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

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

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

The most occurred mcqs of Electrochemical Processes ( ) in past papers. Past papers of Electrochemical Processes ( Advanced Machining Processes ) Mcqs. Past papers of Electrochemical 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 Electrochemical Processes ( Advanced Machining Processes ) Mcqs. The Important series of Electrochemical Processes ( Advanced Machining Processes ) Mcqs are given below:

Electro Chemical Machining-Introduction and Principle of electrolysis

1. In advanced machining processes, what is the full form of ECM?
a) Electrochemical manufacturing
b) Electrochemical milling
c) Electrochemical machining
d) Electrochemical masking
Answer: b
Explanation: In advanced machining processes, full form of ECM is Electrochemical machining.

2. In the following scientists, who was the one to introduce first patent on ECM?
a) Balamuth
b) Steve O Flawer
c) Gusseff
d) McGeough
Answer: c
Explanation: Gusseff was the one, who introduced the first patent on ECM in 1929.

3. When was the first significant development of ECM occurred?
a) 1920s
b) 1930s
c) 1950s
d) 1960s
Answer: c
Explanation: After the first patent in 1929, the first development of ECM was done in 1950s.

4. Which of the following material removal mechanisms is implemented by ECM?
a) Mechanical abrasion
b) Electrochemical dissolution
c) Chemical corrosion
d) Mechanical erosion
Answer: b
Explanation: In ECM, material is removed by electrochemical dissolution.

5. Electrolysis occur when which of the following takes place between electrodes?
a) Electric current flow
b) Electron flow
c) All of the mentioned
d) None of the mentioned
Answer: c
Explanation: When there is an electron flow there is current flow in the opposite direction. For electrolysis to take place there should be flow of current between electrodes.

6. The system which consists of electrolytic solution and electrodes can be referred to as ____________
a) Electrolytic cell
b) Electrode system
c) Electrolytic system
d) Electrode cell
Answer: a
Explanation: The system of electrodes and electrolytic solution is referred as electrolytic cell.

7. The chemical reactions occurring at electrodes are called with, which of the following names?
a) Anodic reactions
b) Cathode reactions
c) All of the mentioned
d) None of the mentioned
Answer: c
Explanation: Chemical reactions occurring at electrodes are called as anodic or cathodic reactions.

8. Amount of mass dissolved is directly proportional to which of the following quantities?
a) Amount of electricity
b) Frequency of vibrations
c) Amplitude of oscillations
d) All of the mentioned
Answer: a
Explanation: Amount of mass dissolved is directly proportional to amount of electricity and also substances’ chemical equivalent.

9. Chemical equivalent is the ratio of which of the following factors?
a) Work piece valence to the atomic weight
b) Atomic weight to work piece valence
c) Tool valence to molecular weight
d) Molecular weight to tool valence
Answer: b
Explanation: Chemical equivalent is the ratio of atomic weight to work piece valence.

ECM-Theory of ECM

1. What is the value of the current density used in Electrochemical machining?
a) 0.01 – 0.4 A/mm2
b) 0.5 – 5 A/mm2
c) 6 – 15 A/mm2
d) 20 – 50 A/mm2
Answer: b
Explanation: High current densities, which range between 0.5 – 5 A/mm2 are used in ECM.

2. What are the values of voltages used in ECM?
a) 1 to 8 V
b) 10 to 30 V
c) 40 to 80 V
d) 90 to 110 V
Answer: b
Explanation: Low voltages, ranging between 10 to 30 V are used in Electrochemical machining.

3. How does the current pass between the two electrodes in ECM?
a) Electrolytic solution
b) Direct contact of electrodes
c) All of the mentioned
d) None of the mentioned
Answer: a
Explanation: Current passes through the solution of electrolyte, which fills the gap between the electrodes.

4. What is the value of velocity with which, electrolyte flows in the inter electrode gap?
a) >1 m/s
b) >3 m/s
c) >5 m/s
d) >10 m/s
Answer: c
Explanation: The velocity of the electrolytic solution must be greater than 5 m/s, in order to intensify the mass and charge transfer.

5. Of the following, electrolyte removes which of the dissolution products?
a) Metal hydroxides
b) Heat
c) Gas bubbles
d) All of the mentioned
Answer: d
Explanation: Electrolyte removes the dissolution products such as metal hydroxides, heat and gas bubbles formed in the inter electrode gap.

6. State whether the following statement is true or false regarding the theory of ECM.
“Application of P.D (potential difference) lead to occurrence of several reactions.”
a) True
b) False
Answer: a
Explanation: When P.D (potential difference) is applied, different reactions occur at anode and cathode.

7. Which of the following reactions takes place at the electrodes?
a) Generation of hydrogen
b) Dissolution of iron
c) Dissolution of NaCl
d) All of the mentioned
Answer: d
Explanation: All the reactions mentioned above, take place at different electrodes in ECM.

8. Which of the following reaction takes place at anode?
a) Generation of hydrogen
b) Dissolution of iron
c) Generation of hydroxyl ions
d) None of the mentioned
Answer: b
Explanation: At anode, dissolution of Fe takes place in the process of ECM.

9. Which of the following reactions take place at cathode?
a) Generation of hydrogen
b) Dissolution of iron
c) Dissolution of NaCl
d) All of the mentioned
Answer: a
Explanation: At cathode, generation of hydrogen takes place in the process of ECM.

10. Positively charged particles (cations) move towards which electrode?
a) Anode
b) Cathode
c) Anode & Cathode
d) None of the mentioned
Answer: b
Explanation: Positively charge particles are directed towards the cathode, which is negatively charged.

11. Negatively charged particles (anions) move towards which electrode?
a) Anode
b) Cathode
c) Anode & Cathode
d) None of the mentioned
Answer: a
Explanation: Negatively charged particles are directed towards the anode, which is positively charged.

ECM – Equipment – 1

1. Which of the following come under the main components of ECM?
a) Feed control system
b) Work piece holding devices
c) Electrolyte supply system
d) All of the mentioned
Answer: d
Explanation: The main components of Electro chemical machining include feed control system, electrolyte supply system, power supply unit, work piece holding devices.

2. Feed control system is responsible for which action in ECM?
a) Giving feed to tool
b) Electrolyte supply
c) Power supply
d) None of the mentioned
Answer: a
Explanation: Feed control system is used for feeding the tool at constant rate during equilibrium machining.

3. In ECM equipment, what is the role of electrolyte supply system?
a) Giving feed to tool
b) Electrolyte supply
c) Power supply
d) None of the mentioned
Answer: b
Explanation: As the name itself indicates, electrolyte supply system is used to supply the electrolyte required for anodic dissolution.

4. What is the role of power supply unit in ECM equipment?
a) Giving feed to tool
b) Electrolyte supply
c) Power supply
d) None of the mentioned
Answer: c
Explanation: In ECM, power supply unit is used to supply the machine current at constant dc voltage.

5. For large size machining, which type of facilities are used in ECM?
a) Semi-automated facilities
b) Automated facilities
c) Automated & Semi-automated facilities
d) None of the mentioned
Answer: c
Explanation: Automated and semi-automated facilities are used for large size machining.

6. Electrolyte supply system should concentrate on which of the following factors?
a) Pressure
b) Supply rate
c) Temperature
d) All of the mentioned
Answer: d
Explanation: Electrolyte supply system should supply electrolyte at a given rate, temperature and pressure.

7. For high strength or rigidity, which type of coatings are recommended for metals?
a) Other metal coatings
b) Non-metallic coatings
c) All of the mentioned
d) None of the mentioned
Answer: b
Explanation: For high strength and rigidity, non-metallic coatings are recommended for metals.

 

Chemical Processes MCQs

 

8. What is the value of voltage that the power supply unit supplies for ECM?
a) 0.01 to 1 V
b) 2 to 30 V
c) 50 to 80 V
d) 100 to 160 V
Answer: b
Explanation: Voltage supply required for ECM ranges between 2 to 30 V.

9. Between which of the following values, does the current range?
a) 0.002 to 0.01 A
b) 0.01 to 10 A
c) 50 to 10000 A
d) 105 to 106 A
Answer: c
Explanation: In Electrochemical machining, current value ranges between 50 to 10000 A.

10. What are the values of current densities used in ECM?
a) 0.1 to 2 A/cm2
b) 5 to 500 A/cm2
c) 600 to 1000 A/cm2
d) 1200 to 2800 A/cm2
Answer: b
Explanation: Current density values in ECM range between 5 to 500 A/cm2.

11. Which type of adjustment is to be done for gap voltages?
a) Continuous adjustment
b) Discontinuous adjustment
c) Periodic adjustment
d) All of the mentioned
Answer: a
Explanation: In ECM, usually continuous adjustment of gap voltage is required.

12. Compared to the tool used in ECM, how should be the work piece size?
a) Greater than
b) Smaller than
c) Same as tool
d) None of the mentioned
Answer: a
Explanation: By an oversize, work piece size is expected to be greater than tool size.

13. Which of the following factors are used to determine the tool geometry?
a) Required shape
b) Electrical conductivity
c) Tool feed rate
d) All of the mentioned
Answer: d
Explanation: For determining a tool geometry we must specify some factors such as the required shape of the surface, tool feed rate, gap voltage, electrochemical machinability of the work material, electrolyte conductivity, and both electrodes’ polarization voltages.

14. Which of the following are the simplest methods for applying the insulation on tools?
a) Spraying
b) Dipping
c) All of the mentioned
d) None of the mentioned
Answer: c
Explanation: In ECM, dipping or spraying are the simplest methods for insulating the tools.

15. State whether the following statement is true or false regarding the tools of ECM.
“With computer integrated manufacturing (CIM), cathodes are produced at high costs and less accurately.”
a) True
b) False
Answer: b
Explanation: Using CIM, cathodes are produced at low costs and more accurately.

ECM – Equipment – 2

1. What are the main functions of electrolyte in Electrochemical machining?
a) Conduct machining current
b) Removal of debris
c) Maintaining constant temperature
d) All of the mentioned
Answer: d
Explanation: Main functions of electrolyte are conducting machine current, removing the debris, carrying away the heat, maintaining constant temperature.

2. Electrolytic solution should ensure which type of anodic dissolution?
a) Uniform
b) Non-uniform
c) Low speed
d) None of the mentioned
Answer: a
Explanation: Uniform and high speed anodic dissolution must be ensured by the electrolyte.

3. State whether the following statement is true or false regarding the electrolytic solution.
“In ECM, formation of passive film is recommended.”
a) True
b) False
Answer: b
Explanation: Electrolytic solution should avoid formation of passive layers on anode.

4. Which type of electrical conductivity is necessary for electrolytic solution?
a) Low
b) Medium
c) High
d) None of the mentioned
Answer: c
Explanation: High electrical conductivity is needed for electrolytic solution in ECM.

5. What are the other features of electrolytic solution in ECM?
a) Non toxic
b) Less erosive
c) Less viscous
d) All of the mentioned
Answer: d
Explanation: Electrolytic solution should be nontoxic, less viscous and less erosive.

6. How much should be the electrolytic solution?
a) Highly expensive
b) Inexpensive
c) All of the mentioned
d) None of the mentioned
Answer: b
Explanation: Electrolyte must be inexpensive and available at ease.

7. Which are the most common electrolytes used in Electrochemical machining?
a) Sodium chloride
b) Sodium nitride
c) Sodium hydroxide
d) All of the mentioned
Answer: d
Explanation: Electrolytes such as sodium chloride, sodium nitride, sodium hydroxide are some of the electrolytes used in ECM.

8. Selection of electrolyte does not depend on which of the following factors?
a) Work piece material
b) Dimensional tolerance
c) Heat affected zones
d) Machining productivity
Answer: c
Explanation: Selection of electrolyte depend up on work piece material, dimensional tolerance, machining productivity and surface finish required.

9. What must be the value of electrolytic temperature in ECM?
a) 2 to 14oC
b) 22 to 45oC
c) 46 to 57oC
d) 62 to 76oC
Answer: b
Explanation: Temperature of electrolyte should range between 22 to 45oC.

10. What must be the value of the pressure of electrolytic solution used in ECM?
a) 1 to 10 kPa
b) 10 to 80 kPa
c) 100 to 200 kPa
d) 300 to 400 kPa
Answer: c
Explanation: Value of pressure of electrolytic solution must range between 100 to 200 kPa.

11. What must be the value of velocity of the electrolytic solution?
a) 10 to 15 m/s
b) 25 to 50 m/s
c) 60 to 100 m/s
d) 120 to 200 m/s
Answer: b
Explanation: Typical velocity of the electrolytic solution must range between 25 to 50 m/sec.

12. Local metal removal rates are high at which gap locations mentioned below?
a) Small gap
b) Medium gap
c) Large gap
d) None of the mentioned
Answer: a
Explanation: Local metal removal rates are high at small gap locations in ECM.

13. When local metal removal rates are high, how will be the current density and current efficiency?
a) High
b) Medium
c) Low
d) Very low
Answer: a
Explanation: When the local metal removal rates are high then current density and efficiency are also high.

14. Current efficiency depends on which of the following in ECM?
a) Anodic material
b) Electrolyte
c) Anodic material & Electrolyte
d) None of the mentioned
Answer: c
Explanation: Current efficiency in ECM depend on electrolyte and anodic material used.

15. State whether the following statement is true or false regarding the electrolytes in ECM.
“In Electrochemical machining, electrolytes should deposit on cathode electrodes.”
a) True
b) False
Answer: b
Explanation: In ECM, electrolytes should not deposit on cathode, so that shape of electrode remains unchanged.

ECM-Basic Working Principles

1. What is the approximate value of faraday’s constant?
a) 65,200 C
b) 53,800 C
c) 96,500 C
d) 85,600 C
Answer: c
Explanation: 1 faraday equals to approximately 96500 C.

2. In the following ratios of metal dissolved amounts, which one represent the current efficiency?
a) Observed to theoretical
b) Theoretical to observed
c) All of the mentioned
d) None of the mentioned
Answer: a
Explanation: In electrochemical machining, current efficiency is the ratio of observed amount of metal dissolved to the theoretical amount of metal dissolved.

3. Apparent current efficiency is due to which of the following factors?
a) Choice of wrong valence
b) Passivation of anodic surface
c) Gas evolution at anode
d) All of the mentioned
Answer: d
Explanation: Current efficiency may be apparent because of choice of wrong valence, passivation of anodic surface or gas evolution at anodic surface.

4. State whether the following statement is true or false regarding the working principles.
“In ECM, grain boundary attacks remove the grains through electrolytic forces.”
a) True
b) False
Answer: a
Explanation: In ECM, grain boundary attacks are the cause for removal of grains by electrolytic forces.

5. In ECM, gap increase proportional to which relation of time below?
a) Square of time
b) Square root of time
c) Cube of time
d) Cube root of time
Answer: b
Explanation: In Electrochemical machining, gap increases proportional to the square root of time.

6. At constant feed rates what happens to gap thickness?
a) Increases
b) Decreases
c) Becomes constant
d) None of the mentioned
Answer: c
Explanation: At constant feed rate, work piece becomes stationary and thus the gap thickness becomes constant.

7. At constant gap thickness material removal becomes equal to feed rate. What is this gap called?
a) Equal gap
b) Equilibrium gap
c) Unique gap
d) Narrow gap
Answer: b
Explanation: When rate of material removal per unit area is same as feed rate, then corresponding thickness is called as equilibrium thickness indicated by ‘ye’.

8. If the gap thickness is greater than equilibrium thickness what will be MRR?
a) MRR is less than feed rate
b) MRR is greater than feed rate
c) MRR is equal to feed rate
d) None of the mentioned
Answer: a
Explanation: When gap thickness is greater than equilibrium thickness, MRR will be less than feed rate.

9. During ECM drilling, decrease in feed rates lead to which type of machining gaps?
a) Wider
b) Narrow
c) Small
d) None of the mentioned
Answer: a
Explanation: Decrease in feed rate lead to wider gap thickness in ECM drilling.

10. Too small gap causes which of the following effects?
a) Sparking
b) Short circuit
c) Sparking & Short circuit
d) None of the mentioned
Answer: c
Explanation: Sparking or short circuit occurs when the gap is too small.

ECM-Process Characteristics – 1

1. Electro chemical dissolution phase starts with the movement of ions between which two components?
a) Cathode and anode
b) Cathode and power source
c) Power source and anode
d) Power source and electrolyte
Answer: a
Explanation: ECD phase occurs by the movement of ions between the two electrodes.

2. Better surface finish and higher accuracy depend on which of the factors below?
a) Chemical composition of the electrolyte
b) Current density
c) All of the mentioned
d) None of the mentioned
Answer: c
Explanation: Proper chemical composition of electrolyte and proper current density are responsible for better surface finish and accuracy.

3. For alloys, which type of electrolyte is used in ECM?
a) Single component
b) Double component
c) Multi component
d) Triple component
Answer: c
Explanation: Depending up on the elements in an alloy multi component electrolytes are used.

4. Nickel can be machined with 100% current efficiency, when current density value is ______________
a) 10 A/cm2
b) 25 A/cm2
c) 45 A/cm2
d) 80 A/cm2
Answer: b
Explanation: Nickel is a metal suggested by Khayry, which can be machined at 100% current efficiency, if current density is 25 A/cm2.

 

Chemical Processes MCQs

 

5. When the electrolyte flow is low, what happens to the current efficiency?
a) Increases
b) Decreases
c) Remains same
d) Increase and then decrease
Answer: b
Explanation: In ECM, if the electrolyte flow is low, current efficiency is reduced due to the accumulation of machining products within the gap.

6. When machining Ti, in Nacl electrolyte, what values of current efficiencies are obtained?
a) 10 – 20 %
b) 20 – 30 %
c) 30 – 50 %
d) 50 – 80 %
Answer: a
Explanation: While machining Ti using NaCl electrolyte, current efficiencies of 10 – 20 percent are obtained.

7. State whether the following statement is true or false about electrolyte in ECM.
“Machinability in ECM is enhanced, when electrolyte is heated.”
a) True
b) False
Answer: a
Explanation: Machinability is increased, when electrolyte is heated, as heating increases the specific conductivity of the electrolyte.

8. In practice, what must be the temperature of electrolyte used in ECM?
a) 10 – 20oC
b) 20 – 40oC
c) 60 – 80oC
d) 80 – 100oC
Answer: c
Explanation: Temperature of electrolyte used in ECM must not exceed 60 – 70oC.

9. What is the value of moderate level of pH of electrolyte used?
a) 1 – 2
b) 2 – 4
c) 4 – 10
d) All of the mentioned
Answer: c
Explanation: Moderate level of pH of electrolyte used in ECM range between 4 – 10.

10. What must be the working voltage in Electrochemical machining?
a) 10 V
b) 20 V
c) 30 V
d) 40 V
Answer: b
Explanation: The electrolytes in ECM employ a working voltage up to 20 V.

11. Surface roughness depend on which of the following quantities?
a) Crystallographic irregularities
b) Alloy composition
c) Distribution of current density
d) All of the mentioned
Answer: d
Explanation: Surface roughness of machined surface in ECM depend on crystallographic irregularities, alloy composition, current density distribution, dislocations and grain boundaries.

12. For a better surface finish, which type of current distribution is required?
a) Even
b) Uneven
c) Even & Uneven
d) None of the mentioned
Answer: a
Explanation: More even distribution of the current density leads to a better surface finish.

13. Between which values does the frontal gap’s surface roughness vary?
a) 0.02 to 0.13 µm
b) 0.30 to 1.90 µm
c) 1.93 to 2.64 µm
d) 2.73 to 4.26 µm
Answer: b
Explanation: Surface roughness varies between 0.30 to 1.9 µm for frontal gap area.

14. Between which values does the side gap’s surface roughness vary?
a) >1 µm
b) >3 µm
c) >5 µm
d) >7 µm
Answer: c
Explanation: Surface roughness value is 5 µm or more for side gap areas.

15. In Electrochemical machining, larger grain size causes which type of finish?
a) Smoother
b) Rougher
c) Finer
d) All of the mentioned
Answer: b
Explanation: In ECM, larger grains cause rougher finish than finer grains.

ECM-Process Characteristics – 2

1. Which type of gap width is necessary for a higher degree of accuracy?
a) Very small
b) Small
c) Medium
d) High
Answer: b
Explanation: A small gap width represents a high level of accuracy. Very small gap width results in sparks and short circuits.

2. Accuracy of machining is affected by, which of the following factors?
a) Material
b) Gap voltage
c) Feed rate
d) All of the mentioned
Answer: d
Explanation: Accuracy of the process is affected by material equivalent, gap voltage, feed rate, etc.

3. Which properties of electrolyte does not affect the accuracy of the process?
a) Temperature
b) Concentration
c) Non-reactive
d) Pressure
Answer: c
Explanation: Electrolyte must be reactive in order to carry on the reactions that occur at the electrodes.

4. For high process accuracy, which of the following factors are needed?
a) High feed rate
b) High conductivity
c) High feed rate & High conductivity
d) None of the mentioned
Answer: c
Explanation: For a higher degree of accuracy, there must be high feed rates and highly conductive electrolytes.

5. Tool insulation that __________ the side machining action is needed in the process of ECM.
a) Limits
b) Enhances
c) Maintains
d) None of the mentioned
Answer: a
Explanation: Tool insulation is needed, which limits the machining of other sides of work piece.

6. If the current density is high as required, what type of machining occurs?
a) Pitting
b) Polishing
c) Etching
d) All of the mentioned
Answer: b
Explanation: When the current density is relatively high as required, then polishing occurs.

7. What happens when the current density is low in ECM?
a) Pitting occurs
b) Etching occurs
c) Pitting & Etching occurs
d) None of the mentioned
Answer: c
Explanation: When current density is lower than optimum, then etching and pitting occurs which are undesired.

8. Fine dimensional control can be obtained if throwing power of electrolyte is ___________
a) Low
b) Medium
c) High
d) Very high
Answer: a
Explanation: Throwing power of electrolyte must be less in order to obtain a fine dimensional control.

9. Passivation is done on electrolytes in order to form which of the following?
a) Passive layer on machined parts
b) Passive layer on cathode
c) Passive layer on machined parts & cathode
d) None of the mentioned
Answer: a
Explanation: Passivation is done on the electrolytes in order to form a passive film on machined parts.

10. If there is an increase in the electrolyte flow, what happens to the rate of film formation?
a) Increases
b) Decreases
c) Remains same
d) All of the mentioned
Answer: b
Explanation: An increase in electrolytic solution flow decreases the anodic product formation, which reduces the rate of film formation.

11. What are the typical dimensional tolerances for frontal gaps in ECM?
a) ± 0.01 mm
b) ± 0.025 mm
c) ± 0.13 mm
d) ± 0.25 mm
Answer: c
Explanation: The dimensional tolerances obtained for frontal gaps are ± 0.130 mm.

12. What are the tolerance values for the side gap in ECM?
a) ± 0.01 mm
b) ± 0.025 mm
c) ± 0.13 mm
d) ± 0.25 mm
Answer: d
Explanation: The dimensional tolerances obtained for side gaps are ± 0.25 mm.

13. What are the typical dimensional tolerances obtained in ECM when there is proper control of machining?
a) ± 0.01 mm
b) ± 0.025 mm
c) ± 0.13 mm
d) ± 0.25 mm
Answer: b
Explanation: The dimensional tolerances obtained by proper machining are ± 0.025 mm.

14. It is difficult to machine inner radii smaller than __________ and outer radii less than ________ in ECM.
a) 0.1 mm, 0.2 mm
b) 0.5 mm, 0.8 mm
c) 0.8 mm, 0.5 mm
d) 0.2 mm, 0.1 mm
Answer: c
Explanation: It is difficult to machine inner radii < 0.8mm and outer radii < 0.5mm.

15. What is the value of the overcut that is obtained using ECM?
a) 0.3 mm
b) 0.5 mm
c) 0.7 mm
d) 0.9 mm
Answer: b
Explanation: An overcut of 0.5 mm is obtained when machined using ECM.

ECM-Process Control

1. If there is a change in the selected machining conditions, it will have impact on which of the following?
a) Process accuracy
b) Surface finish
c) Process accuracy & Surface finish
d) None of the mentioned
Answer: c
Explanation: Selected machining conditions should remain unchanged, because, it will have a direct impact on accuracy and surface finish.

2. Surface roughness depends on current density, which is affected by which of the following?
a) Tool feed rate
b) Gap voltage
c) Work piece material
d) All of the mentioned
Answer: d
Explanation: Roughness depend on current density, which is affected by tool feed rate, gap voltage, work material, pH number, temperature, conductivity and pressure.

3. Machining conditions leading to high accuracy are associated with ________ surface roughness and ________ productivity.
a) Greater, greater
b) Smaller, greater
c) Greater, smaller
d) Smaller, smaller
Answer: b
Explanation: Accuracy is associated with smaller surface roughness and greater machining productivity.

4. Non stationary behaviour of ECM is due to, which of the factors below?
a) Gas generation
b) Heating
c) Passivation
d) All of the mentioned
Answer: d
Explanation: Non stationary behaviour of ECM is due to the inter electrode gap conditions such as gas generation, passivation, heating and other electrode reactions.

5. For large components, actual machining time constitutes to how much percentage of the total machining time?
a) Very low
b) Low
c) Medium
d) High
Answer: d
Explanation: Actual machining time of large components constitutes to a high percentage of total machining time.

6. What happens to the product cycle time, if the machining performance is improved?
a) Increases
b) Decreases
c) Remains same
d) None of the mentioned
Answer: b
Explanation: As the machining performance is improved, the time take for a product to complete its production cycle, decreases.

7. The cost of additional control hardware remain a _________ fraction of total machining cost.
a) Small
b) Large
c) Equal
d) None of the mentioned
Answer: a
Explanation: Cost of additional control hardware is very less, which constitutes to a small fraction in total machining cost.

8. With an increase in unmanned machining hours, what happens to the efficiency of ECM?
a) Increases
b) Reduces
c) Decreases
d) Increase and then decrease
Answer: a
Explanation: Increase in unmanned machining hours lead to a raise in efficiency of ECM.

9. State whether the following statement is true or false regarding the process control of ECM.
“In Electrochemical machining, increase in unmanned machining hours reduces the possibility of integration of process with CAD/CAM systems.”
a) True
b) False
Answer: b
Explanation: An increase in unmanned machining hours, enhances the process integration with CAD/CAM systems.

10. Which type of damage is caused by deterioration which is caused by spark?
a) Reparable
b) Irreparable
c) All of the mentioned
d) None of the mentioned
Answer: b
Explanation: Deterioration by sparking may cause irreparable damage to the work pieces.

ECM-Applications and Micro-ECM

1. Which of the following use ECM for different applications?
a) Gas turbines
b) Jet engines
c) Bio medical implants
d) All of the mentioned
Answer: d
Explanation: ECM has its applications in industries such as gas turbines, jet engines, automobiles, medical etc.

2. Which of the following processes can be done using ECM?
a) Die sinking
b) Profiling and contouring
c) Drilling and trepanning
d) All of the mentioned
Answer: d
Explanation: ECM can be used for die sinking, trepanning, drilling, contouring, grinding and profiling.

3. Which of the following material cannot be machined using ECM?
a) High strength alloys
b) Hardened steels
c) Nonconductive materials
d) All of the mentioned
Answer: c
Explanation: ECM can be used for machining high strength alloys and hardened steels which led to many cost-saving applications.

4. ECM is used to _________ the sharp edges produced after rough cuts.
a) Enhance
b) Dull
c) Improve
d) None of the mentioned
Answer: b
Explanation: Using deburring process through ECM, sharp edges are dulled, which are produced after rough cuts.

5. ECM is usually characterized as low accuracy machining, for which of the following reason?
a) Narrow gap width
b) Wider gap width
c) High current densities
d) All of the mentioned
Answer: b
Explanation: ECM is usually characterized as low accuracy machining because of its wider machining gap.

6. In micro ECM, which of the following is used as micro tool?
a) Electrolyte jet
b) Electrodes
c) Power supply
d) All of the mentioned
Answer: a
Explanation: Electrolyte jet in micro ECM acts as the micro tool for machining.

7. Micro ECM is used to machine which type of parts?
a) Large parts
b) Micro parts
c) Normal sized parts
d) All of the mentioned
Answer: b
Explanation: Micro ECM is used to machine micro parts which can be from micro scale to mesoscale in size.

8. Which of the following produces small indents and cavities using micro ECM?
a) Moving the work piece
b) Switching the pulse current
c) Moving the work piece & Switching the pulse current
d) None of the mentioned
Answer: c
Explanation: Indentation and cavitation can be done using micro ECM by moving the work piece or switching the pulse current.

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

Author: Abdullah

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