Manufacturing Processes Multiple Choice Questions & Answers on “Micromachining – 2”.
1. There is no thermal damage to the workpiece in IBM.
a) True
b) False
Answer: a
Clarification: In case of IBM. An ion hits an atom at the top surface of the workpiece and removes the material atom by atom or in the groups of atoms. Therefore, there is no thermal damage to the workpiece in IBM.
2. Thermal micromachining processes can be used to produce reduced hole diameter, lower hole pitch.
a) True
b) False
Answer: a
Clarification: Reduced hole diameter, lower hole pitch and longer head can be manufactured by thermal micromachining processes. These processes are used to manufacture computer hard disc drive heads, inkjet printer heads, sensors, infrared images.
3. Chemical micromachining is used for engraving the metal.
a) True
b) False
Answer: a
Clarification: It is an ancient process being used for engraving the metal for making ornaments and other products. It removes material in a controlled manner by the application of maskant and etchant.
4. It is required to remove material in the form of atoms for finishing of the surface.
a) True
b) False
Answer: a
Clarification: To finish surfaces to nano level, it is required to remove material in the form of atoms or molecules individually or in groups. Most of the nano finishing processes are using abrasive particles either suspended inliquid or held by the viscoelastic material, carbonyl iron particles, or by the magnetorheological fluid as a carrier.
5. Magneto rheological abrasive finishing (MRF) is a magnetic field assisted process.
a) True
b) False
Answer: a
Clarification: MRF is a deterministic and magnetic field assisted precision finishing process. MRF uses MRP fluid which is invented by Rabinow in late 1940s consist of CIP (Magnetic), abrasive (non-magnetic), carrierliquid (Oilorwater), additives (glycerol, grease).
6. MRF is used for finishing of brittle materials.
a) True
b) False
Answer: a
Clarification: MRF has been used for finishing a large variety of brittle material ranging from optical glasses to hard crystals. The major limitation of this process is that Internal and especially complex surfaces can’t be finished.
7. Abrasive flow machining (AFM) is used for _____
a) de-burring
b) etching
c) drilling
d) cutting
Answer: a
Clarification: AFM was developed by Extude Home Corporation USA in 1960 as a method to deburr, polish and radius difficult to reach surface like intricate geometries and edges by flowing an abrasive laden viscoelastic medium over them.
8. In chemo-mechanical polishing (CMP) process, material is removed due to abrading.
a) True
b) False
Answer: a
Clarification: CMP uses both chemical and mechanical type for material removal mechanism. Chemical reaction is used to soften material and then mechanically polish off this layer. Mechanical removal takes place due to abrading.
9. CMP is used for flat surfaces only.
a) True
b) False
Answer: a
Clarification: CMP is not deterministic in nature. End point of CMP is difficult to control for a desired thickness. This process is used for only flat surfaces. Basically, CMP is used to polish the silicon wafer.
10. MAF was developed to produce efficiently and economically good quality finish material.
a) True
b) False
Answer: a
Clarification: MAF was developed to produce efficiently and economically good quality finish on the internal and external surface of tubes as well as flat surface made of magnetic or non-magnetic material.
11. Magnetic Float Polishing is a technique based on_____
a) magneto-dynamic behaviour
b) magneto-hydrodynamic behaviour
c) kinematic behaviour
d) viscosity
Answer: b
Clarification: Magnetic Float Polishing is a technique based on the Magnet on hydrodynamic behaviour of the magnetic fluid which in the presence of magnetic field can levitate a non-magnetic float and abrasive particles suspended in it.
12. Ferromagnetic particles are attracted towards the area of a higher magnetic field.
a) True
b) False
Answer: a
Clarification: When the magnetic field is applied the ferromagnetic particles in the ferrofluid are attracted downward to the area of higher magnetic field and upward buoyant force is exerted on all non-magnetic materials to push them to the area of lower magnetic field.
13. MRAFF is the hybrid finishing process of MRF and AFF.
a) True
b) False
Answer: a
Clarification: 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.
14. In magnetic flow polishing process, very small force is applied by the abrasives.
a) True
b) False
Answer: a
Clarification: 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.
15. For replication of micro parts moulding is preferred
a) True
b) False
Answer: a
Clarification: 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.
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