Re: [CAD_CAM_EDM_DRO] Re: LOOKING for homeshop EDM or its power supply?

Hi Luis:
Wire EDM cutting performance is measured in square inches per unit time.
Sinker performance is measured in cubic inches per unit time.
The numbers can be very misleading with sinker EDM, because the process is
so dependent on the shape that is being cut.
Typically, the objective is to burn as fine a finish as possible in as short
a time as possible, with as little electrode wear as possible.
Electrodes wear the least when they are given low frequency discharges with
long "on times" and negative polarity.
This gives coarse finishes and big overburns, but fast cutting.
Fine finishes at low currents, high frequencies and short "on times", lead
to very slow burning and rapid electrode wear.
Typically, I can rough burn a one inch deep cavity within 0.002" or so in
relatively little time.
The last 0.002" can take twice or three times as long as the first 1 inch
did!!!
It will also consume far more electrode material.
If I have a shape with some bulk to it...say a rectangular cavity, I can put
lots of power into the cut, because I have lots of surface area to absorb
the energy.
If I have a skinny rib to burn, I'll burn up the electrode if I put too much
amperage into the cut, so the rib will take longer even though I am removing
far less material.
In addition, the flushing is poor in a skinny shape, so my electrode "on
time" has to be reduced to allow the dielectric to recover and keep the burn
going.
So"how slow is it" is not a simple question to answer at all.
But overall, compared to milling, EDM is very slow.
Cheers

Marcus

----- Original Message -----
From: "luisguillermo98" <luisguillermo98@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Wednesday, July 16, 2003 6:16 PM
Subject: [CAD_CAM_EDM_DRO] Re: LOOKING for homeshop EDM or its power supply?


> wow, It is a very slow process? so does it run 1" every 15 minute? I
> did not know EDM was that slow.. Could you tell how the speed on
> these machine are rated. I heard they are rated in inches square per
> minute..
>
>
> Luis ..