Hey Ed,

Next time you're up this way, com'on over and watch, and you tell me.
I'm just going by what I see happening in my buddies tool and die
shop. He has quite a variety,, maybe 8 EDMs, (mostly sinkers) from
24" X 36" tables and 100 gallon tanks and full manual operation, to
full CNC 2500mm X 1000mm tables with 4,000 litre plus filter tanks,
and 5 Axis CNC wire (can't guess at that size, but not huge). You
can't see where the burn is if it's "in" the oil already. Used mostly
to burn ribs in the tools. He's even got one "home-made" some years
ago that was made from a big old planer, and uses the gantry for
holding the hot rods. Used for big heavy tools.

He tried to give me a big old Elox (Spark-O-Matic??) power cabinet,
but it was right at the time I was having trouble getting all the
stuff I already had to move into a trailer, and it was 575VAC, which I
will sadly never have here. So I didn't take it, and I see it's gone
from there now.
As Gunner says.............Siiiigggghhh..............!!.

Take care.

Brian Lawson,
Bothwell, Ontario.
XXXXXXXXXXXXXXXXXXX
On Fri, 02 Jan 2004 20:52:00 GMT, "Ed Huntress"
wrote:

"Brian Lawson" wrote in message
news
On Fri, 02 Jan 2004 01:48:55 -0500, Gary Coffman
wrote:

BIG SNIP OF GOOD STUFF

But this is all pretty much moot since EDM isn't done with
arcs through a gas. It is done with arcs through a liquid.
little snip

Gary

Hey Gary,

I think this last part of your reply is not really correct. Most EDM
I see is set up and started in free air. After location and some
other things are adjusted to suit the operator, then the work is
flooded, either by flooding the tank to immersion, or on smallish
parts or small burn area just with direct flow of die-electric
externally or through internal created flow ports. After the
die-electirc is applied, the rate of burn is then further adjusted to
the need, which seems to me to almost ALWAYS be MAX!!

Ed Huntress says that the arc starts without actual physical contact,
and I can't argue, but if so it sure isn't obvious. I always figured
that on die-sinkers the electrode (always carbon in my cases) does
touch and then retract ever so slightly, and now-a-days maintains the
arc through sophisticated controls on the newer CNC EDM's.

Happy New Year.

Brian Lawson,
Bothwell, Ontario.


The only reason they ever touch is to establish dimensional zeros, Brian.
And that's done with the EDM power supply turned off.

BTW, I've never seen an EDM started in air. The electrode has to be
submerged before you start.

Ed Huntress