McqMate
These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Mechanical Engineering .
| 151. |
When forming “Z” sections, the product is twisted in the opposite direction to compensate the machine generated twist. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: a common method used to compensate for the anticipated twist is to twist the product in the opposite direction in the mill, from pass to pass. this principle is used when forming “z” sections. in other cases, the counter-twisting is accomplished just in the last one or two passes. | |
| 152. |
Which of the following is a type of extrusion process? |
| A. | direct |
| B. | indirect |
| C. | impact |
| D. | all of the mentioned |
| Answer» D. all of the mentioned | |
| Explanation: classification of extrusion processes are shown below. | |
| 153. |
In direct extrusion process at higher temperature which of the following is used to avoid friction? |
| A. | oil |
| B. | lubricants |
| C. | molten glasses |
| D. | wax |
| Answer» C. molten glasses | |
| Explanation: for steels, stainless steel, and high temperature materials, glass is a good excellent lubrication. the reasons for this are as follows. i. glass contains its viscosity at elevated temperatures, ii. has good wetting characteristics, and 3. glass acts as a thermal barrier between the billet, the container and the die, thus minimizing cooling. | |
| 154. |
In which of the following process frictional loss is eliminated at the billet container interface? |
| A. | direct |
| B. | indirect |
| C. | impact |
| D. | hydrostatic |
| Answer» D. hydrostatic | |
| Explanation: in hydrostatic extrusion process frictional loss is eliminated at the billet container interface. this elimination increases the quality of the product. | |
| 155. |
In which of the following process fluid medium is used to apply the load on the billet? |
| A. | direct |
| B. | indirect |
| C. | impact |
| D. | hydrostatic |
| Answer» D. hydrostatic | |
| Explanation: in hydrostatic extrusion process fluid medium is used to apply the load on the billet. as hydro stands for fluid and static for rest. | |
| 156. |
Extrusion is similar to? |
| A. | rolling |
| B. | forming |
| C. | welding |
| D. | casting |
| Answer» A. rolling | |
| Explanation: extrusion is similar rolling in producing constant cross-sectional shape. | |
| 157. |
Which defect arises due to high friction or high speed? |
| A. | tearing |
| B. | surface cracking |
| C. | tearing & surface cracking |
| D. | flaking |
| Answer» C. tearing & surface cracking | |
| Explanation: the defects such as, surface cracking and tearing, occurs with high friction or speed. these can also occur with stickling of billet material on die land. | |
| 158. |
Which of the following defect is also known as bamboo defect? |
| A. | blow hole |
| B. | cold shut |
| C. | surface cracking |
| D. | pipe defect |
| Answer» C. surface cracking | |
| Explanation: bamboo defects are periodic surface cracks that develop due to the extruded product sticking to the die land. | |
| 159. |
Which of the following defect tends to draw surface oxides and impurities towards the centre of billet? |
| A. | blow hole |
| B. | cold shut |
| C. | surface cracking |
| D. | pipe defect |
| Answer» D. pipe defect | |
| Explanation: pipe defect is the formation of sin hole at the end of the billet. it is associated with direct extrusion. the use of | |
| 160. |
Which of the following defect is also known as fish tailing? |
| A. | surface cracking |
| B. | pipe defect |
| C. | tearing |
| D. | internal cracking |
| Answer» B. pipe defect | |
| Explanation: in extrusion, the pipe defect is also termed as “tail pipe”, and “fish tailing”. it occurs during hot extrusion due to the presence of impurities and oxides. | |
| 161. |
For proper stretching operation, the metal sheet should be stressed above its yield strength. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: in stretch forming, a metal sheet is stretched by the help of stretcher machines. for proper and complete stretching of sheet, the material is deformed plastically which is also called as permanent deformation. the metal sheet is stressed above its yield strength for successfully achieving the plastic deformation of the metal sheet. | |
| 162. |
In stretch forming, forming limit curve (FLC) is defined as a locus of all the limit strains in different strain paths of the sheet metal. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: in stretch metal forming process, the forming limit curve (flc) provides quantification about the formability of sheet metal, which basically gives the details about the quality of material. the forming limit curve (flc) is generally defined as a locus of all the limit strains in different strain paths like deep drawing and biaxial stretching, of the sheet metal. | |
| 163. |
The stretch forming process is generally performed by using a hydraulic operated ram. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: the stretch forming process is generally performed by using a hydraulic operated ram. in this process, first a single form block is used along with the gripping jaws, and then the metal is gripped and stretched by applying high tensile forces until it deforms plastically. and then the sheet metal is bent and rolled around a form block. | |
| 164. |
Rubber forming is a type of forming process in which polyurethane is used as a die material. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: rubber forming is a type of forming process in which a polyurethane or rubber pad is commonly used as the die material instead of a rigid material. these materials are highly resistance to the abrasion and have a better fatigue life. and pressures of the order of 100 bar are typical of this process. this process is also called as guerin process. | |
| 165. |
The metal forging operation can only be performed by manual means. |
| A. | true |
| B. | false |
| Answer» B. false | |
| Explanation: metal forging is a forming operation which usually performs hammering process to shape the metal part. in the forging process, the metal part is heated sufficiently, and then it is hammered by using a hammer which can be performed by manual means or by automation, depending on the scale of production. | |
| 166. |
Which of the following metal forming processes performs squeezing out of material through a hole? |
| A. | forging |
| B. | rolling |
| C. | drawing |
| D. | extrusion |
| Answer» D. extrusion | |
| Explanation: extrusion process is a type of metal forming process, in which the material is forced or squeezed out through a hole called die. this process is very similar to squeezing out the toothpaste from the tube. this process is mainly used for metals that are ductile in nature like copper, steel, | |
| 167. |
Metal forming is a process in which the metal is deformed plastically to get into the desired shape. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: in general, the metal forming is a large set of manufacturing processes in which the metal is deformed plastically to get into the shape of the die geometry. the tools like dies and punches are mostly used in the processes for the deformation of the material. for the plastic deformation, stresses beyond the yield strength of the material is required. | |
| 168. |
Which of the following processes is not the type of bulk forming process in the metal forming? |
| A. | bending |
| B. | rolling |
| C. | forging |
| D. | extrusion |
| Answer» A. bending | |
| Explanation: bulk forming is a deformation process which results in a massive shape change of the material. the ratio of surface area to volume of the material is relatively small. it includes processes like forging, extrusion and rolling. but the bending process is a part of sheet metal forming which has surface area to volume ratio relatively high. | |
| 169. |
Which of the following manufacturing processes is mainly considered for producing the components of very high strength? |
| A. | casting |
| B. | forging |
| C. | extrusion |
| D. | rolling |
| Answer» B. forging | |
| Explanation: forging is a deformation process in which the material is compressed | |
| 170. |
In metal forging process, the gravity drop hammers are operated by a ram using steam or pressurized air. |
| A. | true |
| B. | false |
| Answer» B. false | |
| Explanation: in the metal forming process, drop hammers are mainly of two types which are gravity drop hammer and power drop hammer. gravity drop hammers are the tools which achieve their energy by the falling weight of a heavy ram. the force mainly depends on the height of the drop and the weight of the ram. and power drop hammers are in which a ram is accelerated by the steam or pressurized air. | |
| 171. |
Which of the following metal forming processes is best suitable for making the wires? |
| A. | forging |
| B. | extrusion |
| C. | drawing |
| D. | rolling |
| Answer» C. drawing | |
| Explanation: drawing is a metal forming process which is widely used for making the wires from round bars of metal. this process is similar to extrusion process, except that instead of pressure on the metal mass, in drawing, the wire is pulled from one side of the metallic round bar which results into the formation of thin wires. this process is only suitable for ductile materials. | |
| 172. |
Stretch forming is a sheet metal forming operation in which shearing is taking place to deform the material. |
| A. | true |
| B. | false |
| Answer» B. false | |
| Explanation: stretch forming is a type of sheet metal forming process in which the metallic sheet is intentionally stretched and bent simultaneously to produce different shapes of the stretched sheet metal. the metal sheet is generally held by jaws at the ends. | |
| 173. |
Metal used for electroforming process absorbs energy from the magnetic field to get deform. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: in the electromagnetic forming process, the conductivity of the metal and the eddy currents which makes contact with magnetic field creates a net pressure on the surface of the metal. then the metal surface moves inward due to the effect of this pressure, this mainly occurs due to the transfer of energy from the magnetic field to the metal. | |
| 174. |
In the electromagnetic forming process, the forming pulse is kept longer to optimize the use of energy. |
| A. | true |
| B. | false |
| Answer» B. false | |
| Explanation: in the electromagnetic forming process, the metal absorbs energy from the magnetic field to get deformed. to utilize most of this energy to forming operation, and to reduce the energy loss due to resistance heating, the forming pulse is kept short for better optimization of energy produced by the magnetic field. in general, pulse has duration of between 10 and 100 second. | |
| 175. |
Which of the following methods of forming is not the part of electromagnetic forming? |
| A. | compression |
| B. | expansion |
| C. | shearing |
| D. | counter forming |
| Answer» C. shearing | |
| Explanation: in the electromagnetic forming process, electromagnetic formation mainly used for three forming methods which can be compression, expansion, and counter forming. for compression, a tubular metal is compressed by a coil, usually against a grooved tube. and shearing is a different | |
| 176. |
The process of electromagnetic forming does not require any kind of lubrication. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: in most of the forming processes, tool contacts with the specimen to get the desired output. but in the case of electromagnetic forming, the magnetic field is used to apply the pressure on the surface of a metal, which normally does not require any kind of lubrication. and it leaves no any tool marks on the metal surface. | |
| 177. |
Which of the following is the main advantage of using the electromagnetic forming process? |
| A. | high speed |
| B. | low maintenance |
| C. | applicable to all materials |
| D. | no spring-back |
| Answer» D. no spring-back | |
| Explanation: in the electromagnetic forming process, the metal is loaded and achieve plastic region, which results in plastic or permanent deformation, so that the spring- back associated with the mechanical forming process is completely eliminated because no any mechanical contact is present during the process of metal forming. | |
| 178. |
What is the maximum pressure required in a compression molding process? |
| A. | 35 mpa |
| B. | 40 mpa |
| C. | 45 mpa |
| D. | 50 mpa |
| Answer» D. 50 mpa | |
| Explanation: the maximum pressure that is required for the complete operation of compression molding is 50 mpa. | |
| 179. |
In compression molding, the curing time does not depend on which of the following factors? |
| A. | material |
| B. | curing temperature |
| C. | geometry |
| D. | thickness |
| Answer» B. curing temperature | |
| Explanation: when there has to be molding done for thermosetting materials, mainly compression molding is preferred. while doing this, curing has to be done. the time needed for curing depends on the material used, geometry and thickness of the material. | |
| 180. |
What is the maximum curing time required in a compression molding process? |
| A. | 2 minutes |
| B. | 3 minutes |
| C. | 4 minutes |
| D. | 5 minutes |
| Answer» D. 5 minutes | |
| Explanation: the maximum curing time that is required for the complete operation of compression molding is 5 minutes. | |
| 181. |
What is the minimum pressure required in a transfer molding process? |
| A. | 20 mpa |
| B. | 40 mpa |
| C. | 50 mpa |
| D. | 70 mpa |
| Answer» A. 20 mpa | |
| Explanation: the maximum pressure that is required for the complete operation of transfer molding is 20 mpa. | |
| 182. |
Speed of production in transfer molding is higher than that of compression molding? |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: it is counted among one of the advantages of transfer molding over compression molding that the speed of production is quite higher. not just that, but the maintenance in transfer molding too is lower than compression molding. | |
| 183. |
Thermosetting plastics are generally used for making products of high strength and rigidness. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: thermosetting polymers basically involve cross-linked molecular structure and thus it is ideal for making products which demand rigidity and strength. due to cross linking in thermosetting polymers, these are made hard, tough, and cannot be re-moulded as thermoplastic polymers. | |
| 184. |
Which of the following types of molecular structure present in thermosetting polymers? |
| A. | linear polymers |
| B. | branched polymers |
| C. | cross-linked polymers |
| D. | network polymers |
| Answer» C. cross-linked polymers | |
| Explanation: cross-linked polymers are described by adjacent linear chains that are brought one to another at several locations by covalent bonds. cross linking is completed by a non-reversible chemical reaction. often, cross-linking is finished by additive atoms which are covalently bonded to the chains in the thermosetting polymers. | |
| 185. |
Polyethylene, polypropylene and polyvinyl chloride (PVC) are the main example of thermosetting polymers. |
| A. | true |
| B. | false |
| Answer» B. false | |
| Explanation: polyethylene, polypropylene and polyvinyl chloride (pvc) are basically examples of thermoplastics material. and thermosetting material’s example includes polyurethanes, polyesters, epoxy resins and phenol resins which are used for manufacturing of aircraft parts, tires and auto parts. | |
| 186. |
Polyurethane plastics are highly reactive to chemical compounds due to lack of elasticity in these plastics. |
| A. | true |
| B. | false |
| Answer» B. false | |
| Explanation: polyurethane plastics come in the category of thermosetting plastics. in this type of plastics, elasticity is generally very high. due to this property of high elasticity, it can be used in decorative and protective coatings. the high elasticity also makes these polyurethane polymers highly resistant to any chemical attack. | |
| 187. |
Phenolic plastics can also be used as binder for holding plies of wood in making of plywood. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: phenolic plastics or polymers are belongs to thermosetting plastics. these are the special type of resins which can be used in potting compounds, casting resins, and laminating resins. they can also be used in making of electrical equipment. phenolic plastics are very popular binders for holding plies of wood in manufacturing of plywood. | |
| 188. |
Thermosetting plastics can be used for manufacturing of windshield for airplane. |
| A. | true |
| B. | false |
| Answer» B. false | |
| Explanation: for the manufacturing of windshield for airplane, poly-acrylics plastics are used which basically belongs to the group of thermoplastics. poly-acrylics are transparent, high tough in nature and can be easily shaped in any form. due to such properties of this material, it is widely used for making of windshields for airplane. | |
| 189. |
How is the die used in injection molding cooled? |
| A. | oil |
| B. | air |
| C. | water |
| D. | contact with cold surface |
| Answer» C. water | |
| Explanation: when it comes to molding of polymers in thermoplastics, injection molding process is the most common of the methods. in this method, whenever the die has to be cooled, there is water used to cool it. | |
| 190. |
How does the piston in the clamping unit move? |
| A. | hydraulic energy |
| B. | pneumatic energy |
| C. | heat energy |
| D. | suction |
| Answer» A. hydraulic energy | |
| Explanation: there is a clamping unit employed for holding the two halves together and for the opening and closing of the mold. a moving piston is provided which operates the power press. this piston works on hydraulic energy. | |
| 191. |
Which of the following material is not made by injection molding? |
| A. | nuts |
| B. | tubes |
| C. | car handles |
| D. | electrical fittings |
| Answer» B. tubes | |
| Explanation: injection molding is one of the most widely used method of molding among molding with polymers. there are various applications of this method such as nuts, bolts, cups, car handles, electrical fitting parts, but not tubes and rods. | |
| 192. |
What is the minimum pressure allowed to be given to the injection molding process? |
| A. | 90 mpa |
| B. | 100 mpa |
| C. | 140 mpa |
| D. | 170 mpa |
| Answer» B. 100 mpa | |
| Explanation: none. | |
| 193. |
The barrel is used for the opening and closing of the mold. |
| A. | true |
| B. | false |
| Answer» B. false | |
| Explanation: a barrel is an instrument that is placed near the nozzle, and it plays no role in the opening and closing of the mold. there is a clamping unit employed for holding the two halves together and for the opening and closing of the mold. | |
| 194. |
In blow molding, to inflate soft plastic, which medium is used? |
| A. | air |
| B. | water |
| C. | oil |
| D. | alcohol |
| Answer» A. air | |
| Explanation: blow molding process is typically used for the blowing process of hollow plastics. while blow molding, the plastic has to be inflated, in order to do so, air has to be blown inside with a high amount of pressure. | |
| 195. |
Which of the following plastics is not used in blow molding? |
| A. | terephthalate |
| B. | polypropylene |
| C. | polythene |
| D. | pvc |
| Answer» A. terephthalate | |
| Explanation: for blowing processes, there are certain plastics only which are properly suited for the operation, while any other | |
| 196. |
What is the minimum air pressure required in the blow molding process? |
| A. | 350 kpa |
| B. | 400 kpa |
| C. | 450 kpa |
| D. | 500 kpa |
| Answer» B. 400 kpa | |
| Explanation: in the blow molding process, there is some amount of pressure that has to be given to the air for blowing the bottles. the amount of pressure to be given depends on the material. the minimum pressure that can be given in this process is 400 kpa. | |
| 197. |
What can be the maximum pressure to be given to plastic for blow molding process? |
| A. | 700 kpa |
| B. | 750 kpa |
| C. | 800 kpa |
| D. | 850 kpa |
| Answer» C. 800 kpa | |
| Explanation: air with an extreme amount of pressure, when is needed, it might mean the material is thicker and denser. the amount of pressure that can be provided depends totally on the material. the maximum pressure that can be provided in blow molding process is 800 kpa. | |
| 198. |
Which of the following is not a type of blow molding process? |
| A. | injection blow molding |
| B. | extrusion blow molding |
| C. | multi-smaller blow molding |
| D. | multi-larger blow molding |
| Answer» C. multi-smaller blow molding | |
| Explanation: blow molding basically is a process of inflation of air under pressure into the plastics inside the mold cavity. there are only three known types of blow molding, | |
| 199. |
What is the minimum thickness required by the plastic for vacuum forming? |
| A. | 0.125 mm |
| B. | 0.25 mm |
| C. | 0.375 mm |
| D. | 0.5 mm |
| Answer» A. 0.125 mm | |
| Explanation: vacuum forming is one of the classifications of thermoforming processes. around its circumference, a clamp is attached or we need to know the minimum thickness. the minimum thickness that can be allowed for this operation is 0.125 mm. | |
| 200. |
What is the maximum thickness that can be allowed for a plastics sheet in a vacuum forming process? |
| A. | 3 mm |
| B. | 3.1 mm |
| C. | 3.2 mm |
| D. | 3.3 mm |
| Answer» C. 3.2 mm | |
| Explanation: vacuum forming process is one of the important processes that are employed in thermoforming processes. the maximum thickness of the plastic sheet has to be noted, as a clamp is to be fitted around the plastic | |
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