1. When machining porous material, which type of mechanism is introduces?
a) Abrasion
b) Erosion
c) Corrosion
d) Vaporization
Explanation: Material removal of porous material takes place by erosion.
2. The rate of material removal depends on which of the following features?
a) Frequency
b) Static Pressure
c) Machining area
d) All of the mentioned
Explanation: Material removal rate depends on all the above mentioned factors.
3. The machinability of USM depends on brittleness criterion.
a) True
b) False
Explanation: Both machinability and MRR depends on brittleness of material.
4. Which of the following are the features of tool affecting MRR in USM?
a) Hardness
b) Wearability
c) Accuracy
d) Mounting
Explanation: Different features of tool also affect the material removal in USM.
5. What is the machinability rate of glass by USM?
a) 25%
b) 50%
c) 75%
d) 100%
Explanation: In the case of brittle materials, Ultrasonic Machining’s MRR is very high.
6. What happens to MRR with an increase in tool amplitude?
a) Increases
b) Decreases
c) Remains same
d) None of the mentioned
Explanation: As amplitude of the tool increases, rate of material removal increases.
7. The vibration amplitude determines, which parameter of the abrasive particles?
a) Force
b) Torque
c) Velocity
d) Pressure
Explanation: Amplitude determines the velocity of abrasive particles between tool and work piece.
8. If splashing occurs, it will result in an increase of material removal rate in USM.
a) True
b) False
Explanation: Splashing occurs if amplitude is very high which in turn decreases the material removal rate.
9. Amplitude of the oscillation ranges between which of the following values?
a) 0.01 – 0.04 mm
b) 0.04 – 0.08 mm
c) 0.08 – 0.10 mm
d) 0.10 – 0.20 mm
Explanation: Optimum value of the amplitude of the tool will vary between 0.04-0.08 mm.
10.As the vibration frequency increases, what happens to material removal rate?
a) Decreases
b) Increases
c) Increase and then decrease
d) Decrease and then increase
Explanation: Up to a certain limit of vibration frequency, MRR increases and after that it decreases.