I was trying to use my Southbend/Ingersoll/Hansvedt 150B Ram EDM over the weekend and ran into some difficulty. Maybe someone can spot what went wrong.
I was trying to burn a .125 hole through a piece of HSS. Things started out ok, but towards the end things kinda went astray. I was using a .125 graphite electrode that I had drilled a .062 core hole for dielectric flushing. I used a small diameter trode since I wanted the test to progress quickly, therefore less material removal.
First problem I had was with the work tank. My system uses compressed air to move the fluid from the holding tank to the work tank. As the work tank filled to 3/4 capacity, if I kept applying air, the air started bubbling though the line causing fluid to geyser out of the work tank and all over the floor. This required that I clean the shop floor several times. I found it easier to shut off the air at 3/4 and submerge the work using the recirc pump.
Once I got going things went slow but smooth until the end. The ram kept oscillating up and down about 1/32" and the volts and amps swung wildly. Then it looks like the end of the electrode melted and it messed up the mouth of the hole. How that happened I don't know. I never broke through the hole. Perhaps if I undercut the electrode that would have been better (wafer type). That means I couldn't core the trode though.
My fluid is old, it came with the machine so it's history in unknown. It is dark amber color, but doen't appear to have suspended particles that could be causing shorts, as least as far as I can tell. I could look at a sample under magnification. I plan on eventually changing it along with the filter but its a messy job.
I posted the pics to the dropbox if it worked.Ed, are you out there?