Advanced Machining Processes Multiple Choice Questions on “EDM-Surface Integrity”.
1. On which of the following factors do the craters depend?
a) Physical properties
b) Mechanical properties
c) Composition of medium
d) All of the mentioned
Answer: d
Clarification: In EDM, craters depend on the physical and mechanical properties of material and composition of medium.
2. The maximum depth of damaged layer is how many times that of average surface roughness?
a) 1.5 time
b) 2 times
c) 2.5 times
d) 3 times
Answer: c
Clarification: Depth of damaged layer is two and half times the average surface roughness value.
3. What happens to the surface roughness values if the MRR increases in EDM?
a) Increases
b) Decreases
c) Decrease and increase
d) None of the mentioned
Answer: a
Clarification: In EDM, the surface roughness values increases linearly with increase in the material removal rates.
4. State whether the following statement is true or false regarding the surface roughness in EDM.
“In EDM, graphite electrodes produce smoother surfaces than metal ones.”
a) True
b) False
Answer: b
Clarification: In EDM, graphite electrodes produce rougher surfaces than that of the metal ones.
5. In Electro discharge machining, what happens to the surface finish if the pulse energy is decreased?
a) Reduces
b) Decreases
c) Improves
d) None of the mentioned
Answer: c
Clarification: In Electro discharge machining, the surface finish improves if the pulse energy is decreased.
6. Using of a mate electrode in Electro discharge machining _____________ the surface roughness of material.
a) Increases
b) Decreases
c) Enhances
d) None of the mentioned
Answer: b
Clarification: By using a mate electrode in Electro discharge machining, the surface roughness values are decreased.
7. What happens to the surface roughness if oxygen gas is introduced in the gap?
a) Increases
b) Decreases
c) Decrease and then increase
d) All of the mentioned
Answer: b
Clarification: In EDM, surface roughness increases with the supply of oxygen gas in gaps.
8. By how much percent surface roughness is reduced if we use proper dielectric flow?
a) 25%
b) 50%
c) 75%
d) 100%
Answer: b
Clarification: In Electro discharge machining, if we use a proper dielectric fluid flow, surface roughness is decreased by 50 percent.
9. What are the tolerance values obtained by machining using EDM?
a) ± 10 mm
b) ± 15 mm
c) ± 25 mm
d) ± 40 mm
Answer: c
Clarification: The tolerance values of ± 25 mm are obtained when we machine components using EDM.
10. How much extra tolerances are achieved when we choose proper variables?
a) ± 5 mm
b) ± 10 mm
c) ± 15 mm
d) ± 20 mm
Answer: a
Clarification: Extra tolerances of ± 5 mm are obtained with a proper choice of process variables.