Your Guide to Electric Discharge Machining

Electrical discharge machining, also known as arc machining or discharge machining, is a discrete manufacturing process where a material is removed from its workpiece using a series of electrical discharges that keep recurring. The process lets the current flow between two electrodes, thus removing the material from the workpiece and creating a particular part dimension. The current flowing is separated using a dielectric liquid.

Today, this process has become an in-demand solution for applications that require extreme precision and accuracy. Owing to its exceptional precision, the process of electrical discharge machining has become a popular method for creating production and prototype parts in various industries like electronics and automobiles. Besides this, EDM is also very effective for crafting medical device parts.

Another range of applications of electrical discharge machining includes small hole drilling. The process uses a separate EDM head mounted on a wire-cut machine and drills small and precise holes in the workpieces. This mechanism is ideal for all the materials that do not perform well with conventional machinings such as single, high-temperature crystal alloys carried out in turbine blades.

Advantages of Electrical Discharge Machining

  • With the use of electrical discharge machining, it is possible to produce complex shapes. These shapes cannot be otherwise machined using traditional machining.
  • Electrical discharge machining is used to manipulate an immensely hard material having tight tolerance.
  • It produces a better surface finish over other methods.
  • There is no contact between the tool and the workpiece. Thus, the part can be machined without any perceivable distortion.

What is the Principle of EDM?

The process of EDM follows a basic principle of spark generation and metal removed by spark erosion. The spark erosion here is similar to electric spark – burning a small hole in the metal it contacts.

The spark generated produces heat, thus removing the metal by erosion and evaporation. The tool and workpiece must be designed with conductive material in the entire process.

How Does EDM Work?

If you want to make the most of electrical discharge machining, ensure that the workpiece is conductive to electricity. No other material can be machined by this method.

  • The process begins by submerging both the workpiece and tool into a dielectric fluid. This fluid helps control the arc discharge. It also removes the work cavity’s suspended particles of workpiece material and tools.
  • After this, a servomechanism is used to maintain a tiny gap between both materials. The gap is necessary for the proper arc formation. The tool is created as the opposite shape of the workpiece.
  • Next, a high-frequency current is supplied to the electrode to produce a spark between the workpiece and the tool. The metal is then removed from the workpiece due to evaporating ions and erosion.
  • All the suspended particles and chips between the workpiece and tools are also removed to prevent the occurrence of a short circuit.
  • The EDM then produces a cavity larger than the electrode due to overcutting.

What is the Importance of the EDM Process?

The scope of this process is increasing manifold in various industries. The electrical discharge machining process is used to make molds. Besides this, it has also become a vital part of creating production and prototype parts.

The application of electrical discharge machines further extends to the fields like electronics, aviation, turbine engines, and aerospace to create precision instruments to work with blades and other hot gas path components parts.


With good electrical discharge machining equipment, cutting and manipulating complex shapes into precise cavities and contour becomes easy. All these factors contribute to the growing popularity and use of this method.

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