Engineering Questions with Answers - Multiple Choice Questions
Manufacturing Processes – Abrasive Jet Micromachining – 14
1 - Question
How many types of catcher are there?
Explanation: Moreover the catcher can be of pocket type or line type. In pocket type, the catcher basin travels along the jet. In line type, the catcher basin only travels along one axis of the CNC table and its length covers the width of the other axis of the CNC table.
2 - Question
Which of the following is not true about entrained type AJWM?
a) Sapphires is used for orifice
b) Pressure range = 2500-4000 bars
c) Impact angle < 50o
d) Depth of cut reached is 1—250 mm
Explanation: The general domain of parameters in entrained type AWJ machining system is given below: • Orifice – Sapphires – 0.1 to 0.3 mm • Focussing Tube – WC – 0.8 to 2.4 mm • Pressure – 2500 to 4000 bar • Abrasive – garnet and olivine – #125 to #60 • Abrasive flow – 0.1 to 1.0 Kg/min • Stand-off distance – 1 to 2 mm • Machine Impact Angle – 60o to 90o • Traverse Speed – 100 mm/min to 5 m/min • Depth of Cut – 1 mm to 250 mm.
3 - Question
In AWJM of ductile materials, material is mainly removed by _____ impact by abrasive particles.
a) low angle
b) 50o —60o
c) 65o —70o
d) 70o —82o
Explanation: Mechanism of material removal in machining with water jet and abrasive water jet is rather complex. In AWJM of ductile materials, material is mainly removed by low angle impact by abrasive particles leading to ploughing and micro cutting.
4 - Question
At higher angle of impact, the material removal involves _____ failure.
Explanation: At higher angle of impact, the material removal involves plastic failure of the material at the sight of impact, which was studied initially by a person named Bitter.
5 - Question
In case of AWJM of brittle materials, the material is removed due to crack formation.
Explanation: In case of AWJM of brittle materials, other than the above two models, material would be removed due to crack initiation and propagation because of brittle failure of the material.
6 - Question
When the kerf formed by the impact of the jet, the top of the kerf _____ than bottom of the kerf.
Explanation: The cut generated by an AWJM in different sections is called a kerf. The top of the kerf is wider than the bottom of the kerf. Generally, the top width of the kerf is equal to the diameter of the AWJ.
7 - Question
The taper angle of the kerf can be_____ of the AWJ
a) reduced by increasing the cutting ability
b) increased by increasing the cutting ability of the
c) reduced by decreasing the cutting ability of the
d) taper angle is not a function of the cutting ability of the jet
Explanation: The taper angle of the kerf can be reduced by increasing the cutting ability of the AWJ. It can be said that the surface quality at the top of the kerf is rather good compared to the bottom part. At the bottom there is repeated curved line formation.
8 - Question
Which of the following is true about AWJM?
a) At the bottom of the kerf, the material removal is by low angle impact of the abrasive particles
b) At the top of the kerf, the material removal is by low angle impact of the abrasive particles
c) At the top of the kerf, the material removal is by plastic failure
d) Striation formation occurs due to excess use of abrasive particles
Explanation: At the top of the kerf, the material removal is by low angle impact of the abrasive particle; whereas at the bottom of the kerf it is by plastic failure. Striation formation occurs due to repeated plastic failure.
9 - Question
Striation factor is an important product quality parameter in AWJM.
Explanation: In AWJM, following are the important product quality parameters; • striation formation • surface finish of the kerf • tapering of the kerf • burr formation on the exit side of the kerf.
10 - Question
Which of the following issues is not of much concern in AWJM?
a) Coolant recovery
b) Abrasive recovery
c) Spent water disposal
d) Chip recovery
Explanation: Nowadays, every manufacturing process is being re-evaluated in terms of its impact on the environment. The environmental issues relevant to AWJM are, • water recycling • spent water disposal • chip recovery • abrasive recovery and reuse.