Electrical discharge machining process is a well-known process and has been known for centuries. In the year 1786, Prestley a British Physicist detected small craters in the electrodes formed during the spark was generated. This process played a vital role in World War I and II for producing various geometries. At the beginning, the process lagged control and thus the possibilities of the technique were negated. Initially for the first time, wear was same for electrode and the workpiece. Later the gap was controlled by vibrating systems which helped in reducing part wear to some extent. The first successful attempt of the technology was made in Moscu in the year 1943 by Dr. Boris and Dr.N.Lazarenko who developed a spark generator and a servo control circuit to maintain a constant spark gap.The developed RC circuit is shown in below figure.
Later in the year 1964 a transistorized spark generator was made which further improved the process. A big step forward in the technology came in 1969 with the invention of wire EDM process by Prof. B. Schumacher. After that the process improved significantly by introduction of electronic control circuits, process automation, increased number of controlled axes etc. which led to increased productivity, decreased electrode wear, better surface finish and improved material properties. Present research is basically focused on machining various difficult to machine materials with higher degree of accuracy and also to produce very highly intricate structures which are a dream to manufacture using conventional machining. The general working process is shown in the figure below.
The process basically involves material removal in the from of vaporization and melting of the workpiece material. The main advantage of this process is that it is independent of the hardness of workpiece material. The foremost requirement of this process is that the workpiece material should be electrically conductive.
No comments:
Post a Comment