Electrochemical machining by Himanshu Vaid basics about the Electrochemical machining ..............

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

4. •Anode : Workpiece
•Cathode : Tool
•Electrolyte : An electrically conductive fluid

5. Process parameters

6. Process

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

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

14. Specialized ECM…

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

17. Ref – L.cagnon,V.lircher,M.cock,R.schuster,G.Ertlth.Gmelin and H.kueck,
Z. Phys chem . 217, (2003), 299-313

19. Further specialized Applications
 Die Sinking
 Profiling and contouring
 Trepanning
 Grinding
 Drilling
 Micro-machining
 Pulsed ECM

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
•Stress free grooves
•Any groove geometry
•Any conductive metal can be
machined
•Repeatable accuracy of 0.0005”
•High surface finish
•Fast cycle time
Important characteristics that can be achieved are :

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

24. Thank You …