Engineering Questions with Answers - Multiple Choice Questions
Manufacturing Processes – Abrasive Jet Micromachining – 4
1 - Question
Performance of the AJMM process is dependent on the quality of the mask.
a) True
b) False
View Answer
Explanation: The quality of the mask influences the performance of AJMM. The main qualification for a good mask material is a low erosion rate. It also requires the capability of an accurate and easy pattern transfer, and the ability to retain the irresistance in discontinuous layers.
2 - Question
How many types of materials can be used during AJMM?
a) 1
b) 3
c) 8
d) there is no compulsion on the material
View Answer
Explanation: Three groups of mask materials can be applied to AJMM: • Ductile materials such as metals. • Elastic materials such as elastomer sand. • Photo-resists as used in IC-industry.
3 - Question
The usability of the mask is affected by imaging accuracy.
a) True
b) False
View Answer
Explanation: Each material used for making mask, needs a sufficient erosion resistance related to the substrate especially at normal blast angles. Furthermore, the achievable imaging accuracy determines the usability of a mask and minimum achievable features size.
4 - Question
Which of the following have a low erosion rate?
a) Ductile materials
b) Malleable materials
c) Hardened materials
d) Low melting point materials
View Answer
Explanation: Ductile materials, like metals, have a low erosion rate, especially at perpendicular impact. This makes them suitable to be used as a mask material. It can be used by means of a thin plate (e.g. stainless-steel).
5 - Question
To apply metal mask plate for AJMM, magnetic clamps are used.
a) True
b) False
View Answer
Explanation: Metals having low erosion rates are suitable for making masks for AJMM. To apply metal mask plate for AJMM, it can be magnetically clamped directly to the target or by introducing an intermediate protection/ adhesion layer.
6 - Question
Limitations in feature size are the major drawback of the metal masks.
a) True
b) False
View Answer
Explanation: The disadvantages of this mask type are the limitations in feature size (approximately 50 μm) and pattern constraints (circular patterns cannot be used because the inner side should be supported).
7 - Question
In AJMM, metals masks can be applied to the workpiece by electroplating.
a) True
b) False
View Answer
Explanation: In order to combine the low erosion rate of a metal, and the high resolution of a lithographic process, a metal mask can be applied to the target by electroplating. Copper is used by this method, while Zinc mask can be made by electro-forming.
8 - Question
The erosion mechanism of rubber-like materials is same as that of brittle materials and ductile materials.
a) True
b) False
View Answer
Explanation: The erosion mechanism of rubber-like materials differs essentially from that of brittle materials or ductile materials. No lateral cracks are formed in elastomers as found in brittle materials. Neither do any evidence of cutting or ploughing wear as found in metals.
9 - Question
Erosion mechanism in elastomer materials is based on fatigue.
a) True
b) False
View Answer
Explanation: The erosion mechanism of this class of materials is based on fatigue; therefore they display a good erosion resistance. The photosensitive materials can be patterned accurately using lithography. Photosensitive-elastomer can be a good option.
10 - Question
Behaviour of elastomer materials is dependent on temperature.
a) True
b) False
View Answer
Explanation: In contrast to ductile or brittle materials, elastomers behaviour is dependent on temperature, rate of deformation and particle velocity. Thus elastomers can show ductile, elastic and brittle behaviour.