EDM Machining Explained: Construction, Principles, and Modern CNC Integration

Electrical Discharge Machining (EDM) is a material removal or fabrication technology. It was first introduced by Joseph Priestly in 1770. However, with the modernization of technology and equipment, the technique is now integrated with computer numerical control (CNC). The modern EDM machines are integrated with automated CNC operations and are used for metal cutting, material removal, etc. EDM machining has gotten immense popularity in the CNC machining operations and other production activities. Despite its popularity, this technology is yet not understood by many. This is why this post discusses the electrical discharge machining (EDM), the construction of EDM setup, and the working principle of the EDM.

An Overview of Electrical Discharge Machining (EDM)

Electrical discharge machining (EDM) is a process of removing material by exposing it to reoccurring controlled electric discharge. It works on the thermo-electrical phenomenon. As the electric discharge takes place between an electrode/wire and workpiece, the thermal energy is generated on a workpiece. This leads to the removal of a material layer. Generally, there are three types of EDM machines: Die-sink EDM; Small Fast Hole EDM and wire-cut EDM. However, in modern production processes, wire-cut EDM machines are integrated with CNC. Therefore, automated, EDM machines are commonly utilized in the industry.

Let us discuss the construction and working principle of EDM Machining

Construction of EDM Machining Setup

The EDM machining setup consists of the following components.

• Dielectric Reservoir and Circulation System:

  This is the bottom-most component of the EDM machine setup. It stores dielectric media such as deionized water. A pumping system is installed to circulate the dielectric medium from the reservoir to the electrode.

• Control Unit and Power Generator:

  The control unit is integrated with the CNC program and operating unit, which controls the flow of dielectric as per the material cutting requirements.

• Tool Post and EDM Electrode Tool:

  Further, the EDM electrode or wire is mounted on a tool post as the wire itself acts as a tool in EDM machining. Other than these components, the servo systems may also be added to the control mechanism. It helps in maintaining a necessary gap between the EDM wire and the workpiece.

Working Principle of EDM Machine

The following steps are performed during EDM machining. These steps sum up the working principle of EDM machine.

• The EDM electrode and the workpiece are mounted. A small gap of a calculated distance is kept between the electrode tip and workpiece. This is done using the servo mechanism.

• The supply of dielectric is turned on to immerse the workpiece in deionized water. Then the supply is turned off.

• By giving command through the power generation and control unit, a potential difference is generated between the workpiece and electrode. As the electrode generates an electric spark, high thermal energy is generated which leads to the melting and vaporization of metal.

• Although the electric spark generated by the electrode is not continuous, it breaks as the layer of dielectric flushes out. The immersion of the workpiece, generation of potential difference, and electric spark repeats in short periodic cycles and keeps removing the layer of material until the required amount of material is cut. Since the control unit of the EDM machines is integrated with CNC automation, the scope of application of this technique has increased in precision machining.

Applications of EDM Machining

The common applications of EDM machining are listed below.

• Mold and die making
• Prototype manufacturing
• Micro-drilling
• Components disintegration

Since EDM machining is used for intricate machining operations, it is essential to source EDM CNC machining from reliable service providers like BDE, Inc. The company is a long-term service provider for precision CNC machining. EDM machining is one of the precision CNC machining services you can source from them. The quality of their services has been well-reputed and certified with ISO 9001:2015 standards.