For Polytechnic Students of Final Year

1. Advanced Manufacturing Processes (AMP-12154)
Unit no:-1
Marks:- 30

2. Development
 Development of harder and difficult to machine
materials such as hastalloy, nitra
alloy, waspalloy, nimonics, carbides, stainless
steel, heat resisting steels and many other HSTR alloys
 Used in aerospace industry, nuclear engineering and
other industries owing to their high strength to weight
ratio, hardness and heat resisting quality.

3. CHIPS FORMATION IN
CONVENTIONAL MACHINING
PROCESS
CHIP
TOO
L
WORKPIE
CE
Thus the major characteristics of conventional machining are:
• Generally macroscopic chip formation by shear deformation
• Material removal takes place due to application of cutting forces –
energy domain can be classified as mechanical
• Cutting tool is harder than work piece at room temperature as well as
under machining conditions TOOL WORKPIECE CHIP

4. Schematic representation of various metal cutting operations .

5. The broad classification is given as follows:
 Thus classification of NTM processes is carried out
depending on the nature of energy used for material
removal.
 Mechanical Processes
 ⎯ Abrasive Jet Machining (AJM)
 ⎯ Ultrasonic Machining (USM)
 ⎯ Abrasive Water Jet Machining (AWJM)
 Electrochemical Processes
 ⎯ Electrochemical Machining (ECM)
 ⎯ Electro Chemical Grinding (ECG)
 ⎯ Electro Jet Drilling (EJD)

6.  • Electro-Thermal Processes
 ⎯ Electro-discharge machining (EDM)
 ⎯ Laser Beam Machining (LBM)
 ⎯ Electron Beam Machining (EBM)
 • Chemical Processes
 ⎯ Chemical Milling (CHM)
 ⎯ Photochemical Milling (PCM) etc.

7. Abrasive Jet Machining (AJM)
Abrasive
Pressure control filter feeder
valve
exhaust
Mixing
Drier chamber
Nozzle
¼ turn valve
Electro-magnetic
shaker work
Air
piece
compressor

8. Ultrasonic Machining (USM)

9. ELECTROCHEMICAL MACHINING
(ECM)

10. Electrolyte
 An electrolyte is any substance containing free ions that
make the substance electrically conductive. The most
typical electrolyte is an ionic solution, but molten
electrolytes and solid electrolytes are also possible.
 Function of electrolyte-
 Carrying current between tool and work peice
 Remove products of machining and other insoluble
products from cutting region
 Dissipate heat produced in the operation.

11. Characteristics of Electrolyte
 Good electrical conductivity
 Non toxicity and chemical stability
 Non corrosive property
 Low viscosity and high specific heat
 Electrolyte used-
Sodium chloride

12. Electric Discharge Machining
(EDM)

13. Wire-cut EDM (WEDM)

14. Dielectric Fluid
 A dielectric is an electrical insulator that can
be ionized by an applied electric field. When a dielectric is
placed in an electric field, electric charges do not flow
through the material as they do in a conductor, but only
slightly shift from their average equilibrium positions
causing dielectric polarization.
 Characteristic-
 Low viscosity
 High fluidity
 Controlled level of toxicity
 Cheap and easily available

15. Function of Dielectric Fluid
 Insulation Until required breakdown voltage attained.
 Should act as conductor after required breakdown voltage
attained.
 Should demonize rapidly after the discharge has been
occurred.
 Clean spark gap by carrying away the molten metal.
 Should cool the tool work piece and spark region.
Dielectric Used:-
light hydro carbon oil, kerosene, paraffin, transformer
oil, try ethylene glycol.

16. LASER Beam Machining (LBM)

17. Electron Beam Machining (EBM)

18. Chemical Machining (CHM)

19. PAM

20. Difference between EDM & ECM
1. Uses dielectric fluid as a 1. Using electrolyte as a
conducting medium between conducting medium between
tool and work piece. tool and work piece.
2. Wear of tool takes place during 2. No wear of tool during process
the process. so tool life is high.
3. Heat is generated during the 3. No heat is generated during the
process. process.
4. Low metal removal rate. 4. Metal removal rate is high.
5. It works on the principle of 5. It works on principle of
spark erosion. Faraday’s law of electrolysis.
6. Metal is removed by melting 6. Metal is removed by
and vaporization. electrochemical reaction.
7. Tools used are oversize for 7. Tool used are of required size of
machining inside surfaces and the work piece.
undersize for machining outside
surfaces.

21. Dielectric Electrolyte
1. It is used as conducting 1. It used as conducting
medium in EDM medium in ECM
process. process.
2. It act as conductor and 2. It always provide
insulator both. passage for supply of
3. Tool wear takes place electricity.
in the dielectric fluid. 3. The electrolyte selected
4. It may or may not be is such that there is no
corrosive in nature. wear of tool.
4. It should be non
corrosive in nature.

22. EBM LBM excited atoms
1. When
1. When high velocity releases photons in the
electrons strikes the work form of chain, a LASER
piece its kinetic energy beam is generated which
converted into heat energy. strikes on w/p & melts it.
2. Electron gun is used as a 2. LASER material is used as
tool. tool.
3. Accuracy is good. 3. Accuracy is comparatively
4. Metal removal rate is low. more.
5. The complete process 4. Metal removal rate is high.
should kept in vacuum. 5. Vacuum is required
6. Usually only metals. between flash lamp and
ruby rod.
6. Any material but not only
suitable for plastic.

23. Questions
1. Which of the following process uses mechanical
energy as principle energy source
a. ECG
b. LBM
c. Conventional milling
d. USM
e. WJM
f. WEDM

24. 2. Chemical milling is used in
which of the following application
a. Drilling holes with high depth.
b. Making intricate patterns on thin sheet metal
c. Removing material to make shallow pockets in
metal.
d. Removing metals from aircrafts wing panels.
e. Cutting of plastic sheets.

25. 3. Which of the following process would be best
suited for cutting a hole of 0.003 inch dia?
a. AJM
b. CHM
c. EDM
d. LBM
e. WEDM

26. 4. Ultra sonic machining can be used for
both metallic and non metallic materials?
 True
 False

27. 5. Which of the following process could be
used to cut a large piece of 1/2inch thick?
a. AJM
b. CHM
c. EDM
d. LBM
e. WEDM