1. MRAFF is the hybrid finishing process of MRF and AFF.
a) True
b) False
Explanation: MRAFF is the hybrid finishing process to take advantage of both the finishing processes MRF (magneto-rheological finishing) & AFF (abrasive flow finishing). Any complex geometry can be finished by this process.
2. In magnetic flow polishing process, very small force is applied by the abrasives.
a) True
b) False
Explanation: The forces applied by abrasives are extremely small and controllable. The balls are polished by the abrasive particles mainly due to the action of the magnetic buoyancy force when the spindle rotates.
3. For replication of micro parts moulding is preferred
a) True
b) False
Explanation: Nowadays, focus is on miniaturization through the development of novel production concepts (especially micro & nano) for the processing of non-ceramic materials. The replication of microparts through moulding is one of the preferred routes for micromanufacture because of its mass-production capability and relatively low cost
4. AJMM is widely used for machining of glass and silicon.
a) True
b) False
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).
5. In AJMM, workpiece is exposed to abrasive action of the particles.
a) True
b) False
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.
6. This method is used for _____
a) making finished surfaces
b) thread finishing
c) making grooves
d) cutting
Explanation: This method is used for making accurate shallow holes or grooves, and, with the use of masks, patterns on target material
7. Resulting abrasive action is dependent on the impact angle of the jet.
a) True
b) False
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.
8. AJMM is capable of machining anisotropic patterns.
a) True
b) False
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.
9. 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
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.
10. AJM applications include drilling, engraving of glass, etc. operations.
a) True
b) False
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.