Electrical discharge machining, or EDM, is a wicked (and expensive) way of cutting metal to extremely fine tolerances. It's a CNC process whereby two electrodes are precisely placed at opposite ends of the workpiece; a powerful spark is then generated between them, essentially vaporizing the material in the path of the spark. The dross is then flushed away by a constant stream of de-ionized water running across the workpiece. Check it out:
That was Ram EDM, also called Die Sink EDM, which was the first type of EDM that manufacturers mastered. But they discovered that the electrodes used would wear away over time, and thus invented Wire-Cut EDM. As the name suggests, with this system a steady stream of wire is used to act as the electrodes, running off of a spool to stay "fresh." Check out the awesome tolerances you can achieve with Wire EDM:
Pretty sick, innit? Stay tuned—next we're going to show you how one industrial designer has used EDM to excellent effect.