This document provides an overview of electrochemical machining (ECM). ECM is a non-conventional machining process that removes metal through an electrochemical process rather than adding it, as in electroplating. In ECM, a tool acts as the cathode and the workpiece the anode, with an electrolyte solution flowing between them. Metal is removed from the workpiece through an electrolysis process governed by Faraday's laws of electrolysis. ECM can machine complex internal and external geometries in hard metals and is well-suited for mass production. Key aspects of ECM covered include the power supply, electrolyte, tool, control system, and principles of operation. Applications and advantages, such as little

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2. Introduction
 Non-conventional machining system in which metalis
removed by electrochemicalprocess
 Characterized as ‘Reverse Electroplating’ meansit
removes metal instead of adding it
 Normallyused for mass productionand for hard
materials that are difficult to machine using
conventional processes
 Both external and internal geometriescan be
machined

3.  We can use both electrical energy and chemical energy
to remove the material
 ECM can be depends on faradays laws of electrolysis
process
 For removing of material electrolyte will play essential
role
 Here ,DC power supply is used i.e. 3-30 V
 Here, gap between tool and work piece is 0.5 mm
 Tool is -ve and work piece is +ve
 MRR is 1600 mm3/min
 Accuracy is +- 0.02mm and surface finish 0.4mm

4. Principle
 Faraday’s law of electrolysis:
The Weightof the substanceproduced during
electrolysis process is directly proportionalto
1.the current which passes
2.the length of time ofprocess
3.The equivalent weightof the material
 Twodissimilar metalsare in contactwith an electrolyte
and anode loses metal tocathode

5. •Anode : Workpiece
•Cathode : Tool
•Electrolyte : An electrically conductivefluid

6. Process parameters

7. Process

8. Main subsytem
 PowerSupply
 Electrolyte
 Tool
 The Controlsystem
 work piece

9. Power Supply
 A constantvoltage has to be maintained and high
density isrequired
1. Type: direct current
2. Voltage: 2 to 35 V
3. Current: 50 to 40,000 A
4. Current density: 20 A/cm2 to 300 A/cm2

10. Electrolyte
 Common electrolytes used are sodium chloride, sodium nitrate,
sodium hydroxide, sodium fluoride, sodium chlorate, potassium
chloride and sulphuric acid.
 These solution on reaction produce an insoluble compound in the
form of sludge.
 Essential for electrolyticprocess
 Itcools thecutting zonewhich becomes hotdue tothe flow of highcurrent
 Electrolyte solution is pumped between the tool/work piece gap at about
2.5 N/mm2and 30 m/s

11. Electrolyte
 The main functions of an electrolyte in ECM are:
1. It carries the current between tool and work-piece.
2. It removes the products of machining
and other insoluble products from the cutting region.
3. It dissipates heat produced in the operation.
 The essential characteristics of electrolyte includes:
1. Good electrical conductivity.
2. Non-toxicity and chemical stability.
3. Non-corrosive property.
4. Low viscosity and high specific heat.

12. Tool
 The most commonly used tool material are copper, brass,
titanium, copper tungsten and stainless steels when electrolyte
is made of salts of sodium and potassium.
 Titanium has been found to be the most suitable tool where the
electrolyte has the tendency to anodize the tool as in case of
sulphuric acid.
 The other tool materials are aluminium, graphite, bronze,
platinum and tungsten carbide.
 The accuracy of tool shape directly affects the work- piece
accuracy.
 Electro-forming and cold forging are two methods of tool
shaping.

13. Tool Requirements of Tool For ECM:
 Good thermal conductivity
 Strong enough to withstand highpressures
 It should be easilymachined
 It should be conductor of electricity.
 It should be chemically inert to the electrolyte.
•Outer insulation material : Vinyl, Teflon,epoxy, enables or
high temperaturevarnish

14. The control system
 Control Parameters include
 Voltage
 Inlet and outlet pressure ofelectrolyte
 Temperature of electrolyte
•Thecurrent isdependenton above parameters
and feed rate

15. Work-piece (anode):
 Work-piece should be conductor of electricity. So it is
almost limited to metals only.
 Work piece is made anode
 Material of the work piece is removed due to anodic
dissolution

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

18. Economics & Products
 The process is economical when a large no. of complex
identical products are to bemade
 Large cavities are moreeconomical on ECM and can be
made in 1/10th time inEDM
 Two most common products:
 Turbine/compressor blades
 Rifle barrels

19. Advantages
 ECM is well suited for the
machining of complex
two-dimensional shapes
 Delicate parts maybe
made
 Difficult-to machine
 geometries
 Poorly machinable
materials may be
processed
 Little or no toolwear
 Disadvantages
 Initial tooling can be
 timely andcostly
 Environmentally
harmful by-products
 Complicated tool
design
 Large power
consumption

20. References
 Electrochemical machining – nptel
 Science Direct – ECM
 Wikipedia – electrochemical machining
 Wendt – electrochemical machining & miccromaching

21. Thank You …
yours…
polaiah chintada…