Submitted by Jim Glass
www.outbackmachineshop.com

Got the home built bench-mounted wire EDM working 2 
nights ago? Is this thing neat! A month ago I posted 
questions about some problems and thanks to some 
pointers received here, I got it working. 

I'm using a power supply from Robert Langalois's book, 
"how to build an EDM". The greatest problem was the 
wire breaking. Got a Variac (varies AC output) so I 
could vary the AC voltage in, hence vary the DC out. 
Originally I used full power (70 volts) but with the 
Variac 55 Volts does a good burn w/o breaking the wire. 

The x/y axis is controlled by 24 v DC gearmotors, also 
home made. One of the reducing gears double as an encoder 
with 50 holes drilled equaly space. 1/2-20 threaded rod 
acts as a feed screw so each drilled hole in the gear 
is .001" movement. The counts go to a Micrologix PLC 
which starts/stops/reverses the appropriate motor to 
make rectangular movement. There are also manual switches 
for freehand burning. Already made some key chains for 
buddies. Holes and angles will be next. I'm posting only 
one PIC because they slow the message board. Other Picas 
are at metalworking.com, DROPBOX. 

Even the wife was impressed? 

Jim