|Wire cut gear.
This is a titanium gear resting in the blank from which it was cut. How was it cut, you might ask? Not with a laser, which couldn't cut that deep. Not with a water jet, which would leave a more ragged cut on the down-stream side. It was cut by wire EDM (electronic discharge machining).
A thin, stretched tungsten wire nibbles slowly away at the titanium by means of an electric current running from the wire to the titanium. Tiny sparks vaporize the titanium more rapidly than the tungsten wire, which is continuously refreshed from a spool.
This method is slow (maybe an hour to finish this small gear) and it can only cut shapes with straight edges. But it's very precise, and it places virtually no stress on the part being made, so you can machine out incredibly delicate, finely detailed shapes without breaking them.
Source: Ethan Currens
Contributor: Ethan Currens
Acquired: 30 October, 2006
Text Updated: 30 November, 2006