Unconventional Machine Process Set 7

Mechanical Engineering

Practice Mode Previous Next
On This Page

This set of Unconventional Machine Process (UMP) Multiple Choice Questions & Answers (MCQs) focuses on Unconventional Machine Process Set 7

Q1 | Which of the following geometries can be machined using EDM?
  • simple
  • complex
  • difficult to cut
  • all of the mentioned
Answer: all of the mentioned
Explaination:
electrodischarge machining can be used for simple as well as complex geometries.
Q2 | State whether the following statement is true or false regarding EDM. “In EDM, process is affected by hardness of material.”
  • true
  • false
Answer: false
Explaination:
edm process is not affected by the hardness of material.
Q3 | Which of the following mechanisms is used for material removal?
  • electro discharge erosion
  • magnetic abrasion
  • electro chemical dissolution
  • mechanical erosion
Answer: electro discharge erosion
Explaination:
material is removed by electro-discharge erosion (ede) in edm
Q4 | What is the value of order of frequency applied between the two electrodes in EDM?
  • 1 khz
  • 3 khz
  • 5 khz
  • 7 khz
Answer: 5 khz
Explaination:
the magnitude of frequency applied between the electrodes in edm is about 5 khz.
Q5 | What are the magnitude of voltages used in Electro discharge machining?
  • 1 to 20 v
  • 20 to 120 v c) 120 to 220 v d) 220 to 320 v
Answer: 20 to 120 v c) 120 to 220 v d) 220 to 320 v
Explaination:
in edm, the magnitude of voltages range between 20 and 120 v.
Q6 | How is material removed in Electro discharge machining?
  • melt and evaporate
  • corrode and break
  • mechanical erosion takes place
  • none of the mentioned
Answer: melt and evaporate
Explaination:
in electro discharge machining, material is melted and then evaporated.
Q7 | What is the radius of channel, when electrical breakdown occur?
  • 4 µm
  • 6 µm
  • 8 µm
  • 10 µm
Answer: 10 µm
Explaination:
in edm, the electrical breakdown occurs in dielectric in a channel of radius about 10 µm.
Q8 | State whether the following statement is true or false about material removal in EDM. “In EDM, high pressures allow the metal to evaporate.”
  • true
  • false
Answer: false
Explaination:
high pressures in edm try to prevent the super-heated metal from evaporation.
Q9 | What are the values of pressure of the plasma in EDM?
  • up to 2 atm
  • up to 20 atm
  • up to 200 atm
  • up to 2000 atm
Answer: up to 200 atm
Explaination:
pressure on the plasma channel rises to values as high as 200 atm when dielectric evaporates.
Q10 | At the end of pulse, super-heated metal evaporates                                
  • explosively
  • normally
  • periodically
  • occasionally
Answer: explosively
Explaination:
at the end of pulse, pressure drops suddenly and super-heated metal evaporates explosively.
Q11 | After the explosion is over, how is the debris carried away?
  • evaporation
  • fresh dielectric
  • old dielectric
  • all of the mentioned
Answer: fresh dielectric
Explaination:
debris is carried away by the fresh dielectric that rushes in.
Q12 | The layer formed when un expelled molten metal solidifies is known as                        
  • reabsorbed layer
  • recast layer
  • un evaporated layer
  • condensed layer
Answer: recast layer
Explaination:
unexpelled molten metal solidifies to form a layer known as recast layer.
Q13 | Amount of material removed from anode and cathode depend on which of the following?
  • electrons
  • positive ions
  • electrons & positive ions
  • none of the mentioned
Answer: electrons & positive ions
Explaination:
the amount of material removed from electrodes depend on the contribution of the charged ions.
Q14 | What happens when the electron current predominates in the discharge?
  • more anodic removal
  • more cathodic removal
  • remains same
  • all of the mentioned
Answer: more anodic removal
Explaination:
when electron current predominates the electrical discharge, anodic material removal is greater than cathodic material.
Q15 | What is the value of gap maintained between the electrodes when we use servo mechanism?
  • 10 – 100 µm
  • 100 – 200 µm
  • 200 – 500 µm
  • 500 – 1000 µm
Answer: 200 – 500 µm
Explaination:
in edm, value of gap maintained between the electrodes range between 200 and 500 µm.
Q16 | Based on the electrode gap, which of the following electric pulses are generated?
  • open circuit pulses
  • sparks
  • arcs
  • all of the mentioned
Answer: all of the mentioned
Explaination:
based on the electrode gap, electric pulses are distinguished which are – circuit pulses, sparks, arcs and short circuits.
Q17 | When the electrode gap is too small or electrodes are in contact, how much material is removed?
  • 10%
  • 20%
  • 30%
  • no material removed
Answer: no material removed
Explaination:
when electrodes come in contact with one another, short circuits occur and material removed is not possible.
Q18 | Which components mentioned below are affected due to arcs?
  • work piece
  • tool
  • work piece & tool
  • none of the mentioned
Answer: work piece & tool
Explaination:
arcs are believed to occur at same spots on electrode surfaces which damage both tool and work piece.
Q19 | Which of the following pulses contribute to the desired material removal in EDM?
  • open circuit pulses
  • short circuits
  • arcs
  • sparks
Answer: sparks
Explaination:
the sparks are the one which contributes to the desired material removal in electro discharge machining.
Q20 | Which of the following are main components of EDM?
  • dielectric system
  • servomechanism
  • power supply
  • all of the mentioned
Answer: all of the mentioned
Explaination:
main components of machining system in edm are – dielectric system, power supply and servomechanism.
Q21 | What is the function of feed-control system in Electro discharge machining?
  • constant gap
  • supply power
  • dielectric fluid supply
  • work piece holding
Answer: constant gap
Explaination:
feed control system is used to maintain constant gap between electrodes.
Q22 | What is the use of power supply system in Electro discharge machining?
  • constant gap
  • supply power
  • dielectric fluid supply
  • work piece holding
Answer: supply power
Explaination:
power supply system is used to supply pulses at certain voltages, current, on time and off time.
Q23 | What is the function of dielectric circulation unit in Electro discharge machining?
  • constant gap
  • supply power
  • dielectric fluid supply
  • work piece holding
Answer: dielectric fluid supply
Explaination:
dielectric circulation unit is used to supply dielectric fluid for flushing.
Q24 | Which of the following materials are used as electrodes in EDM?
  • graphite
  • copper
  • brass
  • all of the mentioned
Answer: all of the mentioned
Explaination:
all the materials mentioned above, can be used as electrodes in electro discharge machining.
Q25 | Metals with                    melting point and                    electrical conductivity are chosen as tools in EDM.
  • low, good
  • low, bad
  • high, good
  • high, bad
Answer: high, good
Explaination:
in edm, metals with high melting point and good electrical conductivity are used as tools.
Previous Next