Engineering Questions with Answers - Multiple Choice Questions
Manufacturing Processes – Abrasive Jet Micromachining – 1
1 - Question
AJMM is widely used for machining of glass and silicon.
a) True
b) False
View Answer
Explanation: Abrasive Jet Micro Machining (AJMM) is a relatively new approach to the fabrication of microstructures. AJMM is a promising technique to three-dimensional machining of glass and silicon in order to realize economically viable micro-electro-mechanical systems (MEMS).
2 - Question
In AJMM, workpiece is exposed to abrasive action of the particles.
a) True
b) False
View Answer
Explanation: It employs a mixture of a fluid (air or gas) with abrasive particles. In contrast to direct blasting, the surface is exposed completely to the erosive action of the particle beam. Hence, before processing, the substrate material has to be partially shielded by applying an erosion resistant mask.
3 - Question
This method is used for _____
a) making finished surfaces
b) thread finishing
c) making grooves
d) cutting
View Answer
Explanation: This method is used for making accurate shallow holes or grooves, and, with the use of masks, patterns on target material.
4 - Question
Resulting abrasive action is dependent on the impact angle of the jet.
a) True
b) False
View Answer
Explanation: The resulting erosion of the target material can be controlled using masks and by varying parameters such as impact angle and particle flux density, velocity, and particle properties.
5 - Question
AJMM is capable of machining anisotropic patterns.
a) True
b) False
View Answer
Explanation: In contrast to conventional micro-fabrication methods, such as wet and dry etching, AJMM is capable of machining anisotropic patterns and suspended structures with high erosion rate and relatively low cost.
6 - Question
Which of the following is true about AJMM?
a) It is a low cost method
b) It is toxic towards the environment
c) It is hazardous to human health
d) It is not capable of anisotropic machining
View Answer
Explanation: Advantages of AJM: (1) low capital and operating costs, (2) environment-friendly process, (3) no major health hazards, and (4) ability to machine anisotropic and suspended structures on the same substrate.
7 - Question
AJM applications include drilling, engraving of glass, etc. operations.
a) True
b) False
View Answer
Explanation: Typical AJM applications include drilling, cutting and engraving of glass, ceramics and some hard materials. It can also be used to etch labels in plastics and metals, deburr, deflash and clean materials after conventional machining.
8 - Question
In AJMM, abrasive particles are accelerated in a gas stream.
a) True
b) False
View Answer
Explanation: Fine micro abrasive particles are accelerated in a gas stream (commonly air at a few times atmospheric pressure). The particles are directed towards the focus of machining (less than 1mm from the tip).
9 - Question
In AJMM, as the jet fracture off the surface after striking it.
a) True
b) False
View Answer
Explanation: As the particles impact the surface, they fracture off the surface and create cavities. As the particle impacts the surface, it causes a small fracture, and the gas stream carries both the abrasive particles and the fractured (wear) particles away.
10 - Question
The choice of abrasive varies with the type of machining.
a) True
b) False
View Answer
Explanation: The choice of abrasive particles depends on the type of machining operation. The abrasives should have a sharp and irregular shape for better performance.