Electrical Discharge Machining

EDM can be integrated with other traditional or unconventional manufacturing techniques to produce a more homogeneous and balanced machining setup. The inherent shortcomings of the EDM technique can be overcome by hybrid or mixed approaches to machining. When combined with traditional production processes, additional manufacturing techniques can considerably increase machining performance in EDM.

Working Principle of EDM

Spark creation and metal removal through spark erosion are the foundations of the electrical discharge machining working method. When an electric spark strikes a piece of metal and burns a hole, that is exactly what happens with EDM spark erosion. This process produces heat, which leads to the erosion and evaporation of metal. Therefore, the workpiece and the tool used in this machining process must be constructed of conductive materials.

Components of EDM

Power generator

This is how the EDM machining process is powered. The power generator is linked to the negative terminal, while the machined component is attached to the positive terminal (i.e. the workpiece). Electrical discharge machining uses a variety of power generators, some of which are listed below:

• Resistance-capacitance type generator (RC type) generator of relaxation
• Rotary type generator
• Electrical pulse generator
• EDM hybrid generator

Workpiece

The item to be machined is known as a workpiece. It is attached to the positive terminal of the power supply and fastened in the dielectric container using a fixture.

Fixture

The workpiece is held securely in the dielectric container using the fixture.

Dielectric Medium

The operation of the EDM Machining process depends heavily on the dielectric medium. The dielectric fluid is typically a low-viscosity hydrocarbon oil. The electrode and the workpiece are kept apart by the dielectric. As the spark is created during the EDM machining procedure, the dielectric is ionized to create a column or path in the tool, which causes a surge of current. When the distance between the tool and work gap reaches about 0.03 mm and a voltage of about 7V, the dielectric medium is raptured. The spark discharge will occur in a very small area at a temperature and pressure of about 10,000 °C. Each spark experiences this in a matter of a microsecond. A very small portion of the workpiece vaporizes as the arc is driven out as the column of ionized dielectric vapor compresses. The minuscule metal particles are cooled to form small spheres, which are swept away by the dielectric fluid's flux.

Types of EDM methods

Wire EDM

Wire EDM is a common procedure that is also referred to as wire erosion or spark EDM. The workpiece is sliced with a brass wire or a thin copper wire. The electrode, in this instance, is a tiny wire. In this instance, deionized water typically serves as the dielectric fluid. The wire is continuously unfurled from an automatic feed using a spool during the procedure. This is due to the possibility that the wire and workpiece could compromise the electrical discharge. A new discharge path is therefore required in the cut. This strategy performs admirably. Engineers must take care that the wire must entirely passes through the workpiece. In essence, it, therefore, makes two-dimensional cuts in three-dimensional components.

Sinker EDM

This procedure creates a positive of the desired shape using electrodes made of pre-machined copper or graphite. Next, the electrode is pressed into the workpiece to make a negative of the original material shape. Several variables may influence the choice of electrode material in sinker EDM. These include the electrode's resistance to erosive wear and its conductivity, with copper material often more difficult to process than graphite. However, copper is better and more robust.

Hole EDM

In contrast to standard drilling methods, hole Electrical Distribution Machining may produce exceedingly tiny and deep holes. Furthermore, these holes don't require deburring. Regardless of the nature or hardness of the metal, this approach drills precise holes more quickly than conventional techniques.

Applications of EDM

• Machining
• Injection molding
• Die casting
• Small hole drilling

Advantages of EDM

• Any hard material, even one that has been heat-treated, can be machined with EDM.
• The tool can be used to create intricate shapes that can be duplicated.
• A great degree of accuracy, roughly 0.005 mm, can be attained.
• Up to 0.2 microns of good surface quality can be attained economically.
• The length of the machining process is the same as that of traditional machining.
• This method does not create mechanical tensions (the tool and work do not have contact).
• Proper cooling and lubrication extend the tool’s life.
• On the dies, it is simple to create hard surfaces that are also resistant to erosion.
• Any electrically conductive material can use it.

Choosing the Correct Electrical Discharge Machining Company

For the most productive outcome when selecting an electrical discharge machining company, it is important to compare several businesses using our directory of electrical discharge machining companies. Each company has a business profile page highlighting their areas of experience and capabilities, along with a contact form to directly communicate with them for more information or request a quote. Review each electrical discharge machining company website using our proprietary website previewer to get an idea of what each company specializes in. Then, use our simple RFQ form to contact multiple companies with the same form.