ME8073 UCMP

1. ME8073
UNCONVENTIONAL
MACHINING PROCESSES
BY
HARIHARAN.M.G
ASSISTANT PROFESSOR
MECHANICAL DEPARTMENT
1

2.  UNIT 1- INTRODUCTION AND MECHANICAL ENERGY
BASED PROCESSES
 UNIT 2 –THERMAL AND ELECTRICAL ENERGY BASED
PROCESSES
 UNIT 3 –CHEMICAL AND ELECTRO CHEMICAL ENERY
BASED PROCESSES
 UNIT 4 – ADVANCED NANO FINISHING PROCESSES
 UNIT 5 –RECENT TRENDS IN NON TRADITONAL
MACHINING PROCESSES
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3. UNIT – I
INTRODUCTION AND
MECHANICAL ENERGY BASED
PROCESES
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4. Traditional machining Process
• In conventional, machining requires the
presence of a tool that is harder than the
work piece. Machined.
• This tool should be penetrated in the work
piece to a certain depth.
• Moreover, a relative motion between the
tool and work piece is responsible for
forming the required shape.
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5. 5

6. 6

7. Unconventional machining process
• There is no direct physical contact
between the tool and the work piece.
• Harder and difficult to machine
materials can be machined by this
process.
• The tool materials need not to be
harder than work piece.
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8. 8

9. 9

10. 10

11. Need for Non Traditional Machining.
Machinability of the Work piece
Materials
Shape complexity of the work piece
Surface Integrity
Precision
Miniaturization
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12. Characteristics of UCM processes
 Performance is independent of
strength barrier
 Use different kinds of energy in direct
form
 In general, low MRR but better
quality products
 Comparatively high initial investment
cost
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13. Classification of Unconventional
machining processes.
a) Based on the type of energy required to
shape the material
Thermal energy methods
Electrical energy methods
Electro chemical energy methods
Chemical energy methods
Mechanical energy methods
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14. b) Based on the mechanism involved
in the process
Erosion
Ionic dissolution
Vaporization
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15. c) Source of energy required for material
removal
Hydrostatic pressure
High voltage
Ionized material
High current density
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16. d) Medium of transfer of energies
High voltage particles
Electrolyte
Electron
Hot gases
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17. i) Mechanical Energy
The material removed by mechanical
erosion of the work piece material.
Abrasive Jet Machining - AJM
Water Jet Machining - WJM
Abrasive Water Jet machining - AWJM
Ultrasonic Machining - UCM
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18. ii) Electrical Energy Method
Electrical energy directly used the
material to get the final shape and size.
Electric Discharge Machining - EDM
Wire Cut Electric Discharge Machining
WEDM
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19. iii) Chemical Energy Method
The material is removed by chemical
etching.
Chemical Machining – CHM
Electro Chemical Machining – ECM
The material is removed by ion
displacement of the work piece material
in contact a chemical solution
Electro Chemical Grinding - ECG
Electro Chemical honing – ECH
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20. iv) Thermal Energy Method
Heat energy is concentrated on a small
area of the work piece to melt and
vaporise the tiny bits of work piece
material
Laser Beam Machining –LBM
Electron Beam machining – EBM
Plasma Arc Machining – PAM
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21. Based on the material the following methods can be
used.
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S.No Work Piece Material Suitable Process
1.
Ceramics, Plastics ,Glass and Non
Metals
USM,AJM,EBM,LBM
2.
Refractories
USM,AJM,EDM,EBM
3.
Titanium
EDM
4.
Steel
ECM,CHM,EDM,PAM
5.
Super Alloys
AJM,ECM,EDM,PAM

22. Advantages
It increases productivity
It reduces number of rejected
components.
Close tolerance is possible
The tool materials need not to be harder
than work piece.
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23. Disadvantages
UCM processes are more expansive
Metal Removal Rate (MRR) is slow.
AJM, CHM, PAN and EBM are not
commercially not economical.
Complex set-up
Skilled operator require.
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24. Applications
Parts can be machined with complex and
Irregular shapes for forging.
Difficult internal shapes for Aerospace and
medical applications
This process is highly economical for machining
hard materials.
It is also used for broach making, making holes
with straight axes.
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25. The following points must be considered for the
correct selection of the unconventional
machining process.
 Physical parameters
 Shapes to be machined
 Process capability or machining characteristics
 Economic consideration
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26. a) Physical parameters
Parameters ECM EDM EBM LBM PAM USM AJM
Potential, V 5-30 50-500 200×103 4.5×103 250 220 220
Current, A 40000 15-500 0.001 2 600 12 1.0
Power, KW 100 2.70 0.15 20 220 2.4 0.22
Gap, mm 0.5 0.05 100 150 7.5 0.25 0.75
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27. Medium Electrolyte Dielectric
fluid
Vacuum Air Argon or
Hydrogen
Or
Nitrogen
Abrasive
grains &
water
N2 or Co2
or Air
Work
material
Difficult to
machine
materials
Tungsten
carbides and
electrically
conductive
materials
All
material
s
All
materials
All
materials
which
conduct
electricity
Tungste
n
carbide,
glass,
quartz
etc
Hard and
brittle
materials
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28. b) Shapes to be machined
For producing micro holes – LBM is used
For producing small holes – EBM is used
For producing deep holes – ECM is used
For producing shallow holes – USM and EDM is
used
For honing – ECM is used
For Grinding – AJM and EDM is used
For Threading – EDM is used
For Deburring – USM and AJM is used
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29. c) Process capability (or)
machining capabilities
The machining characteristics can be
analyzed with respect to,
Metal removal rate obtained
Tolerance maintained
Surface finish obtained
Depth of surface damage
Power required for machining
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30. Process Process capability
Metal removal
rate (mm3/s)
(MRR)
Surface finish (µm
, CLA)
Accuracy (µm) Specific Power
(KW/cm3/min)
LBM 0.10 0.4-6.0 25 2700
EBM 0.15-40 0.4-6.0 25 450
EDM 15-80 0.25 10 1.8
ECM 27 0.2-0.8 50 7.5
PAM 2500 Rough 250 7.5
USM 14 0.2-0.7 7.5 9.0
AJM 0.014 0.5-1.2 50 312.5
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31. d) Economic consideration
The economics of the various processes
are analyzed by considering the
following:
Capital cost
Tooling cost
Power requirements
Metal removal rate efficiency
Tool consumption
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32. Process Capital
cost
Tooling and
fixtures
Power
requirements
Efficiency Total
consumption
EDM Medium High Low High High
CHM Medium Low High Medium V. Low
ECM V. High Medium Medium Low V. Low
AJM V. Low Low Low High Low
USM High High Low High Medium
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33. EBM High Low Low V. High V. Low
LBM Medium Low V. Low V. High V. Low
PAM V. Low Low V. Low V. Low V. Low
Conventional
machining
V. Low Low Low V. Low Low
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