What’s Electrical Discharge Machining (EDM)?
Electrical discharge machining (EDM) is a type of machining operation employed for shaping conductive workpieces into geometrically complex parts. Electrical discharge machines are particularly ideal for machining components which have complicated contours or subtle cavities that might be hard to produce with other conventional machining equipment. The procedure involves supplying electricity to both shaping tool along with the workpiece and then bringing the tool into closeness with the workpiece, that is completely immersed in a dielectric fluid bath. This proximity causes the electrical field intensity between the oral appliance workpiece to beat the effectiveness of the dielectric fluid, and creates a number of electrical discharges together. These electrical discharges remove material in the workpiece, and also the pattern or shape of material removed relies upon the shape from the tooling electrode. After the machining operation, the dielectric fluid is replaced between the electrodes. Aside from serving as a dielectric between the two 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 such that, while materials are being removed from the workpiece; the tooling electrode can also be gradually eroded, making periodic replacement necessary.
The electrical discharge machining process is extremely precise and usually used in the production of components which are typically complex and require extreme accuracy. Additionally, another area 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, as well as hardened steel. However, the only real caveat with the electrical discharge machining process is that it could be only be used with conductive materials.
There are essentially two kinds of electrical discharge machines, which differ within the kind of tooling electrode that they’re outfitted with. They’re sinker EDMs and wire EDMs. The sinker EDM, also known as a ram EDM uses a shaped tooling electrode to facilitate the machining process. This tooling electrode is created by conventional machining right into a shape that is specific to the application it is employed for as well as an exact reverse of the shape to be machined into the workpiece. The tooling, typically machined from graphite, is used with an insulating fluid such as 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 Machine is typically used for precise machining of complex 3D parts, such as injection molding, die tooling, along with other components that require exceptional accuracy.
The wire EDM, however, is definitely an electrical discharge machine that uses an excellent metallic wire, usually made from brass, which acts as a cutting electrode to accurately shape intricate, complex components from thick metal plates. The wire and workpiece are generally supplied with electricity so when the wire approaches the workpiece, electrical discharges occur together. These discharges remove material from the workpiece in a shape that is similar to a cutting or slicing action. Because the wire electrode is eroding along with the workpiece, it’s continuously fed into the workpiece from a spool to make sure 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 are CNC controlled for cutting. The cutting operation occurs on a workpiece that is completely immersed inside a dielectric fluid bath, normally de-ionized water, which is used like a coolant and also to eliminate the removed material. This machining process is used to chop complex and complicated 2D shapes on thick metal parts, especially aspects of 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 arrival of upper guides and multi-axis freedom of movement in the newer wire EDMs, allows these machines to chop intricate tapers and transitional shapes too.