Re: Gecko + Servos + Taig Mill

I thought that sounded a bit on the low side. The Taig is a small
machine, and you can't expect too much out of it (although it is much
more rubust than a Sherline).

I just ran downstairs and did some tests. The Taig seems to like
5400RPM with a 3/8" cutter on 6061-T6 aluminum. I was taking 0.1"
depth of cut, with ~40% of the diameter cutting, and was craking as
fast as I could, about 0.2"/second, 12IPM. At this rate, it was
almost like craking without cutting anything, so there was very
little force. However, I'd like to have lots of power under the hood.

The motor I'm using is a 1/5 HP, 1725 RPM with pullies. Max spindle
RPM is 5400, min is about 500 IIRC. Max cutter diameter will be 3/8".
The max X travel is 8", IIRC, and the max Y travel is 5.5". I would
like to have about 100 IPM rapid feed. The max workpiece weight
should be about 10lbs, although probably not even that. Right now,
the leadscrews are 1/2-20, but I'd like to replace them with
ballscrews. Probably with a 5TPI pitch. I will be cutting everything
from wax to stainless steel.

If anyone can suggest a size (# of watts, holding torque, etc) of
motor, I'd be quite open to comments. Where does one look for motors
on the surplus market? Is it possible to just buy an appropriatly
rated DC motor, and then add my own encoder? Seems like it could be
cheaper. I'd like to use the Gecko, so where can I find compatable
encoders?

Thank you all for being tolerant of my rather simple questions. I'm
starting at almost zero here, so it's a big help to have a list like
this.

Regards,

Robin

--- In CAD_CAM_EDM_DRO@y..., Jon Elson <jmelson@a...> wrote:
>
>
> lasernerd@h... wrote:
>
> > Ok. So I need a servo that's rated for about 5-15W (although
higher
> > couldn't hurt). With a 5000RPM servo I'd need an ~8:1 gear ratio.
>
> I didn't notice this in an earlier reply - I think 15 W is WAY too
small
> a servo motor for machine tool use! What were the speed and force
> numbers you were using?
>
> Jon