Building a Pulse EDM machine

whitmore said:
I had a fluid spill from an EDM (which, naturally, was working unattended)
once, and it was a mess. If possible, my preference would be for NO holes
in the bottom of tanks (suction from a dip tube instead, or submerge
the pump in the tank). Every valve and fitting that's above the tank
is under zero fluid pressure when the pumps are off. That's a happy thought.

Another thought, is that someday the fluid may be drained either for shipment
or for replacement; a way to redirect pump flow to a bucket could save some
messy bailing-with-tin-cans work. That seems to be present already (the
blue-handle valve in the loc-line assembly), if I'm interpreting the pix
correctly.
Click to expand...
Well, I have changed tbe design again. ( If I keep working on it long enough .... I'll get it as perfect as possible.)
The ideal system would be simple, safe, and idiot proof.
It would be too expensive and difficult to not have any holes in the tanks.
In the final design, there will be a drain line from the bottom of the work tank to the storage tank. This will be made of bilge hose for flexibility and go through the lid of the storage tank, (a 10 gallon steel drum), into a 10 micron filter bag suspended in the tank. ( This is to return somewhat clean oil to the tank and keep junk in the tank to a minimum.) It is simply a gravity drain.
There will be a fitting at or in the bottom of the storage tank that connects to the pump, ( the external pump must be lower than the supply as it is not a self priming pump.) The pump will pump the oil through the filter unit ( to pump as clean oil as possible) into the work tank through a line hung over the top edge of the tank. The level set by a stand pipe in the drain. ( The tank cannot overfill).
That's it. No valving, one pump, simple design and safe. The design has been in front of me all along ( in the book, on the net) I guess I had to work through the thought process to see it. I'll post the diagram when i get back to my computer.
 
savarin said:
Looks good Mark, sparks flying soon?
Click to expand...
I wish...... It is getting closer. I still have to get the X Y table (from Grizzly) for the work tank to mount on, make the base frame to hold the storage and work tanks, pump, and filter ( this will be about 60 feet of 1 1/2" square steel tubing ), the 10 gallon drum for fluid storage, and the piping. This will cost about $300 and then it will be ready for the fluid and testing. The 10 gallons of fluid cost $200 plus $50 for shipping ( I may drive to pick it up ).
The availability of funds is slowing things down quite a bit, but I will get there eventually. ( This project when completed will cost about$1000 )
This project is a long way from a simple tap burner, but should be quite useful. There has been some discussion about broken bolt removal service for the hot rod community to save expensive parts ( I already make or repair some small parts for them now and then, that are not available anywhere by machining new ones.)
 
mark_f said:
RC stands for relaxation circuit I believe. It uses a capacitor discharge to spark the gap.

These machines use standard 110 v house current.
Click to expand...
RC stand for Resistor Capacitor circuits, great work, all my parts are ordered
 
chp said:
RC stand for Resistor Capacitor circuits, great work, all my parts are ordered
Click to expand...

The book I am looking at says it is a " relaxation circuit" . It charges a capacitor and discharges a spark across the gap. When the gap widens, the capacitor(s) charge again and discharge again as the gap closes. This happens very fast, around 60 times per second, or more depending on the supply used. Years ago these were called spark eroders and used a coil to "vibrate" the electrode to open and close the gap. Each discharge burns away a tiny piece of material. These are still made today and sold as a tap burner.

You are correct that in the electronics world, RC stands for resistance - capacitance circuit, but in the EDM world it is a relaxation circuit.
 
mark_f said:
The book I am looking at says it is a " relaxation circuit" . It charges a capacitor and discharges a spark across the gap. When the gap widens, the capacitor(s) charge again and discharge again as the gap closes. This happens very fast, around 60 times per second, or more depending on the supply used. Years ago these were called spark eroders and used a coil to "vibrate" the electrode to open and close the gap. Each discharge burns away a tiny piece of material. These are still made today and sold as a tap burner.

You are correct that in the electronics world, RC stands for resistance - capacitance circuit, but in the EDM world it is a relaxation circuit.
Click to expand...
Often I am ask what is the difference between the RC and the Pulse machines. The primary difference is the Resistor Capacitor (RC) type, discharges a capacitor across “the gap” to remove metal and the Pulse machine does not. this is a copy paste from Ben's book
 
This project is basically complete, but I still need a $150 positioning table and $250 of fluid. When I can get these , I will begin testing. I unfortunately don't have a time frame for when that will happen. I am as anxious as many of you.
 
hi can i ask two questions
if i go with book pcb pack ,and build one
what kind performances it will have ?
example , tube fi 15mm with hole 8mm ,and i need to carve pocket inside 20mm
and pocket will be 2mm tick 4mm wide
how much time edm will need to make that pocket inside ?
and last
how to connect edm head with ramps controls to have cnc like control with mech3/4 ?
thanks
 
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