What is Electrical Discharge Machining: Definition, Types & Uses
EDM is a machining method that utilizes a pulsed electrical discharge to etch conductive materials to obtain certain shapes and sizes. It is an innovative method that differs from traditional cutting and shearing techniques. The process is versatile and contains a lot to understand.
In this article, we will take an in-depth look at the definition of EDM, its historical development, exactly how it works, the main types of EDM machining, its advantages and disadvantages, which materials are suitable for EDM machining technology, as well as the specific applications of EDM machining and the adjustments it faces, so let's read on!
What is the Electrical Discharge Machining?
EDM also known as Electrical Discharge Machining, is a process in which controlled sparks of electricity are used for shaping the materials with precision. That is to say, is the workpiece and tool electrode (copper male) as two electrodes immersed in the working fluid, and put between the two poles in line with a certain impulse voltage, when the distance between the two poles is small to a certain extent, between the poles of the working fluid medium will be pierced, resulting in a spark discharge.
It allows the machining of components which are electrically conductive irrespective of their hardness. This process helps to create intricate geometries for the components, which cannot be achieved through traditional machining methods.
The History of EDM Machining
EDM originated in the 1940s and developed from the idea of preventing the corrosion of tungsten electrical contacts. The discovery of these techniques led to their use in modern manufacturing processes. As time passed on, EDM became an embraced option in the medical, aerospace and tooling industry.
The wire EDM was developed to create complex shapes and detailed cavities, and now EDM has expanded to endless capabilities, helping to achieve excellent craftsmanship.
How Electrical Discharge Machining Works?
The process of manufacturing components through EDM consists of using a soft graphite electrode, which ignites a spark between the target region and the electrode. The temperature of the spark varies between 14500 to 21500 Fahrenheit and leads to the vaporization of the target region.
Once the vaporization takes place, the dielectric fluid takes the vaporized part away from the workpiece region, which is already machined. The process is repeated till the desired cut and precision is attained. EDM has the ability to machine materials that are good conductors of electricity.
Types of EDM
There are different types of EDM processes, and they are discussed below.
Wire-Cut Electrical Discharge Machining
Wire-cut EDM is known for its ability to create highly precise components with detailed cuts. The process uses a thin wire that is electrically charged and made of copper or brass. The wire is fed through the component, repeatedly following the path of the program, and slices the material. It has the ability to cut the toughest material with excellent precision.
This method is suitable for creating detailed shapes with contours. Hence, it is used mostly to create dies, punches, and tools. Moreover, the method manufactures components with tight tolerance and is suitable for the aerospace industry.
Sinker Discharge Machining(Die-Sink EDM)
Sinker Discharge Machining is the process in which the component and electrode are both submerged in the dielectric fluid. The electrodes present in the sinker EDM can be customized in terms of shape to create the required cavity in the component.
The process is beneficial for complex geometrical shapes like molds and tools, which require intricate cavities. The electrode movement can be controlled by using the right materials for electrodes, which are composed of copper and graphite.
The sinker EDM consists of involving electrical discharges in the form of a series between the workpiece and electrodes. This process can create undercuts and cavities, which are not possible to attain through other methods. The versatility of this method makes it possible to deal with various industries to create challenging components.
Hole Drilling Electric Discharge Machining
Hole drilling EDM is a technique designed to create holes which are deep and accurate in a material which is electrically conductive. The process consists of creating quick holes with precision in sensitive applications. This method has made the process of creating precise holes simpler and faster.
The electrode consists of a copper or graphite material and the electrode goes further into the workpiece while removing the material. Unlike conventional drilling processes, the EDM drilling process can produce small, deep holes.
Advantages of EDM
The advantages of the EDM process are as follows:
Complex Shapes: EDM has the ability to manufacture complex shapes that have sharp internal corners and contours.
No Deformation of the Workpiece: EDM minimizes tool wear; cutting is done by EDM, there is no physical contact between the workpiece and the tool, and no machining distortion occurs
High Precision: EDM offers high accuracy and precision, which is important for sensitive applications.
Suitable for Machining Hard Materials: It can help shape and cut hard materials, which cannot be done through other machining methods like titanium, tungsten carbide or hardened steel.
Perfect Surface: EDM offers an excellent surface finish. Does not leave any burrs or marks on the surface of the workpiece.
Disadvantages of EDM
The disadvantages of EDM comprise the following:
Conductive Material: EDM works with materials that are only electrically conductive and have a limitation in the application range.
Slow Machining Speed: When compared to traditional machining methods, it is slow when working with hard materials.
High Cost: EDM has a high maintenance cost, as well as equipment and electrical consumption.
Environmental Impact: Dielectric fluids require careful disposal and handling and, hence, pose environmental hazards.
What Materials Can Be Machined by EDM?
The different materials that can be machined by EDM are as follows:
- Steel: Steel is hard and tough and is often used to make molds.
- Aluminum: It is a strong yet lightweight material opted for lightweight parts.
- Brass: Brass is a copper alloy that can be easily manufactured through EDM.
- Copper: Copper has excellent electrical conductivity and excellent machinability, making it suitable for machining complex shaped parts.
- Tungsten Carbide: It is a highly wear-resistant and hard material; hence, EDM can work perfectly on it.
- Titanium: Titanium is a resistant and strength-oriented material, which makes it suitable for industries like aerospace.
When To Use EDM
EDM is used with a wide range of applications, and some of these comprise the following:
Aerospace: Components that comprise engine parts and turbine blades have complex shapes and undercuts that are used in the aerospace industry and are manufactured using EDM.
Medical: In the medical industry, EDM helps manufacture prosthetics, implants and surgical instruments.
Automobile: EDM creates, dies and molds for the components of vehicles.
Tool and Die Making: EDM is opted in the tool-making industry for manufacturing customized stamps, molds and dies.
Electronics: The electronic sector requires precise connectors and semiconductor components, and EDM technology is able to meet the tiny size requirements.
Challenges Associated With EDM Technology
The EDM technology has some challenges associated, which are as follows:
- The setup required by EDM is precise and takes a lot of time; it even requires expert technicians to operate the process and achieve accuracy.
- Due to the high-temperature sparks, the risk of thermal damage to the component is prevalent.
- The electrodes used in the process are usually customized and add to the cost.
- When it comes to very deep cuts, it gets difficult to maintain accuracy, and hence, issues like inefficient flushing and selection of electrodes persist.
What is the Difference Between CNC and EDM?
A comparison of the differences between CNC machining and EDM machining is as follows:
Machining Principle: CNC machining cuts through computer-controlled mechanical tools, while EDM machining utilizes electric sparks to remove material.
Applicable Materials: CNC machining is suitable for a wide range of metallic and non-metallic materials, while EDM machining is suitable for metals with higher hardness (e.g. steel, tungsten alloys) and materials that are difficult to machine.
Precision and Surface: EDM machining can achieve better precision and surface finish, especially suitable for complex shape.
Machining Speed: CNC machining speed is fast and suitable for mass production, while EDM is relatively slow in deep hole or complex shape machining.
Cost: CNC is suitable for mass production, the unit cost is relatively low; EDM is suitable for small quantities, complex shape parts production, the unit cost is relatively high.
Conclusion
The process of EDM has made it very easy to manufacture highly complex components with fine details in a very accurate way. However, if you want to have hands-on experience with such custom components for your application that are exceptionally accurate, you can get in touch with us at DEK. We provide high-quality components manufactured through EDM.
DEK focuses on precision wire cut EDM, offering machining services for high precision, accuracy, and complex parts. Our sinker EDM, wire cut EDM, and small hole drilling EDM services are perfect for achieving tight tolerances, complex shapes, small inner radii, and machining extremely hard conductive materials that are challenging to work with.
FAQs
What Are the Key Components of an EDM System?
The key components in the EDM system consisted of an electrode, dielectric system, feeding system for electricity, pulsed supply of power and components.
What Are the Technological Parameters in EDM?
The technological parameters in EDM are pulse on time, discharge current, pulse off time, voltage, and flushing pressure.
Is Electrical Discharge Machining expensive?
EDM machining requires a high initial investment, has a high cost of operation and also requires maintenance. However, the quality of components is exceptional, so some applications may find it expensive and some may not.
How is EDM Different From Other Machining Processes?
EDM doesn't make direct contact with the workpiece which helps to control the tool wear compared to other machining processes.
