Electrochemical Machining (ECM): In this process, the combination of electrical energy and chemical energy makes the removal of material from the surface of a workpiece. It works on the principle of Faraday’s law of electrolysis.
Principle-Faraday’s law of electrolysis: The mass of a substance deposited or liberated at any electrode on passing a certain amount of charge is directly proportional to its chemical equivalent weight.
Electrolyte used: NaCl (Conducting Electrolyte).
Wear Ratio: Infinity (because of no Tool Wear)
DC Power Supply: (3-30)V
The Positive terminal is given to the Workpiece and the Negative terminal is given to the Tool.
The tool used in the Electrochemical Machining Process is either Copper or Brass or Stainless steel etc.
Properties Possessed by the Tool:
It must possess high
- Thermal Conductivity
- Electrical conductivity and
- Corrosion resistance.
The optimum gap maintained between the tool and workpiece is 0.5 to 2 mm.
MRR(Material Removal Rate):
The initial Material Removal Rate(MRR) mainly depends upon the number of Ions displaced from the workpiece.
The number of Ions displaced is directly proportional to
- The current passing through the circuit
- The gram atomic weight of workpiece materials.
- The electrical conductivity of the electrolyte.
Diagram of Electrochemical Machining:
The electrochemical machining setup consists of
- Fixture: To hold the table.
- Table: To hold the workpiece.
- Pump(Pumps electrolyte to work region)
- Filter(Filters the electrolyte)
- Pressure gauge(To check the pressure)
- Feed unit (Servomotor)
- Power supply.
Working of Electrochemical Machining Process:
The electrolyte is pumped to the work region by the pump via a filter, pressure gauge, flow meter and finally, it enters into the work region from the passage.
When the Power supply is given an optimum gap is maintained between the tool and workpiece because of Faraday’s laws of electrolysis, the ions have started displacing from the workpiece and trying to deposit over the tool.
Before the ions are depositing on the tool, the electrolyte present between tool and workpiece is pumped out. Then, the ions also moving along with electrolyte without depositing on the tool.
From the above, the mechanism of material removal is Ion displacement and because there is no disturbance taking place in the tool, the same tool can be used for producing an infinite number of components.
Hence, we can say that the wear ratio of the tool is infinity(because of no tool wear)
This is the detailed explanation of the electrochemical machining process along with the basic terms and working.
Advantages of Electrochemical Machining Process:
- Complex Concave curvature components can be easily produced by using Complex Concave curvature tools.
- Because of ion displacement, the surface finish produced is excellent.
- Because no forces are acting, no residual stresses will be present.because of no heat generation, no thermal effects are present on the workpiece.
- Because of no tool wear, the same tool can be used for producing an infinite number of components.
Disadvantages of Electrochemical Machining Process:
- Workpiece material must be electrically conductive.
- Out of all the Non-traditional machining methods, electrochemical machining requires the highest specific cutting energy Therefore, the cost of machining will be high.
- This is preferable for producing contours only but not for holes.
Applications of Electrochemical Machining Process:
- It is mainly used for producing Complex concave curvature components such as Turbine blades etc.
- The ECM process is used for profiling and contouring, die sinking operation, drilling, trepanning and micromachining.
This is the explanation of Electrochemical Machining Process with its advantages, limitations, and applications in a detailed way.
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