic cylinder
directly on the table, the other way is to use a hydraulic motor to
drive
a leadscrew. Until recently, that was the only way to move behemoth
machines like gigantic Kearney & Trecker bed mills. The hydraulics
need hoses to stacked axes, suffer from air entrapment, leaks, worn
out servo valves and hydraulic motors, and the dangers of a pinhole
leak or a blown-off hose are no joking matter! The hydraulic pumps
make incredible noise, and waste huge amounts of power.

> Linear motors are spendy and consume lots of power.
>
> Ball screws are well understood and while not inexpensive must be the
> most cost effective solution or something else would be in
> the marketplace.
>
> I know absolutely nothing about acoustic wave motors. Best I shut up
> while I can.

I think these are fine for microscope stages and such (I'm assuming this
is one
name for inchworm type drives and related technologies) but not for
rapid
movement or large forces.

Jon