Re: EMC & Wire EDM? -  reverse toolpath

> > in EDM, the electrode cannot arc on the part, if it does, it is

too

> > close and needs to back off a little.  in wire EDM that toolpath
> > might be on some part of some gear tooth.  Since the wire needs

to be

> > free from contact to spark, it is imperitive that it is in an open
> > section.  this would be the last section of the cut.  so the

software

> > would have to be capable of not only reversing direction, but

also to

> > run the toolpath in reverse from any point in the program.
>
> Right on. The tests that I've run here show that a simple position

history

> file should be sufficient to move the wire back along the cut

path. I

> wouldn't keep the history for much over a few thousandths. If we

can't clear

> a short in that distance we have bigger problems.
>

exactly, some programs look ahead some number of lines of code so as
to make very smooth transsitions between vectors. I think something
150 lines is what the really high dollar programs do. I've seen that
number advertised in articles in mags like Modern Machine Shop.

for our uses, probably the last 5 would handle all but the most
intracate parts.

all it really has to do is back up the electrode to the last clear
area and that should only be a few thou.

and once the part is done, all one needs do is cut power and stop in
place. there is no need or want to either back all the way out or
spend the time cutting itself out.

Dave