EDM (electric discharge machining) Machine

[scorch]

Homemade plunge EDM (electric discharge machining) machine built based on the book "Build an EDM" by Robert Langolois. (https://secure.villagepress.com/stor...age/2/item/797) The book consists of a series of articles that originally appeared in The Home Shop Machinist.

I deviated from the book in a couple of ways. First I sourced some of the components from scrap electronics and an electric clothes dryer that I picked up for free on the side of the road. The main transformer came from a microwave oven along with a cooling fan. A smaller transformer was sourced from an old stereo. The heating coil that I used as a power resistor was also taken from the old electric clothes dryer. The motor from the same clothes dryer is still in use on my http://www.homemadetools.net/forum/g...9966#post41061.

Additionally I used a sand cast aluminum part to support the linear actuator components and finished the whole thing off with a few custom 3D printed parts to fasten the linear actuator parts together.

Here are a couple pictures of the major components with and without the case cover installed:


Here is the machine setup for cutting a part:


These are a couple of pictures of items that were machined using the EDM. On the left is a piece of hex stock that I machined with a small electrode. On the right is a neodymium hard drive magnet that I cut a circle out of.


In the video below I talk about some of the major parts used to build my machine and show a couple of parts that I cut using the EDM. At the end of the video there is a short clip of the machine in action.

The posting of this tool finishes off the list of homemade tool I posted in my original forum post about a year ago in April 2015 (http://www.homemadetools.net/forum/s...omething-17270)

[DIYer]

Thanks scorch! We've added your EDM Machine to our EDMs category,
as well as to your builder page: scorch's Homemade Tools. Your receipt:

EDM Machine by scorch

tags: machining, EDM

[Paul Jones]

scorch,

This is amazing work and wonderful ways to source the parts. This is great information and lots of references. I think you will have many views for this project.

Thank you, Paul

[scorch]

Thanks Paul. The EDM was an interesting project but I have yet to find a practical usr for it. This project was more about the journey.
Scorch

[Jon]

Congratulations scorch - Your EDM Machine is the Tool of the Week!

You'll be receiving an online gift card, in your choice of Amazon, PayPal, Giftrocket, or bitcoin. Please PM me your current email address and I'll get it sent over right away.

This is your fourth Tool of the Week win.

One more and you'll join Brendon, Christophe Mineau, and rossbotics as a 5-Time Tool of the Week winner, and the silver wrench-on-pedestal graphic will be added to your trophy showcase in your postbit beneath your avatar. Here are all of your wins so far:

Injection Molding Machine by scorch

tags: arbor press, electrical, cylinder

Aluminum Foundry by scorch

tags: foundry

Gingery Lathe by scorch

tags: lathe, chuck, motor

EDM Machine by scorch

tags: machining, EDM

Nice work and congrats again.

[Pa1963]

Nice build! I got the book many years ago from Lindsay Books. Sadly he closed up shop.

[Pa1963]

I wonder how this would work with a CNC table, as opposed to a plasma cutter.

[Moby Duck]

Possible practical uses for your EDM. I don't know much about EDM but more than 30 yrs ago I had an Evinrude OBM that I was overhauling and many of the S/S bolts were completely seized into the alloy and sheared off. The solution was to use a portable EDM machine to erode the stainless bolt from the alloy. If I remember rightly, a dam of Plasticine was built around the sheared off stud, it was filled with fluid and the EDM ate away all the stainless and left the alloy threads intact. I never did work out how it managed to do that without destroying the alloy. A colleague did the work for me and for about a year the machine had some intermittent use doing similar work, and then I never heard of it being used again in the next 30 years. Today they tend to machine out studs like this and perhaps fit Helicoils, but at the time it was a good solution to my problem.

[CNCfan]

These people are keeping the books alive. Glad I found them a while back. I have quite a few of the old books and find them very interesting. Plan on getting a few more.
Your Old Time Bookstore

[scorch]

I wonder how this would work with a CNC table, as opposed to a plasma cutter.

Most commonly EDM is used in CNC applications in the form of wire EDM. With a wire EDM the electrode is a wire that is feed between two spools. The use of the wire keeps the electrode size constant because there is always fresh wire being fed into the cutting area. If you CNC with a plunge EDM you would likely need to account for the tool wear.