Electrical Discharge Machining Working, 10 Parts, Advantage, Application [PDF]

Electrical Discharge Machining is also known as Spark machining, spark eroding, burning, die sinking, wire burning, or wire erosion. This is a manufacturing operation in which we used to make desired shapes by using an electrical spark. This spark temperature is nearly about 8000 to 12000º C.

Electro Discharge Machining
Photo By NezzerX

What is Electrical Discharge Machining

Electrical Discharge machining is the process of metal removal from the work surface due to an erosion of metal caused by electric spark discharge between the two electrodes tool (cathode) and the work (Anode).

Electrical Discharge Machining or EDM process
Photo By Dreamstime

Parts of Electrical Discharge Machining

An Electro Discharge Machine consists of the following parts

  • DC pulse Generator
  • Voltmeter
  • Ammeter
  • Tool
  • Die electric fluid
  • Pump 
  • Filter
  • Servo Controlled Feed
  • Fixtures 
  • Table
Photo By Dreamstime

DC Pulse Generator

Voltmeter

  • The voltmeter measures the voltage.

Ammeter

  • It measures the flow of the current. If Ammeter is not connected we might not see or check current is flowing or not.

Tool

  • A tool is connected to the negative terminal of power whereas the workpiece is connected to the positive terminal. from the filter, the fluid comes to the tool for the operation.
  • When Power supply will increase, between tools workpiece the spark generates and then machining starts.

Die electric fluid

It possesses the property of insulation which means no current flows from one point to another. The Die electric fluid will be ionized in the form of an ion which will help between the tool and workpiece again when the power supply stops the fluid comes to its initial position.

Pump

  • The pump is connected there for sending the fluid to the filter.
  • This works like flowing the fluid from one source to another one.

Filter

  • As the name indicates the filter, is used to filtrate the different particles In this device, if there are dust particles present the filter will remove that particle and then it will send it to the tool for operation.

Servo controlled feed

  • The constant feed will be supplied by the servo for the operation.

Fixture

  • To hold the table.

Table

  • To hold the workpiece. 

Working Principle of Electrical Discharge Machining

It consists of an electric power supply, the dielectric medium, the tool, the workpiece, and the servo control. The workpiece is connected to the positive terminal and the tool is connected to the negative terminal of the DC power supply. An air gap of 0.005 to 0.05 mm is maintained between the tool and the work. The die electric fluid which is a non-conductor of electricity is forced under pressure through the gap. When DC power is supplied, the fluid in the gap gets ionized and produces a spark between the tool and workpiece, causing a local rise in temperature at about 1000 degrees Celsius, when melts the metal in a small area of the workpiece and vaporizes.

Electrical Discharge Machining Working or
Electrical Discharge Machining Diagram
Photo by By EngineeringClicks

The DC supply generates a pulse between 40 to 3000 V and the frequency of spark at the rate of 10000 sparks per second can be achieved. The electric and magnetic fields on heated metal cause a compressive force that removes the metal from the work surface. The die electric fluid acts as a coolant to carry the cooled metal from the work surface. The die electric fluid acts as a coolant and carries the eroded metal particles which are filtered regularly and supplied back to the tank. A servo mechanism is used to feed the tool and continues to maintain a constant gap between two electrodes. An accuracy of about 0.005 mm can be achieved in this process.

How electric machining discharge works

Video by ADTWlearn

Types of EDM Machines

Electrical Discharge Machining (EDM) is a non-traditional manufacturing process that involves the use of electrical energy to shape and form metallic parts. This process is widely used in the manufacturing industry for creating complex and intricate shapes that are difficult or impossible to achieve with conventional machining techniques. There are four main types of EDM which are as follows

  • Conventional EDM
  • Wire EDM.
  • Hole EDM
  • Sinker EDM

Conventional EDM

Conventional EDM, also known as Ram EDM, employs a metallic electrode that is shaped to the desired form of the workpiece. The electrode is then brought into contact with the workpiece, and a high voltage is applied to create a spark discharge. This spark discharge melts away small portions of the workpiece, resulting in the desired shape.

Conventional Electrical Discharge Machining or conventional EDM
Photo By Dreamstime (Conventional EDM)
Capabilities and applications of Conventional EDM Machines
  • Suitable for making dies and molds
  • Useful for small-batch production and prototyping
  • Can accurately produce complex engine parts
  • Widely used in industries such as automotive and aerospace
  • Mostly used for injection molding processes in a variety of industries.

Wire EDM

Wire EDM, on the other hand, uses a thin wire as the electrode that is fed through the workpiece. The wire is charged with a high voltage, and as it moves through the workpiece, it creates a series of spark discharges. This process is highly precise and is often used for creating intricate shapes and small parts.

Wire Electrical Discharge Machining or Wire EDM
Photo By Dreamstime (Wire EDM)
Capabilities and Applications of Wire EDM Machines
  • Ease of production
  • Speed
  • Low maintenance

Hole EDM

Hole Electrical Discharge Machining (EDM) is a type of EDM that is used to create small holes in hard and conductive materials. In this process, a hollow tube made of brass or copper is used as an electrode. The electrode is advanced towards the workpiece while a dielectric fluid is pumped through the tube to flush away the eroded material. This type of EDM is commonly used to make cooling holes in turbine blades, fuel injector nozzles, and small holes in electronic components.

Hole Electrical Discharge Machining or Hole EDM
Photo By Dreamstime (Hole EDM)
Capabilities and applications of Hole EDM

Capabilities

  • Can produce holes with a high aspect ratio, which means that the depth of the hole is much greater than its diameter.
  • Can create holes with a diameter as small as 0.02mm.
  • Can create holes in complex shapes and angles.
  • Can be used to drill holes in any conductive material.

Applications

  • Used in aerospace and aviation industries to create cooling holes in turbine blades and nozzle guide vanes.
  • Used in the automotive industry to drill fuel injector nozzles.
  • Used in the medical industry to create holes in surgical tools and dental instruments.
  • Used in the electronics industry to drill small holes in circuit boards and semiconductor components.
  • Used in the jewelry industry to create holes in precious metals.

Sinker EDM

Sinker EDM, also known as conventional EDM or die sinking, is a type of EDM machine that uses shaped electrodes to create intricate shapes in workpieces. The machine submerges the electrode and workpiece in a dielectric fluid, and then an electrical discharge between the two creates the desired shape. Sinker EDM is particularly useful for creating dies and molds, and it can accurately produce complex engine parts in the automotive and aerospace industries. Its applications are vast and it is often used for small-batch production or the production of prototypes.

Sinker Electrical Discharge Machining or Sinker EDM
Photo By Dreamstime (Sinker EDM)
Capabilities and applications of Sinker EDM
  • Uses shaped electrodes for intricate shapes
  • Suitable for creating dies and molds
  • Accurately produces complex engine parts
  • Used in the automotive and aerospace industries
  • Often used for small-batch production or prototyping.

Applications of Electrical Discharge Machining (EDM)

  • Drilling for micro holes in the nozzle.
  • Used in thread cutting.
  • Used in wire cutting.
  • Rotary form cutting.
  • Helical profile milling.
  • Curved hole drilling.
  • Engraving operation on harder materials.
  • Cutting off operation.
  • The shaping of alloy steel and tungsten carbide dies.
Application of EDM or Applications of Electrical Discharge Machining
Photo By Deposit Photos

Advantages of Electrical Discharge Machining (EDM)

  • It can be used for any hard material and even in the heat treatment condition.
  • Any complicated shapes made on the tool can be reproduced.
  • High accuracy of about 0.005 mm can be achieved.
  • Good surface finish can be achieved economically up to 0.2 microns.
  • Machining time is less than the conventional machining process.
  • No mechanical stresses are developed in this process (There is no contact between tool and work)
  • Higher tool life due to proper lubrication and cooling.
  • Hard and erosion resistant surface on the dies can be developed easily.
  • It can be applied to any electrically conductive materials.
Electrical Discharge Machining
Photo by Wevolver

Disadvantages of Electrical Discharge Machining (EDM)

  • Excessive tool wear.
  • High power consumption.
  • The sharp corner cannot be reproduced.
  • High heat developing causing the change in metallurgical properties of materials.
  • The workpiece must be an electrical conductor.
  • Surface cracking may take place in some materials.
  • Redressing of a tool is required for deep holes.
  • Over-cut is formed.
  • Difficult finding expert machinists.

FAQ

What Are The Applications Of Electrical Discharge Machining (EDM)
  • Drilling for micro holes in the nozzle.
  • This is used in thread cutting.
  • Used in wire cutting.
  • Rotary form cutting.
  • Helical profile milling.
What is Electrical Discharge Machining (EDM)

Electrical Discharge machining is the process of metal removal from the work surface due to an erosion of metal caused by electric spark discharge between the two electrodes tool (cathode) and the work (Anode).

Name some Electrical Discharge Machining product

The different EDM machines in the market are as following

  • Sodick AQ327L Wire EDM
  • Mitsubishi EA12V Advance EDM
  • GF Machining Solutions FORM P 350 Die-Sinking EDM
  • Makino U6 H.E.A.T. Extreme Wire EDM
  • Fanuc Robocut C800iB Wire EDM
What is the cost of Electrical Discharge Machining (EDM)

According to various machining service providers and research web sources, the cost of EDM can range from $50 to $200 per hour for simple to moderately complex parts. For more complex parts that require specialized programming and setup, the cost can be higher, ranging from $200 to $500 per hour. Additionally, the cost of materials and other factors such as location and machine type can also impact the overall cost of the EDM process. It is recommended to obtain a quote from a machining service provider for a more accurate estimate based on specific project requirements

What does an EDM machine do?
  • This is a manufacturing operation in which we used to make desired shapes by using an electrical spark.
  • An EDM machine utilizes electrical discharge to shape and cut through tough materials.
  • This is achieved by creating sparks between the workpiece and electrode to remove material from the surface.
  • The machine operates on the principle of erosion and melting, resulting in highly accurate and detailed cuts.
  • EDM machines are commonly used to work with materials that are difficult to machine using traditional methods, such as metals with high melting points.
  • These machines are often utilized in industries like aerospace, automotive, and electronics to produce various parts and components.
Describe wire Electrical Discharge Machining process

Wire Electrical Discharge Machining (EDM) is a subtractive manufacturing process that utilizes an energized wire electrode to remove material from a workpiece. The wire electrode is fed continuously through the workpiece, creating an electrical discharge between itself and the workpiece. This discharge erodes the material and creates a cut.

CNC-controlled rollers guide the wire electrode, allowing for precise cuts to be made. Wire EDM is particularly useful for machining complex shapes and hard materials that are difficult to cut with traditional methods. It is commonly used in the aerospace, medical, and automotive industries.

Electrical Discharge Machining Price
Photo By Dreamstime

Conclusion

In conclusion, electrical discharge machining (EDM) is a non-traditional machining process that utilizes electrical sparks to remove material from a workpiece. EDM is commonly used in industries that require high precision and intricate shapes in hard materials. The EDM machine comprises various parts, including a power supply, electrode, dielectric fluid, and workpiece.

The advantages of EDM include high accuracy, the ability to work with hard materials, and no direct contact between the tool and the workpiece. However, it also has some disadvantages, such as a slow material removal rate and high operating costs. Overall, EDM is a valuable tool for certain industries and applications, and understanding its working, parts, advantages, and disadvantages is crucial for its proper utilization.

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