Updated Mechanical Engineering MCQs – Thermal Processes ( Advanced Machining Processes ) MCQs

Updated Mechanical Engineering MCQs – Thermal Processes ( Advanced Machining Processes ) MCQs

Latest Mechanical Engineering MCQs

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Mechanical Engineering MCQs – Thermal Processes ( Advanced Machining Processes ) MCQs

The most occurred mcqs of Thermal Processes ( ) in past papers. Past papers of Thermal Processes ( Advanced Machining Processes ) Mcqs. Past papers of Thermal Processes ( Advanced Machining Processes ) Mcqs . Mcqs are the necessary part of any competitive / job related exams. The Mcqs having specific numbers in any written test. It is therefore everyone have to learn / remember the related Thermal Processes ( Advanced Machining Processes ) Mcqs. The Important series of Thermal Processes ( Advanced Machining Processes ) Mcqs are given below:

EDM-Applications – 1

1. Which of the following shapes can be produced using Electro discharge machining?
a) Complex shapes
b) Simple shapes
c) All of the mentioned
d) None of the mentioned
Answer: c
Explanation: Electro discharge machining is used to machine complex shapes to a high degree of accuracy.

2. Which of the following materials can be machined using Electro discharge machining?
a) Heat resistant alloys
b) Super alloys
c) Carbides
d) All of the mentioned
Answer: d
Explanation: EDM is used to machine materials such as carbides, heat resistant and super alloys which are difficult-to-machine materials.

3. Which of the following are the applications of Electro discharge machining?
a) Holes
b) Slots
c) Texturing
d) All of the mentioned
Answer: d
Explanation: Micromachining of holes, slots, dies, texturing, milling, surface modification and mechanical pulsing are some typical applications of Electro discharge machining.

4. State whether the following statement is true or false regarding the applications of EDM.
“In advanced machining processes, the incorporation of EDM with CIM increased the length of time for unit operation.”
a) True
b) False
Answer: b
Explanation: The incorporation of EDM in CIM reduced the length of time per unit operation.

5. Which type of electrode is used for drilling in Electro discharge machining?
a) Flat electrode
b) Cuboidal electrode
c) Tubular electrode
d) Spherical electrode
Answer: c
Explanation: Tubular electrode is mostly preferred in Electro discharge machining, for drilling purpose.

6. The dielectric fluid is flushed in thorough which part of the electrode in drilling in EDM?
a) Interior hole
b) Side gaps
c) All of the mentioned
d) None of the mentioned
Answer: a
Explanation: EDM drilling uses a tubular electrode which flushes the dielectric thorough the interior holes for removing debris.

7. Which type of holes can be produced through drilling using Electro discharge machining?
a) Irregular
b) Curved
c) Tapered
d) All of the mentioned
Answer: d
Explanation: Drilling of work piece using EDM produced holes which can be irregular, curved, tapered as well as inclined holes.

8. What are the values of general feed rates used for drilling in EDM?
a) 0.1 mm/min
b) 0.3 m/min
c) 0.5 mm/min
d) 0.7 mm/min
Answer: a
Explanation: Usually a feed rate of 0.10 mm/min is used for drilling the work piece using Electro discharge machining.

9. What are range of diameter values obtained by drilling using EDM?
a) 0.01 to 0.05 mm
b) 0.1 to 0.5 mm
c) 1 to 5 mm
d) 10 to 15 mm
Answer: b
Explanation: Diameter values while drilled using Electro discharge machining, ranges from 0.10 to 0.50 mm.

10. What are the values of overcuts left behind after drilling of work piece?
a) 0.01 to 0.05 mm
b) 0.1 to 0.5 mm
c) 1 to 5 mm
d) 10 to 15 mm
Answer: a
Explanation: Overcut values from 0.01 to 0.05 mm are obtained after the drilling process in EDM.

11. Electro discharge sawing is an application of EDM which employs __________ as tool material.
a) Steel band
b) Disc
c) Steel band & Disc
d) None of the mentioned
Answer: c
Explanation: Electro discharge sawing is an application of EDM which employs either steel band or disc as tool.

12. When compared to the conventional abrasive sawing, how many times faster is the MRR?
a) Twice
b) Thrice
c) Four
d) Five
Answer: a
Explanation: Electro discharge sawing cuts the work piece material at the rates which are twice that of conventional abrasive sawing method.

13. How much amount of burr is produce while machined using Electro discharge sawing?
a) 10%
b) 20%
c) 50%
d) No Burr
Answer: d
Explanation: The cuts produced in Electro discharge sawing have smaller kerf widths which hav no burrs in it.

14. What are the values of finish obtained by machining work piece thorough Electro discharge sawing?
a) 0.1 to 4 µm
b) 6.3 to 10 µm
c) 12.4 to 23 µm
d) 25.6 to 40 µm
Answer: b
Explanation: The finish obtained ranges from 6.3 to 10 µm when machined using Electro discharge sawing.

15. What are the recast layer thickness values obtained in ED sawing?
a) 0.001 to 0.022 mm
b) 0.025 to 0.130 mm
c) 0.236 to 0.352 mm
d) 0.432 to 0.568 mm
Answer: b
Explanation: The recast layer thickness values obtained from ED sawing range from 0.025 to 0.13 mm.

EDM-Applications – 2

1. Which of the following electrodes are used for machining spherical surfaces in Electro discharge machining?
a) Tubular electrodes
b) Flat electrodes
c) Cuboidal electrodes
d) All of the mentioned
Answer: a
Explanation: Simple tubular electrodes are used to machine convex and concave spherical surfaces.

2. What are the values of dimensional accuracy obtained while machining spherical surfaces?
a) ± 1 µm
b) ± 3 µm
c) ± 5 µm
d) ± 7 µm
Answer: a
Explanation: Dimensional accuracy of ± 1 µm is obtained while machining spherical surfaces using EDM.

3. What are the surface roughness values obtained while machining spherical surfaces using Electro discharge machining?
a) <0.1 µm
b) <0.3 µm
c) <0.5 µm
d) <0.7 µm
Answer: a
Explanation: The surface roughness values obtained while machining of spherical surfaces are <0.1 µm in Electro discharge machining.

4. Which motion of tool is used for machining spherical surfaces in Electro discharge machining?
a) Oscillatory
b) Vibratory
c) Rotary
d) All of the mentioned
Answer: c
Explanation: The rotary motion tool is used for machining spherical surfaces of conducting ceramic materials in EDM.

5. Which type of electrodes are used for milling application in Electro discharge machining process?
a) Tubular type electrodes
b) Cylindrical type electrodes
c) Flat type electrodes
d) Spherical type electrodes
Answer: b
Explanation: Standard cylindrical electrodes are used for milling application in EDM process.

6. Which type of cavities can be machined using milling process by Electro discharge machining?
a) Complex cavities
b) Simple cavities
c) Simple & Complex cavities
d) None of the mentioned
Answer: c
Explanation: Simple cavities and complex cavities are machined by successive NC sweeps of electrode over the desired path.

7. The simple electrodes are rotated at which speed for milling of work pieces in Electro discharge machining?
a) Very low
b) Low
c) Medium
d) High
Answer: d
Explanation: Simple electrodes are rotated at high speeds for milling in Electro discharge machining same as that of conventional milling.

8. What happens to the dielectric flushing while milling tool is rotated at a high speed in EDM?
a) Improved
b) Worsen
c) Reduced
d) All of the mentioned
Answer: a
Explanation: Milling by electro discharge machining enhances the dielectric flushing due to high speed rotation of tool.

9. State whether the following statement is true or false regarding the applications of EDM.
“In EDM, milling process can machine complex shapes with sharp corners.”
a) True
b) False
Answer: b
Explanation: EDM milling has a main limitation i.e.., it cannot machine complex shapes with sharp tools because of rotating tool.

10. Which of the following are the steps included in the die sinking process of EDM?
a) CAD of electrode
b) Electrode manufacturing
c) Programming for die sinking
d) All of the mentioned
Answer: d
Explanation: Designing of electrode, then manufacturing, and programming of die sinking are the steps to be followed for die sinking process in EDM.

11. Wire EDM is a special form of Electro discharge machining which contains __________ electrode.
a) Continuously moving
b) Periodically moving
c) Discontinuously moving
d) All of the mentioned
Answer: a
Explanation: Wire EDM is a special type of EDM which uses a continuously moving electrode for removal of material.

12. Which path of the components in wire EDM determines the path to be machined?
a) Horizontal worktable movement
b) Vertical worktable movement
c) Horizontal & Vertical worktable movement
d) None of the mentioned
Answer: a
Explanation: Horizontal movement of the work table determines the path to be machined in Wire Electro discharge machining.

 

Thermal Process MCQs

 

13. Which of the following materials are machined using Wire Electro discharge machining?
a) Polycrystalline diamond
b) Cubic Boronitride
c) Matrix composites
d) All of the mentioned
Answer: d
Explanation: Polycrystalline diamond (PCD), cubic boron nitride (CBN) and other matrix composites are the material than can be machined using wire EDM.

14. How much amount of burr is produce when we use Wire Electro discharge machining for machining of work pieces?
a) 10%
b) 20%
c) No burr
d) Small amount
Answer: c
Explanation: In Wire Electro discharge machining no burr is produced without any distortion while machining work pieces.

15. Which of the following industries use wire EDM for different applications?
a) Chemical industry
b) Aerospace industry
c) Automobile industry
d) All of the mentioned
Answer: d
Explanation: Industries such as chemical, aerospace, automobile, nuclear etc.., use wire EDM for a wide variety of applications in their industries.

EDM-Applications – 3

1. While machining insulating ceramic materials using EDM, where is the sheet metal placed?
a) Over material
b) Below material
c) Under material
d) None of the mentioned
Answer: a
Explanation: Sheet metal is placed over the material in machining of insulating materials using EDM.

2. Sparks occur between which of the following components?
a) Work piece and sheet metal
b) Tool electrode and sheet metal
c) Work piece and electrode
d) None of the mentioned
Answer: b
Explanation: Sparks occur between sheet metal and tool electrode for macining insulating ceramics.

3. Texturing is applied to the steel sheets at which stages of cold rolling?
a) Initial stages
b) Middle stages
c) Final stages
d) All of the mentioned
Answer: a
Explanation: At the final stages of cold rolling, texturing is applied to the steel sheets.

4. What is the full form of EDT in EDM processes?
a) Electro discharge Tinplating
b) Electro discharge Texturing
c) Electro discharge Tapping
d) Electro discharge Turing
Answer: b
Explanation: Electro Discharge Texturing is a variant of EDM which is the full form of EDT.

5. Which of the following are the process variables for texturing process in EDM?
a) Pulse current
b) Electrode polarity
c) Dielectric type
d) All of the mentioned
Answer: d
Explanation: Pulse current, polarity, dielectric, electrode material and roll rotation speed are some process variables of texturing.

6. What are the values of current amplitudes used in EDT?
a) 0.2 to 1 A
b) 2 to 10 A
c) 20 to 100 A
d) 40 to 200 A
Answer: b
Explanation: The values of current amplitudes in EDT range from 2 to 10 A.

7. What are duration values of current amplitude in EDT?
a) 0.1 to 1 µs
b) 1 to 10 µs
c) 10 to 100 µs
d) 100 to 1000 µs
Answer: c
Explanation: Duration of current amplitudes used for EDT range from 10 to 100 µs.

8. What are the spindle rotation speeds used in EDT?
a) 1 to 4 rpm
b) 10 to 40 rpm
c) 20 to 60 rpm
d) 30 to 90 rpm
Answer: b
Explanation: Spindle rotation speeds for EDT process range from 10 to 40 rpm.

9. What are the values of diameter which are machined using Micro-EDM?
a) 0.001 to 0.01 mm
b) 0.01 to 0.1 mm
c) 0.1 to 1 mm
d) 1 to 10 mm
Answer: c
Explanation: Values of diameter in Micro-EDM range from 0.10 to 1.0 mm.

10. What happens to the machine capital cost in EDT when there is an increase in tool quantity?
a) Decreases
b) Increases
c) Remains same
d) None of the mentioned
Answer: b
Explanation: With increase in tools quantity machine cost increases but texturing cost reduces.

11. What is the value of depth to diameter ratio in Micro-Electro discharge machining process?
a) 10:1
b) 5:2
c) 4:3
d) 2:1
Answer: a
Explanation: Value of the depth to diameter ratio in Micro-Electro discharge machining is about 10:1.

12. What are the values of depths that can be machined using Micro-EDM?
a) 1 mm
b) 10 mm
c) 100 mm
d) 1000 mm
Answer: c
Explanation: Micro-Electro discharge machining can machine up to a depth of 100 mm in the work piece material.

13. What are the machining rates used in Micro-EDM process?
a) 0.1 to 2 mm/min
b) 1 to 20 mm/min
c) 10 to 200 mm/min
d) 100 to 500 mm/min
Answer: b
Explanation: Machining rates used in Micro-EDM process range from 1 to 20 mm/min.

14. What are the values of hole diameters obtained using Wire electro discharge grinding?
a) 1 µm
b) 3 µm
c) 5 µm
d) 7 µm
Answer: c
Explanation: Values of hole diameters up to 5 µm can be obtained using Wire electro discharge grinding process.

15. What are the feed rates used in WEDG process?
a) 1 to 5 mm/min
b) 5 to 10 mm/min
c) 10 to 15 mm/min
d) 15 to 20 mm/min
Answer: b
Explanation: Feed rate values in WEDG process range from 5 to 10 mm/min.

EDM-Process Control, Automation, Environmental Impact

1. Which of the following is a major difficulty in the Electro discharge machining process?
a) Proper sparks
b) Abnormal discharges
c) Optimum feed rates
d) No burr
Answer: b
Explanation: Avoidance of abnormal discharges has become a major difficulty in Electro discharge machining process.

2. What has been done to the off time when there is a no-load voltage of electric discharge?
a) Increased
b) Decreased
c) Reduced
d) Remains same
Answer: a
Explanation: The off time of pulse is increased in order to avoid the abnormal electric discharges.

3. In a simple application which of the following parameters are inputs?
a) Pulse duration and current
b) Normal and abnormal pulses
c) All of the mentioned
d) None of the mentioned
Answer: a
Explanation: Inputs used are pulse duration and current in a simple application.

4. In a simple application which of the following parameters are outputs?
a) Pulse duration and current
b) Normal and abnormal pulses
c) All of the mentioned
d) None of the mentioned
Answer: a
Explanation: Outputs used are normal and abnormal pulses in a simple application.

5. Which of the following are correlated with the machining conditions at output stage?
a) Machining depth
b) Surface roughness
c) Accuracy
d) All of the mentioned
Answer: d
Explanation: Machining depth, surface roughness, accuracy are correlated with the machining conditions at the output stage.

6. How are EDM’s levels of integration when compared to conventional machining?
a) Slower rate
b) Faster rate
c) Same rate
d) None of the mentioned
Answer: a
Explanation: EDM’s levels of computer integration is at a slower rate when compared to conventional machining processes.

7. Manufacturing of tool electrode undergoes which of the following processes?
a) Milling
b) Turning
c) Finishing
d) All of the mentioned
Answer: d
Explanation: The tool electrode manufacturing used in EDM has to undergo the basic production processes such as milling, turning and finishing.

8. High temperatures produced in the working gap results in which of the following potentials?
a) Hazardous smoke
b) Toxic vapours
c) Aerosols
d) All of the mentioned
Answer: d
Explanation: The temperatures in the working gap increases leading to hazardous smoke, vapours and aerosols.

9. Hydro carbons present in the dielectric fluid have impact on which of the body parts?
a) Eyes
b) Teeth
c) Skin
d) Nails
Answer: c
Explanation: Hydrocarbons present in dielectric fluids of EDM will have a negative impact on the skin in our body.

10. What happens to the Electro discharge machining process under unfavourable working conditions?
a) Will remain stable
b) Explosion may occur
c) Machining rate increases
d) Nothing happens
Answer: b
Explanation: Explosion occurs if Electro discharge machining is done under unfavourable process variables and conditions.

11. Reduction in the electrical energy consumption will have impact on which aspects mentioned below?
a) Environmental
b) Economic
c) Environmental & Economic
d) None of the mentioned
Answer: c
Explanation: The reduction of electric energy consumption has economic as well as environmental benefits.

Laser Beam Machining-Introduction

1. What is the full form of LBM in advanced machining processes?
a) Laser Beam Manufacturing
b) Laser Beam Machining
c) Light Blast Manufacturing
d) Light Beam Machining
Answer: b
Explanation: The full form of LBM is Laser Beam Machining in the advanced machining processes.

2. LBM offers a good solution for which material properties below?
a) Thermal conductivity
b) Specific heat
c) Boiling temperature
d) All of the mentioned
Answer: d
Explanation: LBM offers good solution for material properties such as thermal conductivity, specific heat, melting and boiling temperatures.

3. What is the abbreviation of Laser?
a) Light allowed simple emission of radiation
b) Light amplification by stimulated emission of radiation
c) Light amplified simultaneous emission of rays
d) Light amplified stimulated emanation of rays
Answer: b
Explanation: Full form of laser is Light Amplification by Stimulated emission of radiation.

4. Which of the following are the properties of a laser?
a) Highly collimated
b) Monochromatic
c) Coherent light beam
d) All of the mentioned
Answer: d
Explanation: Highly collimated, high monochromaticity and the coherence of the light beam are the properties of a laser.

5. Laser beam machining uses which type of power sources for machining?
a) Very low power
b) Low power
c) Medium power
d) High power
Answer: d
Explanation: High power densities are used for the generation of laser and for machining in Laser beam machining.

6. Which of the following are different types of lasers used in Laser beam machining?
a) Solid-state ion
b) Neutral gas
c) Semiconductor
d) All of the mentioned
Answer: d
Explanation: Laser such as solid-state ion, neutral gas, molecular, semiconductor etc.., can be used in LBM.

7. Which types of lasers are used in Laser beam machining?
a) Continuous wave
b) Pulsed mode
c) Continuous wave & Pulsed mode
d) None of the mentioned
Answer: c
Explanation: Laser may be in continuous wave (CW) or in Pulsed mode (PM) for machining in LBM.

8. What is the wavelength value of Ruby laser used in Laser beam machining?
a) 633 nm
b) 694 nm
c) 856 nm
d) 1064 nm
Answer: b
Explanation: The value of wave length of Ruby laser used in Laser Beam machining is 694 nm.

9. What is the wavelength value of Nd-YAG and Nd-glass lasers used in LBM?
a) 633 nm
b) 694 nm
c) 856 nm
d) 1064 nm
Answer: d
Explanation: The value of wave length of Nd-YAG and Nd-glass lasers used in LBM is 1064 nm.

10. What is the wavelength value of neutral gas laser used in LBM?
a) 633 nm
b) 694 nm
c) 856 nm
d) 1064 nm
Answer: a
Explanation: The value of wave length of Neutral gas laser used in Laser beam machining is 633 nm.

11. What is the wavelength value of CO2 laser used in Laser beam machining?
a) 0.16 μm
b) 1.6 μm
c) 10.6 μm
d) 106 μm
Answer: c
Explanation: The value of wave length of CO2 laser used in Laser Beam machining is 10.6 μm.

12. What are the values of wavelengths of GaAs laser used in LBM?
a) 100 – 200 nm
b) 200 – 400 nm
c) 600 – 700 nm
d) 800 – 900 nm
Answer: d
Explanation: The wavelengths of GaAs laser used in LBM range from 800 – 900 nm.

13. What are the values of wavelengths of Excimer laser used in LBM?
a) 100 – 200 nm
b) 200 – 500 nm
c) 600 – 700 nm
d) 800 – 900 nm
Answer: b
Explanation: The wavelengths of Excimer laser used in LBM range from 200 – 500 nm.

14. What are the values of wavelengths of Argon laser used in LBM?
a) 120 – 230 nm
b) 220 – 310 nm
c) 330 – 530 nm
d) 760 – 940 nm
Answer: c
Explanation: The wavelengths of Argon laser used in LBM range from 330 – 530 nm.

LBM-Material Removal

1. What is the material removal mechanism of Laser beam machining process?
a) Melt and evaporate
b) Electro chemical corrosion
c) Mechanical erosion of materials
d) Electro chemical dissolution
Answer: a
Explanation: The material is removed by melting and evaporation in Laser Beam Machining process.

2. Physics of laser is very complex due to which of the reasons below?
a) Scattering loss
b) Reflection loss
c) Scattering & Reflection loss
d) None of the mentioned
Answer: c
Explanation: Physics of laser is very complex because of scattering and reflection losses.

3. What happens when the heat is diffused into bulk material?
a) Phase change occurs
b) Melting occurs
c) Vaporization may take place
d) All of the mentioned
Answer: d
Explanation: The heat diffusion into bulk material causes phase change, melting or vaporization in the materials.

4. State whether the following statement is true of false regarding LBM.
“In LBM, high intensity laser beams are recommended for more material.”
a) True
b) False
Answer: b
Explanation: High intensity laser beams are not recommended since they form a plasma plume near surface of material.

5. What happens to the process efficiency if plasma plumes are formed in LBM?
a) Increases
b) Enhances
c) Decreases
d) Improves
Answer: c
Explanation: In Laser beam machining, the process efficiency is reduced due the absorption and scattering loses when plasma plumes are formed.

6. Machining of LBM takes place when power density is ____________ than what is lost by conduction and radiation.
a) Greater
b) Smaller
c) Lower
d) Same as
Answer: a
Explanation: Machining of laser takes place when power density is greater than what is lost by conduction, convection and radiation.

7. Which of the following phenomenon take place before melting and evaporating in LBM?
a) Conduction
b) Reflection
c) Absorption
d) All of the mentioned
Answer: d
Explanation: Material in LBM is removed through several effects such as conduction, absorption, reflection following melting and evaporation.

8. What happens to the material removal rate when reflectivity is higher?
a) Will decrease
b) Will increase
c) Will enhance
d) Remains same
Answer: a
Explanation: In LBM, as the reflectivity of the metals is increased the material removal rates of the process are decreased.

 

Electrochemical Processes MCQs

 

9. Reflectivity of the materials depends on which of the following factors?
a) Wave length
b) Properties of material
c) Surface finish
d) All of the mentioned
Answer: d
Explanation: Reflectivity of the materials depends on wavelength, the properties of materials, surface finish and temperature.

10. How much amount of incident radiation is reflected at lower power densities?
a) 10 percent
b) 20 percent
c) 50 percent
d) 90 percent
Answer: d
Explanation: Most of the metals reflect nearly 90 percent of incident radiation if the power densities are low.

11. How are minimum energies required for plastics when compared to that required for metals?
a) Lower than
b) Higher than
c) Same as
d) None of the mentioned
Answer: a
Explanation: The minimum energies required for plastic are lower than that required for metals.

12. Which of the following has high machining speeds in Laser Beam Machining?
a) Metals
b) Non metals
c) Metal alloys
d) All of the mentioned
Answer: b
Explanation: Non metallic material machine at higher speeds than metallic ones due to higher reflectivity in metallic materials.

LBM-Applications – 1

1. Which of the following are the applications of Laser Beam Machining?
a) Drilling
b) Cutting
c) Texturing
d) All of the mentioned
Answer: d
Explanation: Drilling, cutting and grooving, texturing and structuring, milling and dressing etc.., are the applications of Laser beam machining process.

2. State whether the following statement is true or false regarding the drilling using LBM.
“Compared to LBM, conventional machining is more accurate and efficient.”
a) True
b) False
Answer: b
Explanation: Conventional machining is less sufficient than Laser Beam machining because of their material toughness.

3. Other non-conventional processes lay behind Laser beam machining in drilling process because of which factors below?
a) High cost
b) Long lead times
c) Low machining speeds
d) All of the mentioned
Answer: d
Explanation: Other non-conventional processes need high costs for tools, long lead times, and low machining speeds when compared to LBM.

4. Laser drilling has proven to be more efficient in which of the following factors?
a) Cost
b) Quality
c) Reliability
d) All of the mentioned
Answer: d
Explanation: Laser drilling has proven to be an efficient one in terms of cost, quality, and reliability for large-scale production applications.

5. Which of the following are different laser drilling processes in Laser beam machining?
a) Direct drilling
b) Drill and ream
c) Trepanning
d) All of the mentioned
Answer: d
Explanation: Laser drilling can be performed by three methods that are – direct (percussion) drilling, trepanning, drill and ream.

6. The hole size in direct drilling depend up on which of the factors below?
a) Input power
b) Focusing adjustments
c) Input power & Focusing adjustments
d) None of the mentioned
Answer: c
Explanation: The hole size in the direct drilling method of Laser drilling process, depend on input power and focusing adjustments.

7. Which method mentioned below is used for drilling of large size holes?
a) Direct drilling
b) Drill and ream
c) Trepanning
d) All of the mentioned
Answer: c
Explanation: Trepanning method of laser drilling process is used for drilling large holes either by rotating or moving the part.

8. What are the values of diameters obtained by using Laser drilling process?
a) 0.0001 – 0.001 mm
b) 0.001 – 0.01 mm
c) 0.005 – 1.25 mm
d) 1.5 – 10.5 mm
Answer: c
Explanation: Values of diameters obtained by using Laser drilling process range between 0.005 – 1.27 mm.

9. What is the value the maximum optimum depth that can be machined using Laser drilling process?
a) 0.17 mm
b) 1.7 mm
c) 17.1 mm
d) 171.7 mm
Answer: b
Explanation: The maximum depth obtained when by using laser drilling is about 1.7 mm.

10. What are the values of entrance angles that vary in Laser drilling process?
a) 0.1 – 1 oC
b) 1 – 5 oC
c) 15 – 90 oC
d) 90 – 150 oC
Answer: c
Explanation: Values of the entrance angles in Laser drilling process range between 15 – 90 oC.

11. The taper obtained in Laser drilling process is how much of the hole diameter?
a) 1 – 5%
b) 5 – 20%
c) 20 – 50%
d) 50 – 90%
Answer: b
Explanation: Taper value obtained in Laser drilling process range between 5 – 20% of the hole diameter.

12. What is the depth-to-diameter ratio obtained in drilling process using Laser beam machining?
a) 10:1
b) 20:1
c) 50:1
d) 80:1
Answer: c
Explanation: Value of the maximum depth-to-diameter ratio obtained in drilling using Laser beam machining is 50:1.

13. What is the maximum value of drilling depth in trepanning method of laser drilling process?
a) 1.7 mm
b) 4.3 mm
c) 6.4 mm
d) 7.9 mm
Answer: c
Explanation: The depth increases when we use a trepanning method for laser drilling process and that is about 6.40 mm.

14. What are the tolerance values obtained when we use laser drilling process?
a) 0.1 – 5%
b) 5 – 20%
c) 25 – 50%
d) 50 – 80%
Answer: b
Explanation: The tolerance values are will range between 5 – 20% of the diameters obtained in Laser drilling process.

15. What is the value of minimum corner radius obtained by drilling in Laser beam machining?
a) 0.10 mm
b) 0.25 mm
c) 0.50 mm
d) 0.65 mm
Answer: b
Explanation: The value of the minimum corner radius obtained while drilling using LBM is about 0.25 mm.

LBM-Applications – 2

1. Peak power should be increased in Laser drilling process by __________ pulse energy.
a) Increasing
b) Decreasing
c) Reducing
d) Constant
Answer: a
Explanation: Required peak power in the laser drilling process can be obtained by increasing the pulse energy while keeping the pulse duration constant.

2. Drilling of holes with larger pulse duration causes which effect to the holes produced?
a) Enlarge holes
b) Reduce hole size
c) Decrease the depth
d) All of the mentioned
Answer: a
Explanation: Drilling the holes with larger pulse duration causes enlargement of the hole entrance.

3. What are pulse duration values used for laser drilling?
a) 0.01 to 0.25 ms
b) 0.1 to 2.5 ms
c) 1 to 25 ms
d) 10 to 250 ms
Answer: b
Explanation: Value of the duration of the pulse range from 0.1 to 2.5 ms.

4. _________ pulse energy and _________ pulse duration are suitable for drilling.
a) Low, short
b) Low, long
c) High, short
d) High, long
Answer: c
Explanation: In LBM, high energy pulses and low pulse duration are more suitable for hole drilling in aerospace materials.

5. Which of the following are the functions of assist gases?
a) Removal of molten material
b) Shield the lenses
c) Better efficiency
d) All of the mentioned
Answer: d
Explanation: Assist are used to remove the molten material, it also shield the lenses from expelled material and they are also used for obtaining better process efficiencies.

6. Selection of assist gas depends on which of the following properties of work piece?
a) Material
b) Thickness
c) Material & Thickness
d) None of the mentioned
Answer: c
Explanation: The selection of different assist gases depends on the work piece material and its thickness.

7. Which of the following properties of material affect the quality of holes obtained?
a) Reflectivity
b) Absorption coefficient
c) Thermal conductivity
d) All of the mentioned
Answer: d
Explanation: Quality of holes depend on reflectivity, absorption coefficient, thermal conductivity, density, specific heat, and latent heat of material.

8. What range of powers are used for cutting through steel?
a) 1 to 20 W
b) 20 to 100 W
c) 200 to 1000 W
d) 1 to 20 kW
Answer: c
Explanation: The power ranges from 200 W to 1 kW for cutting through steel.

9. Which gas jet assisted process is suitable for most of the metals?
a) Oxygen gas
b) Nitrogen gas
c) Helium gas
d) All of the mentioned
Answer: a
Explanation: Oxygen-jet assistance is used for most metals, as the gas liberates additional energy by the exothermal chemical reactions.

10. What happens to the cutting speed with an increase in the work piece?
a) Increases
b) Decreases
c) Enhances
d) Remains same
Answer: b
Explanation: The cutting speed of the process of drilling decreases with an increase in the thickness of the work piece material.

11. What is the full form of LBT in the processes of LBM?
a) Laser Beam Tempering
b) Laser Beam Templating
c) Laser Beam Texturing
d) Laser Beam Tinning
Answer: c
Explanation: Full form of LBT is Laser beam texturing which is an application of Laser beam machining.

12. Depth and the crater size depends on which of them below?
a) Energy of beam
b) Dwell time of beam
c) Energy & Dwell time of beam
d) None of the mentioned
Answer: c
Explanation: Depth and the crater size depend on the energy and the dwell time of beam.

13. Where are the textured surfaces used that are obtained in LBT?
a) Mould makings
b) Bearings
c) Printer roll manufacturing
d) All of the mentioned
Answer: d
Explanation: Textured surfaces obtained in LBT are widely used in mold making, bearings and printer roll manufacturing.

14. The roll is _________ and the laser beam is moved ________ along the roll.
a) Stationary, axially
b) Stationary, perpendicularly
c) Rotated, axially
d) Rotated, perpendicularly
Answer: c
Explanation: In texturing process of LBT, the roll is rotated and laser is moved axially along the roll.

15. State whether the following statement is true regarding the texturing in LBT.
“In LBT, hardness of the material is a limitation to the process.”
a) True
b) False
Answer: b
Explanation: In Laser beam texturing, hardness of material is not a limitation to the process.

Updated Mechanical Engineering MCQs – Thermal Processes ( Advanced Machining Processes ) MCQs

Author: Abdullah

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