1. PROPERTIES AND SELECTION OF MATERIALS
“ELECTRO MACHINING”
Presented by:
MUDIT RAJ YADAV 2008AMD3110
DEPTT. OF APPLIED MECHANICS
IIT DELHI
Presented to:
PROF. M.P. GURURAJAN
DEPTT. OF APPLIED MECHANICS
IIT DELHI

2. ELECTRO DISCHARGE MACHINING(EDM)
ELECTRO MACHINING
ELECTRO DISCHARGE MACHINING(EDM)
ELECTRO CHEMICAL MACHINING(ECM)

3. ELECTRO DISCHARGE MACHINING (EDM )
ELECTRO CHEMICAL MACHINING (ECM)
Electrical energy is use to cut material to final shape. (SPARK EROSION PROCESS).
When a difference of potential is applied between two conductors immersed in a dielectric fluid. Fluid will ionize, if the potential diff. reaches a high enough value and a spark will occur.
If both the electrodes are of same material then +ve one (anode, work piece) will have more erosion.
A gap of 0.01 to 0.05 mm is maintained, it governs the MRR
Current vary from 0.5 to 400 amp
Voltage V DC
Fluid is pumped with a pressure of 2 kg/cm2.
Electrical energy is use to cut material to final shape (No spark)
In this process an electrolytic cell is formed by the anode (work piece) and cathode (tool) in the midst of a flowing electrolyte.
Due to electrolytic process at the cathode, -ve ions are released which combine with the metal ion of anode to form insoluble metal hydroxides.
Thus the metal is mainly removed in the form of slugs and precipitates
This process is reverse of electro plating but the metal is pumped in the flowing electrolyte before it gets stuck on the tool surface
Gap mm
voltage D.C. supply(5-30 volts)
current of order amp
Fluid pressure =14 kg/cm2

4. CIRCUIT DIAGRAM

5. SPARK GENERATION
Sparking time period is of order=100 micro-sec

6. VARIATION OF MRR WITH DIFFERENT FACTORS

7. FEATURES OF EDM Used for:- Super alloys Ti Steels Fluids:-
Paraffin with
White spirit or
Transformer oil
Tool materials:-
Graphide Cu
Cu-Wc
Applications:-
Dies, punch
Aircraft industry-fuel injector, nozzles
To make holes in turbine blades
Change in properties:-
Residual stresses
Plastic deformation may occur
Fine cracks in machined area

8. (2)ELECTRO CHEMICAL MACHINING

10. FEATURES OF ECM Applications:- Profiled cavity Carbide tools
Used for:-
(>400BHN)
Ni alloys
Ti alloys
WC alloys
Fluids:-
Natural salts
Acids
Alkalis
Tool materials:-
Brass Cu
Steels
Applications:-
Profiled cavity
Carbide tools
Dies, punch
Fuel injector, nozzles
To make holes in turbine blades
Change in properties:- (No spark)
So no metallurgical change (temp about C)
No change in properties like
Melting point
Composition
Hardness, toughness, brittleness etc

11. CONCLUSIONS
Both used electrical energy as source.
Both processes are highly précised and modern techniques of machining.
Both are used for machining of hard materials(>2000BHN ).
Change in properties are negligible or none.
But can be used for electric conductor materials only.
Both can produces complex shape.

12. THANK YOU