2. Introduction
Non-conventional machining system in which metal is
removed by electrochemical process
Characterized as ‘Reverse Electroplating’ means it
removes metal instead of adding it
Normally used for mass production and for hard
materials that are difficult to machine using
conventional processes
Both external and internal geometries can be
machined
3. Principle
Faraday’s law of electrolysis :
The Weight of the substance produced during
electrolysis process is directly proportional to
1. the current which passes
2.the length of time of process
3.The equivalent weight of the material
Two dissimilar metals are in contact with an electrolyte
and anode loses metal to cathode
7. Main subsytem
Power Supply
Electrolyte
Tool
The Control system
The machine
8. Power Supply
Available in sizes upto 10,000 amp (some circuits are
available upto 40,000amp)
Range of voltage – 2 to 30 volts d.c.
A constant voltage has to be maintained and high
density is required
9.
10. Electrolyte
Essential for electrolytic process
It cools the cutting zone which becomes hot due to the
flow of high current
Neutral salts are used as electrolyte in place of highly
corrosive acids and alkalies
Electrolyte solution is pumped between the
tool/workpiece gap at about 2.5 N/mm2 and 30 m/s
11. Tool
Requirements of Tool For ECM :
Good thermal conductivity
Strong enough to withstand high pressures
It should be easily machined
•Material for tool : Copper,brass or stainless steel
•Outer insulation material : Vinyl, Teflon, epoxy,
enables or high temperature varnish
12. The control system
Control Parameters include
Voltage
Inlet and outlet pressure of electrolyte
Temperature of electrolyte
•The current is dependent on above parameters
and feed rate
15. STEM
Figure The shaped-tube electrolytic
machining (STEM) cell process is a
specialized ECM technique for drilling
small holes using a metal tube electrode
or metal tube electrode with dielectric
coating.
16. Electrochemical Micro-machining
•Improves resolution
of anodic dissolution
from millimetres to
micrometres
•Micromachining
applies pulses in
nanoseconds instead
of direct currents
19. Further specialized Applications
Die Sinking
Profiling and contouring
Trepanning
Grinding
Drilling
Micro-machining
Pulsed ECM
20.
21.
22. Economics & Products
The process is economical when a large no. of complex
identical products are to be made
Large cavities are more economical on ECM and can be
made in 1/10th time in EDM
Two most common products :
Turbine/compressor blades
Rifle barrels
Important characteristics that can be achieved are :
•Stress free grooves
•Any groove geometry
•Any conductive metal can be
machined
•Repeatable accuracy of 0.0005”
•High surface finish
•Fast cycle time
23. ECM is well suited for the
machining of complex
two-dimensional shapes
Delicate parts may be
made
Difficult-to machine
geometries
Poorly machinable
materials may be
processed
Little or no tool wear
Initial tooling can be
timely and costly
Environmentally
harmful by-products
Complicated tool
design
Large power
consumption
Advantages
Disadvantages
Die sinking is a process used to machine or create a specific size or shape cavity or opening in steel blocks.
Most often, die sinking is used to place names, numbers, and other sources of information onto metal