Home Built EDM

Tonyr1084

Joined Sep 24, 2015
6,633
The finish is amazingly smooth.

I tagged a job at an aircraft hydraulic servo manufacturer as an EDM operator. My background is in inspection and the group leader was of the opinion that inspectors are inspectors because they can't do anything else. Well, it's my opinion that this is not true. Maybe largely it is - but not in all cases. Since age 7 I've been messing with things and even began building things when I was about 10. Anyway, the reason for mentioning this is because the guy treated me like a red headed step child and I got tired of it and ended up deciding to leave the company. But as an EDM operator I learned the basics that there are two types of EDM - the hole drilling as this video shows AND profile cutting done with a brass wire that is constantly pulled through the machine. The reason for continuous motion of the wire is to prevent electrode erosion, which would change the dynamics of the shape being cut. As I recall, the finish was pretty impressive. I've seen mill cutting and EDM cutting. EDM is much smoother. I would not call it a mirror finish but it is smoother than milling.
 

danadak

Joined Mar 10, 2018
4,057
Whats interesting here, case where hole is drilled perfectly strait thru
side of bearing, but diameter not exact, one could follow up with standard
drill and wind up with all dimensions dead on.

What he does not talk about is for jobs where edm bit substantially more rigid,
eg. larger holes for example, the hole diameter variation problem goes away.

Cool stuff.

Regards, Dana.
 

Thread Starter

joeyd999

Joined Jun 6, 2011
4,477
Nice thread. The only thing wrong was the head line of the thread. He didn't build it himself, just assembled a bunch of off the shelf parts. https://baxedm.com/
You are still on my ignore list -- but since this is an important point, I will pay you a modicum of attention:

No, he did not build it from clay and pop sickle sticks, but he made clear that he did design and fabricate many parts on his own using a 3D printer.

It'd be a long and difficult row to hoe had he attempted to build each individual part of the system.

Integrating some purpose-made parts and instrumentation into a final system saves a considerable amout of time and effort -- and the project would probably be next to impossible to complete otherwise.

But the final "product" is home built -- in my ever so humble opinion.
 

Tonyr1084

Joined Sep 24, 2015
6,633
one could follow up with standard
drill and wind up with all dimensions dead on.
That's not so easy to do with hardened parts - or even carbide parts.

The arc causes local vaporization of the material. Hard or soft - doesn't matter.

Here's what I'm thinking: I have an airless paint sprayer just like the one he's using in the video. I wonder if I could use the water jet to do some cutting of softer materials. Of course, the kerf would depend on the diameter of the water stream, but imagine cutting limbs off a tree using water pressure (for instance). I DO know that most water cutting machines also use a grit of some sort to aid in material removal. However, just using my pressure washer I have been able to cut grooves in concrete. Albeit painstakingly slow. Cutting bricks might be another useful endeavor IF one had a need to cut a brick.

But for my money - - - it's MY money. How many projects would I need an EDM or hydraulic cutter for? No sense in spending all that money for a one time (or two or even three) job.
 

shortbus

Joined Sep 30, 2009
9,073
Integrating some purpose-made parts and instrumentation into a final system saves a considerable amout of time and effort -- and the project would probably be next to impossible to complete otherwise.

But the final "product" is home built -- in my ever so humble opinion.
But there are a few of us doing it on this forum, and many more doing it world wide.

Kind of like a guy making a HVAC vacuum gauge.
 

shortbus

Joined Sep 30, 2009
9,073
Whats interesting here, case where hole is drilled perfectly strait thru
side of bearing, but diameter not exact, one could follow up with standard
drill and wind up with all dimensions dead on
As some one who did EDM for a living for quite a few years, I can tell you that isn't true. It is done to size by changing the size of the electrode. Meaning you adjust the electrode size by what is called the "over burn", the amount the spark takes out. You can easily get drill accuracy and with experimentation reamer accuracy.
 

MaxHeadRoom

Joined Jul 18, 2013
24,272
Then there is the (technically) simpler & similar Tap Disintegrator or tap buster, for removing broken taps etc.
Max.
 
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Tonyr1084

Joined Sep 24, 2015
6,633
Maybe use the water jet for cutting styrofoam. I suppose I could cut foam panels for my garage door and insulate it a little better than just a thin sheet of steel. Plenty of YouTube videos on how to do that as well. But again, I don't have a pressing need for such.
 
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