Re: [CAD_CAM_EDM_DRO] Cheap 56,000RPM milling upgrade (not a dremel :)

JanRwl@... wrote:

>All these compressed-air spindles EAT so much air; even the PRECISION ones
>are not only too expensive, but wasteful. I built a little X-Y PCB drill
>using a 400 Hz. "capacitor-run" motor which I powered via a 400 Hz. circuit I
>built. VERY fine! The little motor was part of some aircraft instrument, I
>think. ANYway, it is clear that high freq. motors are MUCH nicer and economical
>to work with than AIR stuff; they are just hard to FIND. Can't we, as a
>group, somehow interest some motor- or quill-manufacturer to make "ideal"
>high-freq. motors for us? And power-supplies? Has anyone "in here" built a quill
>using 800 Hz? For PCB work, 400 Hz is "OK", but it'd sure be nicer if TWICE
>that! (FYI: "Real" CNC PCB machines turn 100,000-300,000 RPM!!!)
>
>

I've got a Westwind air bearing drilling spindle that runs on 80 V @ 400
Hz, or
160 V @ 800 Hz if I had a VFD that would go that high. It drills PC
boards like
a laser or something - incredibly smooth and clean. I've drilled .018"
holes all
day with it. So far, I can only drill one .062" panel at a time when
.018" holes
are being drilled. If I try to drill through two panels at a time, it
breaks drills
due to chip packing in the deep, narrow hole. But, if I keep it to one
thickness,
it works like a charm.

This motor uses about 3-4 CFM of air, almost all for cooling the motor.

You can see this gadget here : http://jelinux.pico-systems.com/wwspndl.html

I also have a Rockwell/Precise spindle that has a TWO phase AC induction
motor. I am planning to try a Scott Tee transformer to convert from 3-phase
to 2-phase for it. I have spun it up using a Gecko 201A stepper driver, and
it did surprisingly well with that.

(I had a picture of this, but I can't find it now.)

Jon