Re: EDM, was Re: Cheap Encoders

>From: PTENGIN@...

> I've used Alumi-tap for a fluid. It doesn't seem to burn. It does smell
>pretty bad when EDMing. I made the power supply as shown in the HSM series
>but never did get the head or electronics for the stepper running. I am using
>an insulated holder in my BP spindle and giving it the "shake up and down"
>job. I was considering a small solenoid with a timer module to vibrate the
>electrode up and down. Of course this would not work for any precision but it
>would cut a broken HS tap out no problem. Peter

I don't know what your BP spindle is but the only mechanism I have got to
work (very slowly though) is hanging the electrode off a solenoid and
passing the arc current through the solenoid. As the electrode falls the
circuit is completed and the solenoid hauls the electrode up. Some
experimenting is required to get the right number of turns on the coil and
additional weight may be required on the electrode to get it to fall
quickly. If someone can tell us what the best current/voltage/repetition
rate is maybe I could speed up the errosion rate? By the way I used Parafin
as a fluid. No problems as long as the work is well covered and you ensure
it stays cool.

Bill Phillips