280+ Manufacturing Technology 1 Solved MCQs

201.

°C.

A. true
B. false
Answer» A. true
Explanation: 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
202.

Shrinkage allowance does not depend on which of the following factor?

A. moulding method
B. casting dimension
C. pouring temperature of molten metal
D. amount of finish required
Answer» D. amount of finish required
Explanation: 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.
203.

The size of the sand particles in the molding sand is the biggest.

A. true
B. false
Answer» A. true
Explanation: 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.
204.

The                is responsible for the impact strength in the molding sand.

A. aggregates
B. refractoriness
C. impurities
D. permeability
Answer» A. aggregates
Explanation: in a foundry, the molding sand
205.

The                                property ensures the removal of excess sand in the mould box.

A. adhesiveness
B. cohesiveness
C. green strength
D. compressive strength
Answer» A. adhesiveness
Explanation: 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.
206.

Binding property of the sand increases because of the                          property.

A. cohesiveness
B. collapsibility
C. flow ability
D. permeability
Answer» A. cohesiveness
Explanation: the cohesiveness is a property of molding sand by virtue which the sand grain particles interact and attract each other
207.

Which of the following is the most important property of the molding sand in cores?

A. dry strength
B. green strength
C. collapsibility
D. cohesiveness
Answer» C. collapsibility
Explanation: 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.
208.

Electric arc furnaces are most suitable for which of the following type of material?

A. ferrous
B. non-ferrous
C. both ferrous and nonferrous
D. neither ferrous nor nonferrous
Answer» A. ferrous
Explanation: electric furnaces are more suitable for ferrous material in a larger capacity.
209.

There is no direct contact of flame and metal in which of the following type of furnace?

A. cupola
B. crucible
C. electric arc
D. induction
Answer» B. crucible
Explanation: in crucible furnace, metal is placed in a crucible of refractory material. the crucible is heated with electric resistance.
210.

In an induction furnace, mixing and melting rates are altered by?

A. controlling the temperature ranges only
B. controlling the number of electrodes used only
C. controlling power and frequency of current only
D. all of the mentioned factors
Answer» C. controlling power and frequency of current only
Explanation: 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.
211.

The machine used to mix shell mould particles consistently is                      

A. mixer
B. cupola furnace
C. mueller
D. mixer & cupola furnace
Answer» C. mueller
Explanation: mueller is the machine used to mix mould particles thoroughly.
212.

Cores used in PMC are usually made up of?

A. metal
B. collapsable material
C. sand
D. all of the mentioned
Answer» D. all of the mentioned
Explanation: in pmc the cores can be made out of any of these materials.
213.

Hollow casting is the other name of which of the following special casting process?

A. slush casting
B. vacuum die casting
C. precision investment casting
D. squeeze casting
Answer» A. slush casting
Explanation: slush casting is used to make casting which is actually hollow projections. hence, it is also called a hollow casting.
214.

Pressure range for low pressure die casting is                        

A. 0.3-1.5 bars
B. 0.5-2 bars
C. 2-6 bars
D. up to 8 bars
Answer» A. 0.3-1.5 bars
Explanation: 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.
215.

Dry sand cores may be required for the provision of spigot at the end section of the casting.

A. true
B. false
Answer» A. true
Explanation: 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.
216.

Which of the following parts is provided in between the mould and casing to reduce the vibrations?

A. steel balls
B. metallic roller
C. viscous fluid
D. grease
Answer» B. metallic roller
Explanation: 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.
217.

In centrifugal casting, the casting yield is approximately equaled to 100%.

A. true
B. false
Answer» A. true
Explanation: 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.
218.

It is also possible to make un-symmetric shape of casting in true centrifugal casting by introducing some variations to the mould.

A. true
B. false
Answer» B. false
Explanation: 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.
219.

Castings made by the centrifugal casting process have negligible porosity.

A. true
B. false
Answer» A. true
Explanation: 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.
220.

Which of the following types of centrifugal casting process is used for the casting, whose shape of casting is not axi- symmetric?

A. true centrifugal casting
B. semi centrifugal casting
C. centrifuging
D. full centrifugal casting
Answer» C. centrifuging
Explanation: 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.
221.

Co2 moulding is mainly used for the increase in strength and hardness of the moulds and cores.

A. true
B. false
Answer» A. true
Explanation: 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.
222.

Continuous passing of Co2 through the mould can decrease the strength of mould and results in a weak mould.

A. true
B. false
Answer» B. false
Explanation: 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.
223.

Additives can be used for the non-ferrous application to avoid the poor collapsibility of the mould.

A. true
B. false
Answer» B. false
Explanation: in co2 moulding, poor collapsibility of the mould is a major disadvantage. although some additives are used for the improvement in the properties of
224.

Sometimes over-gassing can cause the sticking of pattern to the mould in Co2 moulding.

A. true
B. false
Answer» A. true
Explanation: in co2 moulding, over-gassing and under-gassing can affects the properties of cured sand adversely. when the continuous passing of co2 is done for long time, this may results into sticking of pattern with the mould which cannot be removed easily, so proper care should be taken while passing of co2 gas.
225.

The rotor of a three phase induction motor can never attain synchronous speed.

A. true
B. false
Answer» A. true
Explanation: because then there will be no torque developed and flux cutting.
226.

A three phase induction motor is sometimes called a generalized transformer in so far as voltage and frequency transformation has been concerned. How a three phase induction motor operates when rotor frequency is greater than stator frequency?

A. rotor will be driven against rmf
B. rotor will be driven in direction of rmf
C. no emf will be induced
D. the losses will be maximum
Answer» A. rotor will be driven against rmf
Explanation: as the rotor rotates at larger speed than the stator, the rmf speed is less than the rotor speed and it tries to rotate in the opposite direction to rmf.
227.

A three phase induction motor is sometimes called a generalized transformer in so far as voltage and frequency transformation has been concerned. How a three phase induction motor operates when rotor frequency is less than stator frequency?

A. it operates as induction motor
B. emf is induced in rotor
C. rmf will rotate at synchronous speed
D. all of the mentioned
Answer» D. all of the mentioned
Explanation: it will operate as induction motor.
228.

A three phase induction motor is sometimes called a generalized transformer in so far as voltage and frequency transformation has been concerned. Then the rotor emf E2 and the rotor current I2 are zero at                    

A. ns
B. 2ns
C. zero
D. slip of 50%
Answer» A. ns
Explanation: the rotor emf and current are zero at the speed of synchronous speed of the machine.
229.

Consider a situation in which a welding operation is being performed with V = 20 volts, I = 200 A, and the cross-sectional area of the weld bead is 30 mm2. Estimate the welding speed if the workpiece and electrode are made of (a) aluminum, (b) carbon steel, and (c) titanium. Use an efficiency of 75%.

A. 35 mm/s
B. 34.5 mm/s
C. 36 mm/s
D. 46 mm/s
Answer» B. 34.5 mm/s
Explanation: for aluminum, the specific energy required is u = 2.9 j/mm3 therefore,
230.

In arc welding, arc is created between the electrode and work by?

A. contact resistance
B. flow of voltage
C. flow of current
D. electrical energy
Answer» D. electrical energy
Explanation: all arc welding utilizes the transfer of electrical energy to heat energy. an arc is a sustained electric discharge through this ionised gas column called plasma between the two electrodes. in order to produce the arc, the potential difference between the two electrodes (voltage) should be enough to allow them to move across the air gap. the larger air gap requires higher potential differences. if the air gap becomes too large for the voltage, the arc may be extinguished.
231.

The coating material used for the electrode is termed as?

A. flux
B. slag
C. protective layer
D. deoxidiser
Answer» A. flux
Explanation: flux is a substance used to prevent the formation of oxides and the other unwanted contaminations, or to dissolve them and facilitate removal. during welding the flux melts and becomes a liquid slag, covering the operation and protecting the molten weld metal the slag hardens upon cooling and must be removed later by chipping or brushing.
232.

Which of the following welding process in which two pieces to be joined are overlapped and placed between two pointed electrodes?

A. seam welding
B. resistance welding
C. projection welding
D. spot welding
Answer» D. spot welding
Explanation: spot welding is the simplest and most used resistance welding process. welding may be performed by means of single (most common) or multiple pairs of electrodes (as many as a hundred or more), and the required pressure is supplied through mechanical or pneumatic means.
233.

In which of the following type of flame, oxygen is of same proportion with acetylene?

A. neutral flame
B. oxidizing flame
C. carburizing flame
D. both oxidizing flame and carburizing flame
Answer» A. neutral flame
Explanation: in neutral flame oxygen is in the same proportion with acetylene. neutral welding flames are commonly used to weld: mild steel, stainless steel, cast iron, copper, aluminium, etc.
234.

If the open circuit voltage is 60 volt and the short circuit current is 20 amperes. Then determine the voltage required for welding if the current required during welding is 10 amperes?

A. 30 v
B. 60 v
C. 20 v
D. 40 v
Answer» A. 30 v
Explanation: voltage = ocv – (     i     )×ocv, where “ocv” is open circuit voltasgcec, “scc”
235.

How does the arc voltage V depends upon the length of arc L?

A. v = f(l)
B. v = 1/f(l)
C. v = f(l2)
D. v = f(√l)
Answer» A. v = f(l)
Explanation: v= a+bl, where ‘v’ is the arc voltage and ‘l’ is the length of arc in cm, a & b are constants.
236.

What is the only difference between Plasma arc welding and TIG welding?

A. flux is not used
B. construction of torch is different
C. gas is not used
D. tungsten electrode is not used
Answer» B. construction of torch is different
Explanation: construction of the torch is the only difference between plasma arc welding and tig welding. both the tig and paw are uses tungsten electrodes.
237.

In plasma arc welding the gas is?

A. ionized
B. heated
C. magnetized
D. vaporized
Answer» A. ionized
Explanation: in plasma arc welding the gas is ionized. electrode used is made of tungsten and filler metal is used addition to it.
238.

If the total efficiency is 0.35 in arc welding. Then what is the welding speed in mm/sec if the cross-sectional area is 5mm2, welding power is 2 kW and the heat required in melting the metal is 100 J/mm3.

A. 1.4
B. 14
C. 1400
D. 140
Answer» A. 1.4
Explanation: n = (p×total efficiency)/(q×a), where p represents power, q represents heat transfer, and a represents the cross-sectional area.
239.

Which of the following inert gas is used with DC power supply only?

A. argon
B. helium
C. co2
D. nitrogen
Answer» C. co2
Explanation: co2 is used only in dc power supply. it cannot be used in ac power supply. argon and helium can be used with ac supply.
240.

Which kind of resistance is experienced in upset butt welding?

A. electric resistance
B. magnetic resistance
C. thermal resistance
D. air resistance
Answer» A. electric resistance
Explanation: in the making of an upset butt welding, there are jaws made of copper, into which the part to be welded is put, and hence a solid contact is made. at this point of contact, while the current flows, it gets transformed into heat because of electric resistance.
241.

How are the metals to be welded connected to each other in spot welding?

A. electric contact
B. magnetic field
C. mechanical pressure
D. direct contact
Answer» C. mechanical pressure
Explanation: in spot welding process, the metal or the alloy parts which are to be welded, are heated in their in their zones. to bring these parts in contact with one another, mechanical pressure is applied, causing them to connect.
242.

Up to what thickness, can steel be welded using spot welding process?

A. 10 mm
B. 11 mm
C. 12 mm
D. 13 mm
Answer» C. 12 mm
Explanation: in spot welding process, to bring the heated parts in contact with one another, mechanical pressure is applied. this pressure can be of three types, by using foot lever, by providing air pressure or by using a hydraulic cylinder. the use of these methods allows steel or other metal parts to be welded up to a thickness of 12 mm.
243.

In flash butt welding, the forced out metal is called flash.

A. true
B. false
Answer» A. true
Explanation: in flash butt welding process, there is a light contact between the edges. a high voltage is supplied when the flashing action takes place. in this process, the metal that is forced out, is called as flash.
244.

In friction welding process, materials are joined by            motion between materials.

A. rectilinear
B. rubbing
C. translatory
D. brownian
Answer» B. rubbing
Explanation: friction welding is a solid-state joining process that produces coalescence in materials, using the heat developed between surfaces through a combination of mechanically induced rubbing motion and applied load. the resulting joint is of forged quality.
245.

All metallic engineering materials which are            can be friction welded.

A. soft
B. weldable
C. forgeable
D. metamaterials
Answer» C. forgeable
Explanation: as a rule, all metallic
246.

Friction welding is            process.

A. costly
B. cost saving
C. time consuming
D. highly material selective
Answer» B. cost saving
Explanation: since dissimilar materials can be joined, a significant cost savings are possible because engineers can design bimetallic parts that use expensive materials only where needed. expensive forgings and castings can be replaced with less expensive forgings welded to bar stock, tubes, plates and the like.
247.

Friction welding produces quality joints, with a 100%            weld.

A. lap joint
B. tee-joint
C. butt joint
D. edge joint
Answer» C. butt joint
Explanation: friction welding produces forged quality joints, with a 100% butt joint weld through the contact area. furthermore, in friction welding heat affected zone is much narrower as compared to other welds, which indeed reduces the cost of post-weld heat treatments (stress relieving processes).
248.

In inertia friction welding              energy of welding machine is used.

A. electrical
B. potential
C. rotational
D. frictional
Answer» C. rotational
Explanation: inertia friction welding is a variation of friction welding in which the energy required to make the weld is supplied primarily by the stored rotational kinetic energy of the welding machine.
249.

In inertia friction welding, one workpiece is connected to            

A. flywheel
B. the pin tool
C. rotor
D. generator
Answer» A. flywheel
Explanation: in inertia welding, one of the workpieces is connected to a flywheel and the other is restrained from rotating. the flywheel is accelerated to a predetermined rotational speed, storing the required energy. the drive motor is disengaged and workpieces are forced together by the friction welding force.
250.

Which of the following defects occur when weld metal layer fails to fuse together?

A. inclusion of slag
B. inadequate penetration
C. incomplete fusion
D. porosity
Answer» C. incomplete fusion
Explanation: incomplete fusion defects occur when weld metal layer fails to fuse together. it causes discontinuity in weld zone.
251.

Which of the following defects occur due to melting or burning away of base metal?

A. undercut
B. spatter
C. cracking in weld metal
D. cold cracking
Answer» A. undercut
Explanation: undercut is the cardinal sin of welding grasshopper! cutting into the steel with the force of the arc leaves a cut out groove in the weld. if this is not filled back in with filler metal, it leaves a weld defect which is a weak point that can cause the joint to fail. this can cause property damage, injury and even loss of life.
252.

Forging is a metal forming operation in which the metal is stretched to form the desired shape of a metal part.

A. true
B. false
Answer» B. false
Explanation: forging is a metal forming operation in which heated metal is beaten by a hammer to give it the desired shape. it is basically a deformation process in which the material is compressed between dies by using impact load to deform it. forging can also be used for making complex shapes of metal parts.
253.

In general, the casted metal part is much stronger and tougher than that produced by the forging operation.

A. true
B. false
Answer» B. false
Explanation: in general, forged parts are much stronger and tougher than the casted parts made from the same metal. the metal components have high strength because the hammering operation maintains its structure that makes proper alignment of grains along the profile of metal components, which leads to an increase in strength.
254.

The open die forging process is also known as upsetting or upset forging process.

A. true
B. false
Answer» A. true
Explanation: in an open die forging process, the metal billet is heated up to a very high temperature and then compressed between two flat die halves. this method is like a compression test, which is also known as upsetting or upset forging. in the process, billet is basically deformed by a decrease in its height and increase in its diameter.
255.

Which of the following processes is mainly used for making the connecting rods?

A. casting
B. deep drawing
C. rolling
D. forging
Answer» D. forging
Explanation: connecting rods are generally manufactured by the forging operation. in forging, a hammer is used which strikes on the heated metallic part to get into the desired shape. the properties like strength, toughness, etc are greatly enhanced by performing the forging operation. forging can be open die forging or closed die forging.
256.

In impression die forging process, extra deformed material is produced which is called a flash.

A. true
B. false
Answer» A. true
Explanation: in impression die forging process, flash can be produced which is considered as scrap material that is removed from the formed part during the finishing of a metal part. but in flash-less forging, the metal is fully prevented within the die, so no flash is produced during the process.
257.

A cone shaped die is used in the orbital forging for the forging of metal parts.

A. true
B. false
Answer» A. true
Explanation: in the orbital forging process, forming is done to the meat part by using a cone-shaped die that is simultaneously rolled and pressed into the material. the metal part is supported on a lower die, because of inclined axis of cone. in the process, only a small area of the metal surface is compressed at the stage of forming.
258.

When an asymmetrical section is roll formed, the finished product will have            

A. camber
B. cross-bow
C. a twist
D. waviness
Answer» C. a twist
Explanation: when an asymmetrical section is a roll formed, the finished product will have a twist after leaving the last pass, even if the starting material is flat.
259.

Which of the following is true about the extrusion process?

A. structure is homogeneous
B. no time is lost in changing the shape
C. service life of extrusion tool is too high
D. its leading end is in good shape as compared to rolling
Answer» B. no time is lost in changing the shape
Explanation: no time is lost in changing the shape as the dies may be readily removed in the process of extrusion.
260.

In which extrusion process the direction of flow of metal is in same direction as that of ram?

A. direct
B. indirect
C. impact
D. hydrostatic
Answer» A. direct
Explanation: direction extrusion is a process in which the metal billet, placed in a container is forced by a ram to pass through a die. in this type, the direction of flow of metals is, in same as that of movement of ram. the punch closely fits the die cavity to prevent the backward flow of the material.
261.

Which of the following is not used because of the problem of handling extruded metal coming out through moving ram?

A. direct
B. indirect
C. impact
D. hydrostatic
Answer» B. indirect
Explanation: indirect extrusion method is not used because of the problem of handling extruded metal coming out through moving ram.
262.

Which of the following is not a cold extrusion process?

A. cold extrusion forging
B. impact extrusion
C. hydrostatic extrusion
D. cold rolling
Answer» C. hydrostatic extrusion
Explanation: cold extrusion is done at room temperature or near room temeprature. the processes, impact extrusion, hydrostatic extrusion and cold extrusion forging are the types of cold forging. the advantages of this over hot extrusion are the lack of oxidation, higher strength due to cold working, closer tolerances, and good surface finish.
263.

The centre of the extruded product can develop cracks called as?

A. centre cracking
B. centre burst
C. arrow headed fracture
D. all of the mentioned
Answer» D. all of the mentioned
Explanation: cracks that are developed in the centre of extruded material is known as internal cracking. these are termed as “centre cracking”, “centre burst”, “chevron cracking”, and as “arrow head cracking”.
264.

Which of the following processes of metal forming is best suited for making products like aircraft wings and window frames?

A. forging
B. rolling
C. drawing
D. stretch forming
Answer» D. stretch forming
Explanation: stretch forming is a sheet metal forming process in which the sheet metal is clamped at the edges and stretched by using the dies or form blocks. and no any lubrication is required significantly during the process. this method is best suited for making the products like aircraft wings, window frames, automobile door panels etc.
265.

Stretch forming is a process which involves tensile and bending forces during the operation.

A. true
B. false
Answer» A. true
Explanation: in stretch forming process, stretching of a metal sheet is basically done by holding its edges and bending it on a cylindrical block, simultaneously is known as stretch forming. this process basically involves tensile and bending forces during the operation. in this process, the materials with high ductility are mostly stretched by rigid dies.
266.

Forming is a process that changes the shape of the metal by changing its phase.

A. true
B. false
Answer» B. false
Explanation: forming is basically a term that covers many manufacturing processes. in the metal forming process, the shape of the material or metal is changed by performing an operation like hammering, squeezing, bending, pulling etc. without changing its phase. the raw materials used in the forming process remained in a single solid phase.
267.

Rolling is a forming process in which thickness of the metal plate is decreased by increasing its length.

A. true
B. false
Answer» A. true
Explanation: rolling is a metal forming process in which the metal plate is squeezed between the two hard rollers. in the operation, the thickness is decreased and the length is increased as the volume of the metal is conserved. this method is mainly used for the production of thin metal plates which can be done by performing hot rolling or cold rolling, depending on the required mechanical properties.
268.

In stretch forming, spring-back is a very complicated problem which causes trouble in operating machines during the process.

A. true
B. false
Answer» B. false
Explanation: spring-back is basically defined as a phenomenon in which the material tries to regain its original shape during elastic loading condition. but in stretch forming process, the stretching and bending operations take place simultaneously which causes permanent deformation of the sheet metal. so, this combined effect results in negligible spring-back in the metal part and hence causes no problem in the operating machines.
269.

3 WORKING PRINCIPLE AND APPLICATIONS - HYDRO FORMING - RUBBER PAD FORMING - METAL SPINNING

A. forging
B. rolling
C. drawing
D. stretch forming
Answer» D. stretch forming
Explanation: stretch forming is a sheet metal forming process in which the sheet metal is clamped at the edges and stretched by using the dies or form blocks. and no any lubrication is required significantly during the process. this method is best suited for making the products like aircraft wings, window frames, automobile door panels etc.
270.

High volume rate of production can be possible by stretch sheet metal forming process.

A. true
B. false
Answer» B. false
Explanation: in stretch forming, the sheet metal is fixed with stretch gripper with the support of a tool, and then operation takes place in a hydraulic stretching unit. the process consumes too much time as the stretching process takes time to strain hardens the material. so, this process includes low volume rate of production, but the process is very versatile and have economic production.
271.

Tangential stretch forming and simple stretch forming are quite similar to each other.

A. true
B. false
Answer» B. false
Explanation: tangential stretch forming is very different from simple stretch forming. however, the purpose is same. in tangential stretch forming, the metal sheet is gripped from two opposite ends. the main difference to the simple stretch forming is that the form block and gripping jaws both are movable in this process.
272.

In electromagnetic forming, highly intense magnetic field is used for the forming process.

A. true
B. false
Answer» A. true
Explanation: in electromagnetic forming, many components like capacitor bank, forming coil, field shaper, conductive material etc. are used to create intense magnetic fields. this magnetic is generally produced by the discharge of capacitors into a coil, which lasts only for a few microseconds. then further processing is done to perform the metal forming.
273.

The magnetic field interacts with metal to generate heat in the metal which causes forming process.

A. true
B. false
Answer» B. false
Explanation: in the electromagnetic forming process, eddy currents are induced in a conductive material that is placed near to the coil. then it interacts with a magnetic field to cause mutual repulsion between the metal and the forming coil. this force of repulsion is mainly responsible for inducing stresses in the metal beyond its yield strength which results in plastic deformation of metal.
274.

Electromagnetic forming cannot be used for materials of poor electrical conductivity.

A. true
B. false
Answer» B. false
Explanation: the electromagnetic forming method uses a high intense magnetic field to deform the material. this process is primarily used for the forming of good conducting materials like copper, aluminum, silver etc.
275.

The efficiency of electromagnetic forming mainly depends on the resistivity of material being formed.

A. true
B. false
Answer» A. true
Explanation: the electromagnetic forming method uses a capacitor and forming coil to create intense magnetic field. the efficiency of the magnetic pulse mainly depends on the resistivity of the material being formed. for better output, the resistivity of the material must be less than 15 micro-ohm-centimeters.
276.

The joints made by an electromagnetic forming process are much stronger than the parent material.

A. true
B. false
Answer» A. true
Explanation: in the electromagnetic forming process, the joints made are much stronger than the parent material. this process also allows increased ductility for several alloys because of the lack of stresses and friction which normally encountered with the process. this method is widely used for a high rate of production.
277.

What is the minimum pressure required in a compression molding process?

A. 0.5 mpa
B. 1 mpa
C. 1.5 mpa
D. 2 mpa
Answer» A. 0.5 mpa
Explanation: processing of thermosetting plastics is classified as, compression molding and transfer molding. the minimum pressure that is required for the complete operation of compression molding is 0.5 mpa.
278.

What is the minimum curing time required in a compression molding process?

A. 0.4 minutes
B. 0.5 minutes
C. 0.6 minutes
D. 0.7 minutes
Answer» B. 0.5 minutes
Explanation: the minimum curing time that is required for the complete operation of compression molding is 0.5 minutes.
279.

What is the maximum pressure required in a transfer molding process?

A. 80 mpa
B. 90 mpa
C. 100 mpa
D. 120 mpa
Answer» C. 100 mpa
Explanation: processing of thermosetting plastics is classified as, compression molding and transfer molding. the maximum pressure that is required for the complete operation of transfer molding is 100 mpa.
280.

Thermosetting materials are the polymeric materials which get soften on heating with or without pressure.

A. true
B. false
Answer» B. false
Explanation: thermosetting materials are the polymeric materials that get permanent hardness once the heat is given to the material. these are the polymers which require heat and pressure to mould them into shape. these polymers cannot be re-softened once they are set and hardened by heat.
281.

Polyurethanes plastics can be made in flexible foams even after belonging to thermosetting polymers.

A. true
B. false
C. topic 5.2 injection moulding - plunger and screw machines
Answer» A. true
Explanation: polyurethane plastics are belonged to the thermosetting plastics or polymers. polyurethane is the only polymer that can be formed in both rigid and flexible foams. the flexible polyurethane foam is generally used in the manufacturing of mattresses, carpets and furniture. and the rigid polyurethane foam is used in making of chairs and mirror frames.
282.

Thermosetting plastics like epoxies can be used for filament wound rocket motor casings in missiles by combining with glass fibers.

A. true
B. false
Answer» A. true
Explanation: epoxies can be used in various ways. in adding with glass fibers, it is capable of making composites that are of high strength and heat resistant. these composites are basically used for making motor casings in missiles, aircraft parts, fixtures etc.
283.

Mechanical properties of any plastics are mainly dependent on the temperature, force and time of load applied.

A. true
B. false
Answer» A. true
Explanation: mechanical properties relate to movement or breakage of the polymer due to some mechanical variation such as application of load. mechanical properties are mainly dependent on the temperature, force or load applied, and the duration of time the force is applied. it can also be affected by ultra-violet radiation when used outside.
284.

Where does the granular molding material get loaded into?

A. barrel
B. hopper
C. pellets
D. split
Answer» B. hopper
Explanation: in a ram or plunger type injection molding system, the granular molding material has to be first loaded into a hopper, after which, with the help of a feeding device it gets metered out inside a cylinder.
285.

There is a varied pressure provided in the solidification unit of injection molding process.

A. true
B. false
Answer» B. false
Explanation: injection molding is considered to be one of the most widely used methods. in this method, there are dies that eject the solidified component, before which it is kept under constant pressure.
286.

Which of the following is not an application of blow molding process?

A. toy bodies
B. door liners
C. bottles
D. pipes
Answer» B. door liners
Explanation: among the following, only door liners is not an application of blow molding process. internal door liners are made using thermoforming process, while toy bodies, bottles and pipes are made using blow molding process.
287.

The heater in the vacuum forming process is heated up to 90°C.

A. true
B. false
Answer» A. true
Explanation: 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
288.

The initial cost in blow molding is low.

A. true
B. false
Answer» A. true
Explanation: in blow molding, there is a mold cavity present inside the soft plastic, into which, the air with high amount of pressure has to be blown. the capital required for mold initially is quite less, making it a little inexpensive process.
Tags
Question and answers in Manufacturing Technology 1, Manufacturing Technology 1 multiple choice questions and answers, Manufacturing Technology 1 Important MCQs, Solved MCQs for Manufacturing Technology 1, Manufacturing Technology 1 MCQs with answers PDF download