Manufacturing Technology I Set 10

Answer: door liners

Explaination:
among the following, only door liners is not an application of blow molding process. internal door liners are

Answer: 3.2 mm

Explaination:
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

Answer: true

Explaination:
in vacuum forming process, there is a clamp that has to be used for holding the plastic sheets. there is a heater employed for heating the mold cavity. the

Answer: true

Explaination:
in blow molding, there is a mold cavity present inside the soft plastic, into which, the air with high amount of

Answer: amount of finish required

Explaination:
shrinkage allowance does not depend on the amount of finish required. the amount of finish needed on the machining portion is a factor on which machining allowance depends. shrinkage allowance depends on all other remaining factors.

Answer: true

Explaination:
the molding sand is made up of several particles. the properties such as porosity, texture are all considered while making it fit for the use of the foundry. out of all the materials used, the size of the sand particles (silica sand) is the highest.

Answer: aggregates

Explaination:
in a foundry, the molding sand

Answer: adhesiveness

Explaination:
the adhesiveness is a property of molding sand to get the stick or adhere to foreign material such as sticking of molding sand with an inner wall of the molding box. hence, as the sand sticks to the box and the excess sand is removed.

Answer: cohesiveness

Explaination:
the cohesiveness is a property of molding sand by virtue which the sand grain particles interact and attract each other

Answer: collapsibility

Explaination:
after the molten metal in the mould gets solidified, the sand mould must be collapsible so that free contraction of the metal occurs and this would naturally avoid the tearing or cracking of the contracting metal. in absence of collapsibility property, the contraction of the metal is hindered by the mold and thus results in tears and cracks in the casting. this property is highly required in cores.

Answer: ferrous

Explaination:
electric furnaces are more suitable for ferrous material in a larger capacity.

Answer: crucible

Explaination:
in crucible furnace, metal is placed in a crucible of refractory material. the crucible is heated with electric resistance.

Answer: controlling power and frequency of current only

Explaination:
due to the principle of induction used, the electromagnetic fields are produced. these emf’s are used to stir the metal. hence, controlling the power and frequency, mixing and melting rates can be altered.

Answer: mueller

Explaination:
mueller is the machine used to mix mould particles thoroughly.

Answer: all of the mentioned

Explaination:
in pmc the cores can be made out of any of these materials.

Answer: slush casting

Explaination:
slush casting is used to make casting which is actually hollow projections. hence, it is also called a hollow casting.

Answer: 0.3-1.5 bars

Explaination:
usually the gauge is set to a range of 0.3-1.5 bars while providing pressure to the molten metal to raise it in the riser.

Answer: true

Explaination:
when after the proper ramming of sand to confirm to the outer contour of the pipe to be made, dry sand cores may be introduced for the provision of end details such as spigot ends, or flanged ends to the casting. meanwhile there is no requirement of any cores for the making of the hollow section of the castings.

Answer: metallic roller

Explaination:
after the completion of the mould, the flask is balanced dynamically so as to reduce the occurrence of undesirable vibrations during the casting process. and the metallic rollers are used in between the rotating mould and the stationary casing to avoid the jerks and for the damping of vibrations.

Answer: true

Explaination:
there is no need for the gates and runners in the centrifugal casting process, which saves a lot of molten metal. this makes the increase in casting yield, reaching almost 100%. and no any application of cores makes the castings very economical for the large scale production.

Answer: false

Explaination:
it is not possible to make un- symmetric shape of casting in centrifugal casting, only certain shapes which are axi- symmetric and having concentric holes are suitable to make in the centrifugal casting. and equipment are also expensive, so this method is suitable only for large scale production.

Answer: true

Explaination:
in centrifugal casting, the inclusions such as slag and oxides get segregated towards the centre and can be easily removed by a machining process. and also the application of pressure on the metal throughout the solidification causes the porosity to be eliminated and gives rise to dense metal.

Answer: centrifuging

Explaination:
centrifuging is a process which is used in order to obtain higher metal pressures during solidification when the shapes of the casting are not axi-symmetrical. this process is mainly suitable for small jobs of any shape. in this method, a number of small jobs are joined together in a radial manner and then the further process of casting is done.

Answer: true

Explaination:
mould is prepared by adding sodium silicate binder. co2 gas is supplied to the mould for sufficient time. it reacts with sodium silicate and produces silica gel which has better bonding properties. due to this strength and hardness of the large sized moulds and cores can be increased.

Answer: false

Explaination:
continuous passing of co2 always results in a strong and hard mould. more the passing of co2 more will be the strength of the mould. only the drawback is the decrease in permeability and collapsibility of the mould. much passing of co2 gas results into difficult breathing of the mould.