Manufacturing Technology I Set 9

Mechanical Engineering

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This set of Manufacturing Technology 1 Multiple Choice Questions & Answers (MCQs) focuses on Manufacturing Technology I Set 9

Q1 | Which of the following is the main advantage of using the electromagnetic forming process?
  • high speed
  • low maintenance
  • applicable to all materials
  • no spring-back
Answer: no spring-back
Explaination:
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.
Q2 | What is the maximum pressure required in a compression molding process?
  • 35 mpa
  • 40 mpa
  • 45 mpa
  • 50 mpa
Answer: 50 mpa
Explaination:
the maximum pressure that is required for the complete operation of compression molding is 50 mpa.
Q3 | In compression molding, the curing time does not depend on which of the following factors?
  • material
  • curing temperature
  • geometry
  • thickness
Answer: curing temperature
Explaination:
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.
Q4 | What is the maximum curing time required in a compression molding process?
  • 2 minutes
  • 3 minutes
  • 4 minutes
  • 5 minutes
Answer: 5 minutes
Explaination:
the maximum curing time that is required for the complete operation of compression molding is 5 minutes.
Q5 | What is the minimum pressure required in a transfer molding process?
  • 20 mpa
  • 40 mpa
  • 50 mpa
  • 70 mpa
Answer: 20 mpa
Explaination:
the maximum pressure that is required for the complete operation of transfer molding is 20 mpa.
Q6 | Speed of production in transfer molding is higher than that of compression molding?
  • true
  • false
Answer: true
Explaination:
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.
Q7 | Thermosetting plastics are generally used for making products of high strength and rigidness.
  • true
  • false
Answer: true
Explaination:
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.
Q8 | Which of the following types of molecular structure present in thermosetting polymers?
  • linear polymers
  • branched polymers
  • cross-linked polymers
  • network polymers
Answer: cross-linked polymers
Explaination:
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.
Q9 | Polyethylene, polypropylene and polyvinyl chloride (PVC) are the main example of thermosetting polymers.
  • true
  • false
Answer: false
Explaination:
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.
Q10 | Thermosetting plastics like epoxies can be used for filament wound rocket motor casings in missiles by combining with glass fibers.
  • true
  • false
Answer: true
Explaination:
epoxies can be used in various ways. in adding with glass fibers, it is capable of making composites that are of high
Q11 | Polyurethane plastics are highly reactive to chemical compounds due to lack of elasticity in these plastics.
  • true
  • false
Answer: false
Explaination:
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.
Q12 | Phenolic plastics can also be used as binder for holding plies of wood in making of plywood.
  • true
  • false
Answer: true
Explaination:
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.
Q13 | Thermosetting plastics can be used for manufacturing of windshield for airplane.
  • true
  • false
Answer: false
Explaination:
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.
Q14 | Mechanical properties of any plastics are mainly dependent on the temperature, force and time of load applied.
  • true
  • false
Answer: true
Explaination:
mechanical properties relate to movement or breakage of the polymer due to some mechanical variation such as
Q15 | How is the die used in injection molding cooled?
  • oil
  • air
  • water
  • contact with cold surface
Answer: water
Explaination:
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.
Q16 | How does the piston in the clamping unit move?
  • hydraulic energy
  • pneumatic energy
  • heat energy
  • suction
Answer: hydraulic energy
Explaination:
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.
Q17 | Which of the following material is not made by injection molding?
  • nuts
  • tubes
  • car handles
  • electrical fittings
Answer: tubes
Explaination:
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.
Q18 | What is the minimum pressure allowed to be given to the injection molding process?
  • 90 mpa
  • 100 mpa
  • 140 mpa
  • 170 mpa
Answer: 100 mpa
Explaination:
none.
Q19 | The barrel is used for the opening and closing of the mold.
  • true
  • false
Answer: false
Explaination:
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.
Q20 | In blow molding, to inflate soft plastic, which medium is used?
  • air
  • water
  • oil
  • alcohol
Answer: air
Explaination:
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.
Q21 | Which of the following plastics is not used in blow molding?
  • terephthalate
  • polypropylene
  • polythene
  • pvc
Answer: terephthalate
Explaination:
for blowing processes, there are certain plastics only which are properly suited for the operation, while any other
Q22 | What is the minimum air pressure required in the blow molding process?
  • 350 kpa
  • 400 kpa
  • 450 kpa
  • 500 kpa
Answer: 400 kpa
Explaination:
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.
Q23 | What can be the maximum pressure to be given to plastic for blow molding process?
  • 700 kpa
  • 750 kpa
  • 800 kpa
  • 850 kpa
Answer: 800 kpa
Explaination:
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.
Q24 | Which of the following is not a type of blow molding process?
  • injection blow molding
  • extrusion blow molding
  • multi-smaller blow molding
  • multi-larger blow molding
Answer: multi-smaller blow molding
Explaination:
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,
Q25 | What is the minimum thickness required by the plastic for vacuum forming?
  • 0.125 mm
  • 0.25 mm c) 0.375 mm
  • d) 0.5 mm
Answer: 0.125 mm
Explaination:
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.
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