Electrical Discharge Machining (EDM) is a process that removes material in a precise manner from conductive materials with an electrode. This electrode leaves in the workpiece a negative imprint. The process is a bit more intricate: in a tiny gap between the electrode and workpiece, a discharge happens that removes the material via vaporizing or melting. For this process, both the electrode and workpiece are submerged in dielectric fluid.
The amount of material removed using a spark is relatively small, yet a discharge occurs just about 100,000 times per second. It causes strong material’s heating, melting it away in small amounts. The excess material is eliminated with the dielectric fluid’s steady flow. The liquid is useful also for cooling, during the process of machining. Furthermore, it is required to control the sparks.
There are three types of electrical discharge machining processes. It is possible to do many different processes with EDM, comprising milling, turning, small hole drilling, and grinding. The process briefed above is known as sinker EDM. It allows the production of intricate shapes. It necessitates electrodes (often produced from copper or graphite) pre-machined for having the required shape. Then, this electrode is sunk to the workpiece, making a negative version of the original shape of it.
The second type is called wire EDM. It uses a thin wire for cutting the workpiece. This wire used in the process serves as the electrode. During machining, it is coming constantly from this automated feed with the spool. If the cut should be made in the center rather the workpiece’s outside, the small hole drilling process is used to create a hole in it through which this wire is later threaded. The wire, often made from copper or brass, is held using diamond guides. The liquid is usually deionized water.
The third type is known as hole drilling EDM. It is used to drill holes, as the name implies. As opposed to traditional methods, it possible to machine very small as well as deep holes in the EDM process. In addition, the drilled holes do not require any deburring. In this process, the electrodes are tubular, and the dielectric fluid used in it is fed through an electrode.
Generally, conductive materials can be machined using electrical discharge machining. The common materials comprise metal alloys or metals like solidified steel, titanium, as well as composites.
Usually, the electrodes are made of graphite or copper for die sinking EDM. The main factors influencing the decision for electrode’s material are its conductivity and resistance to erosion. The benefit of graphite is that it is more easy to machine in relation to copper. However, the copper material is highly conductive as well as strong. Brass, which is an alloy of copper and zinc, is frequently used for wire EDM or tubular electrodes that are small.
In contrast to electrodes for the die sinking process, the wire used for the wire EDM process does not have to provide good resistance characteristics, since the new wire is constantly fed during the cutting. Relying on EDM makes sense in some cases than others. These things have to be considered prior to settling on it.
Key Benefits of Electrical Discharge Machining
The main benefit of EDM is it can be used upon any conductive material. Therefore, it is possible to machine a workpiece made from titanium or tungsten carbide that is tough to machine using 
traditional cutting methods. Another benefit of EDM is the lack of sheer mechanical force put to the workpiece. A fragile outline is easier to make since there is no need for high cutting force to remove the material.
The process also allows for both shapes and depths, which are not possible to be arrived at using a cutting tool. Particularly deep processing, where the tool length to the diameter ratio would be extremely high, is a common application for it. Sharp internal corners, narrow slots, and deep ribs are three other specialties of EDM. Another argument for relying on it is the surface finish quality is typically better than with other traditional methods. EDM produces a surface with high precision and a fine finish.
Furthermore, the EDM process allows machining hardened workpieces. While other machining methods have to be performed before their workpiece is solidified using heat treatment, EDM can also be applied upon the hardened materials. Therefore, any potential deformation of it from the heat treatment machining process can be avoided.
There are several examples of businesses who managed to put EDM to use for their benefit. An update to an even newer, more modern EDM equipment has done the trick in many cases.
Combined with CNC, EDM has become a reliable and accurate machining technique, which is now a standard among more traditional cutting methods. In addition to die and mold making, it is usually applied in the aerospace and automotive industry; for instance, in the making of aircraft engines.
Pacific Die Casting uses EDM often to make molds and dies for die casting. It is well-suited especially for cutting ribs as well as other details that would otherwise be tough to make using a mill or standard cutting tools.
EDM or Electrical discharge machining is frequently used at Pacific Die Casting Corp. to make dies and molds for die casting. EDM, is especially well-suited for cutting thin ribs and other details that would be difficult to produce with a mill or other cutting tools. Often times with lighting die casting molds or die cast roof tile molds, intricate cuts are required. A graphite electrode must then be shaped and aligned in an EDM machine to produce the desired feature.
EDM is sometimes called “spark machining” because it removes metal by producing a rapid series of repetitive electrical discharges. These electrical discharges are passed between an electrode and the piece of metal being machined. The small amount of material that is removed from the work piece is flushed away with a continuously flowing dialectic fluid. The repetitive discharges create a set of successively deeper craters in the workpiece until the final shape is produced.
3D Printing
If you feel you need a physical 3D prototype before beginning the mold fabrication, Pacific Die Casting’s new Rapid Prototyping System can quickly turn computer design data into a 3D prototype. Here is how it can help:
- 3D physical prototype
- Communicate and evaluate design concepts more efficiently
- Collaborate with partners and vendors more effectively