Electrical Discharge Machining: Construction, Application, Pros and Cons

To further elaborate on the working principle, below is a breakdown of the basic construction of an electrical discharge machining (EDM) system.

1.   DC Pulse Generator

This component converts the AC power supply to a pulsating DC supply high enough to generate a spark between the eroding tool and the work part.

2.   Electrode Tool

This part of the system is connected to the cathode of the power supply while being mounted on a tool post. The profile of your tool will be the exact same profile left on your work part. During the process, a very tiny gap called the arc gap (identified by manufacturing engineers) is maintained between the electrode tool and the work part. The most common materials used for electrodes are Copper, Tungsten alloy, graphite, steel, and cast iron.

3.   Servo Motor Mechanism

This mechanism controls the feed and movement of the tool in the EDM machine. The arc gap, previously mentioned above, is critically controlled by a programmed servo motor mechanism.

4.   Spark generator

This component supplies the right amount of voltage needed for spark generation and discharge maintenance. The generation of one hundred thousand sparks per second makes it possible to create a significant subtraction of material from the work part.

5.   Di-electric fluid

Both the electrode tool and the work part are submerged in a dielectric fluid while having the fluid supplied at the gap between the tool and the work part. Moreover, the dielectric fluid should be set to circulate at a constant pressure to flash away metal parts that have eroded from the work part. Too much fluid pressure may cause the metal chips to be removed quickly resulting in a slower cutting action. Too weak fluid pressure might cause a short circuit in the system due to the unevacuated chips during the erosion process.

The most common dielectric fluids used in this process are deionized water, glycol, and silicone oil.

6.   Workpiece

This completes the EDM machine ecosystem because the work part is connected to the anode. To make the process possible, the work part should be a good electric conductor.