Re: Bridgeports (revisited, I'm sure)

To give some reference, the popular Bridgeport retrofits use
28 in-lb DC servos. The manufacturers bolt these on. No pulley
changes, just the 1:1 or 2:1 pulleys that came with the original
BOSS series. Drivers for DC servos are far more popular, even
though you can get AC servo drivers from Rutex, I have not heard
any feedback on using them. I am using 12.5 in-lb servos on my BOSS
with a 4:1 ratio. This will give me 50 in-lb at the leadscrews
which is comprable to the commercial retrofits. These motors are
rated at 3000 RPM and will give me 150 ipm rapids. You can use larger
motors and just adjust your gearing accordingly. Some folks here use
giant 40 in-lb servos on their axis, but this is just overkill.
BTW, the calculated cutting force with my setup is 1440 lbs.
The peak cutting force is a wopping 5652 lbs. This force will break
just about any mill cutter.


Scott

>
> And bottom line, how big do they need to be? If it needs high

acceleration,

> can I drive the motors with controlled surges? Would it mean being

forced

> into brushless servos to avoid high currents through the commutator?
>
> I've got the electronics and computer stuff covered, BTW.
>
> Dennis
>
>
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