EDM is among the earliest non traditional manufacturing process, having an inception 50 years ago in a simple die-sinking application. Anyone who has ever seen what happens when a bolt of lightening strikes the ground will have a fair idea of the process of EDM. EDM CONSUMABLES
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THE history of the EDM process dates back to the days of World Wars I and II. Earlier very few saw the benefits of this process and the popularity of the primitive technology wasd scarce. As much electrode material was removed as that of the work piece and the manual feed mechanism lead to more arcing than sparking. During this time the dither or the vibrator came into the picture and this represented the first attempt towards controlling the spark gap. Vibrating the electrode allowed material removal to be effective. Two Soviet scientists were convinced that many more improvements could be made. Doctors B.R. and N.I. Lazarenko were the people who invented the relaxation circuit, they invented a simple servo controller too that helped maintain the gap width between the tool and the work piece. This reduced arcing and made EDM machining more profitable.
The two principle types of EDM processes are the die sinking and the wire EDM process. The die sinking process was refined as early as the 1940 with the advent of the pulse generators, planetary and orbital motion techniques, CNC and the adaptive control mechanism. From the vacuum tubes, to the transistors to the present day solid state circuits, not only was it possible to control the Pulse on time, but the pause time or the Off time could also be controlled. This made the EDM circuit better, accurate, dependable and EDM industry began to grow.
During the 1960 the CIRP and ISEM conferences were held for the first time in Czechoslovakia which proved to be a driving force in the progress of the EDM process. EDM research was inspired by the old paradigm of technology that each problem in a field must be solved. The founders of this paradigm were Newton and Maxwell.
There were a number of problems faced when mathematical modeling of the ED process was done. The gap pollution, the hydrodynamic and thermodynamic behavior of the working fluid are hard to model. Getting a model in all with practical technological results was difficult. This inability along with the high demand from the market lead to a more pragmatic, application oriented research into the EDM process. EDM CONSUMABLES
The research going on today aims at a more application oriented field rather than searching for a unified EDM model. Today the EDM market is growing owing to increasing popularity of EDM in the manufacturing market and secondly due to the indirect influence of fundamental and applied EDM R&D, carried out at various labs, industrial ones and at universities.
The evolution of the wire EDM in the 70’s was due to powerful generators, new wire tool electrodes, better mechanical concepts, improved machine intelligence, better flushing. Over the years the speed of wire EDM has gone up 20 times when it was first introduced, machining costs have decreased by atleast 30% over the years. Surface finish has improved by a factor of 15, while discharge current has gone up more than 10 time higher . EDM CONSUMABLES
