- Stands for Electric Discharge Machining.
- It is simply a spark between an elecrtode/wire (Depending on which machine variant is used) and a workpiece that are seperated by a dielectric fluid (Usually high purity water (Double Distilled or Deionized) or oil)
- It does super precise cutting and small hole drilling in electrically-conductive materials.
- Good explanation + Demo in this video at 13:26
- Uses 0.25 mm brass wire for cutting, Mcmaster has 0.5 mm wire - $30/lb - 
- Voltage is 50-300V. Current for 1" cut below is 35A.
- 1 pound of wire used per hour to cut a 1/2" hole in a 3" piece of hard metal. - . that is $5 in wire cost. About $1 per inch of metal.
- 10x slower than waterjet - 
- Waterjet appears to be much better for the speed and cost. But EDM advantage is 10x more precise - 
Examples of EDM Cut Objects
- The following was cut using a high precision Wire-Cut EDM Device. The Cut is so precise that the shape can seem to dissapear into the cube it was cut from when it is reinserted:
<a href="//imgur.com/DAs75ze">THE FINAL FORM</a>
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Existing Open Source Designs
- DIY, cuts 1" stainless at 2 mm/min -  Howto - 
Book on DIY EDM machines
Books and Starter Kits
- MIT Machines That Make -