This presentation aims on discussion of EDM process

1. Lecture Series
Advanced Manufacturing
Processes
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2.  In order to satisfy modern application
requirement.
 Work-piece material should be harder than
the material should be machined in the
conventional machining.
 Work piece hardness isn’t important in
advance machining processes.

3.  Based on Type of Energy Used
Mechanical
1. Abrasive water jet Machining(AJM)
2. Ultra sonic Machining(USM)
Chemical
1. Chemical Blanking
2. Chemical Machining(CHM)
3. Chemical Milling

4. 1. Electro chemical machining(ECM)
2. Electro chemical Grinding(ECG)
3. Electro chemical Honing(ECH)
4. Electro chemical discharge grinding(ECDG)
5. Electro Impulse machining(EIM)

5. 1. Electric Discharge Machining(EDM)
2. Wire cut-Electric Discharge
Machining(EDM)
3. Ion Beam Machining(IBM)
4. Plasma Arc Machining(PAM)
5. Laser Beam Machining(LBM)
6. Electron Beam Machining(EBM)

6.  Introduction
 Electrical discharge machining (EDM)
removes metal by discharging electric
current from a pulsating DC power supply
across a thin inter electrode gap.
 It is also called as spark erosion or Electro
erosion or Spark Machining.
 It has gap which is filled by a dielectric fluid,
which becomes locally ionized
 Two different types of EDM exist based on
the shape of the tool electrode
 Ram EDM/ sinker EDM
 Wire EDM

7. Figure 1: EDM or spark erosion machining of metal, using high-
frequency spark discharges in a dielectric, between the shaped tool
(cathode) and the work (anode)

8.  Metal is removed by the erosion of the
electrically conductive material by the
initiation of the rapid and repeated spark
discharge between electrode (Anode) and
the work piece(Cathode) which are
separated by the small gap.
 The gap is flooded with the dielectric fluid.
 When sufficient voltage is applied between
the cathode and anode the dielectric breaks
down and very high local temperature up to
order 100000C is generated which remove the
metal particle.

9.  Electric Power supply
 The Dielectric Medium
 The Work piece(Anode)
 Tool or Electrode(Cathode)
 Servo Control

10.  The work piece is connected to positive
terminal and tool to the negative terminal.
 Both are immersed in the dielectric fluid and
the separated by the gap of 0.005mm to
0.5mm.
 When the suitable voltage in the range of 50
to 450V is applied the dielectric breaks
down and electrons are emitted from the
cathode and GAP GETS IONIZED.
 When more electrons are collected in the
gap the resistance drop causing electric
spark to jump between W/p and tool.

11.  Each electric spark causes a focused
stream of electrons to move with very high
velocity from cathode to anode which
created the compression wave which
generates the local rise in the
temperature.
 The whole sequence of operation occur in
the few micro seconds, the local rise of
temperature causes the melting of
temperature.

13. Advantages
 Applicable to all
materials that are
fairly good electrical
conductors
 Hardness, toughness,
or brittleness of the
material imposes no
limitations
 Ra up to 0.O5µ.
 No distortion as no
contact between tool
and work piece.
Disadvantages
 Slow MRR.
 High power
consumption.
 Cant use for non
conductive
materials.
 Cant produce sharp
corners.

14. 1. It is used to make holes, slots and other
cavities.
2. It is specially used in the die making.
3. Drilling a very small holes up to 0.080mm
particularly in the fuel injector nozzle using
the steel tungsten electrode.
4. For manufacturing of tools of complex profiles.
5. For producing the complex cavities in the
moulds for plastics
6. For making punching dies ,wire drawing
,extrusion dies, blanking and forging dies.
7. For producing internal threads and gears with
the rotary spindle.

15.  MRR
 It is volume of metal removed from work
piece per unit time.
 Surface Finish
 It depends on MRR
 High MRR produce poor surface finish
 Ra Upto 0.2µ is possible
 Tolerance
 ±0.05 mm is easily possible.

16. Thank You