Electrical discharge machining is one the most fastest growing manufacturing process.

1. NON-CONVENTIONAL
MACHINING PROCESSES

2. Processes that remove excess material from the
workpiece with help of various techniques
involving mechanical, electrical, chemical, electro-
chemical or combination of these techniques.
No use of a sharp cutting tool is required as in
case of conventional machining processes.
There is no contact between the tool and the
workpiece.
NON-CONVENTIONAL MACHINING
What is non-conventional machining?

3. To machine hard and brittle materials like
tungsten carbide, high speed steels, stainless
steels, ceramics etc.
Good surface finish.
Very high dimensional accuracy.
Computer controlled precise cutting.
NON-CONVENTIONAL MACHINING
Why Non-conventional machining?

4. 1. Mechanical Processes:
• Abrasive Jet Machining (AJM)
• Ultrasonic Machining (USM)
• Water Jet Machining (WJM)
• Abrasive Water Jet Machining (AWJM)
2. Electrochemical Processes:
• Electrochemical Machining (ECM)
• Electro Chemical Grinding (ECG)
• Electro Jet Drilling (EJD)
NON-CONVENTIONAL MACHINING
Classification based on energy used
for material removal:

5. 3. Electro-Thermal Processes:
• Electric discharge machining (EDM)
• Laser Jet Machining (LJM)
• Electron Beam Machining (EBM)
4. Chemical Processes:
• Chemical Milling (CHM)
• Photochemical Milling (PCM)
NON-CONVENTIONAL MACHINING
Classification based on energy used
for material removal:

6. ELECTRIC DISCHARGE MACHINING
NON-CONVENTIONAL MACHINING
Thermal metal removal
process which removes
metal with help of electric
sparks.
The electrical discharge
takes place in presence of
dielectric fluid.
Electric spark is used as
cutting tool.

7. Exotic materials can be machined with ease.
No contact between tool and workpiece.
Mirror like surface finish is possible.
Workpiece can be machined to very accurate
tolerances (upto +/- 1 micron).
Complex sections can be produced accurately.
NON-CONVENTIONAL MACHINING
Key features of electrical discharge
machining

8. Types of electric discharge machining
NON-CONVENTIONAL MACHINING
I. Ram type EDM
(Die sinker EDM)
II. Wire type EDM
III. Small hole EDM

9. Ram type electric discharge
machining
NON-CONVENTIONAL MACHINING
 Preshaped electrode is
used to produce blind
cavities in the w/p.
 Reverse shape of the
electrode is eroded into
the solid w/p.
 Dielectric oil is used for
this process.

10.  Servo mechanism maintains precise gap between the
electrode and the w/p.
 Toxic fumes are produced while machining some
materials like Boron carbide, titanium boride, and
beryllium.
 +ve or –ve charges are applied according to desired
conditions i.e. electrodes with +ve polarity wear
better and having –ve polarity cut faster.
NON-CONVENTIONAL MACHINING
Ram type electric discharge
machining contd.

11. Wire type electric discharge
machining
NON-CONVENTIONAL MACHINING
 MAJOR COMPONENTS:
1) Computerized
Numerical Control
(CNC) (“The Brains”).
2) Power Supply (“The
Muscle”).
3) Mechanical Section
(“The Body”).
4) Dielectric System
(“The Nourishment”).

12.  Continuous travelling vertical wire is used which is
under tension.
 Wire diameter varies from 0.05mm-0.33mm.
 Wire to w/p distance is approx. 0.025mm.
 Hundred thousand sparks occur in 1 second.
 Deionized water is used as dielectric.
 Flushing or submerged type machines are available.
NON-CONVENTIONAL MACHINING
Wire type electric discharge
machining contd.

13. Small hole electrical discharge
machining
NON-CONVENTIONAL MACHINING
 Tubular electrodes are
rotated while machining
(aids in flushing and uniform
electrode wear).
 Wire diameters ranging
from 0.152mm to 6mm used.
 Depth to diameter ratio
upto 100:1.
 Wire diameters ranging
from 0.152mm to 6mm

14.  Any electrically conductive material can be cut.
 Hardened and exotic materials can be machined with ease.
 Complex sections can be produced accurately, faster and at lower
rates.
 Burr free operation.
 Fragile and thin sections like webs or fins can be easily machined
without deformation of the part.
 No cutting forces induced.
 Superior finish, accuracy and repeatability.
 Minimum operator intervention.
NON-CONVENTIONAL MACHINING
Advantages of electric discharge
machining

15.  Not suitable for non-conductors.
 Low metal removal process as compared to chip
machining.
 Matte type appearance is obtained and further polishing is
required if gloss finish is needed.
 Rapid electrode wear makes the process more costly.
 Smoke produced is harmful to lungs and eyes.
 Chances of flash fire in dielectric fluid (oil).
 Specific power consumption is high.
NON-CONVENTIONAL MACHINING
Limitations of electric discharge
machining

16. Applications of electric discharge
machining
NON-CONVENTIONAL MACHINING
 Die making.
 Aerospace components.
 Form tools.
 Stamping tools.
 Medical and dental
instrumentation.
 Prototype parts.
 Micropins, micro-nozzles,
and micro cavities.

17.  http://www.thomasnet.com/articles/custom-manufacturing-
fabricating/Wire-Cut-EDM
 http://www.njpt.com/wire-edm.html
 http://www.scribd.com/doc/31289146/EDM-Wirecut#scribd
 http://www.mechteacher.com/manufacturing-technology
 http://en.wikipedia.org/wiki/Electrical_discharge_machining
 http://www.edmmachining.com
 http://www.reliableedm.com/
 WIRE EDM “THE FUNDAMENTALS” by DONALD B. MOULTON (EDM
NETWORK Sugar Grove, IL USA)
 “Complete EDM Handbook” by Carl Sommer & Steve Sommer
NON-CONVENTIONAL MACHINING
References

18. Due to the rapid advances of technology, many traditional
ways of today’s machining are performed with the EDM
process. Manufacturers are realizing dramatic results in
achieving excellent finishes, high accuracies, cost reductions,
and much shorter delivery times. Therefore In today’s highly
competitive world, it is essential to understand the electrical
discharge machining (EDM) processes for its great potential
in the future in machining industries as the leading machining
process.
NON-CONVENTIONAL MACHINING
Conclusion

19. "The EDM process is only limited by
our imagination!"
NON-CONVENTIONAL MACHINING