Hello friends, Today we will cover all aspects related to the electrical discharge machining process like definition, parts, working procedure, application, advantages, disadvantages, etc.
This machining process uses an electric spark to cut the metal.
The spark generated by this process produces heat, which removes the metal by erosion and evaporation.
This process takes place in dielectric fluid. In this non-traditional machining process, both the workpiece and the tool are made of conductive material.
So without wasting time let's get started.
What is Electrical Discharge Machining Process?
The electrical discharge machining process works on the basic principle of spark generation and metal removed by spark erosion.
The spark generated by this process produces heat, which removes metal by erosion and evaporation. In this machining process, both the workpiece and tool must be made with conductive material.
This machining process is also known as the electric discharge machining process, spark machining process, spark eroding process, die sinking process, wire burning, or wire erosion process.
Principle of Electric Discharge Machining
In this process, metal is removed by a powerful electric spark. Electric discharge machining is also known as spark erosion machining.
Parts of Electrical Discharge Machining
There are several key components that make up an electrical discharge machine:
- DC Pulse Generator
- Tool
- Workpiece
- Servo Control
- Dielectric Fluid
- Dielectric Storage Tank
- Filtration System
- Dielectric Circulation Pump
- Nozzle Flushing
- Fixture
- Table
DC Pulse Generator
A DC pulse generator is the power source through which DC power is supplied. In which the negative terminal is given to the tool and the positive terminal is given to the workpiece.
Tool
The tool is used to create electrical discharges. It can be made of various materials, such as copper or graphite, and is shaped to match the desired shape of the machined surface.
Workpiece
This is the material that is being machined using the electric discharge machining process. It is typically made of conductive material, such as metal.
Servo Control
The gap between the workpiece and the tool is maintained by servo control.
Dielectric Fluid
This is a non-conductive fluid that is used to surround the workpiece and the tool during the electric discharge machining process.
It serves to insulate the workpiece and electrode and also helps to remove the material that is eroded during the machining process.
Dielectric Storage Tank
It is a kind of storage tank where dielectric fluid is stored. The dielectric fluids mostly used are petroleum-based hydrocarbons such as paraffin, Transformer oil, Kerosene, Mineral oil, etc.
Filtration System
This is a system that is used to filter the dielectric fluid as it is circulated around the electric discharge machine. It helps to remove any contaminants or debris that may be present in the fluid, which helps to extend the life of the fluid and improve the overall performance of the electrical discharge machine.
Dielectric Circulation Pump
This pump is connected to the dielectric storage tank, which supplies the dielectric fluid to the workpiece and tool through the filter.
Nozzle Flushing
This is used to circulate the dielectric fluid around the workpiece and tool.
It helps to keep the electrical discharge machining process cool and to remove the debris that is generated during the machining process.
Fixture
This is a device that is used to hold the workpiece in a specific position during the electric discharge machining process. It may be a simple block of material or a more complex structure, depending on the shape and size of the workpiece.
Table
This provides a stable and rigid foundation for the electric discharge machine.
It is typically made of a heavy, durable material such as cast iron.
Controlling Parameters of Electrical Discharge Machining
The main process parameters or controlling parameters in electrical discharge machining are:
- Supply Voltage
- Break Down Voltage
- Resistance and Capacitance
- Spark Gap Setting
- Pulse Duration
- Spark Frequency
Supply Voltage
Which is provided by the power supply system.
It ranges between 50 V to 400 V DC supply.
Break Down Voltage
It is the voltage at which the dielectric breakdown.
Resistance and Capacitance
In this process, the resistor is connected in series and a capacitor is connected in parallel.
Spark Gap Setting
This results in a better surface finish and high accuracy.
Pulse Duration
It is the duration between successive pulses for producing the spark.
Spark Frequency
It is about 1000 sparks/sec.
Construction of Electrical Discharge Machining
- A workpiece is held in the dielectric fluid.
- The positive terminal is connected to the workpiece.
- The negative terminal is connected to the tool.
- The tool is used as a hollow. And it is made of copper or brass.
- Dielectric fluid is passed in the tool pipe.
- 0.005 mm to 0.05 mm gap is maintained between the workpiece and the tool.
Working Process of Electrical Discharge Machining
- First of all, both the workpiece and the tool are immersed in dielectric fluid. This dielectric fluid helps to control the arc discharge.
- There is a very small gap (about 0.5 mm) between the workpiece and the tool.
- When the DC supply is given, an electric spark is produced in this gap and high heat up to 1200°C is produced.
- A small area of the material is melted by this heat due to erosion and evaporating ions and molten metal is spitted into small particles.
- These particles are carried away by the dielectric fluid.
- Chips and suspended particles are removed from between the workpiece and the tool so that it does not cause a short circuit. All this is possible by a continuous supply of dielectric fluid.
- The dielectric fluids generally used are petroleum-based hydrocarbons such as paraffin, Transformer oil, Kerosene, Mineral oil, etc.
- This fluid also acts as a coolant.
Advantages of Electric Discharge Machining
- The machining process does not depend on the mechanical properties of the work.
- No residual stresses will be generated because no forces are acting.
- The deeper hole is possible to produce up to 20.
- Out of all the non-traditional machining methods, EDM is the method with the higher Material Removal Rate.
- The surface finish is better due to melting and vaporization.
- Conductive materials and complex and irregular surfaces can be machined.
- A complex dies section and complex shape can be produced with precision.
- This process is independent of burrs, and Thin sections can be easily formed without deforming any parts.
- Pieces of hard workpieces can be easily cut.
Disadvantages of Electric Discharge Machining
- High electric power is needed.
- Suitable only for conductive material.
- Square corners cannot be formed.
- In this machining process, the equipment wears out more.
- Good electrical conductors can only be made by electrical discharge machining.
Applications of Electrical Discharge Machining
- It is specially used for master die makers.
- Used to make small holes in nozzles.
- It is used to machine hard and brittle materials.
- It is used to cut off the workpiece.
- It is used to sharpen the tool and cutters.
- It is used in making stamping tools, wire drawing and extrusion dies, header dies, forging dies, etc.
- Internal threads can also be produced in harder material by using a rotary spindle.
- It is used in micro-hole drilling and curved-hole drilling.
- It is also used for mold and die-making, prototype manufacturing, and micro-drilling.
I hope that I have cleared all your doubts related to the electrical discharge machining process.
If you have any doubts related to this topic then you can ask me through the contact us page or directly mail me.
Thank You.
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