Electrical discharge machining or EDM is a not as new of a technology as many people assume. The power and effect of exposing metal to electric discharge was first discovered in 1770, and then, in 1943, two Russian scientists determined that erosion of metal through electrical discharge was more effective when the electrodes were covered with dielectric liquids.
This early discovery led to the development of the first EDM machine, which was ideal for use in working with specific metals, including tungsten, that were challenging to work with using other techniques of the time.
At about the same time, three Americans developed a similar type of EDM machine that had the specific job or removing drills and taps from aluminum casings. While the first designs were not rugged and dependable, they kept refining the design. Over time, and through the use of technology, the advancement of EDM technology allows for high levels of precision work.
The Wire EDM Process
The first use of wire EDM, which is sometimes called wire-cut EDM, occurred in the mid part of the 1960s. This method was used for die making where the workpiece was made of hardened steel.
The CNC machines of today are able to use a variety of different diameters of wires as the tool electrode. The wire is wound on two spools and is constantly cycled through, preventing excessive use of one part of the wire that would result in a break.
As with most EDM applications, wire EDM is particularly effective for the machining of hard metals and alloys that are resistant or difficult to machine using standard types of processes. Most materials that are machined using this technology are hardened steels or metals, but it can also be used for machining of specific types of ceramics.
The process offers the advantage of providing highly precise cutting and contouring of the workplace that will not require additional processing after the machining is completed. This reduces the cost of production and also speeds up production times.
