What is Electrical Discharge Machining (EDM)?


Electrical discharge machining (EDM) is a kind of machining operation used for shaping conductive workpieces into geometrically complex parts. Electrical discharge machines are particularly well suited for machining components that have complicated contours or subtle cavities that might be difficult to produce with other conventional machining equipment. The procedure involves supplying electricity to both the shaping tool along with the workpiece after which bringing the tool into closeness using the workpiece, that is completely immersed in a dielectric fluid bath. This proximity causes the electrical field intensity between your oral appliance workpiece to beat the strength of the dielectric fluid, and creates a number of electrical discharges between them. These electrical discharges remove material in the workpiece, and also the pattern or form of material removed relies upon the form of the tooling electrode. After the machining operation, the dielectric fluid is replaced between the electrodes. Apart from serving as a dielectric backward and forward electrodes, the fluid also plays a vital role within the machining process, as it is accustomed to eliminate the removed material and cool the machined area. The character of the process is really that, while materials are being taken off the workpiece; the tooling electrode is also gradually eroded, making periodic replacement necessary.

The electrical discharge machining process is incredibly precise and generally utilized in producing components which are typically complex and need extreme accuracy. In addition, another section of application that EDMs perform above par is incorporated in the machining and shaping of hard or exotic materials such as titanium, Hastelloy, Kovar, Inconel, in addition to hardened steel. However, the only caveat with the electrical discharge machining process is that it could be only be used with conductive materials.

You will find essentially two types of electrical discharge machines, which differ in the kind of tooling electrode that they’re outfitted with. They are sinker EDMs and wire EDMs. The sinker EDM, also referred to as a ram EDM utilizes a shaped tooling electrode to facilitate the machining process. This tooling electrode is formed by conventional machining right into a shape that’s specific towards the application it’s used for and an exact reverse from the shape to be machined into the workpiece. The tooling, typically machined from graphite, can be used with an insulating fluid for example oil or any other dielectric fluids. This shaped tooling is connected to a power supply and made to approach the workpiece electrode, creating electrical discharges between them, which cause erosion in the desired shape. This type of EDM is usually used for precise machining of complex 3D parts, for example injection molding, die tooling, and other components that require exceptional accuracy.

The wire Taiwan EDM, on the other hand, is an electrical discharge machine that utilizes a fine metallic wire, usually made from brass, which provides a cutting electrode to accurately shape intricate, complex components from thick metal plates. The wire and workpiece are both provided with electricity and when the wire approaches the workpiece, electrical discharges occur between them. These discharges remove material in the workpiece inside a shape that is similar to a cutting or slicing action. As the wire electrode is eroding combined with the workpiece, it is continuously fed into the workpiece from a spool to ensure uninterrupted cutting operation. The wire is fed through two guides, typically made from diamonds, each placed above and underneath the workpiece electrode. These guides are movable on the 2-axis x-y plane and therefore are CNC controlled for cutting. The cutting operation occurs on a workpiece that’s completely immersed inside a dielectric fluid bath, normally de-ionized water, which is often used like a coolant and to flush away the removed material. This machining process is used to cut complex and complicated 2D shapes on thick metal parts, especially components from hard and exotic metals for example Inconel and titanium. Some components commonly machined using wire EDMs are stripper plates, custom gears, along with other parts that should be intricately cut out. However, the advent of upper guides and multi-axis freedom of motion within the newer wire EDMs, allows they to chop intricate tapers and transitional shapes as well.

EDM - Conoptica