Re: RTLinux lessons, and EDM's

Brad Heuver wrote:

> Yesterday I succeeded in getting RTLinux to run the Frank Zappa
> demo.

?? Can you elaborate, please ?? (just gaining an appreciation for
Zappa's talents...)

> Jon Elson mentioned having EMC monitor the spark current and
> advance the electrode into the work. THis is essentially what the
> stepper control in the HSM design does.

Strictly IC also did an in-depth series on a EDM setup. As I recall, in
these setups, the spark sensor actually backs up the Z drive to break
contact, then feeds forward again until it senses spark again. There has
been interest by a couple folks in making wire EDM's. This process would
not work for wire very well. Imagine trying to back out of a radius cut
slightly, then moving back in.
I'm not sure how wire EDM works, but suspect it tries to maintain a
constant level of arcing. Part of the retract cycle in a ram EDM is to
facilitate flushing, not a problem with wire.
I wonder if an EDM module could be setup to work either way. Speaking as
a total electronics dimwit, I see the circuit as need to discriminate
the level of arcing to a much finer degree to accomplish this than for a
simple ram setup. Also, in a wire setup would the parameters change when
cutting 1" vs .125 stock?

Jon