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All Springer/NP/PCP Air Gun Discussion General > Machine Shop Talk & AG Parts Machining

EDM - Anybody build one?

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sb327:
I’ve got most of the parts gathered for the mechanism but haven’t settled on how I want to supply the erosion circuit.

I too will use arduino for control because I’m familiar with the platform and it can be easily programmed.

Dave

OTmachine:
Thanks for the replies.  An Electro-Arc came up for sale on facebook and kind of renewed my interest.  It was cheap, but from what I recall caps and such seem to fizzle after so many years and repair parts were not cheap.  And the Electro-Arc has a larger footprint than I care to dedicate space to.   I had started researching in the past, but like a lot of things,  it got put on the back burner.  I am retiring at the end of the year, so I should finally have some time.  A home made sinker type of EDM would do a Lot for me.  Carbon electrodes are really easy to machine and produce pretty close tolerance features.    When I get it together, I will post.

sb327:
For sure share it here. Sounds like there is definitely interest.

Dave

OTmachine:

--- Quote from: JuryRigger on October 30, 2022, 02:37:17 AM ---Watching, interesting relevant link added:
http://mikesworkshop.weebly.com/a-spark-erosion-apparatus.html
Jesse

--- End quote ---
Jesse,  That is a good basic one.  I had saved that link back in May.  But I am looking at ones with vibratory feed, which can be accomplished pretty easily.  I have some old industrial battery charger transformers which I was saving for this.  Lots to research.  Thanks again!

sb327:
So I threw some stuff together. It looks unsanitary as hel but is working as planned (sort of).

Of course I’m controlling the stepper with arduino. It monitors voltage between the workpiece and electrode. Really simple program. I have a potentiometer to adjust the max voltage the arduino sees (5v) and a smoothing cap. It handy to be able to adjust that quickly without having to adjust your program.

The erosion circuit starts with a variac to a bridge rectifier through a current limit bulb. Then two larger caps. Then a 200v mosfet driven by a cheap pwm generator. I can adjust duty and frequency on the fly.

It works but it needs a bit of refinement, lol. And it was reasonably cheap to build. The only expensive item is the variac that I have for other stuff as well.

I want to try a different (carbon) electrode (in the video I’m just using some solid copper wire). I also will play with the freq/duty as well as input voltage.

Anyway, initial testing has went well.

Dave



And a picture of the hole in the aluminum, I may need to turn it down some…not sure. Looks like it is pretty rough. You can’t tell from the picture but the holes are about 3/16” deep.

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