This was the turning point in the history of the Electrical Discharge Machining process. This greatly reduced DC arcing (short circuits) and made the EDM cut more effective. Lazarenko are credited for the invention of both the pulse circuit and a simple servo controller that helped maintain the gap width between the tool and the work piece. Vibrating the electrode allowed material to be removed more effectively. It was during this time the vibrating circuit (dither) came into being, this represented the first attempt toward controlling the actual spark and spark gap. At the beginning few saw any potential benefits of this process and support of this primitive technology was scarce. The initial problems included as much electrode material being removed as was material being removed from the work piece as well as the manual feed mechanism they were using lead to more short circuits (DC arcing) than actual cutting discharges. With this understanding in hand, they made the first attempts to remove material with the cutting action of electricity. Through their investigation, it was discovered that material transfer could controlled by varying the electrical properties and materials. Lazarenko were studying why electrical breaker and contact points were suffering degradation from material transfer. There are two distinct varieties of EDM, die-sink and wire cutting. The history of the EDM process dates back to the days of World War I and II. EDM is a subtractive manufacturing method that uses electrical discharges to machine features on a mold. EDM is sometimes known as "spark machining" because of this action. If you were to observe the EDM process under a microscope, you would discover that the electrode itself does not actually touch the material being cut. The repeating discharges create a set of successively deeper pits or craters in the work piece until the final shape is produced. The small amount of material that is removed from the work piece with each electrical discharge (pulse) is flushed away with the continuously flowing die-electric oil or fluid. With thousands to millions of these craters or pits being created every second, the EDM cutting action results. This process repeats its self over and over. The electrical pulses are very short in duration, approximately 1 microsecond to 1 millisecond each. A die-electric oil or fluid causes the melted material to cool and harden before it can re-adhere to the workspace. Each discharged spark leaves a tiny crater or pit in the workspace. The EDM cutting action works by bombarding the work piece with short but intense bursts (sparks) of electricity. These electrical discharges are passed between an electrode and the piece of metal or material being machined. EDM removes material by producing a rapid series of repetitive direct-current (DC) electrical discharges. Anyone who has ever seen what happens when a bolt of lightning strikes the ground has a fair idea of the process of Electrical Discharge Machining.
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