Unconventional Machining Processes Solved MCQs

Multiple Choice Questions 139 Pages

Anna University

Mechanical Engineering

Contributed by

Arvind Ramson

R2017
ME8073 - UNCONVENTIONAL MACHINING PROCESSES
Multi Choice Questions (MCQ)
UNIT I - INTRODUCTION AND MECHANICAL ENERGY BASED PROCESSES
[Syllabus]
[Unconventional machining Process – Need – classification – merits, demerits and
applications. Abrasive Jet Machining – Water Jet Machining – Abrasive Water Jet Machining
- Ultrasonic Machining. (AJM, WJM, AWJM and USM). Working Principles – equipment used
– Process parameters – MRR- Applications.]
Non Traditional Machining
1. Non-Traditional machining is recommended when we need which of the following
features?
a) Complex shapes
b) High surface quality
c) Low-rigidity structures
d) All of the mentioned
Answer: d
Explanation: For above requirements this machining is used.
2. Non-Traditional machining can also be called as ________
a) Contact Machining
b) Non-contact machining
c) Partial contact machining
d) Half contact machining
Answer: b
Explanation: Tool and work piece are at a distance apart in this type of machining.
3. In which of the following industries, Non-traditional machining methods play an important
role?
a) Automobile
b) Aerospace
c) Medical
d) All of the mentioned
Answer: d
Explanation: Non-traditional methods are used widely in many industries.
4. Different classifications of Non-traditional machining based on source of energy are
________
a) Mechanical
b) Thermal
c) Chemical and electro-chemical.
d) All of the mentioned
Answer: d
Explanation: It can be classified into the above mentioned categories.
5. In mechanical machining, material is removed by ___________
a) Erosion
b) Corrosion
c) Abrasion
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d) Vaporization
Answer: a
Explanation: Abrasive grains remove material by mechanical erosion in USM.
6. Material in thermal machining is removed by which of the following means?
a) Vaporization
b) Melting
c) Electro-plating
d) All of the mentioned
Answer: d
Explanation: In this machining, heat is the source of energy.
7. Which of the following process comes under mechanical machining?
a) USM
b) EDM
c) LBM
d) PAM
Answer: a
Explanation: USM removes material by mechanical erosion.
8. Surface defects that may be occurred during thermal machining are ________
a) Micro cracking
b) Heat affected zones
c) Striations
d) All of the mentioned
Answer: d
Explanation: During thermal machining surfaces defects occur.
9. Sources used in thermal machining are ________
a) Ions
b) Plasma
c) Electrons
d) All of the mentioned
Answer: d
Explanation: Different sources are used to remove the materials accordingly.
10. Vacuum is the machining medium for ________
a) LBM
b) WJM
c) EBM
d) None of the mentioned
Answer: a
Explanation: Vacuum is the medium for Laser Beam Machining and Ion Beam machining.
11. In chemical machining is material removal takes by?
a) Chemical reaction
b) Erosion
c) Electron removal
d) None of the mentioned
Answer: a
Explanation: Chemical machining removes material by chemical reactions.
12. Which of the following is an example of hybrid machining?
a) Ultrasonic Machining
b) Electron Beam Machining
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c) Ultrasonic assisted electrochemical machining
d) Laser Beam Machining
Answer: c
Explanation: More than one phase is used to combine to form hybrid machining.
Water Jet Machining (WJM) – Introduction and machining system
13. What is the full form of WJM in advanced machining processes?
a) Water Jack Manufacturing
b) Water Jet Machining
c) Water Jet Manufacturing
d) Water Jack Manufacturing
Answer: b
Explanation: The full form of WJM is water jet machining in advanced machining
processes.
14. What is the key element of water jet machining for material removal?
a) Tool Holder
b) Work piece
c) Water jet
d) Power source
Answer: c
Explanation: Water jet is the one, which is used to cut the work piece and to remove
material.
15. What is the velocity of water jet stream in water jet machining?
a) 100 m/sec
b) 300 m/sec
c) 700 m/sec
d) 900 m/sec
Answer: d
Explanation: Velocity of water jet stream that is used in Water jet machining is about 900
m/sec.
16. Which of the following is not a part of machining system of Water jet machining?
a) Transducer
b) Accumulator
c) Jet cutting nozzle
d) Hydraulic pump
Answer: a
Explanation: Transducer is not a part of Water jet machining and other components come
under WJM
17. What is the general power rating of the hydraulic pump, used in WJM?
a) 10 kW
b) 20 kW
c) 30 kW
d) 40 kW
Answer: c
Explanation: The power rating of the motor of hydraulic pump, which is used in WJM is
about 30 kW.
18. Which of the following are the components of intensifier present in water jet machining
system?
a) Piston
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b) Plunger
c) Limit switch
d) All of the mentioned
Answer: d
Explanation: The above mentioned components are present in the intensifier of water jet
machining.
19. Intensifier increases the pressure water by which of the following values?
a) 10 – 100 MPa
b) 100 – 200 MPa
c) 200 – 400 MPa
d) 400 – 1000 MPa
Answer: c
Explanation: Use of intensifier is to increase the inlet water pressure to 200 – 400 MPa.
20. On which property of water, will the accumulator in Water jet machining rely on?
a) Density
b) Compressibility
c) Viscosity
d) Velocity
Answer: b
Explanation: Accumulator relies on compressibility of water (12% at 3800bar), in order to
maintain a uniform discharge pressure in WJM.
21. What are the values of typical tube diameters in the machining system in WJM?
a) 0.1 to 1 mm
b) 1 to 6 mm
c) 6 to 14 mm
d) 14 to 25 mm
Answer: c
Explanation: Typical tube diameter values range between 6 to 14 mm.
22. What is the expected life of the nozzles used in WJM?
a) 10 hrs
b) 20 hrs
c) 100 hrs
d) 200 hrs
Answer: d
Explanation: The life that is expected from the nozzle, which is a part of machining
system, is 200 hrs.
23. Which of the following does not damage the nozzle used in Water jet machining?
a) Particles of dirt
b) Mineral deposits
c) Water
d) All of the mentioned
Answer: c
Explanation: Only dirt particles and mineral deposits are responsible for damage of
nozzle.
24. What are the uses of catcher in machining system of Water jet machining?
a) Collecting dirt
b) Collection of debris
c) Reduce noise levels
d) All of the mentioned
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Answer: d
Explanation: Catcher in WJM is used to collect the dirt, machined debris and reduce the
noise levels.
WJM – Process Parameters and Material removal
25. Distance between which components, is the stand-off distance?
a) Nozzle-inlet and work piece top
b) Nozzle-outlet and work piece-top
c) Nozzle-inlet and work piece-bottom
d) Nozzle-outlet and work piece-bottom
Answer: b
Explanation: Stand-off distance is the distance between top of work piece and
nozzle outlet.
26. What is the value of diameter of the jet cutting nozzle in WJM?
a) 0.01 – 0.1 mm
b) 0.1 – 0.3 mm
c) 0.3 – 0.7 mm
d) 0.7 – 1.5 mm
Answer: b
Explanation: In WJM, diameter of the nozzles range between 0.10 – 0.30 mm.
27. What is the value of stand-off distance in Water jet machining?
a) 0.1 – 1 mm
b) 1 – 2 mm
c) 2 – 6 mm
d) 6 – 14 mm
Answer: c
Explanation: Stand-off distance value ranges between 2.5 – 6 mm in Water jet
machining.
28. What are the values of jet velocities in Water jet machining?
a) 100 – 200 m/s
b) 200 – 500 m/s
c) 500 – 1500 m/s
d) 1500 – 3000 m/s
Answer: c
Explanation: Velocity of the water jet stream ranges between 540 – 1480 m/s in WJM.
29. State whether the following statement is true or false.
“As the pump pressure increases, depth of cut decreases in Water jet machining.”
a) True
b) False
Answer: b
Explanation: As the pump pressure is increases, the depth of cut also increases in
WJM.
30. What is the value of material thickness of work piece in WJM?
a) 0.001 – 0.25 mm
b) 0.8 – 25 mm
c) 50 – 100 mm
d) 100 – 500 mm
Answer: b
Explanation: The material thickness value of work piece range between 0.8 – 25 mm.
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31. What is the value of feed rate in Water Jet Machining?
a) 0.0001 – 0.025 m/min
b) 0.05 – 0.25 m/min
c) 0.5 – 200 m/min
d) 200 – 500 m/min
Answer: c
Explanation: In Water jet machining, value of the feed rate ranges between 0.5 – 200
m/min.
32. In WJM, what are the properties of jet fluid that affect the MRR?
a) Velocity
b) Flow rate
c) Viscosity
d) All of the mentioned
Answer: d
Explanation: All the mentioned properties above, of jet fluid affect the MRR in Water jet
machining.
33. Which of the following property/ies of nozzle does not affect the material removal rate in
Water jet machining?
a) Material
b) Diameter
c) Outside temperature
d) Stand-off distance
Answer: c
Explanation: In the nozzle, outside temperature has no effect on the rate of material
removal.
WJM – Applications
34. In the following materials, Water jet machining can be used on which type of material?
a) Metals
b) Plastics
c) Ceramics
d) All of the mentioned
Answer: d
Explanation: WJM can be used on metals, cloth, paper, plastics, food, leather, and
ceramics.
35. What are the processes and applications, where Water jet machining can be used?
a) Cutting
b) Drilling
c) Deburring
d) All of the mentioned
Answer: d
Explanation: Water jet machining can be used for drilling, cutting, deburring, surface
treatment and many more applications.
36. What is the tolerance limit range of thin materials in WJM?
a) ± 0.1 mm
b) ± 10 mm
c) ± 25 mm
d) ± 50 mm
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Answer: c
Explanation: In Water jet machining, the range of tolerance is ± 25 mm.

37. In cutting of rocks using water jet machining, which type of pressure is needed?
a) Low pressure
b) Medium pressure
c) High pressure
d) None of the mentioned
Answer: c
Explanation: In WJM, very high pressures and velocities are needed while cutting rocks.

38. In deburring, which combination removes the material from non-metallic materials?
a) High pressure and low flow rate
b) High pressure and high flow rate
c) Low pressure and low flow rate
d) Low pressure and high flow rate
Answer: a
Explanation: For non-metallic materials high pressure and lower flow rates are used in
deburring.
39. Which of the following materials has some drawbacks of cutting WJM?
a) Food
b) Rocks
c) Fibre-reinforced plastics
d) None of the mentioned
Answer: c
Explanation: Water gets deflected due to the fibre embedded in the matrix of fibre-
reinforced plastics when we use WJM.

40. What is the accuracy level obtained when PCB’s are cut by WJM?
a) ± 0.05 mm
b) ± 0.13 mm
c) ± 0.26 mm
d) ± 0.33 mm
Answer: b
Explanation: In WJM, accuracy obtained in cutting of PCB’s is ± 0.13 mm.

41. In WJM, surface treatment includes which type of processes?
a) Removing deposits
b) Removing chemicals
c) Degreasing
d) All of the mentioned
Answer: d
Explanation: Surface treatment is done using WJM to clean the surface from many toxic
chemical, deposits, residues etc

WJM – Advantages and Disadvantages
42. In how many directions, can the cutting takes place in Water jet machining?
a) Uni-directional
b) Bi-directional
c) Multi-directional
d) None of the mentioned
Answer: c
Explanation: Water jet machining has multi directional cutting capacity i.e.., in any
direction in three dimensional space.

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43. In Water jet machining, cuts can be started at which place of workpiece?
a) From left
b) From right
c) From middle
d) From any point
Answer: d
Explanation: In WJM, cuts can be started from any point on the workpiece.

44. State whether the following statement is true or false.
“To start the cuts in Water jet machining, pre-drilled holes are not necessary.”
a) True
b) False
Answer: b
Explanation: In Water jet machining, we need not require any pre-drilled holes to start
the cuts.

45. Which of the following is not an advantage of Water jet machining?
a) Burr produced is minimal
b) No Heat is produced
c) Relatively low hourly rates
d) Environmentally safe
Answer: c
Explanation: Costs per hour are relatively high in Water jet machining.

46. In Water jet machining, tool need not require sharpening once the machining is done.
a) True
b) False
Answer: a
Explanation: Tool does not wear in water jet machining, so it need not be sharpened.

47. Which of the following secondary processes are eliminated in Water jet machining?
a) Grinding of surface
b) Surface treatment
c) Polishing of surface
d) All of the mentioned
Answer: d
Explanation: All the mentioned secondary processes above, are eliminated in Water jet
machining.

48. How many parts are cut using Water jet machining, on a single blank?
a) One part
b) Two parts
c) Three parts
d) Multiple parts
Answer: d
Explanation: Depending up on the kerf width, multiple parts can be machined using a
single blank.

49. Which of the following is the disadvantage of water jet machining?
a) Narrow kerf width
b) Small diameter of nozzle
c) Not suitable for mass production
d) Burr is minimal
Answer: c
Explanation: Due to high maintenance, WJM cannot be used for mass production.
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Abrasive Jet Machining (AJM) – Introduction and Machining system
50. . In advanced machining processes, what is the full form of AJM?
a) Automatic Jet Manufacturing
b) Abrasive Jet Machining
c) Automated Jet Machining
d) Abrasive Jet Manufacturing
Answer: b
Explanation: In advanced machining processes, full form of AJM is Abrasive jet
machining.

51. In AJM, which of the following materials are used as abrasive grains?
a) Al
2
O
3

b) SiC
c) Glass beads
d) All of the mentioned
Answer: d
Explanation: In Abrasive jet machining, any of the particles mentioned above can be
used as abrasive grains.

52. In Abrasive jet machining, work piece material of removed by which of the following
means?
a) Vaporization
b) Electro plating
c) Mechanical abrasion
d) Corrosion
Answer: c
Explanation: Abrasive particles hit the surface with high pressure and high velocities,
which removes the material.

53. Which type of materials can be machined using Abrasive jet machining?
a) Glass
b) Ceramics
c) Hard materials
d) All of the mentioned
Answer: d
Explanation: Materials like ceramics, glass, hard and super hard materials can be
machined using Abrasive jet machining.

54. In machining system of AJM, which is the medium of carrying the abrasive grains for
machining?
a) Liquids
b) Gases
c) Any fluids
d) None of the mentioned
Answer: b
Explanation: In AJM, different types of gases are used as the medium for carrying
abrasives.

55. In machining system of AJM, what is/are the gas/es used for carrying the abrasives?
a) CO
2

b) Air
c) Nitrogen
d) All of the mentioned
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Answer: d
Explanation: In AJM, gases like CO
2
, air or nitrogen are used to carry the abrasives.

56. What is the pressure of gas that is to be supplied, for carrying the abrasives?
a) 0.1 to 1.0 kg/cm
2

b) 2.0 to 8.0 kg /cm
2

c) 10.0 to 18.0 kg/cm
2

d) 25.0 to 35.5 kg/cm
2

Answer: b
Explanation: The pressure of the carrying gas should range between 2 to 8 kg/cm
2
.

57. Which of the following gas, should never be used as the carrier of abrasives?
a) Nitrogen
b) CO
2

c) Oxygen
d) Air
Answer: c
Explanation: Oxygen should not be used as carrier because it causes a violent chemical
reaction with abrasives or work piece.

58. What is the frequency of mixing chamber, consisting of gas and abrasives?
a) 10 Hz
b) 30 Hz
c) 50 Hz
d) 70 Hz
Answer: c
Explanation: Mixing chamber consisting of carrier gas and the abrasive grains, vibrates
at a frequency of 50 Hz.

59. In Abrasive jet machining, what may be the size of the abrasive grains used?
a) 10 – 40 µm
b) 50 – 100 µm
c) 100 – 150 µm
d) 200 – 300 µm
Answer: a
Explanation: Abrasive grains of size, between 10 – 40 µm can be used for machining.
60. What are the processes where Abrasive jet machining can be used?
a) Cleaning
b) Cutting
c) Deburring
d) All of the mentioned
Answer: d
Explanation: Abrasive jet machining can be used for deburring, cutting, cleaning and for
many other heavy duty applications.

61. State whether the following statement is true or false.
“In Abrasive jet machining, commercial grades powders can be used for machining.”
a) True
b) False
Answer: b
Explanation: For AJM, commercial grade powders are not used because their sizes are
not classified widely.

62. In machining system of AJM, which of the following controls the relative motion between
work piece and nozzle?
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Unconventional Machining Processes Solved MCQs

Unconventional Machining Processes Solved MCQs

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