Controlled Explosions: The Physics of Electrical Discharge Machining
What is EDM machining and why is it important?
Electrical Discharge Machining (EDM) is a process in which a metal workpiece is machined using electrical sparks. This technique allows tight tolerances, leaves no burrs, can be used on hardened material, and does not introduce mechanical stress to the workpiece because it doesn’t make physical contact. These attributes make EDM well-suited for engine components, medical devices, aerospace components, and other high-precision applications. The only requirement is that the work piece must be conductive.
How have we applied this technology?
Digitronik has been engaged by Titan International Sales, a national distributor of EDM machines, to develop a brand new EDM drilling platform called Titan Force. This type of system is known colloquially as a “hole-popper” because it uses circular electrodes to cut small holes in the workpiece. The first completed Titan Force system was deployed in October, and the next five systems are currently being assembled. Digitronik and Titan are proud to offer the only American-made small-hole EDM drill on the market!
How does this process actually remove material?
The electrode and workpiece are electrically connected to a switching power supply. The electrode is mounted on a servo that advances and retracts the electrode according to the average voltage between the electrode and workpiece (the so-called “gap voltage”).
During drilling, water flows through the negatively charged electrode as it approaches the workpiece. When the electrode is close enough, the electrical pressure between the electrode and workpiece overcomes the resistance of the water and causes it to ionize. The water suddenly becomes conductive and a controlled amount of electrical current flows between workpiece and electrode for a predetermined amount of time (between 1’s and 100’s of microseconds).
This sudden burst of energy heats the metal workpiece so intensely that a small amount of material is vaporized and dispersed by the flowing water. The system then turns off and allows the water to de-ionize so that the process can be repeated.
This ionizing and sparking cycle repeats many thousands of times per second while the electrode continues to move toward the workpiece and remove material to “drill” a tidy hole. A hole measuring 40 thousandths of an inch in diameter can be drilled through a one-inch thick steel block in than a minute.
What’s next for Titan and Digitronik?
Titan International Sales plans to release two more small-hole EDM systems in the Titan Force line, including a smaller manual system and a larger system that will accommodate a rotating turntable for even more positioning flexibility. Digitronik continues to support Titan’s products, developing new features and functionality that the EDM market has never seen before.