The unconventional subtractive manufacturing method known as electrical discharge machining, or EDM for short, is particularly effective at sawing through extremely tough materials.
EDM, as opposed to conventional machining, is capable of cutting through metals without making contact with them. This is accomplished by the production of an electrical spark that eats away at the material of the metal workpiece. Although EDM is not appropriate for all applications, it is an essential tool that every machinist should have in their arsenal.
Sinker EDM and wire EDM are the two most common subtypes of EDM, although there are several other subtypes. This article compares and contrasts two different machining processes, focusing on the kinds of work that are typically done with each technique.
What exactly is meant by the term "electrical discharge machining"?
Manufacturing metal can also include processes such as electrical discharge machining. Traditional machining (in which a metal cutting tool removes sections of a workpiece) is very similar to some aspects of this process, but in other respects, it is very different and very innovative.
EDM stands for electrical discharge machining, and the primary distinction between it and conventional machining is that EDM does not require the tool and the workpiece to make direct physical contact in order to make a cut. EDM, on the other hand, employs the utilization of an electric current in order to generate sparks that are capable of eroding the workpiece. Electrical discharges can penetrate even very hard metals without significant part deformation; however, the types of cuts that are possible are more limited, and the process is more difficult to set up. This has both advantages and disadvantages.
Electrical discharge machining is a process that is used on electrically conductive metals. Due to the nature of the process, it can cut through even very hard metals (hardened steel, tungsten, titanium, etc.) without causing damaging vibrations and chatter like an ordinary machine tool would. Because of this, the level of precision achieved is very high, and the tolerances that can be achieved are potentially very tight. Having said that, the EDM process also causes erosion to the tool, so either the tool needs to be carefully managed or it needs to be replaced on a regular basis.
Despite the fact that each of these three processes operates in a very different manner, electrical discharge machining is typically categorized alongside other nonstandard machining techniques such as water jet cutting and laser cutting.
The EDM procedure broken down and explained
The use of a tool, a dielectric liquid, a workpiece, and an electrical discharge machine are all necessary components for performing electrical discharge machining.
- The process requires an electric voltage, which, when applied between two electrodes, causes a succession of current discharges to take place
- The metal tool and the metal workpiece are the two electrodes in this scenario; however, they do not come into contact with one another because they are kept apart by the dielectric liquid, which is typically either hydrocarbon oil or deionized water
- The spark-gap is the name given to the gap that exists between the tool and the workpiece, and it is precisely controlled by the machine
The voltage is increased by the operator during the EDM process, which causes dielectric break down of the liquid. This means that the liquid abruptly changes from an electrical insulator into an electrical conductor. This abrupt change causes an electric arc to form in the tight space that exists between the tool and the workpiece. This arc erodes material from both electrodes as it travels through the space. The end result should be the workpiece being eroded, but the erosion of the tool itself must be carefully managed. One way to do this is to continually replace the eroded section of the tool with a fresh section of metal. In addition to its role in the production of the electric arc, the dielectric fluid serves other purposes. During the intervals between the current discharges, the fluid transports the chips and other metal debris away from the workpiece, and then it is replaced with fresh fluid. The act of doing this is known as flushing. A variety of electronic dance music styles are used for a variety of purposes. In this article, we will discuss sinker EDM and wire EDM; however, there are other variations, some of which are more specialized, such as fast hole drilling EDM. What is sinker EDM? Sinker electrical discharge machining is a type of electrical discharge machining that might not seem all that similar to conventional machining at first glance. This type of EDM is also known as ram EDM, volume EDM, and cavity EDM, among other names. The process is sometimes referred to simply as die sinking, which is a reflection of its tenuous relationship with the process of machining. This is because the process shares some characteristics with the processes of molding and forming. The tool and the movement that it makes are the primary determinants of the difference between sinker EDM and wire EDM, which is the other primary type of EDM. Sinker electrical discharge machining (EDM) is used to create complex-shaped cavities in the workpiece; in order to accomplish this, the tool used in the process needs to take the form of a positive copy of the cavity that is desired. For example, a tool that is shaped like a pyramid is utilized so that a cavity in the workpiece can be formed to resemble a pyramid. In most machining processes, a fine cutting tool would move along three axes — side to side, back and forth, and downwards — to cut out the pyramid shape (as opposed to being itself pyramid-shaped). This is in contrast to the fact that the shape of the tool itself is pyramid-shaped. Sinker EDM is a process in which the shaped tool, also known as a die, is typically CNC machined from a material such as graphite, copper, or tungsten. This causes the process to take longer and result in higher costs.(It is also possible to make it with wire EDM.)In addition, it is standard procedure to make use of a roughing tool (to get rid of the majority of the material) and then follow that up with a finishing tool (to get the finer details). During the sinker EDM process, the tool is slowly lowered (sunk) into the workpiece, eroding material and creating a cavity that matches the shape of the tool while maintaining a consistent spark-gap as it descends. This allows the tool to create a cavity that precisely matches the shape of the tool. There are hundreds of thousands of sparks that happen every single second. Although other fluids can also be used, hydrocarbon oil is typically what is utilized as the dielectric liquid when utilizing sinker EDM.