Category: Manufacturing Engineering Objective Questions

Manufacturing Engineering Multiple Choice Questions on “Slotter”.

1. Cutting of material during slotting operation takes place in
a) Forward stroke
b) Backward stroke
c) Both forward and backward stroke
d) None of the mentioned
Answer: a
Clarification: Cutting always takes place in forward stroke. Backward stroke is an ideal stroke.

2. Which of the following part of slotting machine supports all of the other parts of machines?
a) Base
b) Column
c) Ram
d) Table
Answer: a
Clarification: Base act as support for all other parts and hence it is made strong.

3. Cutting of material during shaping operation takes place in
a) Forward stroke
b) Backward stroke
c) Both forward and backward stroke
d) None of the mentioned
Answer: a
Clarification: Cutting always takes place in forward stroke. Backward stroke is ideal stroke.

4. Which of the following act as housing for an operating mechanism in slotting machine?
a) Base
b) Column
c) Cross rail
d) Table
Answer: b
Clarification: Column acts as housing for an operating mechanism in slotting machine and hence it is made of hard material.

5. Which of the following part of slotting machine carries table elevating mechanism?
a) Base
b) Column
c) Ram
d) Table
Answer: b
Clarification: Column carries table elevating mechanism. Column act housing for an operating mechanism in slotting machine and hence it is made of hard material.

6. Which of the following part of slotting machine carries vertical guide ways mechanism?
a) Base
b) Column
c) Cross rail
d) Table
Answer: b
Clarification: Column carries vertical guide ways mechanism. housing for operating mechanism in slotting machine and hence it is made of hard material.

7. Which of the following part of slotting machine hold and supports the work piece?
a) Base
b) Column
c) Cross rail
d) Table
Answer: d
Clarification: Table supports work piece and its made of very hard material.

8. Which of the following part of slotting machine carries tool head?
a) Cross rail
b) Column
c) Ram
d) Table
Answer: c
Clarification: Ram carries tool head. It is present on the upper part of machines.

9. Which of the following part of slotting machine provides straight line motion of tool?
a) Cross rail
b) Column
c) Ram
d) Table
Answer: c
Clarification: Ram carries tool head and provides straight line motion to a tool. There is kinematic straight line mechanism in ram.

10. Which of the following part of slotting machine is used to hold the tool?
a) Cross rail
b) Tool head
c) Ram
d) Vice
Answer: b
Clarification: Tool head is used for tool holding purpose. Different types of tool head used to hold different types of workpiece.

11. Which of the following can be used as job holding device in slotting machine?
a) Cross rail
b) Column
c) Ram
d) Vice
Answer: d
Clarification: Vice is a job holding device. It is holding a device with good efficiency.

Basic Manufacturing Engineering Questions & Answers on “Grinding Wheel-3”.

1. Which of the following will be better to use for machining of soft work piece?
a) V-bond
b) R-bond
c) Both V and R bond
d) None of the mentioned
Answer: b
Clarification: Rubber bond grinding wheel is generally used for machining of soft work piece. Fifth place of ISO designation of grinding wheel represents type of bond.

2. Which of the following grinding wheel would be more economical for grinding of hard work piece?
a) Soft grinding wheel
b) Hard grinding wheel
c) Both hard and soft grinding wheel
d) None of the mentioned
Answer: a
Clarification: In soft grinding wheels, during machining of hard work piece glazing will occur after long time.

3. Which of the following grinding wheel would be more economical for grinding of soft work piece?
a) Soft grinding wheel
b) Hard grinding wheel
c) Both hard and soft grinding wheel
d) None of the mentioned
Answer: b
Clarification: In hard grinding wheels, during machining of soft work piece glazing will occur after long time and grains of grinding wheel will be effectively utilized before coming out from the wheel.

4. Which of the following grinding wheel would be more economical for grinding of hard work piece?
a) Open structure grinding wheel
b) Dense structure wheel
c) Both dense and open structure grinding wheel
d) None of the mentioned
Answer: b
Clarification: In dense structure grinding wheels, during machining of hard work piece material removal rate is small and also wheel has good strength.

5. Which of the following grinding wheel would be more economical for grinding of soft work piece?
a) Open structure grinding wheel
b) Dense structure wheel
c) Both dense and open structure grinding wheel
d) None of the mentioned
Answer: a
Clarification: In open structure grinding wheels, during machining of soft work piece material removal rate is large and space for chip flow is also large due to more space between grains of wheel.

6. Material removal rate of grinding process in comparison to material removal rate in facing on a lathe is
a) Small
b) Large
c) Same
d) Can’t say about material removal rate
Answer: a
Clarification: Material removal rate in grinding process is very small. Hence grinding is mostly use as a finishing process. Only small portion of abrasives are involved in grinding process and hence has less material removal rate.

7. Material removal rate in grinding operation is small due to
a) Negative rake angle
b) Positive rake angle
c) Zero rake angle
d) Material removal rate does not depend on the rake angle
Answer: a
Clarification: Grinding wheel have negative rake angle and hence have very small material removal rate. Hence grinding is mostly use as a finishing process.

8. Material removal rate in grinding operation is small due to
a) Only small portion of abrasives are involved in cutting
b) Positive rake angle
c) Zero rake angle
d) Material removal rate does not depend on the rake angle
Answer: a
Clarification: Only small portion of abrasives are involved in grinding process and hence has less material removal rate. Hence grinding is mostly use as a finishing process.

9. Material removal rate in grinding operation is small due to
a) Large portion of abrasives are involved in cutting
b) Positive rake angle
c) Due to temperature rise during grinding
d) Material removal rate does not depend on the rake angle
Answer: c
Clarification: Due to the increase in temperature during grinding operation some material get welded again with the chip.

10. Grinding ratio generally lies between
a) 0.5-10
b) 100-200
c) 1000-200
d) 30-40
Answer: a
Clarification: Grinding ratio = (volume of material removed/volume of wheel wear). G.R is generally between 0.5-10.

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Manufacturing Engineering Multiple Choice Questions on “Resistance Welding-1”.

1. Which of the following is not true about fusion welding?
a) It depends upon the characteristics of heat source.
b) It depends upon the nature of deposition of the filler material
c) It does not depend upon the heat flow characteristics in the joint
d) It depends upon the gas metal or slag metal reaction
Answer: c
Clarification: Fusion welding depends upon the heat flow characteristics in the joint. The quantity of heat required to melt a given volume of metal depends on: (1) The heat to raise the temperature of the solid metal to its melting point, (2) The melting point of the metal, (3) The heat to transform the metal from solid to liquid phase at the melting point.

2. Which of the following is not used to produce heat during welding?
a) Electric arc
b) Chemical flame
c) Electrical resistance
d) Acetone flame
Answer: d
Clarification: For welding heating, different kinds of energy are converted into heat, typically, electrical, beam, chemical and mechanical energy and also their combinations.

3. In which of the following welding process heat and pressure is applied on the joint but no filler material or flux is added?
a) Arc welding
b) Resistance welding
c) Gas welding
d) Thermite welding
Answer: b
Clarification: Resistance welding is the method to joint two plain metal work pieces together by running an electrical current through them. No filler metal and no flux are needed in this type.

4. Total resistance in welding is composed of:
(i) Resistance of electrode
(ii) Contact resistance between electrode and work piece
(iii) Contact resistance between two work piece plates
(iv) Resistance of work piece
Which of the following is correct?
a) i
b) ii, iii and iv
c) ii and iv
d) I, ii, iii and iv
Answer: d
Clarification: Total resistance is the equivalent resistance of all resistances present in the welding circuit during the process of welding.

5. If 20 amperes of current is flowing in a wire for 1 minute of time having a resistance of 1000 ohm. Then the amount of heat generated in resistance welding will be (in kilo joules)?
a) 24000
b) 240000
c) 24000000
d) 2400
Answer: a
Clarification: Heat produced = I²RT, where ‘I’ is the current, ‘R’ is resistance and ‘T’ is the time in seconds. For the given problem, heat produced = (20²)×(1000)×(1×60)
Therefore heat produced = 400 × 1000 × 60 = 24,000 KJ.

6. Which of the following is true about electrodes?
a) Low electrical conductivity and low mechanical strength
b) Low electrical conductivity and high mechanical strength
c) High electrical conductivity and low mechanical strength
d) High electrical conductivity and high mechanical strength
Answer: d
Clarification: To get maximum efficiency, electrodes should have high electrical conductivity and high mechanical strength.

7. Which of the following is true about resistance welding?
a) Electrodes of higher resistivity is used for lower resistive piece
b) Electrodes of higher resistivity is used for higher resistive piece
c) Electrodes of lower resistivity is used for lower resistive piece
d) Electrodes of lower resistivity is used for higher resistive piece
Answer: a
Clarification: To get high efficiency, electrodes of higher resistivity is used for lower resistive piece.

8. According to the joules law?
a) The poor conductor heats up to a higher degree than a good conductor
b) The poor conductor heats up to a lower degree than a good conductor
c) The poor conductor heats up to equal degree than a good conductor
d) Joules law does not relate to heat
Answer: a
Clarification: Joules law relate power with voltage and current as: Power (P) = Voltage (V) × Current (I). It conveys that poor conductor heats up to a higher degree than a good conductor.

9. Which of the following electrode has very high electrical conductivity but low strength?
a) Copper chromium alloys
b) Copper cobalt alloys
c) Copper beryllium alloys
d) Copper cadmium alloys
Answer: d
Clarification: Copper cadmium alloys have very high electrical conductivity but low strength. They produce very less heat during the current flow.

10. Which of the following electrode has low electrical conductivity but high strength?
a) Copper chromium alloys
b) Copper cobalt alloys
c) Copper beryllium alloys
d) Copper cadmium alloys
Answer: a
Clarification: Copper chromium alloys electrode has low electrical conductivity but higher strength. They generate more heat during the current flow.

Manufacturing Engineering Multiple Choice Questions on “Metal Casting Defects”.

1. The major defects of casting are __________
a) gas defects
b) shrinkage cavities
c) molding material defects
d) all of the mentioned
Answer: d
Clarification: Following are the major defects, which are likely to occur in casting:
i) gas defects
ii) shrinkage cavities
iii) molding material defects
iv) pouring metal defects
v) mold shift.

2. The defects caused by trapping a gas in molten metal or by mold gases while pouring the melt is known as?
a) Gas defects
b) Shrinkage cavities
c) Molding material defects
d) Pouring defects
Answer: a
Clarification: Shrinkage cavities are caused by liquid shrinkage occurring during the solidification of the casting while gas defects are a condition existing in a casting caused by the trapping of gas in the molten metal or by mold gases evolved during the pouring of the casting.

3. The causes of gas defects are ___________
a) metal contains gas
b) mold is too hot
c) poor mold burnout
d) all of the mentioned
Answer: d
Clarification: The lower gas-passing tendency of the mold, which may be due to lower venting, lower permeability of the mold or improper design of the casting. The lower permeability is caused by finer grain size of the sand, high percentage of clay in mold mixture, and excessive moisture present in the mold.
Metal contains gas
Mold is too hot
Poor mold burnout.

4. The defects caused by liquid shrinkage during the solidification of the casting?
a) gas defects
b) shrinkage cavities
c) molding material defects
d) hot tears
Answer: b
Clarification: Shrinkage cavities are caused by liquid shrinkage occurring during the solidification of the casting while gas defects are a condition existing in a casting caused by the trapping of gas in the molten metal or by mold gases evolved during the pouring of the casting.

5. In casting, which of the following are not material defects?
a) cut and washes
b) metal penetration
c) fusion
d) hot tears
Answer: d
Clarification: The defects in this category are cuts and washes, metal penetration, fusion, and swell.

6. The defect caused when the melt is unable to fill the mold cavity completely and thus leaves cavities is termed as?
a) cold shut
b) misrun
c) hot tear
d) porosity
Answer: b
Clarification: A mis-run is caused when the metal is unable to fill the mold cavity completely and thus leaves unfilled cavities and a cold shut is caused when two streams while meeting in the mold cavity, do not fuse together properly thus forming a discontinuity in the casting.

7. The defect caused when two streams do not fuse together (while melting), thus forming discontinuity in casting is termed as?
a) cold shut
b) misrun
c) hot tear
d) porosity
Answer: a
Clarification: A mis-run is caused when the metal is unable to fill the mold cavity completely and thus leaves unfilled cavities and a cold shut is caused when two streams while meeting in the mold cavity, do not fuse together properly thus forming a discontinuity in the casting.

8. A casting defect which occurs near the ingates as rough lumps on the surface of a casting is?
a) Shift
b) Sand wash
c) Swell
d) Hot tear
Answer: b
Clarification: Swell is caused under the influence of metallostatic forces, the mold wall may move back causing a swell in the dimension of the casting whereas Sand wash is a casting defect which occurs near the ingates as rough lumps on the surface of a casting.

9. A casting defect which occurs due to improper venting of sand is known as?
a) Cold shuts
b) Blow holes
c) Shift
d) Hot tear
Answer: c
Clarification: The mold shift defect occurs when cope and drag or molding boxes have not been properly aligned and a cold shut is caused when two streams while meeting in the mold cavity.

10. Scabs are casting defects which?
a) result in a mismatch of the top and bottom parts of a casting
b) result near the ingates as rough lumps on the surface of a casting
c) occur as rough and irregular projections on the surface of the casting
d) occur as smooth and regular projections on the surface of the casting
Answer: c
Clarification: A casting defect which occurs near the ingates as rough lumps on the surface of a casting is sand wash and scabs are casting defects which occur as rough and irregular projections on the surface of the casting.

Manufacturing Science Puzzles on “Heat Transfer-2”.

1. Ratio of rate of heat conduction to the rate of internal energy storage is in solid is known as?
a) Biot number
b) Drag coefficient
c) Eckert number
d) Fourier number
Answer: d
Clarification: Fourier number is the ratio of heat conduction to the rate of heat storage. The significance of Fourier number is 1. It signifies the degree of penetration of heating or cooling effect, 2. It is a measure of heat conducted through a body relative to heat stored.

2. Ratio of pressure drop for internal flow through ducts is known as?
a) Friction factor
b) Grashof number
c) Colburn factor
d) Nusselt number
Answer: a
Clarification: Friction factor (µ) is defined as the ratio between the force required to move a section of pipe and the vertical contact force applied by the pipe on the seabed, in simpler terms, it is the ratio of pressure drop for internal flow though ducts.

3. Ratio of buoyancy to viscous forces is known as?
a) Prandtl number
b) Grashof number
c) Colburn factor
d) Nusselt number
Answer: b
Clarification: Grashof number in natural convection is analogous to the Reynolds number is forced convection. Grashof number indicates the ratio of the buoyancy force to the viscous force. Higher Gr number means increased natural convection flow.

4. Which of the following is known as the dimensionless heat transfer coefficient?
a) Friction factor
b) Grashof number
c) Colburn factor
d) Weber number
Answer: c
Clarification: Colburn factor obtained from the Reynold-Colburn analogy relates to the local skin friction coefficient (from fluid mechanics) to the local convective heat transfer coefficient.

5. Which of the following is known as the dimensionless heat transfer coefficient?
a) Friction factor
b) Grashof number
c) Nusselt number
d) Prandtl number
Answer: c
Clarification: Nusselt number is a dimensionless number and it is defined as the ratio of convective heat flux to the conductive heat flux (where fluid is in rest). Convection in fluid = conduction in fluid + advection in fluid (occurs due to motion of fluid). So, practically we can understand it as a comparison of heat taken by fluid due to moving fluid and heat taken by a static fluid when flowing over a heated plate (or inside a pipe).

6. Ratio of convection heat transfer to conduction is known as?
a) Friction factor
b) Grashof number
c) Colburn factor
d) Nusselt number
Answer: a
Clarification: The Nusselt number is the ratio of convective to conductive heat transfer across a boundary.
Nu = (frac{hl}{k}), where, h = heat transfer coefficient, l = characteristic length and k = thermal conductivity.

7. Product of Prandtl number and Reynolds number is also known as?
a) Peclet number
b) Prandtl number
c) Rayleigh number
d) Biot number
Answer: a
Clarification: Peclet number is the product of Prandtl number and Reynolds number, in other sense, it is the ratio of the heat transfer by convection to the heat transferred by conduction. So, you can consider a pipe with some wall thickness. The wall conducts heat to the fluid. While the heat can also be carried away by the fluid in motion which is called as advection. If the advection term is dominant, then the Peclet number is going to large and thus the hat transfer from the wall is of less importance. Conversely, the heat transfer form the wall to the fluid can be of higher importance in the case of a smaller Peclet number.

8. Ratio of molecular diffusivity to thermal diffusivity is also known as?
a) Biot number
b) Prandtl number
c) Rayleigh number
d) Biot number
Answer: b
Clarification: Prandtl number as explained by others here, is a dimensionless number, which is the ratio of molecular diffusivity of momentum to molecular diffusivity of heat. It shows the relative thickness of the velocity boundary layer to the thermal boundary layer.

9. Product of Grashof and Prandtl is known as?
a) Peclet number
b) Biot number
c) Rayleigh number
d) Reynolds number
Answer: c
Clarification: Rayleigh number is the product of Grashof and Prandtl number.

10. Ratio of inertia to viscous forces is known as?
a) Stanton number
b) Prandtl number
c) Rayleigh number
d) Reynolds number
Answer: d
Clarification: The Reynolds number is the ratio of inertial forces to viscous forces. The Reynolds number is a dimensionless number used to categorize the fluids systems in which the effect of viscosity is important in controlling the velocities or the flow pattern of a fluid.

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